Wireless-World-1922

4th NOVEMBER, 1922. THE PRICE61).NET. WIRELESS WORLD AND RADIO REVIEW

Registered at theG.Y.C. ,No. 168. [VOTE. 5:X. 4th NOVEMBER, 1922. as a Weekly Newspaper.

NO NEED FOR AERIALS if you attach the

to any electric lampholder. See Page See Page VI. TRY IT VI, DUBILIER The Dubilier Condenser Co. (1921) Ltd. Ducon Works, Goldhawk Road, Shepherd's Bush, London, W.12 Telephone-Hammersmtth 1084. -Hivolteon, Phone, London. Marconi International, THE WIRELESS WORLD AND RADIO REV I EW NOV FNIBER 1, 1922 STERLING No. 1 CRYSTAL WIT RECEIVING SET Specially designed for use in connection with the Wireless Telephony Broad- casting Scheme, and is suitable for a rangeofabout 2 5 miles. PRICE £7-12-6 TO BE OBTAINED FROM ALL DEALERS OR DIRECT FROM :- STERLING TELEPHONE & ELECTRIC CO., LTD. 210-212, Tottenham Court Road,

LONDON s ; t W.1 I elephone No. : 4144 Museum () lines) Telegrams : " Cucumis, Wesdo, London." works: DAGENHAM, ESSEX. BRANCHES NEWCASTLE -ON -TYNE r 9, Clavering Place. IMMEDIATE DELIVERY CARDIFF :8, Park Place. "Wireless for all" Before you decide on the construction of your set. It will pay you to have particulars of- Condensite Celoron For PANELS and OTHER PARTS. This material is waterproof, immune to atmospheric and climatic conditions, will not warp, has high surface and volume restivity, highdi -electric strength, low specific gravity. LET US QUOTE YOU SEND PARTICULARS OF TOUREX1CT REQUIREMENTS TO THE MANUFACTURERS

DIAMOND -FIBRE HIGH ROAD WORKS SOUTH TOTTENHAM .NJS .NOVEMBEE 4, 1922 THE WIRELESS WORL, RADIO INS AS SPECIFIED AND USED BY TI

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TUBES DISCS PLATES, &c. MANUFACTURED IN ALL FORMS, SIZES AND THICKNESSES BY THE MICANITE & INSULATORS Co. LTD. EMPIRE WORKS WALTHAMSTOW LONDON, E.17 TELEGRAMS .-"MYTILITE. PHONE, LONDON.. TELEPHONES -WALTHAMSTOW 758.739 Ediswan Valves. THE manufactureof Thermionic Valvesisa highly skilled operation and every Ediswan Valve has behind it the experience and operative skillof over forty years of lamp making. The A R Valveillustratedisspecially made for Amateurreception. Platevoltage30-80volts. Filamentvolts3.5-6.ovolts. Filamentcurrent o'75 amperes.High amplification-silent working. Price 15/- each. Alway ask for Ediswan Valves.If you are unable to obtain them at your Dealers write to us for the name and address of the neatest supplier. THE EDISON SWAN ELECTRIC CO., LTD., Head Office :123/5, QUEEN VICTORIA STREET, E.C.4. [London .Showrooms :x23/5. Queen Victoria Street, E.C.4, & 72, Victoria Street, S.W.I. Type A R Works:Ponders End, Middlesex.

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HOWROOMS .it. rand. W.C.2. _LoneII. . vs u-valve Broadcast Receiver with & self-contained valves and H.T. 'Battery,Wavelength range 250 to i0 metres, which can be extendedas desired by substitutingspecialcoilsfor plug marked " X." British Broadcast stations audible up to 80 miles Supplied in PolishedWalnut on head telephones, and 25 to 30 miles on a loud Cabinet, 13 X 13 X le inches, com- speaker.Givesperfectresultseven when plete with Valves, and H.T. Battery operated by a novice. Approved by Postmaster- General, and licensed under Marconi Patents. Price-£25 Guineas Write for our NEW ILLUSTRATED CATALOGUE 1/- Post Free. BUR N D EPT, LTD., Aerial and Eastnor Works,Blackheath, S.E.3

111 111111111111111111 II 111111IIIIII 11111111 ,...24 -HOUR SERVICE No Waiting. Delivery from Stock LWe make it our boast that every letterreceivedhasattention Perry Head Phones within twenty-four hours. Send 4,000ni/per your enquiry along and test our Ohms L I/me pair service for yourself. Specially designed for Wireless Telephony. Receivers arranged ELECTRICAL SUPPLY STORES, inseries, Aluminium Cases Wireless Specialists. and fitted with extremely light 5 and efficient Head Bands, and 5, Albert Terrace, King Cross, Twin Connecting Cords. Illustrated Wireless Catalogue flOtt, Halifax, Eng. ready, post free 3d. N/ 111.1,, I ,.Aulr RI 11)} The JEARY ElectricalCo.,I td. 24 -HOUR SERVICE- 8, LAMBETH HILL 8 97, Queen Victoria St., London. E.8.4 "WESTERN COUNTIES" ACCUMULATORS Write for Complete Write for Complete Price List. FOR WIRELESS USE Price List. The most Reliable and Moderate Priced Accumulator onthe Market. 4 Volts. 6 Volts. The Western Counties 80 amphours U. 86 60 amphours £1176 120 1 176 Electrical & Engineering 90 99 2 50 Company, 150 99 2 56 180 2 196120 2 126 MidlaudBankChambers, Telegrams- Sole Agent, for Messrs. BURIIDEPT LTD., forSouth-"Alid!and and South -Western "Electron. YEOVIL. Telephone- Counties. " NOVEMBER 4, 1922 THE WIRELESS 1VORLD AND RADIO REVIEW

11111111111111111, IIIIIIII BURN DEPT IIIIIIIIIIIIIIIIIIIIIIIIIII .147, . ....V;7;"5! Of interest toyou Reduction of Prices.

OWING to our winding machineshavingbeenre -designedwe have been able to effect considerable economies in the manufacture of the famous Bumdept coils, which we can now offerto the public at greatly reduced prices. The Burndept coils, in addition to being the most efficient produced, a saving over any other coil of reputable make. New Prices effective from November 1st. Send mail orders with cash to Aerial and Eastnor Works, Blackheath, S.E. Immediate delivery-coils dispatched same day.Or from stock from our London Office and Showrooms, 15 Bedford Street, Strand, W.C.2

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S1 160 26o 310 38o 33o S2 175 290 350 170135 470 420 20/- the set S3 210 360 430 640 23o 575 S4 270 470 boo 900 340 810 75 350 570 700 IGO 450 moo 5/6 100 450 750 950 1450 boo 5340 71- 150 650 1050 1300 2100 83o 1900 7/6 200 900 1450 1900 3000 1200 2700 8/6 300 1250 2000 2600 4100 1600 3840 9/- f.4 10s. 400 1750 2900 3700 5800 2300 5400 10/6 the Set 500 2600 4300 5500 9000 3500 8 zoo 12/- 750 4000 6600 85oo 13500 5400 12500 13/6 6000 1000 10000 12500 21000 7900 18000 I 16/6 NOTE. --A beautiful coloured reproducton of the Burndept Radio Girl wil be sent post free on application. Our Illustrated Calalogue containing much useful information and details of our apparatus will be sent post free 1/ London Office & Showrooms: 15 Bedford St., Strand,W.C.2 BURNDEPT, LTD. Aerial and Eastnor Works, Blackheath, S.E.3 AllI BURNUEPT IValve Apparatus Is duly licensed under Marconi Patents for Amateur use in Great Britain

A THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 4, 1922

Radio Music from every Electric Lampholder

Every electric lampholder can now be used with safety for picking up radio signals," Broadcasting,"etc. The " DUCON " forms a perfect attachment between the radio receiver and the electric light wires. Every " DUCON " is tested at 2000 volts A.C., and has the highest possible insulationresistance. Shocksand short-circuits are thus rendered impossible. The " DUCON " fits directly into any standard B.C. electric lampholder, and is provided with terminals for connections to the radio receiver. Simplicity with Perfect Safety is the Keynote of the " Ducon." Price 10/- each DUBILIER CONDENSERS FOR ALL PURPOSES THE DUBILIER CONDENSER CO. (1921), LTD., DUCON WORKS, Goldhawk Road, Shepherd's Bush, London, W.12 Telephone-Hammersmith 1084 Telegrams- Hivoltcon, Phone, London. Marconi International 'NOVEMBER 4, 1922 THE WIRELESS WORLD AND RADIO REVIEW vii RADIO BLOCKS THE MOST EFFICIENT UNIT SYSTEM AVAILABLE

Size 31" X 21" Your attention is drawn to the way in which the units are connected up (see illustration). Available forall combinationsofHigh -Frequency and Low -Frequencyamplification. The Aluminium Case has a screening effect, thus making thesetfree fromnoises no matter how many valves areused. An instructive and interesting report on these Radio Blocks appeared on pages 14 and 15 of October 7th issue of the '` Wireless World and Radio Review." PRICELIST OF RADIO BLOCKS. Detector Block ... £1166Compensating Detector Block ... £280 1 60 Resistance Block Reaction Plug ... 036 L.F. Amplifier Block... 2120Input Plug ... 063 H.F. Amplifier Block, ... 250Output Plug ... 063 Allpur Valve Apparatus is licensed under Marconi patents for amateur use in Great Britain. Send for our NEW BOOKLET with details of our NEW M.H. RECEIVERS.It is sent with our 16 page, 100 illustrations, Catalogue.6d. POST FREE. LESL1EillMIC L1TD. PROVIDENCE PLACE, WEST END LANE, KILBURN, N.W.6

Telephone. HA MPSTEADI261 Nearest Tube Station. KILBURN PARK ( BAKERLOO) THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 4, 192t

BRITISH MANNESMANN TONS WELDLESS STEEL TUBULARIof EBONITE SHEET inStock for immediate delivery in qualities suitable forallclasses of MASTS WIRELESS WORK. FOR SHEETS-RODS Wireless Aerials. TUBES-PANELS TUBES for Variometers. UNRIVALLED INSTABILITY AND IMOULDED KNOBS ,various patternsf, EFFICIENCY, UNSURPASSED FOR COMBINED DIALS AND KNOBS, NEATNESS OF OUTLINE AND 3 . 31" and 4 diameters. APPEARANCE, ECONOMICAL Do. do. for Fil. Res. and Vario- IN COST Couplers. AERIAL INSULATORS. Wholesale only. THE BRITISH MANNESMANN TUBE COMPANY, LIMITED AMERICAN HARD RUBBER NEWPORT (Mon.) & LANDORE, S. WALES. COMPANY (Britain) LIMITED, LONDON OFFICE -67, Queen Victoria Street, E.C.4 13a, Fore Street, London, E.C.2 BRANCH OFFICES-Birmingham, Glasgow, Leeds, Tetra. " Ebonisetlt. Ave. London.' 'Pk ne ; Central 12954. Manchester, Newcastle, 16 IMii MiNi. a

The most reliable and efficient Batteries for Wireless Work are

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The WHITECROSS XJ COMPANY, LIMITED STORAGE WARRINGTON :: BATTERIES Manufacturers of All Descriptions of D.P. Batteries are made to fit almost any size of box. The output of our Works runs to hundreds WIRE ROPES ofthousands of plates yearly. Write us for particulars AND WIRES The D. P. BATTERY CO., LTD., BAKEWELL - DERBYSHIRE & 11 Victoria St., London, S.W. NOVEMBER 4, 1922 THE WIRELESS WORLD AND RADIO REVIEW i

H.FFITTED.TRANSFORMERS 3 -WAY COIL HOLDERS KNOBS EBONITEMoulded in ONE PIECE Sheets, Rods, Tubes, Panels, Bevelled Dials, 3 in. by 21 in. Fil. Resist. Bases, Knobs, Condenser Tops, 4 in. Discs, Slider Knobs, Headphones, Var. Condenser, L.F. Transformers, from stock. SYDNEY JONES, 31a, SPRAY STREET, WOOLWICH, S.E. 18. THE WIRELESS WORLD AND RADIO REVIEW THE OFFICIAL ORGAN OF THE WIRELESS SOCIETY OF LONDON A MAGAZINE DEVOTED TO WIRELESS TELEGRAPHY AND TELEPHONY CONTENTS An Experimental Radio Transmitting Set.By E. M. Deloraine, Ing. E.P.C.I. - - 151 Electrons, Electric Waves and Wireless Telephony.By Dr. J. A. Fleming, F.R.S. (continued) - - 159 A New Coil Winder ------164 Contents continued on next page.

Wireless Telegraphy and Telephony Protect your apparatus from lightning and other heavy static dischargesandatthe same timeobviate the necessity of having an unsightlyearthingswitch by installing a Protector Spark Gap.

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This article is of very neat appearance, being made of solid brass well lacquered and mounted on an ebonite base size 22" x 12°. Itis a permanentsafeguard whether " listening -inor not.No station should be without one.

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CONTENTS(Continued) Wireless Society of London 165 Notes- 174 Calendar of Current Events 175 Wireless Club Reports 176 Questions and Answers 181 Share Market Report - 184

THE WIRELESS WORLD AND RADIO REVIEW iS published weekly on Saturdays. Allcorrespondence relatingtocontributions should be addressedto THE EDITOR, THE WIRELESS WORLD AND RADIO REVIEW, I2-13, Henrietta Street, Strand, London, W.C.2. No responsibility can be taken for MSS. or photographs sent without stamps to defray cost of return postage. Editorial and Publishing Offices :12-13, Henrietta Street, Strand, London, W.C.2. Telegraphic Address :" Radionic, Rand, London." Telephone No.:Gerrard2807. Advertisment Managers, Bertram Day & Co., Ltd., 9 and 1o, Charing Cross, S.W.I. Telephone No. :Gerrard 8063 and 8064 SUBSCRIPTION RATES. 28s. per annum, post free.Single Copies 6d., or post free 7d. Registered at the G.P.O. for transmission by Magazine Post to Canada and Newfoundland.

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Call andseethis Receiving Set Demonstrated.

No intricate adjustments axe necessary with this highly efficient Broadcast Receiving Set to obtain Telephony and Telegraphy signals with remarkable clarity.All the adjustment necessary to receive any particular wavelength is the movement of one switch arm. Its dimensions are 9" 9" and 81" high, the Hertzite crystal13enclosed in glass, one adjustment being almost permanent. Supplied complete in highly polished mahogany case together with Sterling R1258 Head 'Phones (4,000 ohms), 100 ft, Black 7/22 Aerial Wire, 2 " Econ " Aerial Insulators, 1 Aluminium Aerial Pulley.It costs but £5 5s. Everything can be enclosed in the case for packing away. In addition to complete Receiving Sets we also manufacture all Component Parts. Honeycomb Inductance Coils from .. .. . 51- " Ideal " Valve Accumulator, 4 -volt 50 amp. per set 26/ - (Carriage, 2/-) " Ideal " Valve Accumulator, 6 volt 50 amp. per set 35/ - (Carriage, 31-)

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I THE WIRELESS WORLD AND RADIO REVIEW THE OFFICIAL ORGAN OF THE WIRELESS SOCIETY OF LONDON

No. 168 [Voril:o. 5XL] NOVEMBER 4TH, 1922. WEEKLY An Experimental Radio Transmitting Set. By E. M. DELORAINE, ING. E.P.C.I. GENERAL. MOST amateur transmitting stations inhaving approximately the same characteristics, this country probably use the " chokeone tube being the oscillator and the other the control "or" constantcurrent "modulator.The plates of both tubes are fed system of modulation. through a low frequency choke coil.The high

Fig. 1.General view of the Transmitter.

Thissystemcomprisesessentiallytwo inductance of this coil opposes rapid variation vacuum tubes (or two groups of vacuum tubes)of current, and so ensures that the supplied 152 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 4, 1922 current remains approximately constant.Be- tween the plates of the oscillator and modulator is a high frequency choke coil which prevents TIME the plate potential of the modulator from varying at radio frequency (Fig. 2). If the grid potential of the modulator is constant the oscillator will supply a wave of high frequency current of constant amplitude, but if currents at speech frequency are impressed on the grid of the modulator, the plate current of the modulator will vary accordingly and produce slight variations of current through the low frequency choke coil.The inductance of the coil being large, the voltage across it varies to a considerable extent.For instance, suppose there is a 20 per cent. variation of current at a frequency of r,000 cycles per 31 second.If the inductance of the choke is 4 Fig. 3. henrys, and the current 20 milliamperes, the variation of voltage:will be :- making use of " grid modulation " is able to 2ir x 1,000 x 4 x 0.2 x 0.02 = 100 voltsdeliver speech or music of the same grade as a set using " constant current " modulation, although the control of the former system probably requires more attention and skill than the latter. GRID CONTROL OF THE OSCILLATOR. It is practically impossible to obtain good modulation, with normal efficiency, using a system of direct control potential of the oscillator.If the variation of grid potential is small and the carrier wave incompletely modulated, no trouble is experienced.Speech isintelligible,if not good, but when the modulating signal is strong, oscillation suddenly Fig. 2.Simplified circuit diagram. ceases and then starts again (Fig. 3).Speech becomes unintelligible and music is of a very If the plate supply is 30o volts, the platepoor quality. potential of the oscillator tube will vary between 200 and 400 volts,in accordance with the PLATE CURRENT impressed speech frequency, thus producing corresponding variations in the amplitude of PARABOLIC the high frequency wave. CHARACTERIETIC CURVE This system of modulationhasahigh efficiency (between 45 and 65 per cent.), and TIME is perhaps one of the most satisfactory as POTENTIAL farasquality and clearness of speech or music are concerned.(See Appendix I.) MODULATION BY GRID CONTROL. It is interesting, notwithstanding the points in favour of the system of choke control, to pursue experiments with other systems of modulation.These are numerous, many of them involving in principle low efficiencies. The author has recently been experimenting with a system of grid control.It seems quite TIME clear that a carefully adjusted transmitting set Fig. 4. NOVEMBER4, 1922 THE WIRELESS WORLD ANDRADIO REVIEW 153 GRID CONTROL OF THE AMPLIFIER. 111111111111111111W TIME The idea which naturally occurs is to make II OSCILLATOR use of a separate and independent oscillator CURRENT and modulator, both acting on the grid circuit of an amplifier tube.This was used as far TIME MODULATOR back as 1915, when speech was transmitted CURRENT from Arlington to Paris, San Francisco and 0 Honolulu:In this case, however, the amplitude of the high frequency oscillations on the JJ GRID grid was small compared with the amplitude ill POTENTIAL of the signal at speech frequency ; the modula- V NEGATIVE tion resulting from the parabolic shape of the gridpotentialspace -currentcharacteristic. PLY.a When the operating point on the amplifier tube 110 J1 - CURRENT characteristic is moving up and down, the amplitude of the variation of space current is increasing or decreasing according to the slope ANTENNA of the characteristic at the operating point, Aiwv\. CURRENT thus producing in the output circuit, a current at radio frequency modulated according to the low frequency signal (Fig. 4). Fig. 5. The efficiency is determined by the amplifier of the characteristics.This system is dis- and remains between 22 and 37 per cent. (See tortionless only to the extent that the character- Appendix II.) istic can be assumed to be a straight line, or MODULATION SYSTEM IN USE. if some steps are taken to compensate the Instead of making use of the fact that a part action of a curved characteristic. of the grid -potential plate -current characteristic The efficiency of this system of modulation is a parabola, let us assume now that there is a can be raised to that of any other system (See region large enough to use which is practicallyAppendix III.) straight. We can make use of a much larger oscillatory PRINCIPLE OF THE CIRCUIT. high frequency voltage, its amplitude being The circuit used for impressing both high now equal to or greater than the amplitude offrequency and signallingcurrents on the the signals at audio frequency.The com-amplifier is, as a rule, as shown on Fig. 7, I. bination of the modulator and oscillator currentWe can call this :magnetic coupling between (I and II, Fig. 5) will result in a curve asoscillator, modulator and amplifier. The author represented (on III). tried a system somewhat different, which might The resulting wave of current is impressed be called a double resistance capacity coupling.. on the grid of the amplifier, taking care that theFig. 7 (II.) grid has such a steady negative potential that PLATE CURRENT the operating point is at the beginning of the T CliARACTERISTIC characteristic (A, Fig. 6), so that when no CARVE oscillations are impressed on the grid, the plate current will be practically zero.The amplitude of the high frequency wave must be of such a GRID value that when the radio positive potential is at its peak value, the negative potential of the grid is halved (as shown on B). Now the signal at voice frequency must have a maximum amplitude equal to A B if complete modulation isdesired, thus moving the peaks of high frequency from A to C.Consequently the output of the plate circuit and antenna current are as represented on IV and V, Fig. 5. The quality depends to a large extent on the different adjustments and also upon the shape Fig. 6. 154 THE WIRELESS WORLDAND RADIO REVIEW NOVEMBER 4, 1922 In principle we can divide this circuit intoefficiency of the coupling can be kept nearly four parts : constant for all frequencies above a certain Oscillator. minimum value. Modulator. DESCRIPTION OF THE CIRCUIT. Amplifier. The circuit used is solely of the experimental Antenna circuit. type and is subjected to frequent modifications. I. Oscillator.The High frequency oscillatorItis shown in Fig. 6.In the photograph, may be of any type.It is connected in seriesFig. t, the part of the set near the camera is with a condenser C of very small capacity andmainly for control of filament and plate circuits a resistance R.The condenser offers an easyand of the motor generator set.Next is the path to the high frequency currents which areoscillator, then the amplifier.Further on can flowing through thecircuitO.C.a.b., thusbe seen the modulator, the output high fre- varying the potential across R, as shown already quency circuits, and finally, a one -stage low inI,Fig.5.These currents cannot passfrequency amplifier with meters and control. through the circuit a.L.M.b. on account of the high impedance offered to radio frequency VACUUM TUBES. currents by the inductance L. The tubes used have been of various types but 2. Modulator.The modulating circuit com- particularly the 20 and 30-o Mullard tubes, prises a microphone transmitter which acts asand Western Electric tubes. a rule through an amplifier.Currents at voice The Mullard type are well known ;they

Fig. 7.Coupling arrant meats. frequency flow through the circuit M.L.a.R.b,have a vertical cylindrical plate made from a thus varying the potential across R, as shownsheet of nickel, the grid being a spiral of in II, but do not flow through the oscillatormolybdenum wire and the filament a straight circuit, owing to the high impedance offeredwire of tungsten.The 0'20 valve requires a by the condenser C to current at voice fre-filament current of 1.5 amperes and is used quency. with a plate voltage up to Soo volts. 3. Amplifier.The grid is connected to the The Western Electric tubes make use of end " a " of the resistance R, the filament beingoxide coated filaments.These filaments offer connected to the other end " b," through thethemosteconomicalsourceof electrons grid battery, which maintains the grid at aat present available, that is, they give a maxi- negative potential. mum electronic emission for a given filament Potential variations of the grid with respectcurrent.When metals are coated with certain to the filament are shown in III.The platechemical compounds their electronic emission current of the amplifier is controlled by the isgreatly increased. Considerations of grid potential and has a wave shape as shownmechanical strength, electrical resistance and in IV. non -oxidisation, led to the choice of a wire Energy is transferred from the plate circuitof platinum -iridium for the filament.This to the antenna through a magnetic coupling.wire is rolled to a ribbon, to increase the surface, The modulated antenna current is representedand the ribbon istwisted to secure better in V. mechanical properties. The main advantage of this circuit is that by Experiments showed thatamixtureof avoiding the use of iron core transformers, itbarium oxide and strontium oxide in a number is to a large extent free from distortion, and theof consecutive coatings give the best results. NOVEMBER 4, 1922 THE WIRELESS WORLD AND RADIO REVIEW 155 The most commonly used process consists inthe case of a coated filament tube having the mixing bariumcarbonatewithstrontium,same characteristics.This larger structure of hydroxide with resin or paraffin and repeatingtubes makes their manufacture an easier matter. the coating process.After each applicationThe life of coated filaments, on account of their the wire is raised momentarily to a temperaturelow temperature, is also longer than the life of of about a thousand degrees, thus burningtungsten filaments.The grid and plate of the away most of the organiccarrier.ThereWestern Electric tube are of nickel, and are of remains a firmly adhering layer of oxide ofa flat type, disposed on each side of a single or barium and strontium, combined with platinumdouble V-shaped filament.(Fig. 9.) and iridium. The tubes of the latter type used in this

/A Ir

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MOTOR GENERATOR 20011 C> o 60nr ?A".A.f.AAAAPCD' 0000 Fig. 8.Circuit diagram of the Transmitter.

The coated filamentoperatesata lowcircuit have the following characteristics :- temperature, corresponding only to a dull red Filament Plate heat.The emission from a square centimetre Current. Potential. of tungsten at high temperature is about ten Amperes. Volts. times greater than that from a square centimetre of coated filament.This greater density Amplification .. I.25 130 of emission from tungsten has the effect of re- Output Power -5 watts1.35 200

quiring for a tungsten filament tube a smaller 35 5o watts 3.4 up;to plate and grid structure than that required in moo 156 THE WIRELESSWORLD AND. RADIO REVIEW NOVEMBER 4, 1922.

OSCILLATOR. The double -button microphone is preferably For the oscillator a Mullard tube is used.placed at a distance of one or two feet from It consists simply of a tunedthe horn and to the side of the gramophone as anode circuit with reaction onshown in Fig. tt.This position minimises the grid by mutual inductance. any needle noise that may be present. MODULATOR. The modulator tube used is either a Western A very importantpartin Electric 5 -watt or a Mullard 0'20. modulation is the starting point, The oscillator and modulator act on the thatis,the transmitter. Anamplifier as previously explained.The ampli- ordinarysolidback standardtude of the voltage at radio frequency is con- transmitter has been found totrolled by a variable air condenser, and modu- give satisfactory results.It mustlation is controlled by varying the resistance be remembered, however, thatcoupling between the last stage of low fre- such a microphone is not wellquency amplification and the modulator. An suited for the transmission ofinductance in series with the couplingr esistance, thehigher frequencies. Theand a small condenser across the input of the voice range of frequencies isamplifier, prevent the distortion which would practicallylimitedtotoo tobe introduced by the capacities in resistance - 2,000 periods, whereas musiccapacity coupling. Fig 9. requires a much larger range ; AMPLIFIER. thepianocoveringarange The amplifier tube is a Western Electric from27to4,138periodspersecond, type and has a tuned plate circuit which acts

the organ from 16 to 4,138.This does not AMPUnE12 include harmonics, which exceed ro,000 periods per second. The microphone current of the solid back transmitter was able to act directly on the modulator but it was found preferable, in order to run the transmitter smoothly, to make use of one stage of low frequency amplification.

A special type of transmitter also has been DOUBLE BUTTON - 6Vlit'111------1 + - 120V + tried.This isa double -button microphone MICROPHONE made by the Western Electric Company, and Fig. 10.Two -stage amplifier. intended eitherforradio telephone trans-either on the antenna or on an absorbtion mission, or for public address systems usingcircuit. loud speakers.The diaphragm isstretched The author does not give precise data on tillits natural frequency is raised to aboutvoltage, currents, etc.,because of the experi- 2,500 periods per second and this frequencymental character of te transmissions.These is furthermore increased by the use of an airwere never twice under the same conditions. damping chamber.Best results are secured PLATE CURRENT SUPPLY. when the transmitter is spoken into at a dis- It may be of interest to amateurs to state tance of two or three feet.The reproductionthat before making use of a motor generator of the speech or music is very clear, owing toset, the plate current supply was obtained as the absence of resonant effects and variationsshown in Fig. 12. in efficiency.The output of this tansmitter, The main supply at 200 volts D.C. charges however, is very small and requires amplifica-a condenser of to microfarads.This con- tion. A two -stage amplifier with 'resistancedenser is then connected in series with the coupling increases the volume of sound to themains and across another condenser of 30 normal standard of an ordinary microphone.microfarads. The latter consequently becomes (Fig. to.) charged at 400 volts, and supplies the plate The position of the microphone with regardvoltage through afilter.These operations to the transmitting instrument is also important.are performed by a simple commutator driven The gramophone used is an Aeolian Vocalion,by a small power motor.This constitutes a with a tone control device, and this gives verysimple method of obtaining twice the value good quality music.The best position of the of D.C. potential directly available, and involves solid back microphone was inside the horn.very little expense. NOVEMBER 4, 1922 THE NVIRELESS WORLDAND RADIO REVIEW 157 APPENDIX I. delivered to the antenna will be If the plate voltage of the oscillator is repre- p = RI 2(1 T K sin (.02-1 f sin2atdt sented by 0 = E (1 K sin tot) with

ck being the frequency of the signal impressed R1,2 27r on the modulator, the plate current of the (1 K sin 042. modulator will be :- The maximum value fo: complete modula- i = I (1 K sin wt). tion, i.e., IC = 1is :- K depends on the amount of modulation p 2R12. and will be unity when modulation is complete. This power is supplied by the amplifier tube. The space current in the modulator will be:- Consequently if Eis the plate efficiency of this i = 1 (1 -K sin (00. tube, we have with 2R12 = i i.,= 21, thus 2/ being the constant current supplied by the p =_ ,}E.EI(1 K sin wt)'. generator. Let us callE the plate efficiency of the oscil- The efficiency of this system is equal to the lator. ratio of the integrated output power p, to the The overall efficiency of the system, ex-input power El. cluding the power dissipated in the filaments, Eff= I c -' (I K sin .02dt will be equal to the oscillatory output power 7 0T divided by the input power :- E K2 K2 = If T(1+2K sin w cos ?(0t)dt. 1 T 0 2 - 7-110El(1 K sin wt)2dt K2\ Eff - E T = = -) 2 E(i, i) 1 fT Ivo 0 -4- 2K sin 'et -K2- - K2sin 2wt)dt - E 2 9 2

K2 1 -}

If modulation is complete the efficiency will be :- Eff = 43- c The efficiency E of the oscillator may be 6o to 85 per cent., so that the overall efficiency of this system will be between 45 and 65 per cent. APPENDIX II. The modulated carrier wave may be represented by = 4, sin 0(1 K sin wt). -4' being the radio frequency. 27r If R is the effective resistance of the antenna for the frequency the modulated power Fig. 11.The microphones used for transmissions. 158 THE WIRELESS WORLDAND RADIO REVIEW NOVEMBER 4, 1922 In the assumed case of complete modulation The antenna current is : 3 i = la sin Ot (1 + sin cot) Eff = e 8 and the output energy : Taking again E between 6o and 85 per cent. Rioa = R42 sing 4t (1 + sin wt)2 the efficiency of this system will remain be-and at signal frequency. tween 22 and 37 per cent. w = RI2 (1 + sin wt)2-1 f Csm 2.clItdt This does not include the power expended t in the separate oscillator and modulator tubes, R/"2(1 + sin wt)2 which still further lowers the overall efficiency.

. The maximum output energy is: 2 This correspondstothe maximum input energy :El.So that c El = 2 R/,2 Consequently the mean output energy is : cEI 1 f T W (1 + sin oit2)dt = -3 EEL 0 8 The efficiency is therefore 3cEI Eff. ___ 3, AEI - 4 The plate efficiency E is about the same when using the grid control or the choke system, i.e., between 6o and 85 per cent., Fig. 12.Method of obtaining plate current supply. providingtheplatevoltageisincreased in the first case, to compensate the effect of the negative gridpotential.The overallplate APPENDIX III. efficiency of the grid control system will be Let us assume the characteristic to be a straightalso between 45 and 65 per cent., so that it line.In the working conditions previouslycan compete as far as efficiency is concerned described, the maximum value 'of impressedwith the " constant current " system, or more signalling voltage is equal to the amplitude ofgenerally with any other existing system. impressed high frequency voltage between A A somewhat different method which has been and B.If we take again the signalling currentsuggested isto work with a very negative grid potential, so that when the high frequency asa sine wave of frequency --(1) the plate 2ir currents are applied (but no signalling at voice current will have an envelope : frequency is impressed) the amplifier anode /(1 ± sin wt) current is zero.In such a case, however, only but due to the fact that only half of the highthe positive half cycle of signalling current will frequency oscillation produces a flow of plateliberate corresponding high frequency in the current, the mean value of plate current atantenna, and distortion results. signalling frequency will be :- The Wireless Society of London 1 (1 + sin wt) The November mee ing of the Society, which will be held at 6 p.m. at the Institution As the plate voltage is constant, the power at of Electrical Engineers on Wednesday, Novem- signalling frequency will_be :- ber 22nd, w:11 be a spec.al gene al meeting for p EI7(1 ± sin wt) the purpo:e of authorising changes inthe constitut onoftheSociety through the and the mean power : alterat:on of certainrules.A lec.ur e and demonstration will also be given illustrating El p El f T0(1 + sin wt)dt = the action of the three electrode valves by means of a mechanical model. NOVEMBER 4, 1922 THE WIRELESS WORLD AND RADIO REVIEW 159 Electrons, Electric Waves, andWireless Telephony V. By Dr. J. A. FLEMING, F.R.S. The articles appearing under the above title area reproduction, with some additions, cf the Christmas Lectu-es on Electric Waves and Wireless Telephony given by Dr. J.A. Fleming, F.R.S., at the Royal Institution, London, in December and January1921-1922.The Wireless Press, Ltd., has been able to secu-e the serial rights of production, andany subsequent re -publication.The articles are therefore copyright, and rights of publication and reproductionare strictly reserved. III.-THE ARCHITECTURE OF ATOMS. I.MOLECULES AND ATOMS. valid reasons began to be given for the belief BEFORE we can discuss the nature andthat material substance, in short, all matter properties ofanother type of waveis not infinitely divisible, but is composed of called an electromagnetic wave, it willdefinite units of mass called molecules and be necessary to consider briefly some of theatoms. things which modem researches have taught Suppose we consider such a substance as us concerning the structure of atoms, and thecommon table salt.We can divide it into elements of which they are built up. small grains and each of these could be divided Twenty-five years ago no one could haveagain under a microscope until we reach a given any information on this subject.Inparticlenearly1/100,000th of an inch in fact, even the.actual existence of atoms wasdiameter, which is about the smallest size then in doubt.The word atom, derived fromof particle visible in a good microscope. We Greek verbal roots, signifies something whichhave good reason to believe that even such a cannot be cut or divided, and any discussionsmall particle would possess all the known on the structure of the interior of an atomqualities of common table salt.If we dissolve would in those days have been very similarsome salt in water and make a solution, no to the contents of a chapter in an old bookmicroscope yet made can show any visible on Natural History, headed " On Snakes inparticles in it, yet each drop of the liquid Iceland," the only information given thereinwould taste " salt " and exhibit all the properties being, " There are no snakes in Iceland." of common salt in chemical actions.Moreover, So with atoms the only answer to questionsby an evaporation or boiling off the water we as to -the structure of an atom would thencan recover the salt unaltered. have been, " we know nothing about their Hence we have good reason to believe that structure and probably nevershall know'when in solution the salt is divided into particles anything." of ultra microscopic size.But chemical experi- Although Greek philosopherstwenty-fivements show that this substance can yield under centuriesagohadtaughtthatmaterialthe action of an agency called an electric substances are composed of small discretecurrent, the nature of which we shall consider indivisible particles, no one had formulatedimmediately, two other substances,viz.,a any theory as to their inner construction, andgreen poisonousgas,chlorine, and asoft they were only mentally pictured as extremelymetal, sodium, and therefore common table small spheres infinitely hard and of unknownsaltiscalledin chemical language, sodic composition.Buttheatomictheoriesofchloride. classicalphilosophers, suchasDemocritus Moreover, effects we shall discuss later on and Lucretius, were mere speculations and hadprove that in very dilute solutions of sodic no basis in observed facts. chloride, and other similar salts which conduct It was not until modern chemistry cameelectric currents and are decomposed by them, into being by the discoveries of Cavendish,the constituents, which in this case are chlorine Boyle, Black, Lavoisier and Dalton, in theand sodium, exist partly in an uncombined eighteenth and early nineteenth centuries, that state. B 2 160 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 4, 1922 Hence there is a certain small mass of sodicThe ratio of oxygen to carbon in the second is chloride whichistheleastpossible massjust double that in the first.It is found that which exhibiti all the properties of commonwhenever there is more than one compound salt.It is called a molecule of sodic chloride.of two elements, the ratio by weight of these The word molecule is derived from Latinelements in the two compounds is always in words and meansa small mass or quantity.a simple integer proportion. There are various substances, about 90 in all, The Law of Relative Proportion is as follows : which have never been resolved or decomposedConsider three elements, hydrogen, oxygen and into any other substances and these are calledcarbon. Thefirsttwocombineinthe elements.The smallest possible quantity orproportion of 1 to 8 or 2 to 16, to form water. mass of any element which can exist as suchThe second and third combine in the ratio of and exhibit the chemical properties of the16 to 12 to form carbon monoxide.Finally, substance is called an atom of it. the first and third combine in the ratio of Hence the molecules of complex substances2 to 12 to form a gas called olefiant gas. We are built up of atoms held together so as tosee then that to each element may be affixed form small similar bunches or groups.Ina certain numerical value called its chemical certain very simple compounds such as tableequivalent, and combinations between elements salt, the molecule may consist of only twoalways take place in the proportion by weight dissimilar atoms, but in organic substances,of the equivalents, or in some integer multiples such as albumen, oils, or starch, the molecule thereof. may contain many scores or even hundreds of These facts, and many others like them, atoms. pointverysignificantlytothe conclusion Even inelementarysubstancessuchas thatelementarysubstancesexistinsmall hydrogen or oxygen in the gaseous state, theultimate units which are of exactly the same constituentmoleculescontaintwosimilarmass and enter intoallchemical reactions atoms held together. without change of mass. We have been able to determine by methods In short, matterisatomic instructure. which cannot here be described in detail, theAtoms unite to form molecules and molecules mass or so-called weight and also approximately to form visible masses, justaslettersare the size of molecules and atoms. combined to form words and words to form The view that small definite units of mass, sentences. called atoms, exist in the case of the elementary The relative mass or so-called weights of substances is strongly supported by the threeeach kind of atom has been measured and is laws of chemical combination, viz., Proust'scalled the Atomic weight.It is expressed in Law of Definite Proportions, the Law ofterms either of the mass of the hydrogen atom Relative Proportions and Dalton's Law oftaken as equal to 1, or of the oxygen atom taken Multiple Proportions. These may be illustrated as equal to 16.The Molecular weight of a as follows :Every pure chemical compound ismolecule isthe sum of the masses of the composed of elementary substances always inconstituent atoms. Two terms, viz., a gram - the same definite and constant proportion bymolecule and a gram-atom are in frequent use. weight.Thus water consists of 16 parts byThese mean respectively the quantity of a weight of the gas oxygen combined withchemical substance or of an element which 2.016 parts by weight of the gas hydrogen, hasamassin gramsnumericallyequal which combine and produce pure water wheneither to the molecular or the atomic weight. the gases are mixed and an electric spark sentThus the atomic weight of oxygen being 16, through them. When the analysis of a purea quantity of oxygen weighting 16 grams is compound is conducted with proper care itcalled one gram-atom of oxygen.The atomic invariably yields the same proportions of itsweight of sodium is 23 and of chlorine is 35.47. constituent elements. Hence the molecular weight of sodic chloride The Law of Multiple Proportion may beor tablesaltis58.47, and a mass of salt explained as follows :-There are two knownweighing . 58.47 grams iscalled one gram - compounds of carbon (charcoal) and oxygenmolecule of sodic chloride. gas, viz., carbon monoxide (CO), a very poison= According to an hypothesis first made by ous gas, and carbon dioxide (CO2).In thethe chemist Avogadro, in1811,agram - first, the ratio of mass of carbon to oxygen ismolecule of every kind of substance contains 12 to 16, and in the second it is 12 to 32.the same number of molecules. NOVEMBER 4, 1922 THE WIRELESS WORLD AND RADIO REVIEW 181 In the case of permanent gases taken at A millimetre(1 mm.) isthe thousandth standard temperature 0°C. and barometricpart of a metre and is about 3/25th part of pressure 760 mm., equal volumes thereforean inch. contain the same number of molecules and a A micron (1p.) isthe thousandth part of a gram -molecule occupies a volume of 22,400millimetre. cubic centimetres. An Angstrom unit (1 A.U.) is the ten -millionth Thus 2 grams of hydrogen, 32 grams ofpart of a millimetre and therefore the ten - oxygen, 28 grams of nitrogen,allhave athousandth part of a micron or volume of 22,400 c.c. at 0°C. and 760 mm.10,000 A.U. = 1µ. and contain an equal number of molecules, Roughly speaking, the diameter of an atom that number being very near to 66 x 1022 oris about two to five Angstrom units. 660,000 times a million billion in English It is possible to prepare gold leaf the thick- reckoning. ness of which is about one -tenth of a micron This means that in one cubic centimetreor 1,000 A.U.Such leaf when held up to there are about 30 million billion molecules.the light has a green colour, orissemi- In a space of one-half of a cubic millimetre,transparent and transmits green light. or about the volume of a small pin's head, This gold leaf has, however, several hundred there are ten million times more moleculeslayers of atoms in its thickness, probably 300 of air than there are human beings alive onto 500 atoms. We can, however, prepare the surface of our earth at present.This thinner films of soapy water.If a soap bubble will give some faint idea of the exceedingis blown with a suitable material, or better minuteness and number of the molecules instill, if a metal ring is filled with a soap film the air we breathe. by dipping it into the soap mixture, and if Non-scientific persons are apt to imaginethis film is placed in a glass dust -free box in that these figures are mere guess work, buta vertical position, the film begins to thin this is not the case. We can now count byaway by drainage from the top part. Presently various methods the number of molecules inwe notice certain small round black spots a cubic inch of air with quite as close an which look like holes, but are not holes, because approximation to truth as we can count thein proper positions we can see an image of a number of men, women and childrenin bright light source, such as the sun reflected Great Britain by a census taken on the nightby them.It is possible to measure by several of any given date. methods the thickness of the film in these 2.-DIMENSIONS OF ATOMS. black spots.It is found to be about 60 A.U. As regards the sizes of atoms and moleculesor six thousandths of a micron.This film, there are various lines of argument whichhowever, must be of a thickness equal to the leadtotheconclusion that approximatelydiameter of several atoms. speaking, the diameter of an atom is of the The lateLordRayleigh(3rdBaron) order of one hundred millionth of a centimetre.measured the thickness of still thinner films of This means that if a million atoms were placedoil floating on the surface of water and found in contact like marbles arranged in a row,them to be about 20 Angstrom units (A.U.) they would only occupy a length of 1/250thin thickness ( = 2 x 10-7 cm.). part of an inch, or less than the thickness M. Devaux, by another method, produced of the thinnest sheet of tissue paper.To films of oil on water of half the above thickness, count this million atoms would take at leastviz., 10 A.U.In this last case the film is a week, counting without stopping day and probably formed of a single layer of molecules night. of oil, and hence we seethatmolecular An approximate measurement of atomicdiameters must be between 1/107 and 1/108 diameters is derived from the study of thinof a centimetre, or approxiamtely be of the films of various kinds. order of one hundred millionth of a centi- Skilled gold beaters can beat out one ouncemetre or fromone to five times this last of gold until it covers an area of 240 squarelength. feet.The thickness of the sheet would then At this stage we must, however, define a be about four -millionths of an inch. little more carefully what we mean by the There are three units of length which arediameter of an atom or molecule. We shall convenient for measuring very small lengthsshow presentlythat atomsare notsolid, or thicknesses and these are as follows :- sharply defined masses like billiard balls, but 162 THE WIRELESS WORLDAND RADIO REVIEW NOVEMBER 4, 1922 in all probability resemble solar systems in 2 my= mv2Hence the miniature, in which a number of still smaller .2 pressure onthe particles circulate round a nucleus like planets round the sun. side of the cube due to the N/3 molecules is * Nmv2. 3.-THE KINETIC THEORY OF GASES. Suppose we now take v to be, not the actual It will be necessary, therefore, to sketch invelocity of one molecule, but the square root outline the kinetic theory of gases or theoryof the mean of the squares of all the various of the motion of gas molecules. molecular velocities, called the R.M.S. velocity, In a mass of air or gas the constituentthen since Nm is the mass of the gas in molecules are not at rest, but flying hither1 c.c. = d, we have for thegaspressure p and thither with immense and various speedson a surface of one square centimetre the in every possible direction. We know thatexpression this must be the case from the facts of diffusion. p = idv2 If we have two vessels, one full of air or other Hence it follows that the mean square velocity gas and the other exhausted or vacuous, and ifv2 is 3p/d and the root -mean -square velocity they are connected by a pipe in which therev is i/3pld, where d denotes the absolute gas is a plug of porous clay or unglazed earthenware,density. we find that after a time some of the gas will The pressure of a gas per square centimetre have passed through the plug and diffusedmeasured in absolute units of force, called intothe vacuous space.Alsoif the twodynes, which corresponds to a height of the vessels contain gases of different densities,barometer of 760 mm. or nearly 30 inches of but at the same pressure such as hydrogenmercury and at 0°C. is very nearly one million and oxygen, then they both diffuse in oppositedynes, and the density of hydrogen gasis directions, but the lighter gas diffuses faster1/11,200because11,200c.c.of thisgas than the heavier gas.In a certain time theweighonegram. HencetheR.M.S. gases will have mixed completely so that eachspeed ofthe hydrogen molecule is vessel will contain the same proportion ofV3 x 10') x 11,200 centimetres or 1,830 metres each gas. per second. We know that the gas in any closed vessel In the case of oxygen, which is 16 times exerts a pressure on the walls.This pressuredenser than hydrogen, the R.M.S. speed of is a force in a dynamical sense of the word,the molecule is close to 460 metres per second. and is due to the bombardment of the walls Itisimportant that the reader should by these flying molecules.Let us supposeclearly understand what the above statements that there are N molecules in one cubicimply. centimetre and that each molecule has a mass The gas molecules are flying in all possible m and is moving with a velocity v.Thisdirections and with very differentspeeds. velocity is not the same for all molecules,If we could divide up the molecules into a some are moving quickly and some slowly atvery large number of groups of nearly equal any instant.Of the N molecules we mayvelocity according to their speed, but without suppose one-third or N/3 to be moving attaking regard todirection of motion, we any instant perpendicularly to one surfaceshould find that a very small number of of the cube of1 cm. in side and 1squaremolecules had a zero or very small velocity centimetre in area.If we take v to be anand a very few had a considerable velocity, averagevelocitythen myistheaveragebut the great majority approximate in speed momentum of each molecule, and when itto a certain " most probable speed," which is strikes the side of the cube and reboundsvery nearly the same as that obtained by from it,its momentum + my is changed insquaring the numerical value of the speeds direction to - my in the time taken for theof the different groups and then taking the molecule to move over a distance of 2 cms.square root of the mean of these squares, Hence the change in momentum is 2 my inin other words, obtaining the R.M.S. speed. a time 2/v seconds. Clerk Maxwell was the first to give a general Force is defined as the rate of change oflaw in the form of a mathematical expression momentum and the time rate of change ofand to give a curve for the distribution of momentum orforce is inthiscase velocity amongst gas molecules.The curve NOVEMBER 4, 1922 THE WIRELESS WORLDAND RADIO REVIEW 163 shown in Fig. 35 is acurve whose equation is In the case of hydrogen gas which has y = x2e-x2 an R.M.S. speed about four times greater than oxygen, the molecules are moving for Where e = 2.71828 . etc., viz., the base ofthe most part with speeds from 2,000 to 8,000 miles an hour or 100 times faster than express trains. In the course of this extremely rapid motion the gas molecules collide with one another. The average distance they move over between two collisions is called the mean free path. In the case of air at normal pressure and temperature the mean free pathisabout 1/250,000th part of an inch or 1/10,000th part of a millimetre, or 1/10th of a micron.This is roughly about 500 times the diameter of a gas molecule.The mean free path varies 0 I x M, 142 inversely as the pressure of gas.Hence, if Fig. 35.MaxweWe Curve Graph of y = x2e-xa we make a so-called vacuum by removing all but one -millionth of the air from a vessel, the Napierian system of logarithms.Thethe mean free path is increased to about four curve is so drawn that the abscissa OI of theinches in length. maximum ordinate is taken as equal to unity. We can now give a more exact definition The value of y is zero both for x = o andof what is meant by the diameter of an atom x = infinity. Ifwetaketwoordinatesor molecule.It is the least distance between PAD P2M2, then it can be shown that the the centres of two atoms or molecules at their value of the area P1M1M2P2 multiplied byclosest approach during a collision. 4/ v-ir gives the fraction of the number of gas If D is the diameter of the sphere of impact molecules in any volume, the speeds of whichor atomic diameter as defined above, and if lie between values denoted by the abscissaeN is Avogadro's constant, or the number of 0M1 and 0M2. molecules in a gram -molecule, and if V is Thus, for instance, in the case of oxygenthe volume of this gram -molecule and L is gas molecules, whose R.M.S. speed is 461.2the mean free path, then Clausius showed long metres per second, the following table takenago that the relation between these quantities from Meyer's Kinetic Theory of Gases, gives isgiven by the equation2r LND2 = V the speeds of various groups of molecules inwhere it is the circular constant 3.1415 .... metres per second. From this equation we can obtain, as given Metres perby J. Perrin in his book on " Atoms," trans- second lated by D. Ll. Hammick (Constable & Co., 13 to 14 molecules have speeds from0 to 100 London), the diameters of various molecules,

81 82 33 33 100 200as below 1.7 by 10-8 cm. 166 167 3) 73 3) 200 300 Helium.. .. 214 215 33 73 75 33 300 400 Argon .. 2.8 37

202 203 77 53 33 73 400 500 Mercury.. 2.9 3)

2.1 151 152 7/ 3> 33 500 600 Hydrogen 31

2.7 91 92 33 33 600 700 Oxygen.. 13

.. 2.8 76 77 33 33 33 700 above Nitrogen.. 15 It will thus be seen that all but about 10 per Chlorine.. 4.1 33 cent. of the molecules have speeds which lie The readershould notethat the symbol between half and double the R.M.S. speed of10-8 means one divided by100 millions, or 461 metres per second. 1/100,000,000. It will thus be evident that in a mass of It will be seen that the diameter lies between oxygen gas the molecules are flying about in about 1and 4 Angstrom units, each of which ail directions for the most part with speedsis one hundred millionth of a centimetre. which lie between 500 and 2,000 miles anSince we know that Avogadro's constant is a hour. A very few are moving more slowlynumber near to 66 x1022, which isthe and a few more quickly . number of molecules of gas in 22,400 cubic

incoming signalisread.These sets have an 0 instrumental accuracy of the order of1degree, a perfectly definite observation being frequently obtained to an accuracy ofdegree under favourable conditions. A standard form of R.A.F. amplifier has been employed in these installations, giving amplification by three valves at radio -frequency, and two or Fig. 1. threestagesofaudio -frequencyamplification, with an intermediate rectifying valve. During the first part of the investigation, the this system employs two frame coils fixed together observations at all the stations were limited to at right angles and rotating about their common " spark " or damped wave signals, but the receiving verticalaxis.The two coilsare connected in sets have now been equipped with specially designed series through a reversing switch to a variablescreened oscillators§forthe reception ofcon- condenser to tune the coil system to the incomingtinuous waves. waves (see Fig. 1).According to the position of From the regular observations carried out by the reversing switch the e.m.f. in one of the coilsthese D.F. stations, many thousands of readings is either added to or subtracted from the e.m.f.have been received which are now being collated inthe other coil.Leads are taken from thefor interpretation.One of the first immediately terminals of the condenser to a standard formobvious results which was observed was that the ofdetector -amplifiertogive audible receptionmajority of the D.F. stations possess permanent of the incoming signals.From a considerationerrors, which vary greatly not only from station of this arrangement itwill be evident that into station, but also in different directions around general, a change in intensity of the signal heard each station.In many cases these errors are small in the telephones will take place when the reversing and negligible for most practical purposes for which a direction finder might be used.In other *A paper read before the Wireless Society ofcases, however, the errors are large and much too London on Wednesday, October 25th, 1922. serious to be neglected. Robinson, " A Method of Direction Finding of 11 Wireless Waves and itsApplication to Aerial § R. L. Smith -Rose, " On the Electromagnetic and Marine Navigation."-Radio Review, Vol.I, Screening of a Triode Oscillator."-Proceedings pp. 213-219, 265-275, 1920. Physical Society, Vol. XXXIV, pp. 127-138, 1922. 11i1 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 4, 1922 centimetres by volume, and since we know1,500 feet or so per second, striking against that this volume of hydrogen weighs 2 gramsother molecules about 5,000 million times in and of oxygen 16 grams, it follows that wea second, moving on an average about four - know the absolute mass or so-called weightmillionths of an inch between each collision, of a molecule of these gases ;it is easy toandso numerous thatabout 400 million find that the mass of an atom of hydrogen isbillion are contained in every cubic inch of near to 1.63 x 10-24 gram, where l0_24 means space.* 1 divided by a billion times a billion.In The pressure which the air exerts on the other woids, a billion times a billion atoms ofsides of a vessel containing it, which at ordinary hydrogen weigh 1.6 grams. barometric weight is about 144 lbs. on the We know, therefore, the mass and diametersquare inch, is due to the incessant bombard- of various kinds of gas molecule and thement of the inner surface of the containing number of them in a cubic centimetre atvessel by these small but numerous projectiles. standard temperature and pressure. We have Since the mass of an atom of hydrogen is to realise that the molecules of the air we 1.6 x 10-" gram and the diameter of a molecule breathe are little particles of matter somewhere(two atoms) of hydrogen is 2.1 x 10-8 cm., it about a hundred -millionthof an inch infollows that the mean density of a hydrogen diameter, flying about in various directionsatom is about 3.3 times that of water, and with the velocity of a rifle bullet, or say,that of an oxygen atom about 51 times. * In English -reckoning a billion means a million times a million, or 1 followed by 12 cyphers, but in the United States a billion means 1,000 times a million or 1 followed by 9 cyphers. A New Coil Winder. A new type of coil winder, possessing manymeans of a pin set in the face of one of the novel features, has recently made its appear- wheels. Coilsarebuilt upon ebonite or ance.It is very robustly built, and has the strawboard cylinders, firmly gripped between advantage that the winding drum is directlytwo grooved cones forced together with a wing . . Tho;11,1ctratinnchnum a10CCrt. firlichPCI

166 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 4, 1922 2. -DESCRIPTION OF ERRORS EXPERIENCED AT This similarity is well demonstrated by comparing ABERDEEN. Figs. 2 and 3.Fig. 3 is a graphical representation In particular, it was soon observed that theof the observations made by the first author with results received from the station installed nearthe same type of direction finding set installed the University at Aberdeen showed large errorson H.M.S. " Fitzroy " during October, 1921.The for which it was difficult to account.These errorsquadrantal nature of the error produced by the were found to remain reasonably constant in themetal hull of the ship is well indicated, the slight day time for several months in succession, the ob-distortion evident being due to the asymmetrical servations made at night being subjected to largedistribution of the metal work, stays, etc., on the variable errors, with which the present papership relative to the D.F. set.It is seen that the is not concerned. error is a maximum for a direction of incoming A summary of the permanent errors at Aberdeen waves at approximately 45' to the ship's axis, being the mean day errors experienced on sparkzero error being obtained for waves arriving either stations, between June, 1921, and April, 1922, withalong or at right angles to the axis. the addition of a few C.W. observations taken more 3. -POSSIBLE CAUSES OF THE ERROR. recently, is given in the following table No. 1 .- Owing to the regularity of the above curve on the Aberdeen site it would appear that the cause Ill&NAuDi of the error is very local, since waves coming from If OM quite different directions are affected in a similar manner.In seeking for an explanation of the error la iiMEMN the following points were considered. 111M (a) Refraction due to Coast Line or other Geo- It =gill il graphical Features. MI MI M 111Z4ZINIC= Since waves coming from oversea are affected 2° WI similarly to those arriving overland the effect 1132=111111MI cannot be ascribed to coastal refraction, i.e., a deviation in the direction of propagation of a 86 e IIMM wave in crossing the boundary between media MI M of different conductivity, such as from sea to MIS 0 1fNI INd& land.The magnitude of the error also is much greater than that previously experienced due to 11 IlLizi1 refraction even at much lower wavelengths* POLDHU' 14 As the ground in the neighbourhood is reasonably 40 80 co 160 200 240280320360 flat, particularly in the direction towards the TRUE DIRECTION OF INCOMING SIGNALS coast at a distance of three-quarters of a mile, Fig. 2. it may be assumed that this large error is not due to hills or mountains, which are also known TABLE 1. to produce changes in the direction of waves MEAN ERRORS AT ABERDEEN FROM JUNE, 1921, passing in their neighbourhood. TO APRIL, 1922. IMMINMill. IMMIMMIM Wave- IMMWI MOM Transmitting length True Mean Station. km.bearingb error. MinBlimmaillinMEM

'OM==MIMEIM , Aberdeen, C.W. - 3.3 299.2° +10.3° Chelmsford, C.W.- 3.8 160.6° - 0.3° = Cleethorpes, S. - 3.0 161.5° 1.2° MANE Clifden, C.W. 5.8 233.8° - 8.5° WI MI Coltano, S. 4.2 144.5° --I- 7.9° AiM Karlsborg, S. 4.2 74.1° 4.0° Nauen, S. - 3.2 111.6° +14.8° 0° ace 80° 163" 200' 140'280' 320' 360 Nauen, C.W. 4.9 111.6° +14.7° OBSERVED READING ON DF SCALE Paris, S. - 2.6 160.6° + 1.3° Fig. 3. Paris, S. - 3.2 160.6° - 1.3° Paris, C.W. - - 8.0 160.6° 1.6° Poldhu, S. 2.8 196.1° -12-6° (b) Overhead Wires. Stonehaven, C.W. 4.5 204.0° -11.9° A planofthe immediate neighbourhood Stonehaven, C.W. 5.6 204.0° -10.7° surrounding the hut in which the D.F. set is situated at Aberdeen is given in Fig. 6.This These results show that the errors obtained are shows that the hut is within 55 yards of a stretch practically independent of the wavelength used of twenty overhead telephone wires, in a direction and also of the type of transmission, i.e., spark nearly due east at this point.Previous experi- or C.W. ;but they vary considerably with the true ments on the effect of such wires carried out by direction of the station.The manner of the latter the authors have shown that at any distance variation is beat shown by a curve as in Fig. 2. This curve indicates that the error is practically * See for example :T. L. Eckersley, " Refraction quadrantal, being similar to that produced by theof Electric Waves," Radio Review, Vol. I, pp. 422-8, metal hull of a ship. 1920. NOVEMBER 4, 1922 THE WIRELESS WORLD AND RADIO REVIEW 167 greater than 40 yards the errors due to them and not necessitating the dissembling or dis- are not greater than 2° or 3°. connecting of the apparatus. It will also be observed from Fig. 6 that a (b) To have a good receptive power over a wire fence passes within 14 yards of the hut. range of wavelengths of from 1.0 to 10.0 kms., It will be shown later that this fence was not and responsible for the errors. (c) To give indications of observed bearings (c) Geological Features. correct to at least 1°. In the absence of any obvious cause of the error The apparatus is shown in the photographs, above ground, it was reasonable tO search forFigs. 4 and 5.The set was made to carry either this below the ground. A study of the geologicalof two box -shaped frame coils, that shown in the maps of the neighbourhood of Aberdeen showedfigure being the larger, and of dimensions 4 ft. square by 8 ins. deep.This coil is wound with 34 turns of No. 20 S.W.G. silk -covered copper wire insulated with ebonite combs at the corners with a spacingof aboutisin. The " area - turns " of the coil are 544 square ft. turns, and its effective inductance = 3.02 millihenries.A pane comprising a variableaircondenser and four fixed mica condensers with paralleling switches is mounted at the bottom inside the frame, rotating centrallywiththelatter. Thesecondensers connected across the frame coil give a tuning range on the latter of from 2.0 to 10.0 kilometres, while the smaller coils gave a range with a lower limit butoverlappingthis.Thissmallercoilwas 2 ft.6 ins.square, wound with 25 turns at in. spacing.The " area -turns " of the coil are 156 square ft. turns, and the effective inductance is 1.17 millihenries.With the above condenser panel, the range of wavelengths covered is from 1.0 to 6.0 kilometres. The small wooden platform upon which the coils were carried was mounted at the top of a brass tube 1 in. diameter, which formed the rotating

Fig. 4a. Photograph showing mode of carrying the D.F. set without dismantling. the sub -soil to be fairly uniform in structure, although the survey was naturally not carried out in sufficient detail to render impossible the existence of a sudden change in structure in the vicinity of the hut. 4.-NEED FOR LOCAL EXPERIMENTS. Owing to the absence of an explanation of the cause of the errors as indicated in the previous paragraph, it was considered desirable to carry out experiments in the neighbourhood of the D.F. station at Aberdeen to verify that the error was purely local and to trace the cause if possible. These experiments were accordingly carried out by the authors during the week ending April 29th, 1922, with a small portable single -frame direction findingset.As this instrument was specially Fig. 4b.View of the set raised on the roof of the designed for the purpose, and contained one or hut at Aberdeen, position lc.(See Table 2.) two novel features, a brief description of it is given. 5.-DESCRIPTION OF D.F. SET USED. spindle of the set.This spindle passed centrally The requirements borne in mind in the designthrough the top of a large wooden box, and was of this instrument were :- supported on a pivot at the bottom of the box. (a) Moderate portabilityofthe whole setThe dimensions of the box are 23 ins. by 18 ins., by by two persons, involving a rapid change in the 15i ins. high, and it is entirely covered with tinned position within one or two hundred yards,iron sheet, one side being removable and normally 168 THE WIRELESS WORLDAND RADIO REVIEW NOVEMBER 4, 1922 closed with about 2i ins. tight overlap.This box Tests made on the set showed that the observed serves as a shielded container for the amplifier.bearings were correct to 1° or 2°, which is within its associated batteries and all connecting leads.the limits of error experienced by a normal D.F. A standard R.A.F. six -seven valve amplifier was set on land. used, which gave good reception for all wavelengths 6.-USE OF THE PORTABLE SET AT ABERDEEN. between 1.5 and 9.0 kms.The batteries employed The " accuracy " or angle of zero signal. to whi h consist of a 70 -volt H.T. battery comprising 50the bearings were observed with this frame coil small dry cells fitting into a compartment of theat Aberdeen, varied from 0.5° to 10°, the latter above box, and a 6 -volt 50 ampere -hour accumu-angles being usually due to the weakness of signals at a compaiatively remote place such as Aberdeen. Signals from Poldhu and Chelmsford, for instance, were practically inaudible at Aberdeen over an angle of 10° to 20° round the minimum position, but experience has shown in both this and other experiments that such large angles do not prevent the mean reading being correct to 1° or 2°. A certain amount of difficulty was also experienced at Aberdeen due to transmissions from Stonehaven, only 16 miles distant, which practically prevented observations on any station on a neighbouring wavelength. 7.-EXPLORATION OF THE SITE. On carrying out a careful inspection of the site in the neighbourhood of the hut containing the D.F. set, it was found that in addition to the possible causes of error mentioned in section 3, there were threeothercircumstances tobetakeninto account :- (a) The first, which was judged to be the most important, was the existence of a large sewer crossing the field and passing directly under the hut.The sewer was located by the discovery of a line of manholes in this and neighbouring fields, its position being shown on the sketch map, (Fig.6). -It rises to a depth of only 1 ft.6 ins, below the surface at a point immediately under one corner of the hut. In fact the Fig. 5a. Portable single frame direction ground inthis finding set localityis piled up toforma latorbatteryfor the valves filamentcurrent. slight mound. The leads from the coil circuit are taken down Inspection by the hollow brass spindle to the amplifier.The means of the filament resistances of the latter are controlled manholes showed externally through two circular holes cut in the the sewer pipe to movable side of the tin box.The telephone cord be of egg- shaped isbrought out through another hole, and the se tion,varying external portion of the cord is encased in a metallic 3 ft. to 6 ft. high spiralsheath connected to the screening box. and to be con- The whole set of frame coil and screened box is structed of brick supported on wooden legs, the bottom of the box a n d concrete. being 15 ins. above the ground.The box is also Exceptatthe provided with a pair of wooden carrying handles manholes, no part projecting on each aide to enable two persons to of it appeared to carry the complete outfit.(See Fig. 4a.) be made of iron A horizontal scale is provided on the top of the and enquiries box over which moves the pointer attached to the made from the rotating table.When the outfit is set up at any local surveyors desired position itis adjusted by means of the confirmed thisFig. 5b. Portable single -frame compass so that the pointer indicates true geo- conclusion. This direction finding set. graphical bearings when the coil is set at the mini- being the case it mum or zero position for received signals. could not be reasonably expected to produce any The top sideofthe wooden framework was errors on radio bearings. covered with tin foil immediately below the wire A survey of the direction of the sewer, however, turns.By connecting this tin foil to the shielded showed this to be 170° from true North, while box below the circuit it was found that the " mini- it will be noted that the error curve in Fig. 2 mum " of the set was considerably improved, and has zero error for the direction 163°, this latter enabled the observation of fairly accurate bearings. being the direction of the axis of the hypothetical NOVEMBER 4, 1022 THE WIRELESS WORLD ANDRADIOREVIEW 169 mass of metalwork which would (in the manner of the hull of the ship) be required to produce a quadrantal error curve of the same general shape as the above.The approximate coin- cidence of these directions, therefore, could not but be regarded as suspicious in spite of the reputed absence of metalwork in the sewer. (b) The second was that at the point where the sewer crossed the small brook an iron plate 3ft.bins. square by tin. thick was discovered on inspecting one of the manholes at this point. It was also found that the brook was conducted under the sewer by means of an iron pipe about 40 ft. long. (c) The third was the existence of two rubbish fo O

dumps as indicated in Fig. 6.These were found 1 to be chiefly composed of metal cans and scrap for the lower three or four feet of their depth, being mixed and covered with cinders and clinker. As one of these dumps of size 115 by 85 yds. and 5 ft. deep was situated at only a Yew yards from the hut, it was not considered impossible that this comparatively large mass of metalwork might produce some errors in bearings. 8.-DESCRIPTION OF EXPERIMENTS. In consideration of the somewhat complicated 0 local conditions, it was decided to experiment in different positions in the neighbourhood with a view to locating the cause of the errors more definitely.In all,18 positions were tried and a total of 350 observations were made of the bearings 00 of various transmitting stations.A summary of these observations is given in Table 2. '7

u.0 7

(+1

0 c0

Fig. 5c. Portable single frame direction finding set. The positions referred to by numbers in the a a t line are shown in the diagram Fig. 7 which is an 1 enlargement of the central part of Fig. 6. rn 4, 1922 170 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER TABLE 3. MEAN ERROR IN VARIOUS POSITIONSOF D.F. COIL.

Within 80' of Within 300' of Along Sewer Sewer line. Sewer line. Transmitter observed. No.No.No.No.No.No.No.No.No.No.No.No.No.No.No.No. 16 17 1 2 6 10 12 13 15 18 7 5 11 14 9 8

Nauen +15+14 0 +9+7-6+7+17+1+6 -4+2+6 0 0 + 1 +9 -2 0 +1+6+2+2 Paris -3 +1-1 Chelmsford -4 +1-6 +1-5+6 -2 Poldhu -13 0 Stonehaven 11 10 3 4 5 +4+7-8-1 -3+4-1+1 0 Clifden - 9 -1 0 -4-7-2 -1-1 In positions lb. the D.F. set was raised two feetconclusively that the part played by the fence in above its situation in position la, whilst in position producing the errors is negligible. lc it was 'raised nine feet above the first position The comparative freedom from errors experienced by erecting it on the roof of the hut.It will be in positions 16 and 17 show equally well that the seen that only a very slight decrease in error isrubbish dumps do not have any appreciable produced by raising it to the latter and none at all effect, and the fact that large errors are experienced to the former position. in positions 13 and 15 is good evidence that the In position 12 the set was very close to the wiretelegraph wires are not alone responsible for the fence shown in Fig. 6 and here the opportunity phenomenon since these positions are over 200 was taken of investigating the effect of the fenceyards from the wires. on the bearings. 9.-INTERPRETATIONOF RESULTS. Accordingly a length of about 100 ft. of the fence On the whole it cannot be doubted that the nearest to the set was isolated, to effect which results are in accordance with the theory that the each wire was cut at either end of this length andmain distortion is caused by a part of the sewer a piece of string inserted in the gap.Observations though the distance from the sewer at which errors taken before and after cutting the fence are recordedcan still be detected is rather great. in the table and it will be seen that no difference In order to make this more clear, the results inbearingscouldbedetected.Thisproves have been rearranged in Table 3, being classified

TELECRP.2H FOOTRALt- GROJND PDL/c-.3 le ABOVE HUT

sou UNE OF TELEGRAPH POLES BEARING 20 WIRES BcOCK MANHOLE WI \.""' FVE-WIRE FE -idON Tb-P "-- BRIM WALL UNNEL UNDER WIRE FENCE SEWER FOR BURN GRAM HUT 280 YDS

230 YDS ,14 WIRE FENCE POWS BURN MANHOLES BRIO( 8 WALL WIRE FENCt

MANHOLE JO VW- ---'--

11 RUBBISH DUMP GRASS ID'HIGH MANHOLE -.4N

DOUBLE TRAMLINES srat c

MANHOLE LO 10 66 III .°YARDS

BROAD Fzg. 6. NOVEMBDR4, 1922 THE WIRELESS WORLD AND RADIO REVIEW 171 TELEGRAPH POLES (BEARING 20 LINES) UNE OF ---- FIVE WIRE FENCE ON TOP OF BRIM WALL II It IA II x t 4 Olt

HUT 49 r7 Ijr3 x5 18 TUNNEL UNDER SEWER loI 12' .....--__.-41-- --

15%11

x14 1314

It II 115 ALE x zooto 40 60 woe Fig. 7. 11 according to their position with regard to the sewer.construction owing to its proximity to the surface. None of the results in Table 2 which have beenReference to the special plans which had hitherto omitted from Table 3 will be found to contradictescaped the notice of the surveyor, revealed the this hypothesis, they are merely left out on accountexistence of a strip of " expanded steel " 6 ft. wide of their irrelevancy. by 300 ft. long and 8 ft. below the surface at the Table 3 shows :- hut, forming the foundation of this special section (a) That in general, the errors decrease asof the sewer. the distance from the sewer is increased, becoming 10.-CONCLUSION. negligible at about 300 ft. from its line ;position This discovery, therefore, fully the 8,however,is an exception, as considerableprediction which could be made from the experi- errorswereexperiencedhere.Itcanonlyments carried out, as to the existence of a mass of be concluded that these were due to the telegraph metal work buried entirely beneath the surface wires which are comparatively close at thisof the ground at a depth of several feet.Owing point. totheseveralotherlocalconditionsalready (b) Iturther shows that the errors at pointsdescribed, which might contribute to the errors along the sewer are a maximum in the localityto a small degree, it was not considered expedient of the hut falling off on each side of it. to continue the investigation in any further detail. (c) That a point on the top of the sewerThis investigation, however, serves to indicate apparently exists (i.e., near position 6) wherehow very difficult it is to find a site on land, par- the errors are practically negligible ;as thisticularly near large towns, which is suitable for point is passed travelling along the sewer theradio direction finding,for there may literally errors from the majority of stations change inbe " more in it than meets the eye."The experi- sign, rising to considerable values on the otherments also suggest a possible application of a side of it (positions 13 and 15). radio direction finder in another sphere for the From these facts the presence of a metalliclocationofmassesof metalwork underground, object of length of the order of several hundredssuch as water and gas mains, streaks of minerals, of feet and of comparatively small width, with itsmetal ores, etc.It is not at all impossible that length coinciding with that of the sewer, seemedwe shall soon be reading in the newspapers that undoubtedly to be indicated, and the result inRadio Expert Blank now offers his services for the (c) though perhaps unexpected, does not contradictlocation of gold or other hidden treasure, at a fee this theory.This suggests the special constructiondepending entirely on results. We may even shortly of a section rather than the whole of the sewerreceive the prospectus of a company to be floated asbeing responsiblefortheeffect.Enquirieswith a view to exploiting this application. already made had obtained from the local authori- The authors desire to acknowledge their in- ties particulars of the structure of the sewer withdebtedness to the Radio Research Board and to the the definite statement that it contained no metalDirectional Wireless Sub -Committee of the Board work.In view of the general evidence, however,for providing the facilities for the carrying out it was now thought necessary to obtain a checkof these experiments, and for granting permission as to the reliability of this information. The authorsto publish the results.They have also to acknow- therefore obtained access to the actual plans of theledge the assistance during the experiments of sewer, when it immediately became clear that theMessrs. J. E. Ritchie, M.A., B.Sc., and J. Coull, particular part of the sewer in the locality of thethe observers of the Radio Research Board at D.F. hut was, in fact, a special section with special Aberdeen. 12 THE WIRELESS WORLD AND RADIOREVIEW NOVEMBER 4, 1922 Recent Developments in RadioTelegraphy and Telephony. mR. E. H. SHAUGHNESSY, O.B.E., will introduce, by wireless, the M.I.E.E.,M.I.R.E., of the Wire- Lord Mayor of Bristol. less Section of the General PostOffice, 7.10 to 7.2o p.m. An address bythe Lord Mayor will give a lecture on " RecentDevelopments of Bristol, given at his resi- in Radio Telegraphy andTelephony " at the dence in Bristol, transmitted Regent Street Polytechnic onFriday, November over the " Wired Wireless " 3rd, at 6 p.m. circuit to Paddington, thence The chair will be taken by Mr. F.J. Brown, to Marconi House by wire, C.B. C.B.E., an AssistantSecretary of the and there broadcasted. H.M. PostOffice, and by permission of 7.25 to 7.3o p.m. RecitalatBristolby Mr. Postmaster General, and with theco-operation E. E. Aickin, of the Post Companies, of the Marconi and Broadcasting OfficeEngineeringDepart- the lecture will be followed by ademonstration ment. of wireless telephony on a scale nothitherto vocal con- attempted in this country.The magnitude of7.3o to 8.3o p.m. Instrumental and the demonstration will be seenfrom the cert broadcasted from Marconi House,thenames of the programme :- artistes being announced. 7.0 to 7.5 p.m.Sir William Noble, Chairman of the Broadcasting Committee, During the concert Major T. Worswick, speaking at Marconi House,Director of Education, will broadcast an address.

British AmateursHeard at Nice. M. Leon Deloy, president ofthe Radiothree home-made honeycomb coils, two con- has sent us thedensers and a single valve on an aerial ten Club de la Cote d'Azur, Nice, from the following report ofreception.Asallthemetres long, stretched one metre reception was done on a singlevalve withwall, between two windows of his flat in town." 40 or 8o volts onthe plate and no filament A further communication from M.. Leon rheostat or grid potentiometer, theyshow theDeloy states that " to night I heard excellent excellence, he says, of the British amateurtelephony from 2MT, and very good telegraphy from 20D, all on same single valve receiver. transmitters. " 2 KF was heard early inOctober on aAlso two stations on telephony around 440 set I had installed inSa8ne et Loire.Signals metresunreadableunder " QRM " from good and easily readable when he wasradiatingspark stations. 0.8 amperes. The receiver wasthree DL coils and two condensers, the telephonesBaldwin THE TRANS -ATLANTIC TESTS. and the aerial a single wire 85 metreslong, With reference to the trial transmissions 8 metres high. conducted in America in connection with the " I am now back at 8AB, Nice, and haveabove tests, will those who have succeeded in already heard 2 JZ when he wasradiatingreceivingthesesignalsinthis country or 1-25 ;signals good ;2 ON telegraphy QSAelsewhere in Europe please communicate their and telephony QSA ;2 OM telegraphy andresults to Mr. Philip R. Coursey, B.Sc., either telephony, signals good and 2 KF signalsQSA. direct or care of this office.Mr. Coursey is All this was heard with a "Tuska " receiveractingassecretary of the sub -committee (variometer in the plate) and anaerial of oneappointed by the Wireless Society of London wire 16o metres long, 20 metreshigh. to organise the Trans -atlantic tests onthis side. result is that ofThe only report of reception so far isreceived " But the most remarkable Details of recep- Mr. Besneux, Treasurer of ourClub, whofrom Mr. W. W. Burnham. heard 2 JZ at the same time as Idid, usingtion will be p ablished later. NOVEMBER 4, 1922 THE WIRELESS WORLD AND RADIO REVIEW 173 Notes Whale Warnings. Wireless in School. Warnings of the locality of whales are now Starbeck Council School, Leeds, is one of the transmitted from the Mosquito Bay Station, East schools where the installation of wireless apparatus Greenland. has been added to the equipment.In order to. Spanish Club Invites Correspondence. make this possible the necessary finance has been In the Club Reports columns of this issue will beobtained by profits on the school gardening. found an invitation to amateurs in this country either individually or collectively to correspondLectures at Nottingham. with the Radio Club de Espana, Madrid. A special course of fourteen experimental lectures on " Wireless, its Origin and Development," by Royal Corps of Signals Lectures. Prof. E. H. Barton, F.R.S., and Mr. A. H. Franks, Lieut. D. J. Davies has arranged to give a seriesB.Sc., is to be delivered at the University College, of public lectures at the Park Street Drill Hall,Nottingham, commencing on Friday, November Cardiff, dealing with the theory and practice of3rd, at 7 p.m. wireless apparatus.Lieut. Davies is in charge of the Wireless Section of the Royal Corps of SignalsAeroplane Control. at Park Street. Experiments are being carried out in France German Valve Case. as the result of which itis hoped to establish Four arrests have been made in Germany on a means of controlling aeroplanes without either pilots charges of obtaining transmission valves belongingor passengers on board.At first a pilot will ascend to the Telefunken Company.The valves, which with a machine and only intervene shouldthe were patented, were sold abroad, but we understandcontrol from the ground fail.Afterwards, if ex- they have been recovered. periments are successful, an attempt will be made to control more than one machine froma master L.C.C. Schools to Teach Wireless. aeroplane occupied by a pilot. An important step in the progress of radio education has been taken by the London County Coucil.Mauritius Naval Wireless Station Closed. Approval has been given for the inclusion in the As the naval wireless Station at Mauritiushas curriculum of 25 schools the tuition of this branch been closed, its service with ships is beingunder- of science.So far 13 schools have actually beentaken for the present by the tug Labourdonnais. given permission.We understand that the appa-The callletters are VRK.Its locationis Port ratus is to be constructed by the boys in the course Louis Harbour.The hours of service are 0400- of their training.The London County Council 0800, and 1200-1400 G.M.T. schools are not the first to he associated with wireless.Several provincial schools have erectedNew Regular Transmission. sets, as we have previously mentioned in this journal, The French high -power station at Basse-Lande but the move on the part of the London Countynear Nantes, call letters UA, has inaugurateda Council will probably arouse interest in educational broadcast private message programmeon C.W. to circles throughout the country. ships at sea which are out of therange of the ordinary Sheffield Society and Press Experiments. coaststationsinFrance.The times of trans- Mr. F. Lloyd's presidental address to the Sheffield missions are 2100 to 2200 G.M.T., andwhen and District Wireless Society was used as a means necessary 1600 to 1700 G.M.T., on a wavelength of testing the ability of the Yorkshire Telegraph of 2800m. (spark).The range of the station is and Star to make use of wireless as a means of 1,500 nautical miles. rapid publicationinpress.At the newspaperMr. E. H. Shaughnessy on Leafield. office a reporter listened in, while at the Mappin At the Borough Technical School, Wellington, Hall of the Applied Science Department of theMr. E. H. Shaughnessy, O.B.E., M.I.E.E.,delivered University of Sheffield, Mr. Lloyd delivered hisa lecture on " The Imperial Wireless Station at address.The speech occupied twenty-five minutes. Leafield."The meeting was held under the auspices Within an hour and three-quarters the paperof the North Wales Centre of the Institutionof containing the speech was on sale a mile away.Post Office Electrical Engineers.Members of the This time could have been reduced had not a delayShropshire Philosophical Society and the Shrewsbury occurred in waiting for other matter which hadand District Radio Society were invited toattend. to be published at the same time.The experiment Permission was given by the P.M.G. for the Leafield was considered highlysuccessful.It must beStation to send a special message to the meeting borne in mind that the reporter's shorthand report and this was received on the apparatus ofMr. had to be transcribed before being handed toC. L. Naylor, a member of the local RadioSociety. the compositor to be set in type. The message was as follows :-" Leafield Wireless For the coming year the following officers haveStation.The first station of the Imperial wireless been elected for the Sheffield and District Wirelesschain sends greetings to the inhabitants ofShrews- Society :-President, Mr. F. Lloyd ; Hon. Secretary, bury.Oxford Wireless Station is anxiously await- Mr.L. H. Crowther :Assist. Hon. Secretary,ing the arrival of its bigger brothers in the Imperial Mr. L. A. K. Halcombe ;Hon. Treasurer, Mr.chain, but in the meantime is ready and willing C. H. Hainsworth ;Chairman ofCommittees,to transmit messages to and receivemessages from Messrs. W. Forbes -Boyd and H. Lloyd.The Society has 112 members, and those sons and daughters of Shrewsbury dwelling theaccountsshow ain the less distant portions of the Empire."The credit balance. message was in Morse code. NOVEMBER 4, 1922 174 THE WIRELESS WORLD AND RADIO REVIEW Calendarof Current Events Friday, November 3rd. THAMES VALLEY RADIO AND PHYSICAL ASSOCIATION. ELECTRICAL POWER ENGINEERS' ASSOCIATION. Presidential address and lecture by the President. At7p.m.At theInstitutionof Electrical Engineers.Lecture on " The Application of PLYMOUTH WIRELESS AND SCIENTIFIC SOCIETY. Radio Methods to the Distant Control of Electrical At Plymouth Chambers. Lecture on " High Apparatus," by Mr. P. R. Coursey, B.Sc. (Mem- Frequency Amplification," by Mr. L. J. Voss. bers of Wireless Societies invited.) LOWESTOFT AND DISTRICT WIRELESS SOCIETY. FINCHLEY AND DISTRICT WIRELESS SOCIETY. Lecture on " Simple Telephony Transmitters," Reception of speech and concert from Bristol by Mr. H. C. Trent. in co-operation with the Broadcasting Companies. EDINBURGH AND DISTRICT RADIO SOCIETY. via Marconi House. At 8 p.m.Lecture on " Wireless Communica- RADIO SOCIETY OF HIGHGATE. tion," by Col. Crawley. At 7.45 p.m.At the 1919 Club, South Grove, YORK WIRELESS SOCIETY. Highgate, N.6.Lecture on " Construction of At 7.30 p.m.At Grand Café, Clarence Street. H.F. Amplifiers," by Mr. G. W. Sutton, B.Sc. Lecture on " Wireless Telegraphy, its History BRADFORD WIRELESS SOCIETY. and Development," by Mr. V. 0. Newton. At 5, Rendallwell Street, Bradford.Debate onWednesday, November 8th. " The Prevention of Self -Oscillation." INSTITUTION OF ELECTRICAL ENGINEERS BELVEDERE AND DISTRICT RADIO AND SCIENTIFIC (WIRELESS SECTION). SOCIETY. At 6 p.m.At Victoria Embankment.Lecture Lecture on " The Thermionic Valve," by Mr. on " The Effect of Local Conditions onRadio S. G. Meadows. Direction -Finding Installations," by Mr. R. L. HORNSEY AND DISTRICT WIRELESS SOCIETY. Smith -Rose, M.Sc., and Mr. R. H. Barfield, B.Sc. Lecture by Mr. Davy. REDHILL AND DISTRICT Y.M.C.A. WIRELESS LEEDS AND DISTRICT AMATEUR WIRELESS SOCIETY. SOCIETY. At Grammar School.Lecture on" Diagram At Station Road, Redhill. Lecture on " Tuning" Interpretation," by Mr. D. E. Pettigrew. Thursday, November 9th. REGENT STREET POLYTECHNIC. HOUNSLOW AND DISTRICT WIRELESS SOCIETY. At 6 p.m. Lecture on Recent Developments in At Council House, Treaty Road, Hounslow. Radio Telegraphy and Telephony by Mr. G. H. Lecture on " Wireless for the Beginner," by Shaughessy, O.B.E. (see also p. 172.) Mr. S. H. Nayler. Saturday, November 4th. HACKNEY AND DISTRICT RADIO SOCIETY. DEWSBURY AND DISTRICT WIRELESS SOCIETY. Special General Meeting to discuss reorganisation At Moot Hall.Also on 6th and 7th Exhibition of membership, subscriptions, etc. and Demonstration. LUTON WIRELESS SOCIETY. GLASGOW AND DISTRICT RADIO CLUB. At 8 p.m. At Hitchin Road Boys' School. From 12 to 9 o'clock. At the McLellan Galleries Practical work and experiments. DERBY WIRELESS CLUB. Hall, Sauchiehall Street. Exhibition and Demon- Lecture stration. At 7.30 p.m.At the Court, Alvaston. on " Protection of OverheadLinesfrom Sunday, November 5th. Atmospherics," by Mr. S. J. R. Allwood. DAILY MAIL CONCERT from the Hague. 3 to 5 p.m., DEWSBURY AND DISTRICT WIRELESS SOCIETY. on 1,085 metres. Lecture on " Inductance," by Mr. Skinner. SOUTHAMPTON WIRELESS TELEPHONY ASSOCIATION. Friday, November 10th.' At 7 p.m. At King's Hall, London Road, S.E.1. HECKMONDWIKE AND DISTRICT WIRELESS SOCIETY. Wireless Concert in aid of King's College Hospital. At 7.30 p.m.Exhibition and Demonstration. Monday, November 6th. Opening by Mr. C. W. Leather, Checkheaton. NORTH LONDON WIRELESS ASSOCIATION. RADIO SOCIETY OF HIGHGATE. Lecture on" The ElementaryPrinciplesof At 7.45 p.m.At the 1919 Club, South Grove. Radio Telegraphy and Telephony, II," by Mr. Informal meeting. F. S. Angel. BELVEDERE AND DISTRICT RADIO AND SCIENTIFIC ILICLEY AND DISTRICT WIRELESS SOCIETY. SOCIETY. At 7.30 p.m.At Regent Café.Demonstration Lecture on " Properties of Crystals," by Mr. and lecture on " A Speculation of the Supposed H. H. Smith. Relation Between Electricity and Matter," by LEEDS AND DISTRICT AMATEUR WIRELESS SOCIETY. Dr. J. B. Whitfield. Lecture on " Some Gadgets of a Faddist," by IPSWICH AND DISTRICT WIRELESS SOCIETY. Mr. G. P. Kendall, B.Sc. At 8 p.m. At 55, Fonnereau Road. Lecture on MANCHESTER WIRELESS SOCIETY. " High Frequency Currents," by Mr. E. Mould. Annual General Meeting. FINCHLEY AND DISTRICT WIRELESS SOCIETY. Saturday, November 11th. Lectureon" Manufacture andConstruction HECKMONDWIKE AND DISTRICT WIRELESS SOCIETY. of Valves. At 3p.m.Exhibition and Demonstration. HORNSEY AND DISTRICT WIRELESS SOCIETY. Opening byLieut.H. W. Burbury,R.N., General Business and Discussion. Crigglestone. Tuesday, November 7th. LIVERPOOL WIRELESS SOCIETY. Transmissions of Telephony by.2 MT; Writtle, FirstmeetingofWinterSessionatRoyal as above. Institution.Address by Prof. E. W. Marchant. 1:7\113EI: 4. 192:2 THE WIRELESS WOE I I AND RADIO REVIEW xiii The Tingey Self -Contained Cabinet Set This is the last word in Self -Contained Sets.

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F GRAMS :" Ebonitical, Han, London." WHOLESALE EL PHONE :Ealing 1689. ONLY. NOVEMBER 4. 1922 THE WIRELESS WORLD AND RADIO REVIEW 175 Books Received The Wireless Society of London TRACKED BY WIRELESS.By William Le Queux. At the OrdinaryGeneralMeeting, held on (London : Stanley Paul & Co.Cr. 8vo.7s. 6d. net. Wednesday, October 25th, the followingwere and Fcap 8vo.2s. net.) elected to membership of the Wireless Society of London :- RADIO FOR EVERYBODY. By A. C. Lescarboura, MEMBERS :-Charles James Pratt, Eric D'Eresby Editor ofScientificAmerican. (London : Moss, Victor Delebecque, Percy Thomas Beard. Methuen & Co., Ltd.170 illustrations.) Major Edward Williams, Charles Menten Benjamin, HowTO RETAIL RADIO. By theEditorof William RossCraik,Ivan ScottSpain,Niels Electrical Merchandising.(McGraw-Hill Pub- NielsenLadefoged,Harry H.Bond,Neville lishing Co., Ltd. Pp. 226, illustrated.6" x 4".Ryland Davis, Egerton G. Pulford, Junr., Colonel Price 10s. net.) GeorgeFrederickHandelMcDonald, ELEMENTS OF RADIO TELEPHONY. By WilliamMajor Phillip Albert Smith,Sir George Stuart C. Ballard.(London : McGraw-Hill Publishing Forbes, John H. White, Owen B. Thomas, Geoffrey Co., Ltd.Pp. 132, illustrated.6" x 4".) E.Duveen,WilliamSamuelJames,Douglas Ashton Wade, John Eaton Monins, B.A., Gerald WORKING DIAGRAMS OF VALVE AMPLIFYING Marcuse, Captain K. E. Hartridge, Henry Charles RECEIVER CIRCUITS. Arrangedby H. W. Parker,William ErnestWallis,CyrilHerbert Sullivan.(London :Winchester House, Old Mocatta, Henry Arthur French, Captain Herbert Broad Street,E.C.2.4th Edition.36 pp. Stanley Prince, M.B.E.,S.Goodchild, Reginald 7" x 4k".Illustrated.Price ls.) CharlesHorrocks, Edward John Bray,Lewis WORKING DIAGRAMS OF VALVE RECEIVING CIRCUITS. Henry Taylor,George Howard Nash,C.B.E., (London :Radio Instruments, Ltd., 12, Hyde Alexander Thomas Wallace, William Smith, Henry Street,OxfordStreet,W.1. 21 diagrams. James Cook,DudleySanders,GeorgeWalter 71" x 41".Price Is.) Bowen, James F. Doyle, Edgar Wilfred Lindley, FrankStanleyWates,CharlesDibdin,John A New Testing Instrument. DelmoreTaylor,WalterWakefieldBurrowes. Messrs. Evershed and Vignoles have recently ASSOCIATE MEMBERS :-Eric Cuddon,Isadore placed upon the market a new insulation tester,Bernard Davidson, Charles Creswick Atkinson. called the " Meg."This instrument is of excellent LIST OF SOCIETIES AND CLUBS ACCEPTED FOR design and construction, and weighs 7 lbs., about AFFILIATION :-Newport and District Radio Asso- half the weight of the well-known " Megger," whichciation,Sutton andDistrictWirelessSociety, Streatham Radio Society,The HamiltonandDistrictRadio Society, Walthamstow Amateur RadioSociety, TheBedford PhysicalandRadio Society, The Finchley and District INSULATION Wireless Society,Hackney and District Radio Society, Chelten- ham Wireless Association, London TESTER County Council Wireless Society, MO MI The Fulham and Putney Radio 0.10 LIM. Trmlow, Society,The Belvedereand ....Gir$, TVIT '40ortC, District RadioandScientific Society, Wanstead Wireless Society,Coventry and District Wireless Association, The Aber- MCWINAg,t PV, ...TV., Rt.. deen and District Wireless Wk.. MUM. pe. Society,FulhamandChelsea EVERSIBMINNOLES Amateur Radio and Social Society.

A Wireless Doll. " Wirelessparties " were The "L G.," an Insulation Tester. catered for at special prices at theStratfordEmpire Theatre has made the name of Evershed and Vignoles duringtheweek endingOctober28th.The famous.Modern production methods and highly programme included an act by Miss Nella Allen, efficient testing and inspection, together enablewho introduced a wireless doll, by means of which the instrument to be moderately priced and backedthe singer was assisted by herself. the close of by a guarantee. A Portable Receiving Set. the performance patrons of the theatig were invited On page 759 under the above title the article byto propose tests should they be sceptical as to the Mr. A. Lovering states, " I can get down to 4,000doll being operated by any other means than those metres."This should have read 400 metres. advertised. 176 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 4, 1922 Wireless Club Reports NOTE.-Under this heading the Editor will be pleased to give publication to reports of the meetings of Wireleas Clubs and Societies.Such reports should be submitted without covering letter in the exact form in which they are to appear and as concise as possible, the Editor reserving the right to edit and curtail the reports if necessary. The Editor will be pleased to consider for publication papers read before Societies. An Asterisk denotes affiliation with the Wireless Society of London.

Finchley and District Wireless Society.* Mr. F. S. Angel was then called upon to deliver the Hon. Secretary, Mr. A. Field, 28, Holmwoodfirst paper of his series," The Elementary Princi- Gardens, Finchley, N.3. ples of Radio Telephony." On October 9th the above Society elected its Thelecturer commenced bydiscussingthe permanent officers, who will hold office for onenature of electricity as a form of energy.He then year.Chairman, Mr. Trussler ;Secretary, Mr.performed some experiments dealing with static Field ;Treasurer, Mr. Nicholls ;and a Committeeelectricity.After showing that differentkinds of six, Mr. Bishop, Mr. Macdonald Brown, Mr.of charges were produced by friction between various Cannon, Mr. Wilck, Mr. Chamberlain, Mr. Cooper.materials, he went on to talk about static induction. Arrangements forthegrandsocialevening From this point he led up to the action of a condenser on October 30th included permission from theand showed an arrangement to illustrate the differ- P.M.G. toreceivemusical transmissions fromence there is in the dielectric constant of various 20M and 20N. Application for affiliation to the materials by means of weights hung at the centres Wireless Society of London was reported to haveof horizontal cords and rubber strips.By means been made. of an electroscope with a plate capable of being A further meeting was held on October 16th, moved nearer to the leaf system, Mr. Angel demon- when the good news that the affiliation was com- strated that the capacity of a condenser increases pleted was made public.Mr. Trusaler continuedas the thickness of the dielectric is diminished. his lecture on the elementary theory of wireless, This being the end of the first paper a discussion after which the Marconi Scientific Co.'s unit system then took place and Mr. Angel was able to give wireless set was demonstrated, musical transmissionssatisfaction to a number of questioners. from 2KT and 20M being made audible on a The meeting closed with a hearty vote of thanks Brown's loud speaker, kindly lent by Mr. Cannon to Mr. Angel for the interesting evening. in conjunction with a Brown's relay belonging Full particulars of the association may be had on to Mr. Chamberlain.During the buzzer class, application to the Hon. Secretary. which was held from 9.30 till 10, the CommitteeWest London Wireless and Experimental met and made the final arrangements for the social Association.* evening on October 30th.Mr. Heppel was given Club -room : Stamford Brook Lodge, Ravens - complete charge of the catering part, and arrange- court Park, W.6. ments for a pianist and a violinist to come and Hon. Secretary, Horace W. Cotton, 19, Bushey supply the music for dancing have been completed.Road, Harlington, Middlesex. Mr. Wick has kindly consented to give a lecture On October 13th, Mr. A. 0. Gibbon, of the on November 6th ;the subject of which will beEngineer -in -Chief's Department, G.P.O., gave a announced later. popular lecture on the present-day position of Arrangements are hoped to be completed for thewireless telegraphy and telephony before a large reception of a wireless speech and concert from gatheringof members and theirfriends.The Bristol, which is to be sent by telephone fromlecture was undoubtedly one of very great interest Bristol to Marconi House, and to be broadcastedto all present.The speaker remarked that wireless from there ; this is to take place at 1 o'clock onwas one of the greatest benefits to mankind,- and November 3rd.Mr.Turner,of Regent Streetreferred to the wonders achieved since the intro- Polytechnic, is in charge of the affair, and he isduction of the thermionic valve, the Aladdin's lamp to give a descriptive lecture of his apparatus to of to -day ;also of the vast research work being the Society before the reception. carried out in connection with the microphone. The Hon. Secretary invites inquiries from allFurther, the presentpositionofbroadcasting interested persons in the neighbourhood. was fully explained, both in the interests of the North London Wireless Association.* bona fide experimenter and the simple " broad- Hon Secretary, Mr. V. J. Hinkley, Northerncaster," or those persons only desiring reception Polytechnic Institute, Holloway Road, N.7. for entertainment only. The 102nd meeting of the association was held In connection with the lecture, Messrs. Burndept, on October 16th, at 8 p.m. at the above Institute. Ltd., exhibited one of the latest pieces of apparatus Mr. Norman Wilson was in the chair. manufactured by themselves, viz., their L.F. II The Chairman pointed out the objects of theReceiver, which was demonstrated by their repre- Association in assisting members over any technical sentative, Mr. F. 0. Read, M.I.Radio E., and all difficulties they may be up against, and that theythose present were delightfully entertained with had only to ask any question relating to wirelessspeech, music and signals from many amateur, to bring fortfr willing help in the matter. Attentionship and land stations. was specially drawn to this as a new member had Mr. Read kindly replied very fully to all questions nearly left the previous meeting without somerelating to the apparatus, which is a three -valve necessary information in connection with a setset, consisting of one detector and two note magni- he was building. fiers, each valve being controlled by a rheostat, NOVEMBER 4, 1922 THE WIRELESS WORLD AND RA1)10 REVIEW XV

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The chair was occupied by the President (Mr. The Secretary will be delighted to hear from anyG. H. Strong), and six new members were elected. gentlemendesirousofinformationrespecting All members who have any pieces of apparatus the objects, etc., of the Association. to dispose of are asked to send in particulars Liverpool Wireless Society.* to the Hon. Secretary, as it is proposed to hold Secretary, Mr. C. L. Lyons, 76, Old Hall Street, shortly asaleof members' surplus apparatus. Liverpool (Telephone, 4641 Central). New members are reminded that there is a small A meeting of the above Society was held ,atlibrary of technical works in connection with the The Royal Institution, Colquitt Street, Liverpool, Society.For the present the library is kept at on October 12th, Mr. J. Wainwright in the chair. the offices of Messrs. G. H. Strong & Son, Prudential There was a record attendance. Buildings, Hull.It is free to members of the Society This was the first meeting of the winter session,and it is hoped that full use will be made of this which promised to be one of the greatest interest. facility. After confirming the minutes ofthe previous Radio Experimental Association.* meeting, the Chairman called upon Professor E. W. (Nottingham and District.) Marchant, D.Sc., to deliver an address. Hon. Secretary, Mr. F. E. Bailey, 157, Trent The Professor addressed the meeting at some Boulevard, West Bridgford, Notts. length, dealing with the subject, " Wireless Broad: The first meeting of the new session was held casting," in a most able and pleasing manner. in the headquarters of the Association, The People's Briefly tracing the early history of wireless tele-Hall, Heathcote Street, Nottingham, on October graphy point by point, right up to the latest 12th, when a considerable number of prospective developments of the science, he entered upon the members turned up. main features of his address, which werethe Mr. Gosling lectured on the construction and advantages and disadvantages of wireless broad-method of using the wavemeter, and later gave casting as we might expect it to develop into in a description of his home-made five -valve amplifier the course of a very shortspace of time.The and tuner.The amplifier was so designed as to professor concludedhisremarksamidst greatpermit any combination of valves to be used from applause, and Mr. Hengler proposed a vote of 1 to 5.The tuner possessed several novel features, thanks. proving beyond doubt that Mr. Gosling is fully The remainder of the evening was devoted tojustified in calling himself a radio experimenter. a practical demonstration by courtesy of Messrs.Prior to of the meeting, Mr. Allan, the B. N.B.Wireless,Ltd.,of Renshaw Street, Treasurer, read out the financial statement for the Liverpool, and reasonably satisfactory results were past year.The same was heartily approved by obtained of telephony, musical items, etc., although those present. only one stage of radio -frequency amplification Gentlemen wishing to become members will be was used and the apparatus was connected to an welcomed at the meetings. indooraerial.Theinstrumentsdemonstrated were the Marconi Scientific Instrument Company's Plymouth Wireless and Scientific Society.* Hon. Secretary, Mr. G. H. Lock, 9, Ryder Road, units, and consisted of 1 H.F. stage, detector panel, and three L.F. units, the sounds being made Stoke,Devonport. audible to all present through a " Magnavox " At a meeting of the above on Tuesday, October loud speaker. 17th, at Plymouth Chambers, experiments were A vote of thanks was passed in favour of Messrs. carried out using the electric lighting mains as B. N. B. Wireless Ltd., and the instruments werean aerial.The results obtained were only fair, left for close inspection by all present. and it was agreed thatanoutdoor aerial was The next meeting was held at the same addressfar superior to this method. on October 26th. Buzzer practice will in future be carried out on Thursday evenings from7.30 p.m., one of the Wireless Society of Hull and District.* members, Mr. B. Clark,an ex -operator, having Secretary'sAddress : 16,PortobelloStreet, Hull. kindly offered to carry out the instructional work. There was a large attendance at the monthlyI,t is hoped also to have a course of elementary lecture on October9th, when Mr. Hy. Stronglectures in the near future. (acting Vice -President) gave an instructive paper Particulars of the Society may be obtained from entitled" Calculation of Inductance."After a the Hon. Secretary. brief description of what inductance really is and Brighton Radio Society.* its varying effects, the lecturer proceeded to give Hon. Secretary, Mr. D.F. Underwood,68, in detail, and at some length, the various formulae Southdown Avenue, Brighton. for calculating this property when constructing A meeting was held at Mr. Volk's workshop, different types and classes of coils such as the Russell Crescent, Brighton, on October 5th.Two solenoid type, pile -wound, basket, slab and others. members were elected. He had gone to considerable trouble in carefully On September 26th a meeting of the Amalgama- preparing a large number of elaborate tables andtion Joint Committee was held, representatives calculations which he exhibited, and if his paper of the Sussex Wireless Research Society and of was perhaps a little too mathematical for some of the Brighton Radio Society being present.As a those present, yet it cannot be denied but thatresult of thismeeting certain recommendations 178 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 4, 1922 were put to the Brighton Society, and it wasFulham and Chelsea Amateur Radio and decided (1) To amend the Society's title to read, Social Society. " The Brighton and Hove Radio Society." (2) Hon. Secretary, Mr.R. Wood, 48, Hamble To elect a supreme council of four members ;Street, Fulham, S.W.6. to elect an organisation committee of six members ; OnOctober 17th three new members were to elect atechnical committee of six members. proposed and seconded, the meeting accepting (3) That there be two classes of membership (a) full their enrolment. Mr.Hubbard .offered to give membership, fees 10s. entrance, 10s. subscription ; a series of twelve lectures, one every alternate (b)Associatemembership,fees5s.entrance, week ;this was accepted.Another member, Mr. 5s.subscription.That all present members beCox, also gave a short lecture dealing simply with full members.That any present member may be-transmission and reception, explaining each part come an associate member if he so desires.That by means of apparatus.He was heartily applauded before any associate member can become a full for the simple way he had expressed himself. member he must satisfy the council or a person The Secretary was then asked to give a short appointed by the council that he has a sufficientlecture on reaction, its use and abuse, and the knowledge of valves and valve apparatus, and more P.M.G.'s objections to the use of it.This was especially of the circuits and apparatus used in thealso simply dealt with for the benefit of junior elimination of re -radiation and interference.(4) members, and again appreciation was shown in That the officers . of the Society be-Presidentthe usual way. (Chairman of the Council ex officio), Hon. Secretary, A library has been started, and a librarian is Assist.Hon.Secretary,Hon. Treasurer,Hon. shortly to be appointed. Librarian.(5) That the funds and effects of the Owing to the increased number of members two Societies be pooled and the funds placedit is proposed to adopt a second room at the college in a banking account.(6) That full membersand divide the meetings. and associate members have the same voting The total membership is now 86. power, but that associate members are not eligible Guildford and District Wireless Society.* for election to the technical committee. The weekly meetings of this Society recommenced It is thus intended to put the new Society on aon October 16th with a demonstration of the superior level, and to do its utmost in the interests" Armstrong Circuit " by Mr. E. P. Brown (a of the science, at the same time regarding the member).Mr. Brown explained at length the decision of the P.M.G. as a very wise attitude. advantages and disadvantages he had experienced Newport and District Radio Association.*with the circuit during his experiments and use of Hon. Secretary, Mr. Edward R. Brown, 92,it, after which Mr. F. A. Love (2HX) very kindly Corporation Road, Newport. obliged with a transmission of speech and music. On October 12th, before a large gathering ofThe whole of the reception was received on a members, Mr. W. D. Lewis Evans, M.A., Aber-frame aerial.The demonstration was thoroughly tillery, gave a very fine address upon " The Con-enjoyed by all present. struction of an Amateur Three -Valve Station." On October 21st a party from the Society visited Added interest was given to the lecture by Mr. the Aldershot Military Wireless Station, and spent Lewis Evans placing on view a three -valve instru-an extremely interesting and instructive time, the ment which he himself had built up-a highlymethod of automatic transmission and reception instructionaladdresspunctuated by anecdotal being the chief point of interest.The visit was the references to the humorous side of the " mysteries "last of several which have been made -to neighbour- ofwireless being thoroughly enjoyed and ap-ing stations, both commercial and amateur, all preciated. of which proved valuable from an educational point, Mr. J. H. M. Wakefield occupied the chair, to those who attended. being supported by the Hon. Secretary, Mr. Edward The Hon. Secretary, Mr. Rowland T. Bailey, R. Brown. 46, High Street,Guildford,will be pleased to A hearty vote of thanks, proposed by Mr. H. W. answer all enquiries regarding membership. Winslow, and supported by Mr. A. Treverton Jones, Radio Club de Espana, Madrid. was accorded the speaker, who, in replying, said Secretary, Sen. F. Castana, Fernandez de los that the Association provided a long -felt want to Rios 25. the wireless amateurs of Monmouth. The establishment of this club took place some Wanstead Wireless Society. time ago and immediately met with satisfactory Hon. Secretary, Mr. A. B. Firman, 18, Clavering results. In twenty days nearly 250 members were Road, Wanstead Park, E.12. enrolled.As readers of this journal the members A very successful meeting of the Society was held through their secretary send greetings to all English on October 12th, when Mr. Nickless, a vice-president amateurs.Reciprocal correspondence isinvited. oftheSociety,demonstrated the comparativeAmateurs wishing to communicate with this club values of the tuned anode circuit and the leakyshould write direct to the Secretary, whose address grid rectifier in the reception of wireless telephony. is given above. The Marconiconcert was received very well Scarboro' and District Wireless Club. on Mr. Nickless's apparatus, also the test records By arrangement with Messrs.Fattorini and of Major Parker transmitted to the Society afterPreese, Bradford, Mr. R. J. Leeves (representing the conclusion of the concert, both of which were Mr. W. R. H. Tingey, London) gave telephony much appreciated by the members present. demonstrations through loud speaking instruments The Society meets every Thursday evening atto the metnbers on October 14th and 15th. St. Gabriel's Church Hall, Aldersbrook Road, E.12, An interesting winter session is being arranged at 8 p.m. by the Committee. NOVEMBER 4, 1922 THE WIRELESS WORLD AND RADIO REVIEW Evil MAGNAVOX THE WORLD'S FInCES'T

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RADIO INSTRUMENTS LIMITED Managing I iirecior :J. Joseph, late Manager to Mr. H. AC. Sullivan. Chief Designer : AA A. Aiiiiffiion, M.I.R.E., late Admiralty Technical Research Officer. ONLY ADDRESS. Works, Offices, Showrooms : 12a, Hyde Street, New Oxford Street, W.C.1 Telephone : Regent 1908. 'Grams :66Instradio, London." (E.P.S.)15 NOVEMBER 4, 1922 THE WIRELESS WORLD ANDRADIOREVIEW 179 Portsmouth and District Amateur Wireless Hyde Amateur Radio Society. Society. Hon. Secretary, Mr. R. G. H. Cole, 34, Bradford Hon.Secretary,Mr.AlfredStainthorpe,5, Road, Southsea. Cheapside, Hyde, near Manchester. The weekly meeting of this Society was attended The above Society holds its meetings in the on October 11th by a good number of members.Flowery FieldHotel. Favourable progressis After the usual buzzer class, a talk was given bybeing made and enjoyableeveningsspentin Mr. R. G. H. Cole, the Secretary, on accumulator " listening -in " to the various signals and telephony charging on the Noden valve system. from Writtle on Tuesdays.The opening of the Following Manchester broadcasting station is eagerly waited discussion, Mr. Cole gave a further interesting for. talk on his transmitting apparatus, and alsoupon Itis hoped to announce an open evening the various receiving sets he had experimentedvery shortly. with at various times.A hearty vote of thanks Information regarding the Societycan be ob- was given Mr. Cole. tained on application to the Hon. Secretary. The Society was very pleased to receive Mr. Simpson, of Radiophones, Ltd., at their meeting,Barnsley andDistrictAmateurWireless and this gentleman gave a very interesting talk Association. uponbroadcastingplans.Mr.Simpsonvery kindly offered to demonstrate his three -valve set Hon. Secretary, Mr. G. W. Wigglesworth. to the Club, and his offer was gladly accepted. At the official opening night of the above Asso- The Society are still anxious to increase their ciation,held on October11th,thePresident, membership, and all amateurs who would care toMajor E. A. Barker. M.C., delivered his inaugural join the Society will be certain of a hearty welcome. address at the new headquarters, Y.M.C.A. Build- Prospective members should address communica- ings. tions to the Hon. Secretary. The address, which included a brief historyof the Association from the time of its establishment WakefieldandDistrictWirelessSociety.in 1913, was followed by a lecture divided intotwo Hon. Secretary, Mr. Ed. Swale,1I, Thornesparts-the first part on " Heterodyning," andthe Road, Thornes, Wakefield. second part on " Directional Wireless."In his A meeting was held on October 6thin theremarks upon Heterodyning, i.e., of beat reception Y.M.C.A., when Mr. R. Leedal read a paperon without an oscillating aerial, the Presidentem- " Accumulators."Many useful hints on the usephasised the necessity for eliminating interference and care of accumulators were given by Mr. Leedal. with other people's reception, and pointedout On October 13th, another meeting was held in thethe great assistance which could be rendered bythe association, by instructingits members in the Y.M.C.A., when Mr. Bateman gave a very interest-theor4y of wireless, so that they may he real inglecture on his own receiving station. Mr. bone had on show a good deal of his apparatusfide experimenters, and not merely " dabblers." and very ably described it, drawing diagrams onTo this end the President stated hisintention the blackboard and showing how one, twoor threeof presenting to the Association a " Heterodyne" valves could be used at will. waverneter. The Society hope to move into new quarters in The President's lecture on DirectionalWireless the Technical and Art School in a week or two. was based upon his extensive experience during the war.This was clearly elucidated bymeans of a large map, and appliances for tracing bothland Tottenham Wireless Society. and air transmitting stations.A series of lantern Hon. Secretary, Mr. R. A. Barker, 22 Broad- slides greatly added to the illustrative partof the water Road, Bruce Grove, N.17. lecture.At the conclusion, a hearty vote of thanks The third meeting was held on October 5th, was passed to Major Barker. precededbyhalf-hour'sbuzzerpractice.The A programme of the future work of the Association Chairman gave a lecture on " Retroactive Ampli-is being prepared, the chief items being fication," which was of great interest. a series of Business lectures on elementary Wireless Theory bythe was then discussed and it was proposed by theSecretary, Mr. G. W. Wigglesworth. Chairman that the future place of meeting should be the Bruce Grove Schools, Sperling Road, and that the evening should be changed to the Wednes- GuildfordandDistrictWirelessSociety. day of every week.This proposition was seconded Hon. Secretary. Mr. Rowland T. Bailey,46, by Mr. Baker and carried unanimously. High Street, Guildford. It was proposed that a General Committee On October 7th the above Society arranged should be formed, and in addition to the presentfor a party of Boy Scouts to " listen in "to the four members, namely, the Chairman, Secretary,Prince of Wales's speech. Treasurer and Mr. Bower, a further three members The speech was heard with wonderful clearness, and the partywere keenly should be elected.These were decided by vote, interested.The weekly meetings of this Society and Mr. Winter, Mr. Hall, and Mr. Glyde wererecommenced on October 16th with a demonstra- appointed. tion of the Armstrong Circuit, by Mr. E. P. Brown. It was also decided that the Society should haveWith the rapidly increasing numbers of wireless a library, and Mr. F. Allard was elected as librarian. enthusiasts it is hoped the membership willswell An interesting programme has been formed forproportionately.The the next four meetings, and intending members invitationisagainex- tended to all who are interested to visit therooms should join immediately. at 46, High Street, Guildford, on any Monday Particulars of membership on application to theat 7 p.m., or communicate with the Hong Secretary Hon. Secretary. at the same address. NOVEMBER 4, 1922 180 THE WIRELESS WORLD AND RADIO REVIEW Portsmouth and District Amateur Wireless Votes of thanks to the lecturer were given for Society. his very interesting lecture, to which he suitably Hon. Secretary, Mr. R. G. H. Cole, 34, Bradford replied. Road, Southsea. Bromley Radio and Experimental Society. The usual monthly business meeting ofthe Hon.Secretary,Mr.J.Fergusson-Croome, Society was held at the John Pile Rooms on 26, Wendover Road, Bromley, Kent. October 18th.There was a good attendance of Another successful meeting of the above Society members, and further new members were elected. was held at the White Hart Hotel on October, 17th Various other matters were dealt with, and it when some 30 members attended. was suggested that the Society should hold a social The Marconi Concert from Writtle (2 MT) was evening at an early date, a committeebeing remarkably well received onafour -valve set elected to deal with this matter. constructed by Mr. Allen, which was amplified After the meeting an address was given by afurther by aBrown " Microphone Amplifier and member,Mr.Harrold,on" Detectors."Mr. rendered audible toall present by aBrown " Harrold dealt with the earliest form of detectors loud speaker. used, and various diagrams were passed among TheSecretaryannouncedthattheweekly the members to illustrate these detectors.Un- meetings of the Society would in the future be held fortunately there was no time for Mr. Harrold toat the Ex -Service Men's Club, where the usual complete his lecture with regard to valve detectors,lectures and demonstrations would be preceded but it is hoped the conclusion will be deliveredby a Morse buzzer class conducted by Mr. Allen. subsequently. A very hearty voteofthanks Mr. Allen was then called upon to give a brief was given Mr. Harrold. description of his set, which proved both interesting Southampton and District Wireless Society.and instructive. Hon. Secretary, Mr. T. H. Cutler, 24, Floating Some further music was received from Blackheath (2 FQ). Bridge Road, Southampton. As a result of the meeting several new members A meeting of the above Society held on October were enrolled, bringing the total membership to 4thresulted in a pleasant evening being spent. Arrangements were made for a visit from the nearly 50. Section," The iapid growth of the Society is in no small SignallingSection,R.E." Wireless way due to the manager of the White Hart Hotel, Capt. Grist, M.C., and various other officers attend- who has so generously given accommodation to the ing.This is the opening of a series of visits being arranged by theSecretary.The Societywill Society and to whom the Society tender their shortly pay a visit to the " R.E." also the Universitybest thanks. College.Mr.C.E. Chester, of the UniversitirCowes District Radio and Research Society. College, is a member of the above Society, and will, Hon. Secretary, Mr. L. Ingram, 1, Mill Hill Road, during the winter months, give several lecturts. Cowes, I.W. At a general meeting held on October I I th, The Society held second rules, etc., were drawn up, and judges appointed foryear at the headquarters, East Cowes, on October the single valve competition. Substantial prizes are 4th.The evening was devoted to an exhibition offered, and quite a large number of membersof receiving sets owned and mostly made by the have entered.Closing date for entry first weekmembers. A numerous and varied assortment in November. of apparatus was exhibited, ranging from a four - The Society have made application for a trans-valve amplifier to a tiny crystal set, measuring mitting licence, and hopes in a short time to erect two inches by one inch, and capable of receiving the same.Anyone in Southampton district cansignals on three separate wavelengths.Several have full particulars of rules, etc., on applying tounique and useful components were on view also. the Hon. Secretary. The different circuits were explained by the members StocktonandDistrictAmateur Wirelessand demonstrations were given, providing a most Society. interesting evening to all concerned. Hon. Secretary, Mr. W. F. Wood, 4, Birkley On October 7th the Society entertained about Square, Norton -on -Tees. thirty members of the local Scouts' organisation, The monthly meeting of the above Society wasincluding representatives of the Boy Scouts, the held in the concert hall of the Malleable Workmen's Sea Scouts, and the Rovers, enabling them to Institute, Norton Road, Stockton, on October 12th. " listen in " to the Prince ofales's message. The The Chair was taken by Mr. J. Mulcaster.The Prince's voice was heard distinctly by all, thanks Secretary announced that the aerial was nearlyto Mr. Ball, who kindly brought along his four - ready for erection, and would be in use in a veryvalveset and a loud speaker for this occasion. short time. The musical items which followed were thoroughly The President stated that during the evening a enjoyed.At the conclusion, Capt. W. Matthews, member had come forward and had kindly arranged thanked the Society on behalf of the Scouts for to provide the Society at once with a very handsomea most interesting and instructive demonstration. receiving set.A set of rules was submitted to the On October I I th the Society enjoyed a splendid members and accepted.The question of entrancelectureupon" DirectionFinding,"givenby fees, etc., was left in the hands of the Committee. Mr.C.Mugliston.The lecturer explained the The membership is steadily growing, and nowapparatus used and the methods adopted in a numbers over 80. very clear manner, also the uses to which it was After the meeting a lecture was given by Mr. R.put.The questions which followed the lecture King,oftheMiddlesbrough Wireless Society,proved how much it was appreciated. on The Applicationofthe Three Electrode Mr. Mugliston has kindly promised to give other Valve to Receivers." lectures during the present session. ,VEMBER 4, 1922 THE WIRELESS WORLD AND RADIO REVIEW xix TKIIrdess

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THE TELEPHONE MANUFACTURING CO. LTD HOLLINGSWORTH WORKS, WEST DULWICH, S.E.21 TELEPHONE :SYDENHAM 2460-1 TELEGRAMS :BUBASTI8 DULGROX \ \ \\ \\ \NI)II \I)I()III:\ IVA\ N,\ 4, 19:22 =111... The Present Wireless Boom has given an enormous impetus to the manufacture of wireless apparatus.The tendency has been to sacrifice quality to quantity in endeavouring to kt-ert pace with the demands.Throughout this period of increasing wireless activity S. G.BROWN, LTD.,have wisely refused to lower their high standard of quality even at the expense of occasional delay in fulfilling orders. As a result they have more than maintained their enviable reputation as RELIABLE wireless manufacturers, and to -day it continues to be recognised by amateur and professional alike that wireless instruments and parts manufacturedby and bearing the name "BROWN" can be bought with absolute confidence in their quility, value and efficiency. The " Brown" Super -sensitive Telephones These Telephonesare unquestionably the clearest and most sensitive made, and, consequently, increase the distance over which wireless can be heard. BROWN'S are recognised as the most comfortable to wear, due to their " A " TYPE. extreme lightness in weight and adaplible adjustment. Low Resistance, 58/ - There are no wireless headphones in the world to compare with BROWN'S. High Resistance, IMPORTANT NOTICE-When purchasing BROWN'S you should 62 - 66 sec that the name BROWN is stamped on the back of each ear piece.This " D " TYPE. isthehail -mark and proofof theirgenuineness. ex- Low Resistance, cellence of finish nit highest efficiency. 48 In Universal Use.As supplied to British, Allied and Foreign Governments High Resistance, 52 - ( All above prices The " Brown " Microphone Amplifier include cords). This Amplifier magnifies signals, speech, or music, without distortion, and is of considerable interest to amateurs and scientific investigators.The magnificationis much greater than that obtained from a two -valve amplifier.In construction, this instrument is much more robust than other relays.This instrument satisfies the urgent demand for a reliable inexpensive amplifier, which the most inexperienced amateur can use, and hickthemostexperiencedrequires.The necessarytransformersare Huded in the base. The " Brown " Loud Speakers with new improved Curved Horns The requisites of a Loud Speaker are pure tone, clear articulation, and good volume of sound.The " BROWN " Loud Speaker possesses these qualities and they are enhanced by the new improved curved horn. PRICES : Low Resistance (12oohms) input,ie 6 AMATEURS do not always need the full sized Loud Speaker (H.x) as used High Resistance(2,000 ohms)input, in Lecture Halls, and a small type (H.2) has been designed to meet their 2/6 extra. more modest home requirements both as to volume of sound and price. THE NEW HORN of dull blacked aluminium used with bothH.xand PRICES: H.2 is constructed on the logarithmic law of increasing openings and is H. r(Large)Lowacoustically perfect. Resistance, 520 ohmsNOTE THIS.-The strength and clearness of all music, speech and Morse Height 21". heard by one person wearing headphones is broadcasted to a whole room (High£6:5:0 resistance . full of people when aBrown Amplifier and Loud Speaker are used with 2/6 to 5/- extra) your set. H. 2 (Small)LowThe most popular and perfect loud speakers ever offered to the public. Resistance, t2o ohmsThousands already in use in all parts of the world. Height 12", CATALOGUE POST FREE. : : 0 (High Resistances Visit Our London Showrooms :zn, MORTIMER STREET, WI. 2'6 to Si-extra). SOLE MANUFACTURERS-

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Head Office and Works : London Showrooms: VICTORIA ROAD, NORTH 19, MORTIMER STREET, ACTON, LONDON. W.3 LONDON. W.1. a . LONDON NOVEMBER 4, 1922 THE WIRELESS WORLD AND RADIO REVIEW 181 Questions and Answers NOTE.-This section of the magazine is plaited at the disposal of all readers who wish to receive advice and information on matters pertaining to both the technical and non -technical sides of wireless work.Readers should comply with the following rules :-(1) Each question should be numbered and written on a separate sheet on one side of the paper, and addressed "Questions and Answers," Editor, THE WIRELESS WORLD AND RADIO REVIEW, 12/13, Henrietta Street, London, W .C.2.Queries should be clear and concise. (2) Before sending in their questions readers are advised to search recent numbers to see whether the same queries have not been dealt with before.(3) Each communication sent in to be accompanied by the " Questions and Answers " coupon to be found in the advertisement columns of the issue current at the time of forwarding the questions.(4) The name and address of the querist, which is for reference and not for publication, to appear at the top of every sheet or sheets, and unless typewritten, this should be in block capitals. Queries will be answered under the initials and town of the correspondent, or, if so desired, under a " nom de plume."(5) In view of the fact that a large proportion of the circuits and apparatus described in these answers are covered by patents, readers are advised before making use of them, to satisfy themselves that they would not be infringing patents.(6) Where a reply through the post is required, every question sent in must be accompanied by a postal order for the amount of ls., or 3s. 6d. for a maximum of four questions.(7) Four questions is the maximum which may be sent in at one time. " A.S." (Morecambe) asks (1) What is thewhich itis at present fitted.A reacting valve difference between rectifying, note magnifying, H. F. circuit, of course, would produce good results, but amplifying, L.F. amplifying, detecting and audio - isliable to cause interference.If you are not frequency panels.(2) If wiring of his panel issatisfied with your present receiver, the only useful correct.(3) For a diagram using the three panels, fitment which it includes being the variometer, and using basket coils or duolateral coils. we suggest that you commence to build a three - (1) Without goingintodetails, the functionvalve receiver, making use of the non -radiating of each panel is indicated by its name.(2) ThearrangementdescribedinourissueofSep- diagram (Fig. 1) shows how to connect the panelstember 30th. together.It appears from your sketch, that the transformers are connected outside the panel.(3) " G.G." (Sydenham).-The diagram to which See the articles on " Experimental Station Design,"you refer shows the connections of a very simple appearing in alternate issues. set.No. 39 S.W.G. enamelled wire is not suitable

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Fig, 1. " D.H." (Beckenham).-It will be quite easy, forwindingintervalvetransformers,and we of course, to convert your " Metro-Vickeis"crYstalsuggest you make the transformer exactly as shown receiving set to a single -valve set, though itis in the issue of August 19th, 1922.Full construc- doubtful if a single valve arranged as a detectortional details are given, and you should meet with would givebetter results than the crystal with no difficulty. - 182 THE WIRELESS WORLDAND RADIO REVIEW NOVEMBER 4, 1922 " G.E.T." (Harrow).-We do not like your about 20 to 26 ft. high.Three of four guys should diagram. We understand you are using a setbe run from the top of the derrick to their proper comprising 1 H.F. transformer coupled valve,places on the mast, while the latter is lying on the 1 detector valve, and 2 L.F. coupled valves. Weground.The mast is then pulled up by pulling suggest you rewire the apparatus to Fig. 2, pagedown the derrick, side guys being used to prevent 880, September 30th issue, or if you would likeeither the mast or the derrick falling over sideways to use switches to cut in or out valves at will,while the mast is being pulled up.See page 261, try the circuit on page 883, September 30th issue, May 27th, 1922 ;also " Mast and Aerial Oon- but omitting the first valve. struction for Amateurs," by Ainsley(Is.6d.). " G.G." (France)asksvariousquestions. (2) A three -valve set with reaction back to the anode (1) The wavelength of your aerial circuit cannotof the first valve would probably give the desired be reduced much below half the natural wavelength results with the stated aerial.(3) No ; two valves of the aerial, which in your case would be halfproperly arranged will be superior to a microphone 300 metres.(2) We suggest for short wavelengthsamplifier, and will give you much less noise in opera- you make up a coil 3" diameter, 4" long, woundtion. with No. 22 D.C.C., taking, say, 6 tappings, and use a series tuning condenser of maximum value " HOME-MADE " (Barrow-in-Furness) asks 0.0015mfds.(3)Highresistancetelephones must be used when you wish to connect directly(1) How much No. 40 wire would be needed for a with the anode and +H.T. When you wish totelephone transformer, and what other wire to use use the low resistance telephones, a telephonewith it.(2) Whether a sample of mica is suitable transformer must be employed.Each have theirfor making condensers.(3) Capacity of a condenser advantages, and we prefer to use the L.R. telephoneswith 59 plates 9 ems. in diameter, using f" spacing and transformer. washers. " A.J.H." (Bexhill-on-Sea).-As to the use (1) 3 ozs. of No. 40 may be used for the H.R. of an artificial aerial for transmission purposes,winding, with 6 ozs. of No. 32 for the L.R. winding. we would point out that an aerial of this' sort is(2) The sample referred to has not come to hand, specially authorised by the Postmaster Generalbut any grade of mica will be of good enough for laboratory test purposes, on the express under-quality for the construction ofreceiving eon- standing that itisspecially arranged to havedensers.(3) 0.0028 mfds. a very limited transmitting range-say not more than a few yards.If your intention is to aim at " R.S." (Grimsby).-We cannot statethe transmitting over a distance of two or three miles,exact number of turns which should be wound a frame aerialis quite unsuitable, and from thein the slots, as you have omitted to tell us what wording of your permit it is obvious that the Postrange of wavelengths you wish to cover, and we Office isnot desirous that you should transmitsuggest you experiment a little until best values over thisrange.You should have stated yourare obtained. We suggest you wind each slot with requirements when making application, supporting 100 turns of No. 40 S.S.C. copper wire.Only a your request by evidence that transmission overfew ounces of wire is required. two or three miles would be helpful to you in your experimental work. " H.W." (Harrogate).-Without entering into " R.E.W." (Camberwell).-We consider thea discussion as to the relative merits of amplifiers connections shown in your diagram " C " to berecommended by various writers, we think you best for your purpose, although a switch to join thewould be well advised to leave the suggested A.T.C. in series or parallel with the A.T.I.is amplifier alone, and construct Bull's " Broadcast recommended.It is very desirable that variableReceiver " (described in the issues of August 26th coupling be provided between coils C1 and C2,and September 2nd).Full constructional particu- and the provision of this adjustment will amplylars are given, and you can easily arrange to cover repay in result any slight effort required to use it.wavelengths up to2,000 metres. We suggest If the inductance of the reaction coil C1 is madeyou employ the coils exactly as described in the suitable for broadcast reception, external induc- article. tance will have to be added when you wish to receivetransmissionsonlongerwavelengths. " E.H.R." (Pirbright).-There is not of neces- Two coils could therefore be connected up to thesity something wrong with your set because you switch as indicated in the sketch, one suitablehear Paris without an A.T.I. Paris is employing such for the Hague transmissions and the other for Paris.a large amount of power that sometimes a crystal It is quite possible to arrange for the inductancesreceiver not connected to the aerial will pick up to be fixtures, but in that case switches will be sufficient energy to produce an audible signal. The required, and it is for you to decide whether toprobable reason for not having received short wave use a number of switches, or to use a few plug-intelephony is that your set will not tune down to the coils.We suggest you use plug-in coils, which are wavelength.The A.T.C. should be in series with easier to build and use than dead-end switches. the A.T.I., and short wave H.F. transformers " B.A." (Thetford) asks (1) The best way ofmust be used.The values of the four condensers erecting a 80' telescopic mast.(2) What sort ofare quite suitable. We think it is very improbable set should be used to get the Hague, Paris and broad- that your aerial is radiating energy. When the casting stations.(3) If a microphone amplifierreaction coil is coupled with the H.F. transformer, would give better results than two valves added to athe only energy which could be radiated is that single valve set. produced by the small grid circuit flowing in the (1) The only satisfactory way of erecting agrid filament circuit of the first valve.This is so mast of this size is by means of a derrick, itselfsmall as to be almost negligible. NOVEMBER 4, 1922 THE WIRELESS WORLD AND RADIO REVIEW xxi

The first Commereial clg?eless gelephone &mice in Gmatg3ntain ts used for eofnmunicattons between the offices of the Aersey Docks Narbour Dowd in Liverpool and the Oar Lghtship beyond the mouth of the .Mersey. She Aarcorzi appouutus in each case is operated by the ordinary 7-lcu.bbur Board staff and has been in continual use since its irzstT//ntion over a year ago. - "erIlling up" is performed by means of the- e) 0 itiarconi wireless bell MARCONI:S. WIRELESS 7'ELEGR_APII CO. MAROON! HOUSE, STRAND, LONDON, wet Telephone! CITY 87/0.

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"(Edinburgh).-Withoutdiscussing with nine or ten tappings, will be quite suitable for the merits of any particular make of H.F. trans-the aerial inductance, while a coil 24" diameter and former, one has to remember that if untuned H.F.4" long, of No. 26 D.C.C., with, say, six tappings, transformers areused,the number oftuningwill be suitable for the closed circuit.The aerial adjustments are reduced ;hence tuning is not intuning condenser should be in series with the A.T.I. any way critical.If, on the other hand, eachwhile receiving short wave signals.(2) If you H.F. transformer is tuned, the number of adjust-possess a set of coils, you might try a small coil in ments is increased, tuning is critical, and the setthe aerial circuit, the next larger for the closed requires more careful handling.To receive tele-circuit, and thebiggest forthereactioncoil. phony properly it is essential that critical adjust- (3) We regret we cannot give you a layout, panel ments are provided, but, of course, they shoulddimensions, etc., and we suggest you look through not be so numerous that tuning in becomes arecent issues of our journal, and we think you will difficult operation. have no difficulty in choosing a suitable design. " C.D." (Liverpool) asks (1) For a diagram " E.R.S." (Bredbury).-We have frequently of connections making use of apparatus alreadystated in this journal that the arrangement you in his possession. (2)Wavelength range of set.propose to adopt is. in our opinion, unsatisfactory, (3) Nearest Broadcasting Station.(4) For advice. and willcause interferencetoother amateurs (1) See Fig.2.(2) and (3) Wavelength range receivingonthewavelengthto whichyour 250 metres to 1,500 metres.You will have nosetisadjusted.If you hold an experimental trouble in hearing the nearest broadcasting stationlicence you are permitted to use just whatever (Manchester).(4) Write tothe Secretary, Postcircuit you like, and it is assumed that you are Office, pointing out the alteration. sufficiently skilled to know whether or not your circuit is likely to cause interference.We recommend you to read the Questions and Answers section of the last few issues, and also to read the article under the heading " Experimental Station Design " in the issueof September 30thlast. A statement has now been made by the Postmaster General, as no doubt you are aware, regarding oscillatingreceivingsets.Thisstatement is reprinted in our issue of October 21st. " H.N."(Huddersfield).-The Postmaster General is not likely to approve the use of the circuit shown on page 780 for reception on broadcasting wavelengths.If you hold an experimental licence you are privilegedto use any circuit you like, using your own discretion as to whether you think it is likely to cause interference.A circuit likely to be approved by the Post Office is given on page 867 of September 30th issue, and the conditions Fig. 2. concerning the types of circuits used in broad- castingapparatushavebeenrecentlystated inthe press, and further information appears " G.R." (Shrewsbury).-We cannot criticise the action of the Postmaster General with re-in the issue of this journal of October 21st. gard to withholding from you an experimental " W.C.B." (Birmingham).-The grid tuning receiving licence, and moreover, we are unablecondenser is very necessary when tuning to short to offer you very much advice as to supporting wavelengths.You may try the circuit without your claim,without knowing the reasons youit, but you will find it is better to tune the grid.A have stated as to why you wish to conductgrid leak is not necessary in a circuit of this des- experimentsinwirelesstelegraphy.The Postcription.Actually the secondary of the microphone Office are prepared to authorise experimenters totransformer acts as the leak.To apply negative use wireless apparatus where it is apparent thatpotential to the grid, dry cells may be used, but they have some serious theme of research in view, it is usual to employ a leaky grid condenser.The and they are qualified in the manipulation ofvalue of the grid leak and condenser required wireless apparatus. We would recommend that youdepends on the anode potential, and is for the pur- become a member of a Wireless Society which ispose of holding the mean grid potential at the most affiliated to the Wireless Society of London, in suitable value. order to show that you have a serious interest in the subject.You might then draw the matter to the " M.S." (Ireland).-The basket coils should notice of the local Secretary, who might,if heeach be wound with No. 22 D.C.C. wire.About considers necessary, endorse your application andsix will be necessary, and each should have a mean pass it to the Wireless Society of London fordiameter of 34".The coils should not be laid recommendation. together so that they touch each other;about 4" space between each coil is necessary.The reac- " L.J.W." (Middlesex).-(1) As you wish to tion coil may consist of coils 31" mean diameter, receive the broadcast transmissions only, a cylin-wound with No. 28 D.C.C. We are afraid we drical tapped coil is the best form of inductance.cannot help you much, as you do not state the A coil 3" in diameter and 4" long, of No. 22 D.C.C.,type of receiver you propose building. 184 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 4, 1922 " DON BEN " (Southall).-If thePlAtes " S.S." (Leyton).-We do not care for the are 2i" diameter, the spacing washers 1/8" thick,circuit as jacks are used in the H.F. circuits. A and the plates 24 mils. thick, 47 plates will givediagram of a 5 -valve set, exactly as you require, you a capacity of 0.0005 mfds. is given on page 883, September 30th issue.The values of the components are marked in.The " S.B." (Hanwell) asks (1) Whether he mayvernier condenser is joined in parallel with the use a circuit given in answer to another correspondent. A.T.C. (2) Resistance of a potentiometer. (1) You may certainly use the circuit given in "M.V.D.T." (Southampton).asks(1)A reply to the question of another correspondent. question about an instrument he has bought.(2) How The aim kept in mind when giving answers to to charge his accumulator off 200 D.0 . wires. queries is to make the answers as generally useful (1) We regret we cannot help you, since we have aspossible.(2) The connection may be made no particulars of the apparatus to which you refer. at the negative L.T. terminal.If you wish to use (2) We suggest you join the accumulator in series a potentiometer, employ one with a resistancewith 200 -volt, 32 candle power carbon filament of about 400 ohms. lamps.The lamps are joined in parallel. " E.M.W." (Cheshire)asks(1)Questions about his set.(2) If proposed H.F. transformer "J.A.F." (Ayrshire) asks variousquestions is suitable.(3) Who is 2 RC.(4') For criticism about his set. of his diagram of connections. (1) You will hear ship stations, broadcast trans- (1) We think if you add 1 H.F. valve to your set missions certainly, and local transmissions.(2) the troubles will disappear.(2) We suggest ,youWe suggest you fix a mast to the stunted tree as employ a tuned anode coil ;one cell will thentall as convenient, and run the aerial from the mast suffice.However, if you prefer the H.F. trans-to the chimney stack.Use a double wire aerial. former arrangement, couple the two coils together. It would be better to make up a H.F. transformer " JUMPER " (Woking) asks (1) For a diagram exactly as described in the issue of September 3rd, of a 3 -valve set using1 H.F.,1 Detector, 1 L.F . page715.(3) We have no information. (4) (2) For particulars of a reaction coil.(3) Range The proposed arrangement will do quite well,of set. but the reaction coil should be connected between (1) The diagram to which you refer (page 883, the anode and transformer. September, 30th issue) is very easily followed, and we think you will be able to modify the diagram " J.E." (Birmingham).-We think the trans- yourself.(2) The reaction coil may consist of formers might suit your purpose, and you should100 turns of No. 38 S.S.C. wire, inductance being certainly try them, and compare them with theadded in the reaction circuit for Jonger wavelengths. results obtained from a standard transformer. (3) You may hear PCGG and should hear all " R.B." (Ireland).-There is no critical valueBritish broadcasting stations. for the anode choke coil, and we suggest you wind a coil 1" diameter, 3" long, with No. 28 D.S.C. wire. "J.H." (Edgbaston) asks (1) For criticism of The anode blocking condenser may have a value his set.(2) Why set howls.(3) What coils to use. of 0.001 mfds.This value isnot at all critical (4) For suggestions to improve set. and the only point in connection with it is that (1),(3) and (4). The reaction coilis shown its insulation must be capable of withstandingcoupled to the aerial coil, and no closed circuit three or four times the voltage of the high tensionis employed.Thisiswrong. We suggest you supply.The aerial tuning inductance may con-use a closed circuit, and couple the reaction coil sist of 40 turns of No. 16 D.C.C. wire on a 3i"to the anode coil of the first valve, as explained in diameter former, tappings being taken at every recent issues.The A.T.C. should be in series with turn at the aerial end ;and the grid coil may con-the A.T.I. when receiving on short wavelengths. sist of 60 turns on a former 3" in diameter. WeThe batteries are correctly connected.(2). The notice you have not shown the key connected inhowling is probably the result of too much reaction, circuit.It is usually convenient to key directlyand with a circuit of this type you will in all in the high tension supply lead, but if the highprobability be causing interference and spoiling tension voltage is above three or four hundredthe enjoyment of others. volts, we suggest you use a grid leak and condenser, then join the key so that when it is depressed the grid leak is connected across the grid condenser. We are afraid we cannot give you much informa- SHARE MARKET REPORT. tion,as the diagram submitted does not show the valves or power you propose using. Prices as we go to press on October 27th are ;- " 0 .P.S." (Dingwall).-The sample of wire Marconi Ordinary.. £2 6 3 submitted isNo. 42S.S.C.copper wire. We Preference.. 2 2 6 suggest you make the low frequency intervalve transformer of the closed core type, making use P Inter, Marine 1 7 3 of a bundle of iron wires.The core should be ,)" PI Canadian .. 1010} diameter and 3" long ;the primary winding should be 10,000 turns of No. 42, and the secondary Radio Corporation of America :- 15,000 turns of No. 42.The primary winding should be wound on first.About 6 ozs. of wire Ordinary.. 1 0 0 will be required. Preference.. 14 NOVEMBER 4, 1922 THE WIRELESSWORLD AND RADIO REVIEW '7Xe W aisrats in MU LLA PHON specially made for the rcccp:ion of wireless broadcasting, Mullard 'phones are thoroughly well made and fit comfortably to the head, &c. British Manufacture. The two high resistance car pieces (4,000 ohms total) are flexibly attached to the fully, adjustable, double head bands. The set is nicely finished in nickel plate and supplied complete with standard flexible cords. Made in Two Qualities: General Purpose quality, Type A, 30/- per set. 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RADIO COMMUNICATIONC C. LTD 34 and35,NorfolkStreet, Telephone: Central 1021 and 3:05 London,W.C.2 Tale;ranas " R-dio.omea, Estrand, London xxviii THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER4, 1922

Oar Price Lists WE ARE BROADCASTING (4d. post free).

104/1 Valve Legs. 104:7. Mounted on matt finished ebonite strips. The thickress ofLaminated Switch Arm. ebcnite varies from 3/16" to 1" according to number of valves.A substantial andwell 109/1 A for 1 valve 1/6 per strip 104/1D for 4 valves 6/-per strip finished article. 2/- each. 104/1 B 2 104/1 E 5 2/6 8/- 104/1C 3 3/6 104/IF 6., 10/6 Huge stocks of valves 104/1 G for 7 valves 11/6 per strip. and wires. Price Lists 4d. post free. Light, Comfortable, Sensitive. We have nearlysoldout the 1,000 LEADINGIN INSULATORS. Phones which we are offeringatthe 102/4 A Sturdy Ebonite, 6" overall following prices : 140 ohms, 23/6 4,000 ohms. 25/-8,000 ohms, 27/6 1/8 each. 11111 Postage 9d. We cannot repeat after these are sold. Remember that they are our 102/4 B Sturdy Ebonite. 12' overall Standard Phone and are offered at this price as an advertisement. 2/- each. 104/9 VALVE SOCKETS Please note new address : Complete with nuts and washer 1 3 doz. J. L. CARTWRIGHT & CO. !land ufalgdugng Legeitrieet 24, London Road, Manchester Works : Berry Street, London Road, Manchester. 'Phone No.: 4209 Central. 'Grams: " Placturam," Manchester. Code: ABC, 5th Edition. Wholesale Distributing Agents for Scotland,L Corston Sinclair &CO.,47, Waterloo St., Glasgow. Retail Agents:-Bradford-The Gramophone Stores, 150, Bowling Old Lane.Blackburn-- Thomas Barton, The Electric Works.

WHOLESALE ONLY.

.-TIIIIIIIEBONESTOS INSULATORS LTD., ROLLINS ST., LONDON,S.E.15.H 11-717 NON -EMBER 4, 1)122 THE WIRE I.F..SS WORLD AND RADIO REV I EW xxix SPECIAL OFFER FOR THIS I WIRELESS CARRIAGE PAID. WEEK TO AMATEURS

Filament Rheostats for Panel Mounting with Pointer 3/- and 3,6 15 Volt Tapped Units .. Great Reductions in 'Prices. 4,000w. Double Headphones (good make) .. 2/7 Valve Holders, with fixing screw form.. .. 10d. Ericsson Nickel -plated Microphones .. 51- Inset Type Microphones .. 2/6 Intervalve Transformers, wound with silk wire.. 21 Mk. ni and MIU Crystals, in cups.. 6d. and 9d. Actual Size Vario Couplers, 200 to 1,200 .. .. 7/6 Set of Six Basket Coils, specially wound .. 6/6 Terminals4 B.A. Double, Solid Brass, special price, 2/6 per doz. 120w. Watch Receivers, with cord.. 4/6 New G.P.O. 'Phones, 300 ohms, with canvas head -bands Imf. and 2mf. Condensers .. 1/6 PRICE per Pair 7/8 50amp. Accumulators (not charged) .. 23/- Sullivan 'Phones, 120 ohms, shop soiled, in good condition .. .. PRICE per pair12/6 Set of Eight Tablets, black or white.. 1/6 Instrument Cases of every description at knock -out prices Ebonite Tubes for Leading -in Aerial .. 1/- Leading -in ..ebonite,R.A.F..pattern .with brass rod PRICE 3/6 Ebonite Knobs (per doz. only) 4/- fittings 25: - Grid Condensers, .0003 and .0005 .. .. 2/6 Accumulator Charging Resistances . PRICE Rubber -covered Wire for Sets Universal Tuners.These tuners have been designed to per 7d. 3d. tune in Marconi concerts, broadcasting, and Dutch 25 ft. Steel Masts, in Sections .. . 18,6 Concerts, so that a baby can use them.Wavelength All above goods guaranteed. range, 300-1,500 metres, with 11005 m.f. condenser, PRICE 7 - B.T.H. Receivers with Microphones 5 6 4,000 ohm 'phones, new patent 3 -magnet type, fitted cords and tags, complete with nickel plated head bands PRICE It will pay you to call and see our enormous stocks. C.S. SWAN, It will pay you to buy. Postage extra on all the above prices. 191, Bishopsgate, E.C.2 The trade supplied. Enquiries solicited. 'Phone ;BISHOPS 1156. J. LIPOWSKY,614, 0 Ii300:ORD RD Under Brandon's, Tailors, and 65, Windsor Road, Leyton, E.10. LONDON,E.3. 'Phone: East 3345 EIFFEL TOWER TYPE." O 0 0 0 0 0 0 0 0 0 0 0 Ebonite Panels MAST S Cut accurately to size, with clean square edges, STRONG. LIGHT. or bevelled. WOOD LATTICE. EASY TO ERECT. Enquiries Solicited for Quantities. ROT AND WATER PROOF. PROMPT DELIVERY. 20 to50 feet - - 1/3 per foot RELIABLE QUALITIES ONLY.

55 100 - - - 1/9 Mouldings, Sheets, Tubes, Rods. FROM STOCK. CASH WITH ORDER. Wholesale only. WILKINSON, Lonsdale Road, Kilburn, N.W.6 RADIO EBONITE SUPPLIES, .° 4 LITTLE COLLEGE STREET, LONDON, E.C.4 Same Address since 1900. Trade Supplied. 'Phone-Central 4711. (2 min. Cannon Street Station). Bankers-LONDONCITY AND MIDLAND, KILBURN,N.W.6. O 0 0 0 0 0 0 0 0 0 0 0 WALTER H. PORTER & CO. International Exchange Buildings, 44. CHURCH STREET, BIRMINGHAM. May we quote you for all kinds Wireless Accessories, and Questions and Answers send you samples Quotations given for any parts made to special design. Samples of the following sent to the trade in order to afford COUPON an opportunity of seeing the quality on receipt of P.O., as follows :- Filament Resistance for panel mounting, 1/8. To accompany Questions Blocking Condenser,1/8.Grid Leak and Condenser,1/6. during the week Coil Mounts in ebonite, 1,-.Coil Holders, 10/6. sent in Telephone Transformers, 9/6.Intervalve Transformers, 13/-. commencing Nov. 4th, 1922. Coil Holders in ebonite, 8/6 each, two-way and three-way, 4,000 ohms 'phones, 16/- per pair.Valve Holders, 7d., knurles knob, 2d.Vernier Condenser, 2/3.001 Condenser, VOL. XI, NO. 5. 10/-..0005 Condenser, 8:-. -0003, Condenser Dial in ebonite, engraved, bevelled, 1/3. Condenser of pure aluminium, 22 gauge, 4'- per gross. See Conditions on Page 181. Please state quantities to belquoted for. XXX THE WIRELESS WORLD AND RADIOREVIEW NOVEMBER 4, 1922

THE MARK OF RELIABILITY British Headphones (Complete with Cords) /MIMEO.. With With purchase17/6purchase value £2 value £2 Ito 12 volts. 1 to 35 amps. These phones, of beautiful construction, sensitive and comfortable, sold almost exclusively elsewhere at 35/-,will be suppliedat17/6 VOLT & AMMETER (below cost price) to all customers purchasing Combined Dead Beat Pocket Type. New and not German. to the value of 40;'-.If purchased separately SplendidInstrumentinNickelPlatedCate. the price of these phones is 22/6. Ideal for TestingCells and Filament Current. POST NUMBER ESTABLISHED 1903 PAID 5/6 LIMITED OTHER EXCEPTIONAL VALUES. Aerial Wire.Bright Hard Drawn, 7/22's Copper, 3/6 "HALL'S" per too'.Enamelled, 7/22's, 5/- per too'. Aerial Insulators.Shelltype,2' x 2k',9d,each. Cheapest and Best Aerial Insulators.Reel type, e diameter, brown , 34. each. Filament Resistances.For panel mounting, 2/8 each. obtainable H.F. Transformers, plug in type, 300 and 70o metres, 6; VARA ivirtfr 4/8 each.ropoo m. 5/8; 2,600 m.8/- each. H.F. Transformers,Formers only, with pins, 2/- each. Value Tangent H.F. Transformers.All ranges, 6/8 each. Switch Arms.Complete fitted with knob, 1/- and 2/6 each. with Quality. Dewar Switches.D.P. Change over, panel type, 2/- each. GOODS Lightning Arresters.Carbon block type, 1/6 each. Dispatch by return. Valve Holders.Flanged " A " type, 1/-.Ebonite with 8 nuts, 1/3 each. Ebonite Panel, fitted with 3 Valve Holders, complete, 3/9, CONDENSERS. Aerial Wire, 100 ft. in length, Ebonite Panel, fitted with 2 Valve Holders, complete, 2/8. Vanes ihi.k 22 gauge. 7/22 co, per, 3/1. Valve Sockets, per set of 4 with 8 nuts, 7d. Valve Lets, 4 f ,r 51.. 1.s. doz. Transformer Holder.With 4 terminals and wired, 3/6 each. Com- wits nuts and washers, High Note Buzzer (Army Type), worth treble, iv- each. Capacityv:n" plete Telephone Transformers (Army Type), 9/- each. Paris EngravedIvorine Scales, Wireless Jacks, with plug, as illus., page 733, 1/- the pair. 0-130, 6d. Brown's Type " A " Headphones.Guaranteed new and .031 57 7/- 8,000 ohms, 49/6 ; Filament Red -lances, Splen- unused. 120 ohms, 42/6.With .0075 43 6/- did Value, 2/6 & cords, 51/6 and 44/6. .0005 29 58 80, Ever Ready Batteries (all sizes).16 Volt, 316 each. .0003 19 3/8 Switch Arms, complete with Rim.Clear Ruby, .00e thick, 3' x 2', 1/- doz. pieces. .001.2 17 8 2/3 knob, collar, nuts, etc., ls., Indtuitance Slider Rod, I" square, 13' long, drilled, 64. each. .0091 2/- 1/8. Slider, complete with plunger for r rod, 6d. each. Contact Studs.Fitted with nut and washer, 1/3 dos. INSTRUMENTS ANDValve Holders, 9d. 1/- & 1/6.1 Condenser Vanes.Best Aluminium, 31", 1/6 doe. pain. Crystal Cups, Plain, ld. ; 2 Condenser Spacing Washers.Small, 3d., large 8d. dos. ACCESSORIES. screws, 21. ; 8 screws, 3d. Condenser Screwed Rod, Brass2" long, a' 4d., 3/16" 66. Single valve melt, £1, com- Assorted colours, &I, per yard. Terminals, all types.Extra- Insulating Tubing. plete in polisael cacineL ordinaryVame, 2d. each, Sheet Ebonite, r to I" thick, 4/- per lb. Ampllying panels,35/-, in witu screws and nuts. Terminals.Mark 3 N. Plated, 4B.A., 2/6 doz. polished cabinet. Small pattern, 94. doz. Terminals. Intervalve Transformers, 15/6.Contact Studs, # by t, 3d. doz. Dubilier Condensers.All capacities at prices advertised. Insulators, 31. each, z" por- Grid Leaks.All resistances, 2/- and 5/- each. Crystal Sets, 15s., 35L, £3. ce.ain. Radio Instrument L.F. Transformers, 25/- each. Single ValveSets,£3,inBrass Nuts ; 2 BA, 4 BA and Tangent L.F. Transformers, 22/6 each. Mahoany Case. 5 BA, 43. dz. Ivorine Scales.oi8o, good quality, 6d. each. Alum. Vann', 22 gang; 18. Ivorine Tablets.Set of seven, 7d. each, fixed and moving, 91.Ebonite Sheet, cut to any size, Skinderviken Microphone Buttons, 5/- each. doz. 4/3 ,b. Burndept and De ForestCoilsinstock.Advertised Spacers, 4 ld. doz., 8/8 grossFixed Condensers, any capa- prices. (small, 2.d. day., 2s. gross). city, 2/-. Potentiometer 300 ohms.Panel type on ebonite, 4/11 each. Gril Leak Condensers, 3/8, Coadenser, 5 -Plate.Panel type on ebonite, 4/- each. EboniteKnobsf -rcentre Crystal lups.4 scr w type ed. each. Spindle, 21., 41., 5d. each. Ebonite Miler Plunger, 8d. Special Lb'. Transformers.Hs. e ch. Fellows 9,000 ohms. 1-, eadphones.30/ - Fellows V aloe and Crystal Iteceivers.List prices. Postage extra. Balance refundedif excess sent. WriteforComplete SupplementaryPriceList of Send for Free Catalogue. Exceptional Values, sent Post Free. All goods sent CARRIAGE PAID but with orders under Trade Dispatch 5,6 add 6d. for postage. Supplied66HALL'S"by return J. H. TAYLOR & CO., 'PhoneRegent 1292. WECTRICAL AND RADIO ENGINEERS. 71 BEAK ST:, REGENT ST., LONDON, W. Macaulay St., HUDDERSFIELD. Between Piccadilly Circus and Oxford Circus, Telephone, 341. Telegrams " Thorough, Huddentheld." Buses 3.6, 12, 13, 15, 32, 51, 53, 59 and t8 pass. NOVEMBER 4, 1922 THE WIRELESS WORLD AND RADIO REVIEW

/. ELWELL 1"4j1g,---r HighPower I fiNC./1 \\ At. .44-;/1 Wirelass \\\11111111 Stations

Oxford

Cairo

Northoltj EP;

Hor sea 1151 a n d

(1)Theself -tightening bull -doggrip fittedtotheElwellplug enables BULL DOG GRIP Eiffel telephones or loud speakerconnec- Tower tions to be changed in a moment. CONNECTORS

(2)By the terminal adaptor, the bull -dog Elwell patented self -tightening grip !Lyons' grip connector can be added to any fittingsareabigconvenience. existing terminals. Without soldering,tighteningof nuts or screws or the use of any 7K INantas tools whatever, electrical connections *--0. (3)For fitting to the face of a panel this pattern is recommended.It combines can be made, broken or changed a standard terminal for fixed con- in a moment. nections with a bull -dog fitting for connections which you requireto Roma change. Moreover, the connections when (4) A series connector with a bull -dog made are electricallyperfect and grip at each end.Invaluable for con- self -tightening.The more you necting telephones in series. pull them the tighter they grip. But they canbereleasedina moment when desired. (5)The series connector in use. Telephones can be connected in series in an instant.No amount of pulling can Ask toseethem at your wireless break the connection.It thus avoids dealer or write for descriptive leaflet. those annoying interruptions caused by involuntary movements. C. F. ELWELL, LTD.,Radioengineers, CRAVEN HOUSE,KINGSWAY, LONDON,W.C.2 Telephone :REGENT_421. THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 4, 1922

Sena No. 5. -- Makers of over Half the World'sTelephones. LONDON Western Electric LOUD SPEAKING EQUIPMENT. Clear and true production over the entire musical range is provided by this equipment which consists of a specially designed LoudSpeaking Amplifier and a Loud Speaking Receiver.For general efficiency and absolute reliability there is no other equipment produced thatcancompetewithit. Makersof over Half 48) * the World's Telephone.

The Loud Speaking Equipment is used in conjunction with any good type of Valve Detector Set for amplifying radio telephone speech or music.

62, Finsbury Pavement, London, E.C.2 Telephone-London Wall 7608 WORKS :- North Woolwich, London, E.16 Telephone-East 384o (to lines) Also at BEXLEYHEATH, KENT, and NEW SOUTHGATE, N.11 Birmingham-Grenville Buildings, 12, Cherry St. Manchester-Northern Assurance Building, Leeds-Standard Buildings, City Square. Newcastle -2o Saville Row. Cardiff-Motor House Chambers, r, Wood St. Glasgow -49, West Campbell Street. NOVEMBER 4, 1922 THE WIRELESS WORLD AND RADIO REVIEW THINK WHAT YOU ARE PAYING FOR! THE "HESTAVOX II" 2 -VALVE BROADCAST RECEIVER. I. II.

A highly sensitive and The right to listen, any beautifully finished andeveryday,foras Receiving Set, manufac- many years as you please. tured under licence from to Morse, Amateur Tele- Marconi Wireless Tele- phony and Concerts, &c., graph Co.. L td., and fully transmitted From the approved by H.M. Post- Broadcasting Stations. master -General.

PRICE PRICE (exclusive of Accessories) (including all Accessories) £12 76. £19 16 0. THEN ASK YOURSELF :IS IT WORTH THE PRICE ASKED?" WE have an ic;pated your answer, and have stocks of various types of receivers ready for your inspection or delivery instructions. Send your order now and mention "Hestavox" on your licence application. TRADE SUPPLIED. LOOSF-LEAF CATALOGUE. Post Free. 6d. THE HESTIA ENGINEERING COMPANY, (Dept. W.), Telephone : 32, Palmerston Road, Acton, London, W.3. CHISWICK 586. Tor theyarefolk' good Fellows': INTERVALVE 41` TRANSFORMERS

Use Fellows Intervalve Transformers, and secure maximum amplification with freedom from distortion and extraneous noises. Oritish made throughout and guaranteed. PRICE 22/6(POSTAGE 6d.) FELLOWS MAGNETO CO., LTD. LONDON, N.W.10. Telephone : Telegrams::

Willesden r 5 tio - . Quixmag, Phone, London. xxxiv THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 4, 1922

The London Telegraph Training College, Ltd. Telephone ESTABLISHED WESTERN 2696. Morse House, Earl's Court, S.W. 25 YEARS. OFFICIALLY RECOGNISEDBY THE WAR OFFICE AND POST OFFICEAUTHORITIES CABLE AND WIRELESS TELEGRAPHY. pARENTS desirous of placing their sons in either of the above Services and of affording them the best training facilities should apply for particulars of Courses and the methods of instruction which place this Institution in the first rank.Cable Telegraphy offers at the present time excellent prospects to youths from 15 years of age and upwards, and the College has exclusive facilities for obtaining posts for qualified students in the leading Cable Companies at commencing ralaries of £150 to per annum, with yearly increments of £12 to £25, and ultimate Iossibilities of obtaining positions as Supervisors, Assistant Superintendents, Managers, etc. In the Wireless Telegraph Service the commencing remuneration at the present time is approximately £150 per annum, and Operators, when qualified by obtaining the Postmaster - General's Certificate of Proficiency, are nominated by the College for appointments. NCorrsspondenoeClassesorBrandies. DAY AND EVENING CLASSES. Prospectus oontaining all information will be forwarded on application to THE SECRETARY (Dept. H.), 262, Earl's Court Road, Earl's Court, London, S.W.5 Sole Proprietors of the "Scott" Training Disc, which contains useful formulas and other information for Wireless Telegraph Operators and is invaluable to Army Signalling Officers for range finding, etc. Price, complete with instructions for use,/-.Postage 2d.

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DoYou get FL?

YCYUR crystal or valve may be the best of their kind-your aerials high as Snowdon, your tuner perfectly accurate, but unless your 'phones are O.K. you won't get maximum "sigs." Signals come "thumping in" through ERICSSON 'PHONES. They're built that way-for never -failing clarity and sensitivity.The magnets never lose their strength and " shorts " don't exist.And they're easy I and comfortable to the head. . Back of ERICSSON 'PHONES isthe accumulated experience of a I generation in telephone manutacture. The BRITISH L. M. ERICSSON I MANUFACTURING Co., Ltd. Head Office : 67/73, International Write for

Buildings, Kingsway, W.C. Particulars

per Pair Li 4000ohms. All Resistances i in stock. Telephones : I

!MN ..ONO

am NOVEMBER 4, l92 THE WIRELESS WORLD AND RADIO REVIEW WE SPECIALISE IN THE MANUFACTURE OF EBONITE VARIABLE EQUIPMENT CONDENSERS FOR Highest Quably Workmanship. Lowest Possible Prices Every Condenser Fully Guaranteed WIRELESS SETS Money returned if not satisfactory SHEETS, KNOBS, COIL FittedCompletewith Knob ReadyforPanelMounting. HOLDERS, VALVE HOLDERS, ENGRAVED DIALS, SOLID '001 - 16/- each. '0005 11/6 EBONITE HORNS FOR '0003 - 9/6 LOUD SPEAKERS, PANELS VERNIER 4/ - VANES - only11d.doz. Carriage Extra. FROM STOCK

Buy 'Direct from the ,/l ctual n'lanufacturers Coventry Wireless Supplies Co. HIGHTENSITE LTD. CLAY LANE, COVENTRY. Normandy St., Custom House, E.16 TEL.: 131i. 'Phone: EAST 3153.

COMPLETE sets of Wire- less Apparatus in stock readyforimmediate delivery ;alsoAmplifiers, Tuners, Loud Speakers and all components.

WE placeourexperience at your disposal-send us your enquiries, or call-we will gladly give you expert advice.

NEGRETTI&ZAMBRA 9 stage H.F. Trans- former, tapped RADIO DEPT., primary and secon- 38, HOLBORN VIADUCT, E.C.1 dary. Range150- 25,000 metres. LONDON

E 2 xxxvi THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 4, 1922 THE A B C OF WIRELESS Di/PERCY W. HARRIS 16 Pawls, nun home FREE coverinthreecolours. THE Book for the " Man in the Street." gives you full inform Ition OUR. NEW BIG - and prices on Wireless ILLUSTRATED CATALOGUE Receiving Sets complete Price 6d, nett. Post free gd. from £3 10s. to £12 10s Hearallthe RADIO concerts,speeches,ser- What is Wireless ?How Does it Work? mons.news.cropand --r-sfStIPPLIEST weatherresorts, now THE " A B C " WILL TELL YOU. being broadcasted daily. Costs you nothingafter first cost.Easy to install and operate. And hundreds of other Wireless articles. THE WIRELESS PRESS, LTD. Write to.daii. 12-13, HENRIETTA ST., LONDON, W.C.2 FREE. \PERMA NENTONLY CRYSTAL 7/6 TO DETECTORPost paid WIRELESS Ready to attach to your set. BROADCASTING Greatest boon everknownto Wireless IExperimenters. APPARATUS MAKERS. Always ready, no 1 fiddlingorsearchingfor a point. Crystal always active. Largest mail- We solicit your enquiries for order firm in Europe. (I, Important Notice.-All our PRE' S TOOLS - STAMPINGS ,, apparatus is guaranteed - your money bact in full'if DIES and MACHINING not satisfii d.V rt.. to-cay. offering you first-class work. c.t Prices. Competitive Send us your ,411 Drawings and Specifications, etc. BRITISH RADIO °1"1-!"- i SALES CO. LTD CHAS. WRIGHT, LTD., STEPHDIS SUILDINGS,GRASSE ST. General En ,ineers. Tool Makers. Stamper,. etc, SATIMONE ILACE, LONDON W.I. EDGWARE, MIDDLESEX. Established2864.

The Popular LISTEN Loud Spoken Buy a set you will be allowed to use. The Holborn Radio Co., Ltd., offer Single Valve Sets, including 4,000 ohm double Headphones, Accumulator, A high-class adjust- High Tension Battery, Tuning Coils,Aerial Wire, able Loud Speaker at Insulators, etc.Complete, ready for use .. 27 15s. Valve Extra . 15/- a popular price. Not A Really well -made Set, easy to operate and guaranteed to give maximum results.

anearpiece with a Headphones, 4,000 ohm, double headpieces . 24/6 horn, but a scientifi- Headphones, 8,000 ohm, double headpieces .. . 28/6 Valve Detector Panel, complete in mahogany case, best cally constructed 28/6 Set of parts with drilled panel and instructions for instrument, 120 ohms, assembling above detector panel .. 14/9 Cabinet to fit .. 3/6 £2 ;2,000 ohms. Amplifying Panel, complete in mahogany case.. 42/- £2 4s. ; 4,000 Condenser, .0005, in mahogany case .. 20/- Condenser,0005, for Panel Mounting.. 14/8 ohms, £2 5s. Condenser, .0005, ready to assemble .. 8/9 Post1 /6. Crystal Set complete with headphones, Aerial Wire, Insulators, Earth Wire, etc... 65/ - (Postage Extra.) PRICE LIST POST FREE Scientific IF YOU ARE IN TROUBLE WITH YOUR SET CALL AND SEE OUR TECHNICAL ADVISER, EXPERT Supply Stores ADVICE GRATIS. ALL ORDERSD ISPATCHED THE SAME DAY AS 8 Newington Causeway RECEIVED. TRADE SUPPLIED. LO, DON, S.E.1 THE HOLBORN RADIO CO.,LTD., 8, High Holborn, London, W.C.l Phone :Hop 4177. Telephone, Chancery 7278.(Five doors from Gray's Inn Road) NOVEMBER4, 1922 THE WIRELESS WORLD AND RADIO REVIEW xxxvii

" ARRESTA " THE IMPROVED LIGHTNING ARRESTER enables you to operate your receivingset at all times, even when the atmosphere is highly charged with electricity.

THE " ARR E STA is an auxiliary earth connection,attachedtothelead-inWire OUTSIDE the building for dispersing to earthlightning and static dischargesBEFOREtheyreachtheinstrument-thus safeguarding operator and apparatus.

DON'T LEAD LIGHTNING INTO YOUR HOME DISPERSE IT OUTSIDE BY USING THE " ARRESTA.- The Arresta gives clarity of reception and increased efficiency.

For Crystal Sets PRISE For Valve Sets PRICE usesizeNo. 1 1/9 use size No. 2 2/9

Obtainable of allWireless Dealers,ordirect from the Patentees and Prov. Pat. No. 21098. Manufacturers (Post Free). Each"Arrests" is adjusted and tested and requires no attention whatsoever after We also supply : TERMINALS, SCREWS aid all COMPONENT PARTS fixing in position. for Wireless Apparatus. (WE INVITE THE TRADE TO WRITE FOR OUR SPECIAL TERMS.) McWHIRR & PATERSON, 99, St. Paul's Road, Highbury, London, N 1

"RADIO -WAVE" Broadcast Valve Receiver itv The Radio -Wave Broadcast Valve Receiver conforms to the Official Regulations for Broadcast Receivers.It has been the aim of the manufacturers to offer in this instrument a splendid PRICE £10 : 10: 0 example of British Workmanship and value for money. Each one is guaranteed to be according to specification. SPECIFICATION. (x) Supplied with genuine Marconi Valve. (2) Fitted with filament current control enabling the user to work at most sensitive temperature of the valve, hence efficiency, economy, satisfaction. (3) Provided with seriesparallel aerial condenser switch, ensuring ultra efficiency on amateur wavelengths. (4) Tuning Inductance is tapped in 12 places.This, in combination with the low capacity tuning condenser, ensures zoo per cent. tuning accuracy, thereby promising maximum signalling distances. (5) Brass fittings are highly burnished and treated with old gold lacquer, rendering them impervious to atmospherical influence. (6) Best quality ebonite panel with engraved matt surface, functions of all knobs and terminals being clearly indicated.

Price with 2,000 ohm Sterling -Brown Telephones,60 -volt Variable H.T. Battery, 4 - volt Accumulator, Aerial Wire, Insulators 15 :15 : 0 THE MEDICAL SUPPLY ASSOCIATION, LTD. 167/185, Gray's Inn Road, London, W.C.2. Works: LONDON & SHEFFIELD. Telephones:MUSEUM 7210, 7211, 7212. THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 4, 1922

4th Edition (Revised and Enlarged) of ELEMENTARY TEXT -BOOK ON WIRELESS VACUUM TUBES By JOHN SCOTT-TAGGART, F.Inst.P. This isthe opinion of Major Armstrong (of super -regenerative fame).A fullaccount isgiven of

,L.-//

f -f74

1 a 4.4/tie /

the ArmstrongCircuits and other new inventions.A book which thebest type of amateur willinsist on having.Price 10/- Let. Boo&youwt.& need

PRACTICAL WIRELESS VALVE CIRCUITS," by the same author. A wellproduced book of diagrams, each of which has been carefully tested.Full notes on each circuit are given.This book should be in the hands of every readerofJohn Scott -Taggares books. Price 2/6 (post free 2/13). " CONSTRUCTION OF WIRELESS RECEIVING APPARATUS."3rd (Enlarged) Edition. By PAUL D. TYERS.Price 1/6(post free 1/71).

PUBLISHERS OF AUTHORITATIVEWIRE LESSLITERATURE DEVEREUX COURT. STRAND W.C.2. OPPOS/TC THE LAW COURTS

11111 NOVEMBER 4, 1922 THE WIRELESS WORLD AND RADIO REVIEW AUCKLAND'S

AUCKLAND' (Igranic) DUO LATERAL COILS. ;Made tinder De Forest Pltent,. PRICES from5/ - Mounted. INTERVALVE TRANSFORMERS. NOTE MAGNIFIER. Most Efficient Cores,being 1 VALVE SELF-CONTAINED built up of Stalloyand in UNIT. correct proportion. For attaching to Crystal Sets, etc. The Bobbin is Layer Wound, Mounted in Cabinet with Terminals, each LayerbeingSpaced. CONDENSER DIALS. and suitably engraved, comprising Designed togive maximum Fitted with Knob and Bush, V -Holder ;Fils. Res.; Intervalve Amplification. Engraved to t8o° Transformer. PRICE 20/- each. 3/9 each. PRICE 65/- Without Valve. Delivery-Stock.

THE NEW A NEW UNI-WAVE AUCKLAND INDUCTANCES PRODUCT. Duo Wound. 3 Coil Holder with Range from 300-30,000 m. Control Remote InductiveValues keepingCapacity are to be found in effects from ho iy. Catalogue. Finish as a first- PRICE per set of8 class instrument. 12/6 PRICK; 22/6 h. We are also Manufacturing CompleteSets,for Broad- cast use or Experimenters. INSIST upon haying AUCKLAND Products. All AUCKLAND Valve Apparatus is duly licensed under Marconi Patents for amateur use in Great Britain.

G. Z. AUCKLAND & SON, StlIONJDo0hNnOFSFtICrESee:t, E.C.1 Faetories-ISLINGTON. N. WIRELESS INSTRUMENT MAKERS. 'Phone - - 3173 CLERKENWELL x I THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 4, 1922 A Superior Variable Condenser -ready for home construction Notacollectionofmiscellaneous material but an excellent Variable Condenser ready to give long and reliable service. PricesforPanel All spacing washers, plates, ebonite end Mounting. pieces, spindles, etc., are accurately cut No OF and standardised throughout. Each set VALUE. PRICE. is supplied in a neat partitioned box PLATES. with full instructions for assembling. .001 57 12/6 Rapidly increasing sales of Peto Scott Variable Condensers encourages us to .0005 29 8/- add to our facilities for quantity production.This, in turn, permits us to .0003 19 7/- reduce our prices materially.Get a Peto Scott and you will obtain a better .0002 13 6/- Variable Condenser forless money. .0001 7 5/6 Showrooms & Offices Featherstone House, 64, High Holborn, W .C.1.

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THE NATIONAL RADIO COMPANY The Broadway Radio Works CarltonHouse, BIRMINGHAM. DEVONSHIRE ROAD. BEXIETHEATH, KENT. offeraseriesofhigh-class Instrument Component parts at the following attractive prices: - Filam entResistances - each 3/- and 4' - Knobs 1r, brassed bushed, 2 B.A. ..each 8d. CRYSTAL SETS Valve Holders, ebonite, matt or polished.. each 1/- and 1,3 Every Setis thoroughly testedbefore it leaves our Condenser Dials, engraved with knob,each 12, 2,- and 3/ - works. Fittedin beautifullyFrenchPolished Condenser Dials, less knob.. .. each 1,-, 1/4 and 2/3 Mahogany Cabinet with Lid. Sliders, ebonite, with plunger .. ..each 1/ - Terminals, ebonite, insulated .. dos. 3/ - Crystal Galena Detectors, on ebonite base.. ..each 4/9 Range 200 to 3,000 metres .... 1400 Contact Studs, with nuts and washers . .. doz. 1/ - Range 200 to 500 metres £3150 Copper D.P. Throw -over Earthing Switch.. .. each 5/6 Condenser and Filament Scales, Ivorine.. each 1/- and 1/8 The second setis specially designedto give maxi- Switch Arms, laminated phosphor bronze.. ..each 2/3 mum efficiency on the Broadcasting Wavelength. Condenser Knobs and Pointers . ..each 1/2 GridLeakandCondenser,sealed,completewith Terminals .. each 2/3 CONDENSERS Blocking Condensers, ebonite parts and screws ..each 1/ - De Forrest Pattern Coil Plug .. each 1/ - Cabinet Pol- Value Panel Panel Twin Ebonite Coil Stand, complete with handle, fitted Cabinet Cabinet Mount-ished plugs, etc. each 9!6 Mount- Mount- Mount- Mount- ing As- Mahog- Three Ebonite Coil Stand, complete with handle, fitted M.F. ing ining As-ing ining As- sembledany plugs, etc. Parts . ..each 13/ - sembled Partssembled in Cabinet Ebonite Bases, matt finish, 346" ins. Cabinet 9d. 12 sq. Ebonite Bases, matt finish, l" . 1/-12 sq.ins.

Ebonite Bases, matt finish, f" 1/6 12 aqins. .0015 . 23/- 25/6 24'- 26/6 83/- 6/3 H.F. Transformer Formers, matt or highly polished, 1'8, 1/10, .001 .. 16/9 19/6 17/9 21/- 26/- 5/6 2/-, 2/2 and 2/4 each. 10075.. 13/6 16,3 14'8 16/6 22/- 5/6 Variable Condensers, .0014 M.F., ebonite dielectric, mounted 10/6 13/- 11/9 13/9 18/- 4/6 in lacquered brass case. 10/- 12/6 ..each 32/ - 11/- 13/3 17/8 4,6 Variable Condensers,0014 M.F. Ebonite airdielectric,for 0003 9/- 11/8 10/- 12/- 18/- panel mounting, brass vanes, fitted with knob and pointer. .0002 7/- 9/- 8/- 9/8 18/8 0001.. . . 8/- 7/- 8/8 12/8 4/ - 0005.. ..10/6 Vernier - 4/6 - 5/- 9/- 3/8 Fitted with Bevelled Ebonite Dial 1;9 extra. .00005 ...... 5i- Special Sizes Made to Order. Price list on request. L.F. Intervalve Transformers, Igranic.. .. 22/6 ALL SUNDRIES AND COMPONENTS IN STOCK. L.F. Intervalve Transformers, Burndept .. 25/- ORDERS OVER20/- CARRIAGEPAID. L.F. Intervalve Transformers, Acme .. .. 27/ -

Telephone Transformers, Acme...... 17/ - TRADE ENQUIRIES INVITED. The above are the very best workmanship throughout.Special quotations for large quantities.Cash with Order. NOVEMBER 4, 1922 THE WIRELESS WORLD AND RADIO REVIEW xli

WIRELESS DIRECTORY

PRICE 216 NETT

An absolutely up-to-date list of all commercial (land and ship), service and amateur transmitting stations. An authoritative book handsomely produced with a two colour cover (blue background).Every real experimenter will find this book a necessity. Published by the Radio Press Limited and obtainable through all booksellers or direct (post free 2/8) from DEVEREUX BUILDINGS, DEVEREUX COURT, STRAND, W.C.2. (Opposite the Law Courts.) xlii THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 4, 1922 THE WIRELESS WORLD EXCHANGE AND MART TARIFF.Advertisements are accepted for this Section at the rate of twopence per word, FOR SALE. with a minimum charge of two shillings.The advertiser's name and address will be charged for Electradix Radios and single letters and single figures will be counted Loud SpeakerHorns. -Guaranteedperfect as words.Compound wordswillbe countedacoustics. Allsizesfrom4s.6d.,complete Telephones in stock as two words. with polishedaluminium receiver base.Usual SterlingMarconi, trade terms. -MIDLAND RADIOPHONE CO., Hearsall 2,000 ohms, 49/- ; DEPOSITS. All advertisements must beWorks, Coventry. 4,000 ohms, 50/-; prepaidintheformofPostalOrders,the Four -valveSet,comprisingdetectorpanel, 8,000 ohms, 57/ - remittance being forwarded to Messrs. BertramMk. III three -valve L.F. amplifier in case, com- per pair, complete Day & Co., Ltd., 9 & so, Charing Cross, S.W.I. plete with valves, 6 volt H.T., 6o L.T., two pairs with cord and tag. Intending purchasers may deposit the purchasetelephones, ooor Var. Condenser Coil, galvo. and Sullivan's L. R. money of any articleadvertised or sold byvolt meter, £20.-MAcicAy,/6,Hilda Road, Head 'Phones with advertisers with Messrs. Bertram Day & Co., Ltd.,Brixton. cord, Mgt per pair. who will acknowledge its receipt to the vendor Accumulator, 2 Volt Celluloid, unspillable I //i6" New L.R.Head and the depositor, the full addresses of whomX 21" x 31", 25. 9d. each, postage gd.-THOMAS Sets, 12/- per pair should be given.Subject to special agreementOLDHAM & CO., Grimsby. with cords. New between the parties,itis understood that all Two One -Valve Receivers and three -valve L.F. I,5oo ohm Head goods are sent on approval, each party payingAmplifier,alsochangeoverpanel,cheap.- Setswithcords, carriage one way in the event of the goods beingDAVIDSON, 56, Granville Street, Barnsley. 20/-perpair. returned.The deposit will be retaineduntil Single Receivers due advice of the completion of the purchase has Low Frequency Transformers,forpanelor and Cord, 4/8 each. been given or until the articles have been retainedbase mounting, fittedterminals, very efficient, and accepted.In order to cover postage, etc.,cheapest on market,15s.6d. each, post free. Large stocks of a fee of 6d. in respect of sums of Li and under,-THREE SPIRES RADIO,14,HighfieldStreet, Ammeters and and Is. for sums in excess of kx, must be paidGreat Heath, Coventry. Voltmeters,Milli -ammeters and Hot Wire at the same time as the deposit.For persons Two Portable Receiving and Transmitting Sets, Ammeters, 10/- to 60/-.Morse hikers, 45/-. not resident in the United Kingdom these feessuitable clubs, £6 exchange. -DRAKE, Toesland, ReceivingSets.MarkIIB. 2 valve,in St. Neots. polished mahogany case, new and guaranteed, are doubled. We cannot undertake to receive £75e. CrystalSets,variable condenser any deposit less than 25. 6d. New Sullivan Telephones, with trans- detector,and fixed inductance, mahogany former,3os.Set of basket coils with ebonite case, 45/-.5o D.C. Sets for Crystal and Two tuning stand, 20S.New table, three coil, stand, Valves,£75s.,inslopingdeskpattern, 205.-48, Wellington Road, Bradford. polished mahogany cabinet, calibratedfor Three complete 5KW Marconi Sets for Sale. broadcastwavelength.SwitchArms,1/6 adal Recent manufacture. Two absolutely like new. and 1/9 each. Prices from £130 each. -LIVERPOOL SCHOOL OF Buzzers.2/8, 8/6 and 5/- each.Terminals, WIRELESS, 12, Colquilt Street, Liverpool. 2/8 and 3/- per dozen.Valve legs, 1.d. each. Seten-Valve Amplifier, R.A.F. pattern, excellent Studs, 1/8 per dozen. order,forsale,price£20. -Write M. L., 441, Condensers.2M.F.,1/6each.4M.F.,5/ - Salisbury House, E.C.a each.VariableforPanel,6/6,11/8and Mark III New, converted into complete single - 18/9..cox Cabinet, 82/6.Murdoch Rheostats valve receiver, km.-WitsoN, Marden Terrace, for panel, 7/8, with vernier extra lever 8/-. Cullercoats. Our make, 3/9. Connecting up wire, 23's/40's, ld. per yard. Insulated Sleeving, 5d. per yard Ex -Army Hornless Loud .ipeakers.Low re- in four colours. sistance.With 14 hole switchboard, 3plugs, Aerial Wire. -7/22 enamelled copper, 5/6 per 7 terminals, ebonite base.By Siemens kEdiswan. 100';hard -drawncopper,5/8perIon'. Voltmeters Ammeters 18s. 6c1. ezch.Post is. 3d.Below. Aerial Down Leads, 12 yd. lengths, 1/- each. 0- 3 0- 3 Telephone Transformers and Condensers, 120 EarthClips,6d.each.Earth Mats, 10/ - 0- 6 I 9%6 0- 6 ohms on teak base, four terminals.8s., post gd, each. 0-10 . Postage0-10 Postage Below. Transformers.Intervalve Transformers, 20/ - 0-15 3d. 0-15 3d. Rs -Navy LowResistanceTelephoneswith each. Telephone, 15/..,all brand new and ALL OTHER READINGS IN STOCK. rubber earpads, spring clips for headband, 4s. each. guaranteed.Lightning Arrester parts, M. Post 9d.pair. Stamp particulars.-CornIAN, Switches.AerialtoEarth,2/9.Dewar Greita Hall, Newton Meatus, N.B. Flush type, three-way lever switches, 8/6 each. " Hart " 4 -volt Accumulators, new and unused. Eight -way A.T.I.Switches,8/-.3o amp. Complete in metal case with handle, only 12s. 6d. D.P.,16/-.R.A.F.LightWeight In- Below. sulators, Ebonite, 4d. each. Revolution Counters by Harding, Richardson, H.T.. Battery Units.4*volts,6d.each ; Rhodes & Co., suitable for counting coil turns x5 volts, 8/2 each. up to Ioo,000 and repeat.Reciprocation motion. All Wireless Components can be Supplied from Easily coupled to lathe or winder.Special low Stock.Write for Catalogue, 4d.Call and price 21S.each. -Sr. GEORGE'S MOTOR,16, inspect our Huge Stocks. Fulham Road, South Kensington, S.W.3.Tele- TheHandiestDepotforCityBuyers. phone, Kensington 5441. Near Aldgate Station, Metropolitan Railway. Condenser Vanes. -Aluminium. zoG.,fixed First on the left in Minories. or movable, 7d. dozen, 6s. gross.Spacer washers, large, 34d. dozen, 3s. gross;small, 24d. dozen, LESLIE DIXON & CO, 2s. gross.Postage extra. -R. DOUGHTY & SON, Cooke Street, Wolverhampton. 9, COLONIAL AVENUE, MINORIES, E.l andSiemens HalskeValves.Ex- Broadcasting 7/22 Phosphor BronzeAerials, A.E.G. 4s.Copper, 25. gd.Stay ropes, 42 wires, 4s. 6d. ceptionally good for Rectifying and Amplifying. 28 wires, 4s., all per too ft.Trade terms only. Filament I Volts.Plate 60;80. Cash On DIVOiee.-PARTRIDGE & CO., 6, Higgitt PRICE 7/6 Each.Post 4d. Road, Attercliffe, Sheffield. Adapter as shown for" R " Type Holders. Whetstone Bridges, 120 ohms, 4/ each.Postage PRICE 3/- EachPost 2d. Is. 6d. -D, 20, Devonshire Road, Forest Hill, S.E. All Wireless Accessories in Stock.Is your Wireless Amateur going abroad wishes dispose Whether1Z asE a sourceS of practical informationri S name on Mailing Listfor New Illustrated of new Marconi Unit Set, comprising plug coil for the Amateur or as a valuable medium for Catalogue ? tuner, 0.1 condenser, three -valve panel,1 H.F., every Adve,liser, thebest resultsare dect., I magn., telephone trans.Every wave- invariablyghobihe .ined ti wireless world flthrou Grafton Electric Company lengthcovered.Allinstrumentsmadeby t Showrooms-54,GRAFTON STREET, Marconi Co. cost over £35.Will sell£27 Los. For Jul, partsoular, and ativer raks apply SI Wireless Mesta -Improved girder type, light BERTRAM DAY & CO., LTD. TOTTENHAM COURT ROAD and strong.Up to 5o ft. at is. 3d. per ft.Over Complete Advertising Service, LONDON. W.I.Telephone -Museum 241. 5o ft.,Is. qd. per ft.Cash with order.Carriage Works -Slough. forward. -F. ARMSTRONG, Weybridge. 9 an,I 10 CHARING CROSS. S.W.1 NOVEMBER 4, 1922 THE WIRELESS WORLD AND RADIO REVIEW xliii THE WIRELESS WORLD EXCHANGE AND MART

FOR SALE-continued. COIL, WINDING, WIRES. THOMPSON'S Surplus Depot, ClearanceSale, Prices per lb. Agents Required make room for fresh stock. S.W.G. S.C.C. D.C.C.S.S.C. D.S.C. Enamd. Crystals. --The best qualitytested government 20 2/2 2/3 4/0 516 2/4 at once in provincial towns where not crystals.BestCarborundum,8/-perlb. 22 2/6 2/11 4/8 6/0 2/6 Cut Crystals per gross, 7/-. Per dozen selected, 24 3/0 8/8 5/0 6/6 2/8 already represented to sell and demonstrate 2/-.700 lb. in stock. 26 3/7 4/1 , 4 8/0 3/2 Chalcorprites.-The finest crystal for long range 28 4/4 4/8 5,'8 9/0 3/6 the Stuart Wireless Telephony Companys' stations that can be obtained, used in nearly 30 5/0 5/6 6/8 10/0 3/10 all government sets. 32 6/0 7/3 8/0 12/6 4/2 Receiving Sets (reception of Broadcasting, [Testimonial) 6, Conway Road, 34 7/0 8/3 10/0 18/6 4/4 Plumstead, 36 8/8 10/0 13/0 15/6 4/8 concerts, operas, speech, etc.).Previous DEAR SIRS, 38 11/8 18/0 18/0 19/0 5/3 It may be of interest to you that the Chalcor- 40 15/0 17/6 20/0 22/8 7/6 knowledge unnecessary for manipulation : prite Crystals you supplied to me have exceeded 7/22 Aerial Wire, plain, 4/- per 100'. my expectations.I have now experimented with' 7/22 Aerial Wire, enamelled, 5/- per 100'. valuable agency, big business, cash or every known crystal on the market, and I find Bobbins Free. Postage extra. that these are far superior to any other crystal Reels 3d. extraifunder lib.of any size. deferred payments ; thosewithshop yet advertisedgiving me a further range of 5 Intervalve Transformer Coils Wound to 6 miles compared with others.Wishing you premisespreferred.Write or call for every success, with best Silk Covered Wire ready Yours truly, for Assembling. particulars W. H. WARMAN, Price complete with Core 10/- (Engineer B.O. Trade). A typeValveHolders,1/-.Knobs,5d. Price per lb. uncut THE STUART WIRELESS .. 8/ - COIL W.PIDEAS TJ THE TRADE. Price per gross 8/- Price per dozen, selected ..2/- PH JhE-HOP 60 0. I,000 lb. in stock. G. GILLIVER & CO., TELEPHONY CO., The demand for this crystal is now getting greater 16, Lorrimore Buildings, Lorrimore Street, and we advise all Traders to keep a stock. London. S.E.17. Kingsway Corner Buildings, Zincite Crystals, Selected, Price per gross 40/ - Price per dozen .. 5/ - 109,KINGSWAY,LONDON,W.C.2 Silicon Crystals, large size, Tested, Price per gross ENGRAVING Price per dozen .. 3/- for every style of instru- Bornite Crystals, ment on anymaterial. Price per gross ..10/ - HEATH & Co., Ltd. Price per dozen .. 3/ - Instrument Works, New Eltham, S.E.9 Galena (Best), F. OSBORNE & CO., LTD. are prepared to undertake in their luny Price per gross .. 7/8 27, Easteastle St., Oxford St., London, W.1 Price per dozen .. 2/6 Est. 1874. Museum 2264 equipped works- Wireless Apparatus Wood'sMetal(Government)inilb.sticks, and Parts for the trade. Quotations given Price per lb... 5oolb. now left in stock. toBluePrints.Immediate attention. Having purchased this large stock of crystals THOMPSON'S continued. Green 3oz. Wire-'Polaris, London and Wood's Metal we are able to supply the trade and do not cause interferehce with aerial radio at a good discount.Don't delay. stations, as all wireless signals from these sets W Spark Coils (Wireless).-All fittings mounted are sent via earth only, having no aerial and on ebonite.Beautiful coils costing £4 each, work off 6 to 8 volts. I Buy Wireless Gear we are now selling the last 5o at 10/8 each,Tranzmitters.-W.T. Sets Forward Spark. 20 watt. 1/- postage.All tested perfect before dispatch. B, M.K. II rear, Transmitter 8o (or 65) metres. of every description. 1" Sterling Spark Coils.-Brand new.Cost £3These sets contain high-class Sterling spark coil, Send your particulars to : each,our price 7/8 each.Post 1/-. beautiful aluminium polished spark cap, with Mica, for building condensers, .002, .003 thick, adjuster, condenser, ebonite adjuster on and WILKINSON, 31X4i, per gross 20/-, per sheet 2d. off switch, and battery plug, all mounted in Accumulators, only a few now left - mahogany case, waterproof.These sets are Lonsdale Rd., Kilburn, N.W.6 4N, olt too amp. actual ..18/- also brand new, costing £12 los. each, to work

SAME ADDRESS SINCE 1900. 6 Volt too amp. actual 26/- off 6 volts.Price 20/- each.

4 Volt 3o amp. ignition 10/- Notice.-Amateurs are not required to have a 6 Volt 3o amp. ignition ..14/ - transmitting licence to purchase any of the These are second-hand but in chargeable con- goods we advertise, and should, therefore, take dition.A good bargain to anyone. advantage of our offer.Receiving came with Your Case Work The following goods are all Brand New Unissued a boom, and so may transmitting in the future. Let us quote you for your wirels Government Stock Terminals. -2,000 in stock.Brand new G.P.O. casework.NA, e are specialists in this M.K. III Power Buzzer Wireless Transmitters.-A Terminals z B.A.Retailing elsewhere at 8d. class of sorts and feel sure our work- high-classinstrument,containingbeautiful each, our price, 4d, each. manship and paces will interest you. buzzer, built of laminations, 3 coils, gunmetalSmoothing Chokes, 250 ohms, 5o henrys, useful on Phone-L.W. 2720. base.Very heavy contacts, micrometer adjust- a lot of circuits, containing /lb. 3o gauge wire ment3 -wayterminalblock.Thisbuzzer totally enclosed by iron core, 2/6 each.These CARRINGTON & NEWBERY LTD., weighs alone 61b., so gives an idea of the work- are also useful for converting to Transformers. 182), Normans Buildings,Cld Striet, E.C. manship. Pullerphone Chokes, Soo ohms.Very fine wire One high-class Morris, Ltd., hot wire ampmeter. half enclosed by iron core, useful as above, One high-class folding Tapping Key with heavy 2/- each. To the Trade platinum contacts, worh alone 10/6. t,000 ohm coils wound on neat iron core bobbin, One 2 -way change over receive and send Rotary 1/8 each. Switch, heavy bearing, mounted on ebonite. 3 H.P. Crypto, Alternating Current, 200 volt, CONNOLLY'S (Blackley) LTD. Three high-class 2-M.F, Condensers. so period, 2 phase motor with starter, a snip, One in and out Switch.All these fittings in- £10 10s. Blackley, Manchester. cluding different terminal junctions are con-Arc Lamps, 5o volts, 5o periods, makers A.E.G., tainedin one Buzzer Transmitter.Costing all brand new and not out of wrappers, with ENAMELLED WIRES for the Government fig. each.All brand new in electric variable rotator automatically adjusting original wrappers, price 20/- each.Mounted in carbon.Cheap enough to break up for experi- MAGNETS and AERIALS brass frame and engraved.200 in stock. menting.18/- each, cost £4 10s. London Office;18, Victoria St., S W. 1 Note.-it is of interest that to note the aboveT. W. THOMPSON & CO., Tel. Vic 6368. Telegrams Lifehold, Vic Power Transmitter is useful for private com- Government Surplus Depot, munication by persons within radius of 5 miles,' 39, London Street, Greenwich, S.E.10. \IR THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 4, 1922 THE WIRELESS WORLD EXCHANGE AND MART

FOR SALE-continued. HIGH TENSION ACCUMULATORS. As Cheap as Dry Cells. WIRELESS CABINETS Satisfactory at Last. E. Valves 10/- each, £5 per dozen. B Valces THE IDEAL H.T. I2/- each, per dozen.All new and tested. Where DC or Rectified AC is available.In Post free.B. CALVER, 52, Linver Road, London, PROMPT DELIVERIES groups of 30 volts, 4 actual amp. hour.Size S.W.6. COMPETITIVE PRICES 9" x 11" x 21", weight 4 lbs.Price, 30 volts, Four -valveSetcomprisingdetectorpanel, 10/- ;300 volts, £4 17s. 6d. Mk III three -valve L.F. amplifier, in case, com- Write enclosing stamped envelope, plete with valves, 6 volt H.T. 6o L.T., z pairs PICKETT BROS., " High Tension Accumulators," telephones, olio'var. condenser, tuning coil, Albion Rd., BEXLEYHEATH, S.E. 121, Honor Oak Park, S.E.23. galvo and voltmeter, £20.-MACKAY, x6, Hilda Road, Brixton. B.A. Screws, Nuts and Washers, assorted gross TO THE TRADE. 25.,lists2d.-J. H. BENNETT, Station Road, Willesden Junction. ONE OF OUR SPECIALITIES Nearly all the principal dealers are stocking Aerial Equipment is Useless without Masts.- OUR Variable Condensers, while most of the We supply from is. 8d. each.Stamp.-DowNEs, big manufacturers are incorporating them in Arthur Street, Derby. "S I D L EY" their Sets.There's a reason ! BOOKS. High -Frequency Transformers. FALLON CONDENSER COMPANY, Do u ble-Groovei. Highest Efficiency. 230a, HERMITAGE ROAD, LONDON, Technical Books.-Second-hand and New No. 1-300/530 1 6i.EACH N.4. Books on every conceivable subject.Catalogue ,,2-500/920 free.Statewants.Books sent on approval. Books bought.-FOYLE, 121, 125, Charing Cross ,3-9C0/1500 tPostage 31. Extra. Road, London. 4- 1450/2600 Complete Set of Five RadioIflagazines,allthelatest," Radio 5-2400/4000 Post Free. A.S.A. Guaranteed World,"to d.; " PopularRadio,"mid.; " Radio Broadcast,"is.6d. ;" Radio News," We also manufacture in-between WirelessProducts is.6d. ;" Science and Invention,"is.9d. ; sizes la, 2a, 3a at same prices. " ScientificAmerican," 2S. 6d.Postfree.- INTERNATIONAL NEWS COMPANY, LTD., 15, Best Filament Resistances 3/- Bream's Buildings, London, E.C.4. G. R. MARSON, LTD. 15v. H.T. Batteries-The Best .. .. 3/ - Electrical and Radio Engineers, Grid Leaks and Condensers ..2/6 Fixed Condensers, 002.. - .. 2/ - MACRHIERY FOR SALE. HALES STREET, COVENTRY. Laminated Switch Arms and Bush .. 2/ - Condenser Vanes, the best .. doz. 1/ - Lorch Lathes, all sizes in stock, send for list.- Vernier Condensers, 0001 .. ..4'6 PIDGEN BROS.,25,Helmet Row, Old Street, Variable Condensers in Cabinet, .0005 ..1816 E.C.I. 100' 7,22 Aerial Wire...... 4/- INDUCTANCE 4000 ohm Headphones (good) 26/ - TRADE ENQUIRIES. . Crystal Receiving Sets . 25/ - Sets of Parts for 2 -Valve H.F. Amplifier . 30/- Working Drawings supplied for wireless ap- 2 -Valve L.F. Amplifier.. paratus.Motors,generators,etc.,designed. 3 -Valve H.F. and L.F. Amplifier.. ..60/ - Informationandadvice.-PucicLE,Buckhurst TUBES Cabinets, 10" x 6" x 4", polished .. 5/ - Hill, Essex. Condenser Boxes, polished .. .. 2/6 Will Manufacturers of Wireless Sets and Com- 3 -Coil Honeycomb Holders .. ..1613 ponents, who have not already done so, kindly Wholesale tradesupplied. H.F. Transformers, for Broadcast .. 3/8 forward trade lists to H. V. ALBROW, Wireless Honeycomb Coils from...... 1/8 Engineer,56, George Street. Portman Square, Strawboard, plain, or impreg- Concert Coils .. .. per pair 2/ - W.I.

Coil Holders, for same.. - 5/ - Wireless Dealers throughout Great Britain are nated. strongly advised to stock parts for making up OUR LIST BEATS THEM ALL. wireless sets.Buy your parts direct from the factory at wholesale prices.-NEWTONIA WIRELESS THE UNDERWOOD Amateur SuppliesAssociation FACTORY, 13 and 15, Whitcomb Street, W.C.2. MANUFACTURING CO., Five per Cent. off (cash with order) any wireless 134, Coteford Street, Tooting, S.W. set, component, accessory or materials.-GENERAL 25,UnderwoodStreet, London, ELECTRICAL SUPPLY CO., The Portway, E.x5. Works: 196,HighStreet,Merton,S.W. Alver.iser wiling to invest £200 in estab ished W.1. whet ss t_cm-aily, active employment r qu red, Six yea s' exper.ence.-Bcx T.5, BERTRAM DAY'S ELECTRADIX WIRES ADVERTISING OFFICES, 9 and to, Charing Cross, Highest Conductivity at Lowest Prices. S.Vk .1. SITUATIONS VACANT. Gauge. D.C.C. S.S.C. D.S. 1 MISCELLANEOUS. SalesEngineer.-Requiredimmediatelyby 18 .. 194 .. - .. Sympathisers with Soldiers and Sailors who haveleading London firm of manufacturers, a really 20 .. 1 11.. 4 .. been blinded or deprived of useful sight in thefirst-class sal s engineer with intimate knowledge war are reminded that the address at which theyof radio apparatus in all its phases.In addition 30.. 5 .. to technical knowledge, must have sound com- 24 .. are being cared for and trained is THE HEAD- Write in QUARTERS OF ST. DUNSTAN'S WORK, Inner Circle,mercial experience and good address. 28 .. 42 .. 5 .. 1 Regent's Park, London, N.W.x.Cheques to beconfidence, stating age, experience, and salary 4 made payable to the Treasurer. (Registered underrequired, Box 905, SELL'S ADVERTISING OFFICES, 32 .. 664 .. 8 .. the Blind Persons Act, 1920.) Fleet Street. E.C.4. .. .. 9 .. 1 Advertiser(17)seekssituation,threeyears' East Ham, Wanstead, Ilford, Manor Park and experienceofwiring,testing,and 8846 .. 92 .. 11 .. 12 4 Forest Gate.Amateurs should not fail to comepractical to the RADIORENDEZVOUS, 709, Manor Parkassemblingwirelesssets.-BoxM6, BERTRAM 40 ..16121.. 17 ..23 Broadway (over Liptons). Club open till to p.m.DAY'S ADVERTISING OFFICES, 9 and co, Charing Prices at per lb.Postage Extra.Earth Clips, nightly. Cross, S.W.I. Kr -Soldier,(24),experiencedwireless,seeks 8d. each.7/22 Aerial Wire, 7/- per 100 ft. any capacity.-Write C. YOUNG, 36, Conduit Way, EVERYTHING FOR WIRELESS IN STOCK. SITUATIONS WANTED. Brentfield Estate, Stonebridge, N.W.ro. Electrical Engineer, 20 years'aU round experience Wanted.-A man with expert knowledge of LESLIE DIXON & CO-, on all kinds installations and apparatus, designingRadio -Telephony Trade experience an advantage, 9, Colonial Avenue, MInories, E.1 and making of complete Wireless sets, etc.-BoxApply by letter stating experience and salary. -WIRELESS, C/O BROWN BROTHERS, LTD., Great (mar A idgatoStattan ) Telephone Avenue 4166. S.5, BERTRAMDAY'S ADVERTISING OFFICES" 9 and to Charing Cross, S.W.I. Eastern Street, E.G. I. NOVEMBER 4, 1922 THE WIRELESS WORLD AND RADIO REVIEW xlv

WIRELESS Our claim tospecialised know- ADVERTISING ledge inWirelessAdvertising is based on Ten Years' practical 1912-1922 experience. This, together with ourCompleteWirelessAdver- tisingOrganization,is atthe disposalof every bona -fide Advertiser entirely free of charge. Nobusinessistoosmallor toolargeto command our BE R TRAM DAY'S promptattentionandcourtesy. (Bertram Day & Co., Ltd.) Whatever your Advertising Organisers of the First All -British problem or difficulty, it will pay Wireless Exhibition - - /922 youtoget intouch withus. Wireless Publicity Spec alists Why buy your experience when Contractors, Printers & Publishers expert advice is yours for theasking 9 & 10 CHARING CROSS, S.W.1 Gerrard 8063 & 8064 BRANCHES AIMANCHESTER & GLASGOW

UM I Laboratories and Factories : All communications to Reg. Offices :I

King's Rd., St. Pancras, ANODE 265, STRAND, W.C.2 LONDON. Tele. Nos.: City 4887, Cen. 3722 WIRELESS AND SCIENTIFIC INSTRUMENTS LTD. I Members oftheBritish,Droadca tingCompany

ANODE POPULAR SETS. ANODE PATENT VARIOMETERS I These Sets Receive Two Bands of Waveleng'hs- (New Type) I 35 -800 metres (for British Broadcasting)

Improved pattern employing Two Lattice Wound Coils 2,00 -3,8:0 metres (for Paris Time Signals an 1 Conceits, also NAITEN. only, so keeping both Resistance and Self -capacity) low POPULAR CRYSTAL SET ...£4 11 6 Model 'A" 350-3,600 metres ...£3 18 6 I (71" x 51"x2)" with Renewable Crystals). 6 Patent Condenser Tuning. "B" 2,500-25,000 metres... 3 18 I POPULAR SINGLE VALVE SET... 7 100 "A" or "B" fitted with Vari- (9" x 8" x 3" with Fixed Reaction). able Reaction Coil 4 15 0 Patent Condenser Tuning I

"C" (simplifiedmodel) 150-

ANODE VARIOMETER SETS. 600 metres ... 1 5 0 Employing our New Type of Patent Variometer 251- 2810 me res continuous. With Reaction... 1 17 6 CRYSTAL SET . ... 6 76 I (7r x 5r x ar with Renewable.. - Crystals). The above Variometers are completein Cases.I SINGLE VALVE ... 8 19 6 (9" x 8" x 58" with Fixed Reaction). conform to the Corresponding Reduction if required for The above ReceivingSets all Panel Mounting,. I Postmaster -General's latest Regulations. I NOW is the Time to Order. Your Final Choice.Why Not Your First? Trade Enquiries Invited. xlvi TILE WIRELESS WORLD AND RADIOREVIEW NOVEMBER 4, 1922 BEFORE YOU CANSTUDY WIRELESSTELEGRAPHY AND TELEPHONY YOUMUST HAVE A KNOWLEDGE OF MAGNETISMAND ELECTRICITY Dear Sir, A HEADMASTPR'S APPRPCIATION. Enclosed please find cheque for 6/-in payment for book, " Magnetismand Electricity for Home Study," whichyou sent me on approval. It is a book for which I have been seeking forquite a long time.The lucid way in which the author puts the matter before thereader ; the sequence followed (proceeding from the known to the unknown) ; the numerous analogies and associations withordinary everyday things and the excellent sketches anddiagrams, together with test and summaries make the work admirable for questions self study or as a book for schooluse.As a schoolmaster I am using it as a base for the sciencescheme in my school.

THE WIRELESS PRESS, LTD. Dept. W.W. Crystal Mastand E. - E12-13, HENRIETTA ST., LONDON, W.C.2 Aerial 11111111111111IIIIII111110rniiitill1IIIIIIIIIIIIIIIIIIIIIIIIIIIIIII Receivers Constructionfor for Broadcast Amateurs Reception By F. J. Ainsley, By Percy W. Harris. A. M.I.C. E. 80 Pages. 75 Photographs and Diagrams. 88 Pages. 70 Photographs & Diagrams PRICE1 /6 NET. (Postage2d.) PRICE 1/6 NET.(Postage2d) This book is one which the amateur will read This book includes directions for building a with gratitude to the author who has ren- simple crystal receiver for wireless telephone dered agreatservice in removing the broadcasting. difficulties of mast and aerial construction. Contents.-General' Principles of Wireless With the use of a few ordinary tools and by Reception.CrystalRectifiersand their following the instructions given in the book Properties.Tuners for Crystal Receivers. this will be found a simple matter. PracticalCrystalDetectors. Telephone Contents.-Various Types Masts.General Headpieces.Aerials and Earth Connections. Information. Scaffold -pole Masts. Plank What you may Expect to Hear. How to Masts.Stayed Lattice Mast.Self -support - Adjust a Crystal Detector.Making Signals Mast.-Tubular Mast.Aerial System. Louder. THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 4, 1922

READY IN A FEW DAYS THE BINDING CASESYEAR BOOK VOL. X. OF The WIRELESS Wireless World TELEGRAPHY AND TELEPHONY & Radio Review (INCLUDING INDEX) 1922. PRICE 151- NET. Price nett. 2/6 Postage Inland 11- Abroad 1/4 (Post free 2/11.) 1476 Pages. Demy 8vo. The Wireless Press, Limited INDEX(IF PURCHASED S EPA RATE LY Dept W.W.,2-13 Henrietta Street, Strand, London, W.C.2

Price 'Post free. 8d. THE RADIO EXPERIMENTER'S HANDBOOK By PHILIPR. COURSEY, A limited number only of B.Sc. (Eng ), F.Inst.P. COMPLETE BOUND VOI,. X 113 pages. 99'Diagrams and Illusliations. (April-September, 1922) PRICE 3 I 6 NETT. (Postage 6d.) Price nett. THE WIRELESS PRESS, LIMITED, (Post free 26/-) Dept. W.W., 12/13, Henrietta St., Strand, London, W.C.2

AMATEURS THISa WANT HAl For the benefit of those of our readers who desire to have their parts bound,we shall be THE VEST POCKET glad to undertake this for themupon receipt of the copies and remittance of 8/6 which Dictionary of Technical includes cost ofBinding Case, Index and TERMS USED IN WIRELESS WORK. return postage. Over 1,500 definitions. Price 2s. 6d. net. Post free 2s. 9d. The WIRELESS PRESS Ld. 12-13, Henrietta St., London, W.C.2 THE WIRELESS PRESS, LTD., 12-13 Henrietta Street, Strand, London, W.C.2 NovEmitEi{ 4, 1922 THE WIRELESS WORLD AND RADIO REVIEW

1 -4 -aft.A.--- talkdie 3vetiorte3 Handphonc which has been specially designedforladies. Ithasno headband to catch or tear the hair. Beautifullyfinished and very com- fortabletouse. PRICE (4000 ohms) 15/- EACH (PostageI /- ) He willuse Fellows Headphones withtwoearpiecesinlightdie cast non -ringingmetalwound to 4000 ohms. PRICE21! -PER PAIR (Postage1/-) All Fellows radio instruments are British Made throughout and guaranteed.

FELLOWS MAGNETO Co., Ltd. LONDON, N.W.10 Telephone :Willesden 1560-1. Telegrams :Quismag, Phone, London

lI arejoatgadIllows THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 4, 1922 H. W. SULLIVAN (LTD.) FORMERLY H. W. SULLIVAN, FOUNDED IN 1900. One of the oldest established manufacturers in this Country of Radio Telegraphy and Telephony apparatus ;the pioneer in the systematic design, construction and supply of Amateur Radio Sets and Components, and infurnishing users withpracticalelectro-technicaladvice, e.g. inter-alia the Sullivan Book of Working Diagrams of Valve Amplifying Receiver Circuits.10,000 copies of this book, the first and most complete of its kind, have been issued to all parts of the World. ImprovediiBroadcast " Crystal Receiver (PATENTS APPLIED FOR) THIS Set has been specially designed for " Broadcasting " and with a view to simplicity, efficiency and reliability. By means of a switch itis adapted for use on aerials varying in dimensions and shape ;it has only one adjustment-for tuning.A sensitive and robust type of crystal, and one which requires no extreme delicacy of adjustment, is employed.

H.W51.11.1.1VAN LONDON

SULLIVAN PATENT TWO VALVE ALTERNATIVE SINGLE CRYSTAL RECEIVER. NOTE MAGNIFIER. VALVE NOTE MAGNIFIER. Beautifully made and remarkable for its appearance and finish, this receiver forms a miniature nucleus cabinet complete in itself, to which Note Magnifier units of similar appearance may be added at will to increase the strength of reception and to enable many telephone receivers to be simultaneously used. The special advantage, so useful in practice, of this arrangement lies in the fact that by simply adding further small units to the system, any desired degree of magnification can be inexpensively obtained. PRICES, including Commission to the British Broadcasting Company (Ltd.), as determined on Oct. 19th, 1922, and Royalty to Marconi's Wireless Telegraph Co. (Ltd.). CRYSTAL RECEIVER (each) ... £2176 CRYSTAL RECEIVER with highly sensitive and distortion - less Sullivan phones, aerial wire, insulators,etc. ... 4176 SINGLE VALVE NOTE MAGNIFIER excluding valve

and batteries .. 4 1 00 TWO -VALVE NOTE MAGNIFIER. (Ditto) 7 50 VALVES (each) 176 HIGH TENSION BATTERIES, dry from 86 ACCUMULATORS ... 1 00 BUZZER TESTING UNIT... 1 00 New ,Book of34Valve Diagrams (4th edition), and New Catalogue W4,Price11-each, post free within the United Kingdom, the British 'Dominions and the Crown Colonies and Dependencies. DEMONSTRATION AND SHOWROOMS :Liverpool House, MiddlesexStreet,E.1 (Two minutes walk from Liverpool Street and Broad Street Stations.) TRADE TERMS ON APPLICATION. Works : " LIVERPOOLHOUSE,"INCHEOSffiTcEesRHOUSE, MIDDLESEX ST LONDON, E,1HW° Sullivanuvan9 LtdLONDON, E,0,2, ENGLAND Phone-Avenue 4871 Telegrams-" Deadbeat, Stock. London:' Phone-London Wall 3518

Printed by Sanders Phillips & Co., Ltd., Chryssell Road, London, S.W.9, for the w Proprietors and Publishers, The Wireless Press, Ltd., 12.13, Henrietta Street, London, ... W.C.2 ; Sydney, N.S.W., 97, Clarence Street ;Melbourne, 422-24, Little Collins Street ;New York. 326, Broadway. 11th NOVEMBER, 1922. THE PRICE 6D. NET. WIRELESS WORLD AND RADIO REVIEW

TINGEY UNIVERSAL RECEIVER

(REGISTERED DESIGN)

All " Tinge), Valve Apparatus is duly licensed under Marconi Patents for Amateur use in Great Britain.

Offices&Works Phone HAMMERSMITHI 916 Telegs. NCO; DAR LONDON' THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 11, 1922 STERLING No. 1 CRYSTAL WIT RECEIVING SET Specially designed foruse in connection with the Wireless Telephony Broad- casting Scheme, and is suitable for a rangeof about 25 miles. PRICE £7-12-6 TO BE OBTAINED FROM ALL DEALERS OR DIREGT FROM STERLING TELEPHONE & ELECTRIC CO., LTD. 210-212, Tottenham Court Road, LONDON : W.1 Telephone No. : 4144 Museum ()lines) Telegrams : " Cucumis, NS esdo, London." Works : DAGENHAM, ESSEX. BRANCHES t NEWCASTLE -ON -TYNE :9, Claming Plane. IMMEDIATE DELIVERY CARDIFF :8, Park Rase. CAMBRIDGE A.M. GALVANOMETER A moving coil galvanometer of good sensitivity, suitable for general laboratory work and student's use. This galvanometer has been designed for quantity production, and, on that accountitis possible to offeritat a price which compares favourably with pre-war prices. SIMPLE AND INEXPENSIVE

Approximate Deflection in mins at r metre. resistance of

Per micro. amp. I Per micro. volt 20Ohms. 13° 7'5 150 320 2.13 400 450 1.124

The Cambridee andPaul INSTRUMENT CO LTD WM., 45 GROSVENOR PLACE, FULL PARTICULARS ON 4 i CATIMUDC,6 6,1ko.,,Ja., LONDON S.W REQUEST NOVEMBER 11, 1922 THE WIRELESS WORLDAND RADIO REVIEW iii Wireless Needs Cost You Less at

FIRST IN FOREMOST 1908 TO -DAY GAMAGES THE PIONEERS OF WIRELESS APPARATUS FOR AMATEURS Upon the quality and design of your apparatus depends the success lowest in London.Gamage's vast experience is at your service - of your experiments. Gamage instruments are of the best and have all orders and enquiries, whether in person or by post, are dealt set the standard of quality throughout, while the prices are the with by Wireless Experts. Gamage Variable Condensers SKEMPTON TYPE as illustration.This pattern is intended for the experimenters who are constructing their own sets, being expressly designed for mounting behind panels.This condenser is of very robust construction, the moving vanes being L clamped at one side and the whole element firmly held together by means of aluminium castings. An engraved ivorine Also supplied irk 1 scale and handle isfitted with capacity of as shown. Capacity, 000762 0004mfd. mfd. PRICE,postfree, 0 IM PRICE, post free IV I lll VERNIER TYPE. An exceedingly usefullittlecondenser, designedexpressly for the purpose of connecting in parallel with an instrument of larger capacity in order to obtain very fine tuning for telephony, and it is really essential that one of these should be added to receiving sets, using a variable condenser of ordinary type.Capacity, 000087 mfd. PRICE, post Pd., z Nos.Variable 1 & 2 Air Dielectric Type Condensers (FARADAY HOUSE CALIBRATION). This instrument is one of the neatest PARLIP HON E " obtainable.It is of the best workmanship,electrically and mechanically LOUD SPEAKER perfect.It has so fixed and 9 moving vanes, and a maximum capacity of (Pros. Patent No. 21967) .0003 mfd.Top and bottom panels of matt ebonite and polished rounded ECONOMICAL. NO METAL edges.Fitted with engraved ivorine USED IN ITS CONSTRUC- scale, as shown. A TION. EQUAL IN EFFI- handsome andeffi- CIENCY TO THOSE THREE cientcondenser. I TIMES THE PRICE. i PRICE,No. x, This Loud Speaker com- No.2, .0043mfd.,33/6. priseshorn and stand mouldedinonesol d p:eceofEbonite. It contains no receiver, but Brown's the interior is screwed and made to receive a Brown's PatentStandard Re- 'Phones ceiver.In this way by Not to be confused with simplyunscrewingone the "reconditioned" ear-p:ece from the exist- 'phones at present on the ing Headphones and in- market. These 'phones were serting it in the " Parli- supplied to His Majesty's Write now fora phone' an efficient Loud Government, andevery Speaker is obtained at a instrumenthastherefore Copy of Gamage's small cost.The remain- passed the strictest test. ing ear -piece can still be BROWN'S HEADPHONES, utilised for tuning in the " A " Type, Reed Pattern, WIRELESS ordinary way. As no metal is used in its con- Aluminium diaphragm, struction, the objection- 120 ohms. CATALOGUE able metallic " ring " so common. to most Loud PRICE,OUR4216 Profusely illustrated Speakers is entirely ob- 8,000 ohms. viated, the result being a PRICE and giving full rich mellow note without OUR PRICE,49 6 details and prices. the slightest SULLIVAN 'PHONES, 8, 000Rohms. ,Z 6/6 Post Free on request Packing andPostage, OUPRICE, 1 3 extra. Carriage paid. Cords 2/9 extra.

GAMAGES HOLBORN LONDON E.C.1 iv THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 1l,1922

111111111111111111111111111111111111i BURNDEPT 11111111111111111111111111111111111111 ,',ZpVertrigivreS:

A Rheostat of Quality.

Adjustable Tension. Diecast Metal Bush. Removable Resistor Element. Hard Brass Connecting Strip. Moulded Asbestos Composition Former. Moulded Stop. Phosphor Bronze Contact Arm.

THIS Rheostat, which is fitted to all Burndept apparatus, has been designed to embody efficiency in action with simplicity in fitting. A special feature enables the tension on the phosphor bronze brush to be adjusted so that a silky smooth movement, combined with perfect electrical contact, can be ensured.Can be fitted to panels from Ith to iths thick by drilling one 4" and two 6 B.A. clearance holes.The resistor element is mounted on a fireproof former to which is moulded thestop, engaging the phosphor bronze brush inoff and full on positions-this brush is riveted to the rotating spindle. PRICE 41. BOXED.

fully Illustrated Catalogue containing much useful information and details of our apparatus will be sent post free //- All Burndept Apparatus is made in our Model Factories- AERIAL AND EASTNOR WORKS, BLACKHEATH, S.E3

A 11 BURNDEPTValve Apparatus is duly licensed under Marconi Patents for Amateur use in Great Britain.

LondonOffice & Showrooms :15, BedfordStreet, Strand BURNDEPT, LTD./ Aerial and Eastnor Works, Blackheath, S.E.3 NOVEMBPR 11, 1922 THE WIRET.IS WORLD AND RADIO REVIEW

111111111111111111111111111111111111 11111111111101111111111111111111111111 BURNDEPT

Ethophone

AThree -valve broadcastreceiverwithself-contained valves, and H T. battery.Wave -length range 250 to 650 metres covering all BritishBroadcast stations ; plugincoils permit indefiniteextension of wavelength, enabling telephony from Air Stations,Paris,Berlin,etc., to be received.Range of reception over 150 miles on head telephones or 80 miles on loud speaker ;longer ranges for powerfulContinentalstations.Resultssurpassallex- pectations, andsimplicity ofoperationenablesachild to use the instrument. Supplied in Polished Walnut Cabinet, complete el A with valves and H.T. Battery. PRICE. L34. Gns. American Amateur Tests. THE Burndept Ultra 111is recommended for the reception of these signals-it gives ample H.F. and L.F.amplification.The followingtestsignalswere received on October 29th between 05.48 and06.00 G.M.T. American amateur 2 ZK 254 metres, strength R.6

R.3 9 9 2 H J 240 ,, and twoothersnotquitestrong enough to be properly read(One, query 5 VL.) BURNDEPT Intervalve Transformer. THE Burndept Intervalve Transformer has been designed to secure maximum amplification with minimumdistortion. The coils are former wound and vacuum impregnated ; they are mounted on a laminated stalloy core.These Transformers will not burn out when used with anode potentials up to 150 volts, as they are tested at a pressure of 500 volts,winding to winding and frame, and also with a current of 10 milliamperes flowing through the windings. Minimum insulation resistance 250 megohms.g5 Guaranteed against breakdown.PRICE, S.BOXED. A fully illustrated catalogue containing muchuseful information anddetailsofourapparatuswill be sentpostfreet 1-. All Burndept Apparatus is made in our Model Factories, Aerial &Eastnor Works, Blackheath, S.E.3. AllBURNDEPTValve Apparatus is duly licensed under Marconi Patents for Amateur use in Great Britain. BURNDEPT, LTD.,London OfficeAert !hfawstr,,00rorror:ks, Bedford reE3 Street, Strand.

111111111111111111111111111111111111111111111111111 11111111111111111111111 IIIIIIIIIIIIIIMBIBB11111111111111111111111111111111111111111111111111M11111111111111I1111111111111111111111111 A 2 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 11, 1922

Radio Music fromevery Electric Lampholder

THE DUBILIER CONDENSER CO. (1921), LTD., DUCON WORKS, Goldhawk Road, Shepherd's Bush, London, W.12 Telephone-Hammersmith 1084. Telegrams-Hivolteon, Phone, London. ( ode-Marconi International. NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REV! 1,:11" VII DUBILIER Dubilier Condensers are used by every Government and Radio Company throughoutthe World. GRID LEAKS FIXED CONDENSERS Types 600 and 600a.

Capacitiesuptoand Each. 2/6 including '0009 Each. 2' /

'001to'005inclusive, Each. FIXED CONDENSERS,1 Type 577. THE,.NERSALCONDENSERDUBILIER TIPE 600 Any capacity up TYPE N°577 to '01mfd. Each - NBCA c DENSFP URiLIER THE "VANICAN" CONDENSER CC (iSZOLJP isa Variable Air Condenser made in three types :- Type A, for panel mounting as With Clips for illustrated. Grid Leak. Type B, in ebonite container. Type C, in Polished wood case. (Prices for tall capacities upon application.) CONDENSER DUSILIER CONDFMSF.,. V121)1.7.

Without Clips for THE "MICON" Grid Leak, is a Variable Condenser with a micadielectric. (Prices forall capacities upon application.)

Buy Dubilier Products-they are the best. THE DUBILIER CONDENSER CO. (1921), LTD., DUCON WORKS, Goldhawk Road, Shepherd's Bush, London, W.12 Telephone-Hammersmith 1084. Telegrams-"Ef.frolteon, 'Phone, London." Coie-Marconi International. viii THE WIRELES 'WORLD AND RADIO REVIEW .NovEmBEn11, 1922 r 4 ARIDNI111111111111111111E11111i1111NlillIff1111111111H111111111111111111111111111111111111( RDION The Ideal Full Range MAHOGANITE RECEIVING SET. A Valve Set com- 0 This is the latest product of our Factories- pletefor working Xi I Ia superior insulating material for high grade sets, which ingrain and colour closely For the successful reception of concerts,telephony resembles mahogany. Its high insulating and continuous wave " Morse," the following set - can be enthusiastically recommended.It includes and non -warpingproperties,combined all the very latest approved advancements of wire- with a beautiful finish, make it an ideal less science-itisthesetthatwillgive most material for Panels. pleasure to the expert as well as the newcomer. As you will see from the particularsbelow the equip- IThe Trade are warned against imitations- ment is complete, and we shall ordinary mottled Eboniteis NO T at all times be pleased to an- RADION - MAHOGANITE. All swer anyqueriesthatany enthusiast might genuine Sheets are stamped "RADION ". desire to raise. dnquiriesfrom bona -fidesManufacturers and AGENTS Wireless 'Dealers solicited. WANTED. IAMERICAN HARD RUBBER COMPANY (Britain) LIMITED, 13a, Fore Street, London, E.C.2 TELEPHONE -12754 CENTRAL.

DON'T HOPE FOR THE BEST DESCRIPTION. stipulate Single valve, mounted on polished 1 -in, ebonite panel, withvariable condenser, smooth act- ingresistance, grid leakandcondenser, and all terminals clearly engraved in white, AND GET IT in a mahogany polished cabinet,9in.by5in. Why haven't you a copy of our illus- by 5in, ACCESSORIES INCLUDED. trated list ? Are you afraid of troubling us ? Siemens 54 volt high tension Battery with plugs is itsenvelope for altering the voltage. A catalogue ready in 4 -volt 50 amp. hr. low tension Accumulator in case and only needs posting to you. with carrying strap. One pair of sensitive headphones of 4,000 ohms We would have sent it to you before now resistance. but we haven't your address. On Mullard " Ora " detecting valve. Set ofcoilsfrom 300 metres to 25,000 metres Will you let us have it ? wavelength. A REFINEMENT.-Ifdesired withacoil holder List 4d. post free, returnable with first order. andasetofbroadcasting coilsasillustration, 25/-extra. These allowa much finer tuning. Send at once for Our Illustrated Catalogue GREENSLADE & BROWN WIRELESS INSTALLATIONSLTD. 15, Aldersgate Street, London, E.C.1 LANSDOWNE ROAD, CLAPHAM, S.W.9 TRADE ENQUIRIES INVITED. Telepltonet-BRIXTON 639 & 3251

1 1 11 1 11 I II I III 111111111111111 III 1011111 Ii 7c,ivEmBEP 11.II -22 THE WIRELESS WORLD AND RADIO REVIEW relk. "DUROS" CELLS The onlyaccumulator suppliedina charged state. They retain their charge for very long periods. Stocked by all leading dealers in " Wireless Supplies." E. G. LIND & CO.,58a, BUCKINGHAM PALACE ROAD, WESTMINSTER, S.W.1 THE WIRELESS WORLD AND RADIO REVIEW THE OFFICIAL ORGAN OF THE WIRELESS SOCIETY OF LONDON A MAGAZINE DEVOTED TO WIRELESS TELEGRAPHY AND TELEPHONY CONTENTS The Transadantic Communication Tests.By Philip R. Coursey, B.Sc., F. Inst. P., A.M.I.E.E. ------185 A Universal Four -Valve Receiver - _ - - - - 187 Electrons, Electric Waves and Wireless Telephony.By Dr. J. A. Fleming, F.R.S. - - 189 A Development in the Problem of Television.By Nicolas Langer - - 197 Discussion at Wireless Society of London ------202 Contents continued on next page.

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MEN IN THE WIRELESSSERVICES DESIRING RAPID ADVANCEMENT should train in spare time with the College which ensures this. "U.E.C."(Regent'sPark, London, N.W.1) has in Twelve Years secured hundreds ofsuccesses by Individual Postal Training for Engineering Examinations and Professional Work. State YOUR ambition in confidence, to-SECRETARY'S DEPT. (Desk W.), UNIVERSITY ENGINEERING COLLEGE, WESTGATE-ON-SEA,KENT, and expert advice with the New prospectus. No. 8. will be sent you without obligation.

CONTENTS(Continued)

Notes - 203 Calendar of Current Events - 205 Correspondence 205 Wireless Society of London Proceedings 206 Wireless Club Reports 208 Questions and Answers 213 Share Market Report - 218

THE WIRELESS WORLD AND RADIO REVIEW is published weeklyon Saturdays. All correspondence relating to contributions should be addressedto THE EDITOR, THE WIRELESS WORLD AND RADIO REVIEW, 12-13, Henrietta Street, Strand,London, W.C.2. No responsibility can be taken for MSS. or photographssent without stamps to defray cost of return postage. Editorial and Publishing Offices :12-13, Henrietta Street, Strand, London, W.C.2. Telegraphic Address :" Radionic, Rand, London." Telephone No.:Gerrard 2807. Advertisment Managers, Bertram Day & Co.,Ltd., 9 and 1o, Charing Cross, S.W.I. Telephone No.: Gerrard 8o63 and 8064 SUBSCRIPTION RATES. 28s. per annum, post free.Single Copies 6d., or post free 7d. Registered at the G.P.O. for transmission by Magazine Post to Canada andNewfoundland.

HAMBLING CLAPP & CO. We shall shortly be able to supply receiving sets conforming inevery way with the latest instructions of the Postmaster -General as related to Broadcasting. Write us now concerning your particular requirements ; no obligation will be incurred byyour so doing. There are no regulations to prevent the sale of our component parts, of whichwe supply a very large number.Advice and assistance freely given.Write or call and see us. Offices and Showrooms : P Phone 88o6Gerrard. 110, STRAND, LONDON, W.C.288o6 Gerrard. NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW VALVES DELIVERY FROM STOCK.

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Writeto -day for our 38 page Radio Catalogue, 150 illustrations. Tele. No.:NORTH 580. Mailed post free for 9d. Telegrams :CONDUCTIVITY, LONDON. IN NI THE WIRELESS WORLD AND RADIO REVIEW THE OFFICIAL ORGAN OF THE WIRELESS SOCIETY OF LONDON

No. 169 [VOL.. XI.] NOVEMBER11TH, 1922. WEEKLY The Transatlantic Communication Tests. By PHILIP R. COURSEY, B.Sc., F.Inst.P., A.M.I.E.E. THE main object of the forthcoming The particulars required are transatlantic communication tests be- Name and Address of Licensee of station, tween American, Canadian, and Euro- and exact location of the station. pean radio amateurs is not only to pick up Call Letters. signals from the other side of the Atlantic Wavelength to be used. as was done last year, but also, if possible, Maximum ranges already attained (tele- to establish communication in both directions graphy). across the ocean solely between amateur stations, These transmission tests will continue for and using the amateur wavelengths. Whileseveral nights, each station taking part being arrangements are well in hand for the use ofallotted a different time for transmission on specially equipped transmittingstationsinsuccessive nights, and being requested to this, country during thesetests,there areadhere strictly to these times and not to trans- doubtless also many other amateur stationsmit on other periods.Owing to the time which have established long-distance signallingdifference between the United States and ranges, and which could therefore take partGreat Britainitwill not be practicable to in the tests with some chance of success.Itcommence the tests until midnight or i a.m. is very desirable that this country should haveG.M.T. severaltransmittingstationsinoperation In order to allow time for the completion during the tests in order to give the Americansof the final arrangements it is requested that plenty of signals to listen for.Several Frencheveryone willing to take part in these tests stations will also be transmitting. will notify the writer before November 22nd, TRANSMISSION TO AMERICA. atthe addressstated below.The special In order to avoid confusion it will be neces-code letters, and details of what is to be trans- sary to arrange a special programme of trans-mitted during the tests will be sent by post missions, so that each station taking part hasto each entrant shortly before the commence- a special period allotted to it, and also a specialment of the tests, the dates of the commence- set of code letters so that the receptions inment of which will be announced later in these America can be checked up. columns. Every amateur transmitting station that has an authentic record of having transmitted RECEPTION FROM AMERICA. signals over at least 40o to 50o miles is there- As inlast year'stests the transmissions fore asked to communicate with the writerfrom America and Canada will be sent on the of this note as soon as possible, if they areusual American amateur wavelengths in the willing to take part in the tests.The exactneighbourhood of zoo metres, and also on the dates of the transmission tests from this sidespecial wavelengths in the neighbourhood of have not yet been settled, but they will follow365 metres, which are licensed to some of their the transmissions from the United States,stations.Transmissions will take place during which are to take place in December. a period of approximately five hours on each 186 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 11, 1922 night, the stations taking part being allotted The separate heterodyne oscillator should a different portion of the five hours periodbe coupled to the plate circuit of the detector on successive nights.The wavelength of thevalve rather than to the aerial or associated transmissions at any given time will thereforecircuits, so as to remove the point at which the be different on successive nights, but it willoscillations are impressed upon the system as be possible to circulate a list of the wavelengthsfar from the aerial as possible. In this manner of the transmissions to be made during eachthe harmful effects of heterodyne radiation period each night a short time before thefrom the aerial will be minimised. commencement of the tests. Details for the construction of a heterodyne In order that any information of this kindoscillator suitable for the shorter wavelengths which may possibly arrive too late for publica-of these tests,viz., around 200 metres, have tion in these columns may be circulated to allbeen given by the writer in these columns. those who wish to listen in for the signals,(Vol. IX. pp. 461-464 and 493-497.), while it is requested that every one desiring to takeother patternsof similar instruments have part in the reception tests notify their namealso been described at a later date which can be and address to the writer before November 22nd.used over a wider range of wave -lengths so as Last year's tests again emphasised the neces-toincludethelonger transmission wave- sity of asking everyone possessing wirelesslengths aswell.One of these patterns of apparatus to refrain from using it during theinstrument suitable for the use of plug-in periods of the tests unless they are actuallycoils for any wavelength that was described using it for listening in.Except in the mostin the The Wireless World and Radio Review for favourable circumstances the signals from theMay 6th (p.161), May 13th (p.194) and May other side will on the whole not be of great27th (p.252) should prove quite suitable, while strength,sothat any local jamming maythe heterodyne wavemeter described in the completely spoil the tests.There is alreadyissue for September 3oth last, is also suitable so much interference on these wavelengthssince it covers all the wavelengths that are to by the harmonics from high power stationsbe used in these tests, as well as the longer waves. thatallotheravoidableinterferencemust For the benefit of those readers who have be eliminated if success isto be attained.not the above issues, an article giv.ng con- The radiation from oscillating receiving setsstructional details of a suitable instrument will on these short wavelengths is so large that abe published next week. single oscillating receiver may spoil the chances As in connection with last year's tests there of many others for several miles round. has already arisen a demand for the trans- Too great an emphasis cannot therefore bemission of testing signals to enable prospective laid on the necessity of avoiding the use of such listeners -intoproperlyadjusttheirsets. apparatus during the tests, and the substitutionArrangements are being made for these, and it thereforof aseparate heterodyne to pickis expected that an announcement with regard to up the C.W. transmissions.The use of onethem will be made in next week's issue of The or more high -frequency amplifying valves in Wireless World and Radio Review. front of the detector valve is helpful in this The arrangements made by the AmeriCan direction too, since not only is the receiverRadio Relay League for their preliminary tests thereby rendered more sensitive, but also thetodeterminetheirbesttransmitters were radiation from theaerialisalsoreducedrecently announced in these columns, and have should the set accidentally be brought intoled a number of amateurs to listen -in for them. the oscillating state.Any of the recognisedReports already to hand indicate that several forms of tuned high frequency amplificationAmerican stations have been heard, so that the can be used for this purpose with great ad-main tests next month should be productive vantage, but precautions must be taken toof even better results than were obtained last prevent the set oscillating, as there is a greatyear. tendency to do so in these arrangements unless BROADCASTING OF RESULTS. additional damping is provided in the circuits, It will be remembered that during last year's either by inserting high resistances in the oscil-tests a broadcast report was made each morn- latingcircuits,or by appropriatereverseding by Carnarvon radio station, which report reaction, or by increasing the damping of thewas repeated slowly by New Brunswick station grid circuits by impressing a positive potentialfor the benefit of the American amateurs, upon the grids of all the amplifying valves. giving the results of the receptions made by NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW 187 Mr. Godley, the representative of the American the United States.These reports will be sent Radio Relay League who was listening -in infrom Sainte Assise immediately following the Scotland.Through the kindness of the Mar-reports from Carnarvon, the times being am> coni Company, and of the Radio CorporationG.M.T. for Carnarvon, and 0710 G.M.T. for of America, it will again be possible to broad- Sainte Assise. cast such daily reports from Carnarvon, so that In order to enable these daily reports to be every amateur in the country will be able toprepared, it is requested that everyone taking obtain information of the progress of the testspart in the reception tests will make a report by listening in to these reports each morning.each day as far as possible setting out the re- They will be sent specially at twelve wordssults that they have obtained, so that they can per minute to make it easy for everyone tobe included in the next report. pick them up. Further details of the codes, etc., that will be The French Committee which is arrangingused for these daily broadcast transmissions the part to be taken by the French amateurswill be given in a later issue. both in listening and in transmitting, has also It is requested that all enquiries and com- arranged for daily transmissions to be mademunications relative to these tests be addressed from Sainte Assise station (near Paris), whichto the writerc/oTheWireless World and reports will be repeated by Marion Station inRadio Review. A Universal Receiver. THE receiver shown in the accompany-potentiometer, and as is seen, can be removed ing photographs is designed for receptionentirely from the box -work without deranging on all wavelengths, and arranged sotheconnections.The terminals are of the

The Valve Receiver.The view of the interior shows the construction of the Inductances and method of wiring. that any combination of valves can be thrownscrew type in order to avoid the unpleasant in circuit.The sloping front panel is securedeffect which is produced by employing a large to the top, which carries terminals, valves, andnumber of tall terminals. 188 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 11, 1922 The aerial circuit is tapped out on to a ten -perikon detector, which can be seen on the point switch, and in moving the arm over front of the panel. the contacts, the rotating spindle operates a The condenser on the left forms part of barrel switch arranged to entirely disconnecta heterodyne wavemeter circuit, arranged to theinductancesnotinuse.The closedcover the full wavelength range and varied by circuit has a six -point switch similarly arranged.plug-in coils shown on the left in the front This closed circuit can either be used as aview. A hinged platform varies the extent of secondary, tuned anode, or reaction coil, bycoupling between the aerial circuit and the operating the two -arm switch in the middle ofwavemeter coil. the instrument. A five -stud switch taps out Aerial tuning and closed circuit condensers singly the end turns of the aerial inductance, are provided, also terminals for connecting up and is very convenient for fine tuning.Thea five -plate vernier condenser. short wave portion of the aerial inductance, A low frequency amplifier can be thrown in which tunes up to about i,000 metres, consistscircuit by a switch.The other switches are partly of a single layer and partly two -pileso arranged that not only can any combination winding.For longerwavelengthsthe in-of valves be used, but also the valves can be ductance consists of two, three, or four -pileabandoned altogether and simple crystal recep- winding followed by spaced basket coils-ion made use of.The telephones are con- an arrangement which gives a minimum ofnected in circuit by plugs and jacks. self -capacity. The wiring up is effected with bare wire High frequency amplification is providedin insulating sleeving, carefully arranged and on the tuned anode principle, and rectificationbundled in order that no detrimental effects is either effected by the second valve or theare produced. F.H.H.

Broadcast from 2 KO Birmingham.

The Rt. Hon. the Lord Mayor of Birmingham Broadcasting an Appeal in aid of .Hospitals front the experimental station of Mr. C. S. Baynton (2 KO), Amateur Transmissions in the London Area. It is obvious to everyone that the time hasof such amateurs to be hed at the Institution come when some further organisation is desir-of Electrical Engineers on November i3th able amongst amateurs holding transmittingat 6.3o p.m Certain schemes will be suggested, licences in the London area.With this end inandit isdesiredthatthereshould be view the Committee of the Wireless Societythefullestpossible discussiononthe of London have arranged for a private Meetingmatter Mr. Maurice Child will be in the chair. NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW

Electrons, Electric Waves, and Wireless TelephonyVI. By Dr. J. A. FLEMING, F.R.S.

The articles appearing under the above title are a reproduction, withsome additions, of the Christmas Lectures on Electric Waves and Wireless Telephony given by Dr. 1. A. Fleming, F.R.S., at the Royal Institution, London, in December and January, 1921-1922.The Wireless Press, Ltd., has been able to secure the serial rights of publication, and any subsequentre -publication. The articles are therefore .copyright, and rights of publication and reproductionare strictly reserved.

4.-ATOMIC STRUCTURE. scientific interest, but in that year W. Röntgen We are then naturally led to consider themade a discovery of great practical importance. very important question of atomic structureHe found that when such a high vacuum tube and architecture to which all the foregoingwas in operation and the glass fluorescent, discussion has been only preliminary. paper or wood coated withafluorescent The first step in this knowledge was takenmaterial such as barium platinocyanide, was about1898or1899,when SirJosephalso made fluorescent, even outside the vacuum Thomson began his epoch-making work whichtube, when held near it, and, moreover, that led to the discovery of the corpuscle or negativesome substances, such as heavy metals, stopped electron as a constituent element of all atoms.the radiation producing fluorescence, whereas This work grew, very naturally, out of thethisradiation passed freely through wood, previous researches of Sir William Crookespaper, leather and other materials opaque to on electric discharge in high vacua, and thelight rays. discovery in 1895 by W. Röntgen of the so-called X-rays, which marked the beginning of a new era in physics. Crookes had found that when a glass bulb exhausted to a very high vacuum had one platinum electrode, called the cathode, sealed through the glass connected to the negative terminal of an induction coil, and another similar electrode, called the anode, connected to the positive terminal of the coil, then when Fig. 36.Crooke's Electron Mill. the induction coil was in action, not only was B-Highly exhausted bulb. the glass rendered fluorescent, but particles C- Cathode or negative cathode. of some kind mere projected from the cathode,A- Anode or positive electrode. which moved away in straight lines, normal to W-Little Rotor with mica waves which rotates and the surface of the cathode, could produce rolls along glass rails R.R. under impulas fluorescence in many substances placed in electrons radiated from cathode. their path, could cause little mica vanes to The great sensation of that day was, however, rotate like a windmill, and also could castthe discovery that the new rays, then called shadows of metal objects on the glass wallX-rays, from their unknown nature, passed of the tube (see Fig. 36).Crookes showedfreely through the fleshy tissues of the living that these particles each carried a charge ofhuman hand, but were more or less stopped negative electricity. by the bones.Also that since these rays Crookes named theseparticles" radiantcould affect a photographic plate enclosed in matter," but they were subsequently calleda black paper envelope,it was possible to " cathode rays " or " cathode ray particles."photograph the bones in the living hand and Up until1895,this high vacuum electricunerringly fix the position of any metallic discharge hardly possessed more than a purelybodies, e.g., bullets, needles, etc., in the flesh 190 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 11, 1922 (Fig. 37).Again, it was found that thesedenoted by the letter e, as regards amount_ X-rays produced a certain degree of temporaryThenwhen the particle carrying an electric electric conductivity inair or other gasescharge of e units moves with a velocity v in through which they passed. a direction at right angles to a magnetic force

Fig. 37. X -ray photograph of a hand with allot embedded in it. X-ray photograph of finger with a needle embedded in it.

The investigation of the nature of the cathode H, it experiences a deflecting force numerically rays and of the X-rays was taken up very care-equal to theproductHey, which is in a fully about the end of last century. Twodirection at right angles to the direction of views had previously been held as to theH and v. cathoderays.Crookesandhisfollowers maintained that they were material particles Under these conditions the electrified particle of some kind projected from the negativeof mass m is being continually acted on by a electrode in the high vacuum tube.Otherforce at right angles to its direction of motion physicistsregarded them as some form ofand hence it moves in a circle of radius v, mtherial vibration. such that Hey = mv2/r. Sir Joseph Thomson settled the question Therefore we have the relation by experiments of a remarkably ingenious and important character.If an electrified particle -v = Hr. is made to move across the space between e the poles of a powerful magnet in a direction Suppose in the next place that we cause an at right angles to the line adjoining these poles,external electric force to act on the electrified it experiences a deflecting force which is atparticle having an electric charge e.Let the right angles to the direction of its motion andmagnitude of this electric force be denoted that of the so-called magnetic force whichby E.Then a force measured by the product last lies in the direction of the line joiningEe acts on the particle.Let the direction of the magnetic poles.This magnetic force isthe impressed electric force E be so adjusted a quantity measurable in certain units.Letthat the deflecting force produced by it on us denote by the letter H the magnitude ofthe electrified particle is exactly opposite in this magnetic force.Let the velocity of the .direction and equal in amount to the deflection electrifiedparticlebevcentimetresper produced by the magnetic force. We can then second, and letit carry an electric charge,equate the two expressions for the deflecting NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW 191 force acting on the particle and have theelectric force we have denoted by E.Also equation that same part of the tube is placed between Hey = E e the poles of a powerful magnet so as to supply E a deflectingforce Hey inthecontrary Or = H- direction, but in the same line as the electric force E. Hence, if we measure, as we can do, the From the deflection caused by the magnetic magnetic force and the electric force, we canforce alone we can find the radius r of the determine fromtheirnumericalratiothecurve along which the cathode particle moves, velocity v of the cathode particle. and we can thus determine both the velocity Again, having found the velocity v we canv and the ratio elm. from the previous equation, viz., Hey = mv2lr When these experiments are carefully con- or Hey = my, find theratio of elm or ofducted, itis found that the velocity of the electric charge to mass of the cathode particle.cathode particle will vary with the potential For from the above equations we see thatdifference, as it is called, of the electrodes, = but in a high vacuum tube may be of the m Her order of 100 million feet per second, or about one -tenth of the velocity of light.This is Hence, if we measure the radius of thean enormous speed, and it is due to this immense circular path of the cathode particle when deflected by the magnetic force H, and also the electric force E, at right angles to H, which is necessary just to annul the deflection, we can calculate the value of E/H2r and thus determine the ratio elm.This ratioisan extremely important number and the investigations for its exact determination have been very numerous.The apparatus generally used Fig. 38.Cathode Ray Tube and Bulb. is shown in Fig. 38.It consists of a glass C-Cathode or negative electrode. tube about two inches wide, ending in a largeB-Highly exhausted bulb with fluorescent screen on bulb B, 10 or 12 inches in diameter. its spherical end S. At theA-Anode. extreme end issealed in a platinum wire, E-Baffle plates. ending in an aluminium dish C, which forms P-Deflecting plates. thecathodeornegativeelectrode.The positive electrode A is another wire sealedvelocity that the cathode particles are able to into a short side tube.When these electrodesmake a luminous spot on the phosphorescent are connected to the secondary circuit of an screen. induction coil, or better still to the poles of Sir Joseph Thomson found, in 1899, that an electrostatic generator such as a Wimshurstthe ratio of e/m for the cathode particle was electrical machine, which keeps the cathodequite independent of the metal of which the negatively electrified,atorrent of cathodecathode was made or of the residual gas in particles are projected from it, when the tubethe tube.Under allcircumstances exactly is highly exhausted of its air so as to make athe same ratio was obtained.The numerical good vacuum in it. value was nearly 1.77 x 107 when the charge In the vacuum tube are placed a pair ofe is measured in the so-called electromagnetic baffle plates, E, with small holes in them,units.This electromagnetic unit of quantity which allows a thin stream of cathode particlesis the quantity of electricity conveyed by a to pass.These fall on the spherical end ofcurrent of 10 amperes when flowing for one the tube, which is coated inside with a phos-second or one ampere when flowing for 10 phorescent material called willemite, or withseconds, or about the quantity of electricity powdered zinc blende.The cathode particleswhich passes through the filament of a 16 impinging on this screen make a bright greencandle -power 200 -volt lamp in a minute and spot of light on it.Within the tube -are alsoa half. placed a pair of metal plates, pq, which can This constancy in the ratio of elm for all be electrified, one positively and the other particlesindicates that they are identically negatively, so as to create the required deflecting the same in every case. 192 THE WIRELESS WORLDAND RADIO REVIEW NOVEMBER 11, 1922 We must make a little digression to explainelectricity from the other plate, re-forming the manner in which this ratio can be deter-hydrogen and oxygen atoms which in turn mined for the hydrogen atom and what con-unite, pair and pair, to form molecules, and clusions can be drawn from it. these constitute the bubbles of gas liberated. If we place two platinum or gold plates in We see, therefore, that the electric current water which is slightly acidulated and connectwhich passes through the electro-chemical these plates with a storage battery of a couplevessel, consists of charges of electricity which of cells, we see bubbles of gas arising fromare carried by hydrogen and chlorine ions. both plates.By collecting these gases inTo every hydrogen atom there corresponds separate tubes we can prove that the gasa certain electric charge.If, therefore, we arising from the plate in connection with thewish to determine the ratio of charge to positive pole (marked red) of the storage cellmass for a single hydrogen atom or ion we is oxygen and the gas collected at the otherhave only to determine how much electricity plate is hydrogen.By measuring the volumepasses, corresponding tothe liberation of of these gases collected we can find that theone gram of hydrogenatthe negative passage of a current of one ampere for oneelectrode. Now, exact experiment shows second through the acidulated water liberatesthat a current of one ampere flowing for 1.04 ten -thousandths of a gram of hydrogenone second, conveys a quantity of electricity in the form of gas.These two gases arecalled one coulomb, whichisone -tenth of produced by the electro-chemical decomposition an absolute unit of electricquantity, and of the acid which is mixed with the water.thisliberates0.0000109 grams of hydro- Suppose for the sake of simplicity that we gen.Hence, the ratio of charge to mass or consider the water to have been acidulatedelm for the hydrogen ion is a number near to with hydrochloric acid.Each molecule of10,000 or 104. We have seen, however, that this acid consists of an atom of hydrogenthe ratio of charge to mass or elm for the united to an atom of chlorine and the chemicalcathode particle is 1.77 x 107 or 1,779 x 104 formula is therefore H Cl. or 1,700 to 1,810 times greater than elm for the Absolutely pure water is not a conductorhydrogen ion. of electric current, or at least a very bad one The question then at once arose :isthis If we put into this water a little hydro-difference due to a difference in charge or chloric acid the water causes a number ofto a difference in mass between the cathode the hydrochloric acid (H Cl) molecules toparticle and the hydrogen atom or ion ? become separated into atoms of hydrogen 5.-CATHODE PARTICLES OR ELECTRONS. which arepositivelyelectrified and atoms Sir Joseph Thomson gave a reply to this ofchlorine which are negatively charged.question in 1899 by experiments of extra- In this state the electrified atoms are calledordinary skill and ingenuity. ions and the acid is said to be partly ionised. It was found that particles in every way The word ion means a wanderer and theysimilartocathodeparticlesareliberated are so called because they wander about infrom the surface of polished zinc and some the liquid. When a hydrogen ion collidesother metals when they are illuminated by with a chlorine ion they may become re-ultra -violet light or light rays of very short united into a hydrochloric acid molecule for wavelength. Also they are liberated from a short time, but presently the ions are detached Radium and the X-rays of Röntgen liberate again.If then we place in the acid water twothem from molecules of air. metal plates which are electrified the negative When produced by either of these methods plate attracts and draws to itat the instantthese cathode particles have the power of when it is free the positively charged hydrogencondensing round themselves water vapour ion and the positive plate similarly attractspresent in air and forming a minute water the chlorine ions. spherule or drop of water. Thecholorineions,however,havea The white clouds we see floating in the strong affinity for hydrogen ions and theysky are composed of such small water drops. even take these away from molecules of water Allair, unless specially dried, has inita thus reforming HC1 and liberating oxygencertain proportion of water vapour which is ions against the positive plate. These hydrogenan invisible gas.If, however, the air is cooled ions then take negative electricity from thebelow a certain point it cannot hold as much negative plate and the oxygen takes positivewater vapour in solution and it gets rid of NOVEMBER 11, 1922 THEWIRELESS WORLD AND RADIO REVIEW 193 and deposits the excess by forming a cloudaction of the cathode particles each of the or mist. This isthe explanation of thelatter condensed round itself a drop of water early morning mists in the atmosphere whichand began to fall downwards.The rate of are really formed during the night, when thefalling, by Stokes' law, is determined by the atmosphere is cooled and the excess of watersize of the drop, and from the observed rate vapour condensed to water spherules.Theseof sinking of the upper sharp surface of the small drops of water fall very slowly throughcloud we can calculate the diameter of the the air owing to the friction or viscosity ofminute drop of water from the formula the air. given above and hence the mass of the drop. Many years ago Sir George Stokes gaveWhen the cloud has sunk a certain distance a formula connecting together the diameterthe upper metal plateisgiven a positive (d) of the drop with viscosity (q) of the airelectric charge and this produces an electric and the final or constant velocity (v) whichforce E in the space between the plates which the falling drop attains. This formula iscan be adjusted until it just arrests the fall 1 gd2 v =- where g stands for the accelerationof the drops. 18 We then know that since each drop contains of gravity and is nearly 981 in centimetresa cathode particle of electriccharge e we and seconds as units. must have the equation When moist air is chilled by being suddenly Mg = Ee expanded it has been found that the excessWhere M is the mass of the drop and g the of moistureisnotreadilyconverted intoacceleration of gravity. From this equation droplets or mist unless there are dust particlese can be determined. in the air.These, however, assist the con- Some admirable measurements of the same densation by affording nuclei round whichkind, only using oil or mercury vapour in the water vapour condenses. Many yearsplace of water vapour, have been carried out ago it was discovered by Mr. C. T .R. Wilsonby Professor R. A. Millikan in America.The that cathode particles could act in the samebest andfinalresultisthat the cathode manner in perfectly pure dust -free air. particle carries a negative electric charge of expanded and4.774 x 10-10 electrostatic units or 1.591 x 10-20 cooled a cloud does not form but the airelectro magnetic units.In other words, six becomes supersaturated with moisture. Ifmillion billion cathode particles carry between then cathode particles are introduced a cloudthem a quantity of electricity equal to that forms at once.Wilson found that if theconveyed by a current of one ampere in one supersaturationdidnotexceedacertainsecond. amount only the negative or cathode particle It was thus found that this very small quantity acted as a nucleus or core for the condensa-of negative electricity is a natural unit which tion of water vapour round it, and a cloudcannot be divided, and is in short an atom or mistis formed in the vesselin which of electricity.Electricity was thus seen to be the moist air is suddenly expanded. a commodity like cigars or cigarettes or things Sir Joseph Thomson and Prof. H. A. Wilsonof the kind that are supplied only in multiples applied this method to determine the cathodeof some finite unit. particle electric charge as follows : To this atom of negative electricity the late He suddenly expanded pure dust -free airDr. Johnstone Stoney gave the name of the in a glass vessel and thus supersaturated theelectron, but the term electron is now applied air with moisture.He then introduced intoto the cathode particle, or negative corpuscle this air a number of cathode particles eitheras a whole. by allowing ultra -violet light to fall on a zinc It became clear,therefore, that identical plate in the vessel or else by exposing the airelectrons were constituentsof allmaterial to the X-rays. The expansion was performedatoms and could be extricated from them. in a glass vessel having in it two metal plates, an upper and a lower, which could be con- 6.-ELECTRONS AS CONSTITUENTS OF ALL nected at pleasure to a voltage battery of a ATOMS. certain number of cells so as to make the upper It was not then a long step from this point plate positive and produce a certain electric tothe suggestion that atoms consisted of force in the space between the plates. When groups of electrons, arranged in a certain way the cloud was formed by the condensingand held together by the attraction of some

B 2 194 THE WIRELESS WORLDAND RADIO REVIEW NOVEMBER 11, 1922 form of charge of positive electricity.The If the opposite pole of a bar magnet is now first suggestion was that this positive chargeheld near the surface of the water the needles of electricity, the nature of which was unknown,will be drawn toitbut will be mutually existed in the form of a sphere of the size repelled.Under this double action they will of the atom and that the negative electronsarrangethemselvesincertainforms(see were distributed through it like pips in anFig. 39).Thus three needles will set them- orange, but able to circulate about or revolveselves at the angular points of an equilateral in it. triangle, four at the corners of a square, five The late Lord Kelvin made this suggestionat corners of a pentagon.Certain arrange- first, and its consequences were mathematicallyments are, however, unstable, especially if the developed by Sir J. J. Thomson. needles or electrons are in rotation round the If we supposethesphereofpositivecentre, and when more than a certain number electricityto be composed of stuff whichof needles or electrons exist in the group the attracts electrons external to itself with a forcearrangement isnot stableunless they are which is inversely proportional to the squarearranged in two or more rings. of the distance, then it can be shown that a Certainfactsdiscovered bySirErnest sphereof suchpositiveelectricitywouldRutherford, and strongly supported by the attract an electron embedded in it, towards theoreticalinvestigationsofProfessorN. its centre, with a force proportional to theBohr, of Copenhagen, seem to militate against distance of the electron from the centre.Ifthe view that the positive electric charge is then by any means the electron isset indiffused over a sphere the size of the atom, motion, it will revolve round the centre of thebut strongly support the view that it is con- sphere of positive electricity in a circular orbitcentrated in a small centre or nucleus which included within the boundary of that positiveis very small compared with the size of the sphere. material atom itself, and perhaps not large If a number of such electrons are includedeven compared with the size of a negative in the sphere they will arrange themselveselectron. in certain rings or orbits, certain arrangements The theory of atomic structure now some- being stable and others unstable.An illus-what widely held, called the Rutherford -Bohr tration of this sort of structure is found intheory, is that a chemical atom consists of a an interesting experiment due to Mayer. nucleuswhichiscomposedofnegative electrons,heldtogetherbystillsmaller positive electrons, the positive electrons pre- dominating in number sothat the whole nucleus has a resultant charge of positive electricity if we assume that the charges of positive and negative electrons taken singly are equal. Thus, for instance, the nucleus of the Helium atom issupposed to contain four positive electrons and two negative, which are bound by mutual attraction and repulsion into a Fig. 39.Mayer's Magnet Experiment. compact mass, which Rutherford concludes Little magnetised needles floating vertically in water has a diameter of not more than one ten - and caused to arrange themselves in a pattern by athousandth part of that of the whole atom, magnet NS held over them. which we have seen to be of the order of one - A large number of sewing needlesarehundred -millionth of acentimetre. This thrustthroughlittlediscsof cork.Thenucleus has, therefore,aresultant positive needles are all magnetised and then, if placedcharge equal to two units, taking the unit to in water in a basin with the cork button slidbe the electron charge.Around this nucleus along to one end, the needles will all floatcirculate two negative electrons like planets vertically in the water.If then the upperround the sun and the atom, taken as a whole, ends are all similar magnetic poles, the needlesis therefore electrically neutral. will repel each other like electrons, and if The atom, on this theory, is a solar system left to themselves will get as far apart asin miniature.The nucleus corresponds to the Fossible. central sun and the negative electrons to the NOVEMBER 11, 1922 THE WIRELESS WORLDAND RADIO REVIEW 195 planets circulating round it.The electronsthe diameter of this circle may be different in need not revolve in the same plane nor even alldifferent molecules of hydrogen, so that these in the same directions, and each orbit may havemolecules are not in all cases of exactly the not only one planet but two, three, or more,same volume. even up to eight, as the case may be. We have seen that the mass of the negative It will be seen, therefore, that an atomelectron is only about 1/1,700th of the mass forming what we usually call solid matter isof the positive electron and this leads to the in fact a very open or porous structure, con-conclusicm that the true mass or gravitative sisting of a certain number of very densemass of the atom resides almost entirely in andextremelysmallparticlesdistributed throughout acertainspace, otherwise un- occupied, which we call the volume of the atom. 7.-A MODEL OF AN ATOM. Thus if we desired to make a model, say, +0------0+ of a helium atom, we might place a sphere, say, the size of a football at a certain position to representthepositivelychargednucleus. 6- Then at distances of about miles, we should have to locate two golf balls to represent the two negative electrons and to assume that these Fig. 40.Model of a Hydrogen Molecule, were revolving round the football like planets round the sun, but not necessarily in the samethe positive electrons.The reason for this plane nor in' the same direction as regardsmay be in the much greater density and smaller rotation. size of the positive electron. In the case of an atom of hydrogen, the In addition to this Rutherford -Bohr theory nucleus consists of a single positive electronof the structure of the atom, another view has and a single negative electron, the two revolvingbeen advanced and supported by Langmuir, round their common centre of mass. Whenwhich regards the negative electrons assembled two atoms of hydrogen unite to form a molecule,round the nucleus as stationary and not in we have two positive electrons at a certainrevolution. We shallnotenterintothe distance apart, and two negative electronsdiscussion of this theory because itentails revolving in a circle, the plane of which ismuch greater mathematical difficulties than perpendicular to the line joining the twothe Rutherford -Bohr theory, in that we have positive electrons and its centre on that line.to account for the fact that there must then The two negative electrons are at oppositebe localities round the nucleus to which the ends of a diameter of the circle in which theyforces acting on the negative electrons converge revolve (see Fig. 40). in all directions so as to produce stability. It appears from certain considerations that (To be continued.) The Signof Official Approval. The accompanying illustration returned to the manufacturer, is reproduced from a seal issued who will retain the sealed ap- by the British Broadcasting Co., proved set for reference when which, according to Post Office necessary.Each set sold will regulations, mustappearon be stamped or bear a transfer everywirelesssetusedby similar to that shown, and these Broadcast licencees. sets will be reproductions, as far Asalreadystated,manu- as possible, of the sealed instru- facturers of broadcast apparatus ment, the electrical conditions are required to submit specimen being carefully reproduced. instruments to the Post Office Only sets bearing this mark forinspection, and eachset can legally be used when broad- approved willbe sealed and casting starts. 196 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 11, 1922 New Type Broadcasting Receiverin the plate circuit of the second valve. A few turns are tapped off along the inductance Messrs. Siemens Bros. & Co., Ltd., have recently introduced a new type of receiver designed essentially for reception of broadcasted telephony.It embodies the use of both crystal detector and valve note magnifier, and by means of a simple change -over switch, can be arranged for employing (a)crystal reception only; (b) single valve reception only; (c) crystal reception with note magnifying valve. The instrument embodiesseveralnovel features ;for instance, it is impossible to close the instrument and leave thebatteriesin circuit, for the battery circuit is broken by the act of replacing the lid.Also, to save the trouble of disconnecting leads every time the

according to the degree of reaction coupling required, these turns being common to the tuned anode circuit and the plate circuit of the second valve. A New Variometer

Siemen's Broadcasting Receiver, Type C.V. instrument is put away, slots are cut in the lid to permit of the leads passing through. The finishisparticularly good, and the arrangement of the controls makes an instrument which is particularly durable. An Approved Circuit. Now thatthePostmaster -General has authorised the introduction of reaction into receiving circuits, when it is arranged between the plate circuit of the first valve and an inductance in a subsequent valve circuit, the problem of the best method of utilising this arrangement presents itself. Tuned anode high frequency amplification means the fitting of an additional tuning con- Igranic Variometer. denser and introduces the complication of Thisvariometer,manufacturedbythe adjusting a number of circuits simultaneously.Igranio Co., is of a particularly novel design, This circuit shows a very simple way ofits two coils remaining in shape solely by the ensuring the setting up of oscillations withoutsystem of winding, which is such as will give the introduction of an additional inductancean absolute minimum of self -capacity. NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW 197 A Development in the Problem of Television. By NICOLAS LANGER.

The following article, contributed .from Hungary, describes experimental work in connection with the problem of TelevisionWhilst the actual process described does not include transmission by wireless, yet this being a logical development from linetransmission, the subject as presented should be of greatinteresttowirelessexperimenters. purpose of the following articlearea of each element or spot must be sufficiently is to describe a development in methodssmall so that no difference in tone, would forenablingobjectsatadistance .a to be seen by the eye by means of electrical circuits or by wireless, in much the same manner as the ear is enabled by means of these methods to hear sounds at a distance. The problem of television has been already partly solved by the methods adopted by Professor Korn.Professor Korn's apparatus, however,relatesonlytothetransmission of photographs, and the process takes from six to fifteen minutes, and the method is not a direct one, but one which necessitates taking a photograph in the ordinary way and afterwards reproducing it by means of the Korn apparatus.The following article will describe apparatus by means of which distant objects can be made visible without the necessity of the use of the intermediary of the camera, and itis even possible to represent at the receiving end pictures in motion in a similar manner to the cinematograph.It is claimed that in this system it is possible to transmit a picture at a speed exceeding that of the Korn transmitter by ro,000 to 20,000 times.The very interesting nature of the problem attracted my attention many years ago.The results ti of my investigations are no doubt of interest, and I will therefore give here a short resume of this work in order to introduce the subject intelligibly. Every picture (if we disregard the colours) may be regarded as consisting of a combination of black and white spots, and for the sake of simplicity, throughout this article, we shall termthesespots" pictureelements."It is easily understood that these picture elements vary in brightness from black down through gradations of tone to white.In order to set about transmitting a picture, we must first 03) analyse the picture into elements. and the Figs. la and lb. 19s THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 11, 1922 With this introduction we may now proceed to divide the process of the transmission of a picture under five headings :- (1) Analysis of the picture into picture elements. (2) Translating the varying tones of the picture elements into a varied stream of electrical impulses by aid of light-sensitive cells, such as selenium. (3) The transmission of the stream of C varying electrical impulses to the receiving station. (4) The rearrangement back into their original formation of the picture elements. B (5) The composition of the picture from the elements so obtained.

be apparent to the eye by any further sub - division.The next processistotranslate the picture which has been subdivided into elements into some form for transmission by telegraph.This is done by running on the picture elements by various degrees of tone, one after the other in a continuous stream and in their correct order, and translating the variations in tone into variations in electric current in the transmitting line. As the picture elements in the form of electrical impulses of varying intensity arereceived Fig. 2. at the receiving station, they are rearranged back into their correct order, and the process gradually builds up a picture which resembles It may be seen, therefore, that the process the original.If itis arranged that at anyresolves itself into a kind of transference of point of the receiving station the stream ofenergy.For thesakeof conveniencein picture elements can be observed by the eye,transmission, the light energy is converted it will be realised that only a single pictureinto electrical energy, and at the point where element is visible at one time, but nevertheless,reception is carried out the electrical energy the whole picture may appear to the eye atis caused to revert to light energy. once, since the process of transmission under We will now proceed to consider in detail the present system is arranged to take placeIhe various headings under which we have within the space of one -tenth of a second.subdivided the problem. It is well known that the human eye suffers Asalready mentioned, this process con- from a limitation which is commonly called sistsinpassing the pictureelements one the lag of the eye, and itis this limitationafter the other in correct order past the light- of the eye which is made use of in practicalsensitive apparatus (selenium cellor other application of the cinematograph.The eyeapparatus) in order to convert the changes can only record impressions of light of aboutin light values into changes in electric current. one -tenth of a second duration, as any changes This process isillustrated in Fig.I(a), in light value of shorter duration than one -(b) and (c).The principal portion of the tenth of a second are recorded as one impressionapparatus is the mirror C, which has a tongue only. R, and is supported between delicate points NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW 199 so that it is free to move between the poles abouttmillimetre in area.On the other of the electro-magnets D1 and D2.The am-side of the diaphragm is located the selenium, plitude of the movement of the mirror isor other light sensitive cell, Se, the electrical controlled by the spacing of the two softconductivity of which varies with varying iron cores, S1 and S2.The mirror is set indegrees of illumination. motion in the following manner. The electro- In the period of one -tenth of a second the magnets are composed of two coils, T1, T2, T3mirror makes too single(half)oscillations and T4, two of which are in series.Thein the plane of the diagram (Fig. 2), so that first circuit is in series with a direct currenta beam of light passes back and forth past battery B, whilst the other is connected inthe aperture in the diaphragm one hundred serieswith an alternatingcurrentsupply, times.During the same period the mirror thefrequency of which issoo a second.also makes one swing inaperpendicular The battery B supplies the polarising voltagedirection so that the beam isdisplaced in for the electro-magnets, the two adjoining a perpendicular direction at a speed too times poles of which are north.The alternatingslower than the other movement. current passing through the other coils results A littleconsideration will show thatat in oscillation of the tongue R, and consequently every movement a different picture element the mirror, back and forth at a frequencyappearsthroughthediaphragmaperture, depending upon the frequency of alternation and in one -tenth of a second the light sensitive of the current. cell Se receives, so to speak, the entire picture. In additiontothismotion, the mirrorThe whole process repeats itself ten times must be made to swing in a vertical plane,a second, so that even the transmission of and to accomplish this the frame is supportedmoving pictures becomes a possibility. between pivots, and is provided with a tongue As light-sensitive cells it is usual to employ R2.This frameiscausedtooscillate byselenium, which is highly sensitive, but pos- means of the synchronous motor M, on thesesses a disadvantage in that it has a " lag," shaft of which is a disc carrying an eccentrici.e., the change in the electrical conductivity coupling.During the period that the motorof the seleniumcelldoes not takeplace makes five revolutions a second, the frame andinstantaneously under the influence of light, the mirror C make five double movementsand with darkness there is an interval before in_a second, so that the mirror C accomplishes the cell reverts to its original state of non - conductivity.Whilst other types of light- sensitive cells may have less lag, yet selenium cellsare recommended for the purpose of this article as their high resistance is a property which can be made good use of in valve circuits, and they are also convenient in many ways. Fig.3illustratesa well-known type of selenium cell.A porcelain or marble tablet is covered with a very thin layer of selenium Fig. 3. and two thin platinum wires are then wound onparalleltoone another and inclose two motions in different planes at the same time with-Ufferent speeds.The firstisa motion on its axis at a frequency of soo a second, and the second is a motion on the axis of the frame F at a frequency of 5 a second. Fig. 2 illustrates the operation performed in translating the picture elements into variations of e.m.f. The apparatus is set up in a dark room, and an inverted and reduced image of the picture is projected by the lens 0 on to the mirror C, from whence it is reflected on to the diaphragm G, in the centre of which is an anerture Fig. 4. 200 THE WIRELESS WORLDAND RADIO REVIEW NOVEMBER 11, 1922 proximity.Thecellsarethensubjected I thought that along these lines it might toa sensitising process, which consists ofbe possible to induce the selenium cell to heating for about one hour at a temperature" self -oscillate,"so tospeak. of 2100 C., and then slowly allowing to cool. The experimental arrangement (simplitiea Then the cell is painted over with a trans-for convenience) is shown in Fig. 6. parent varnish for the purpose of protecting A narrow beam of light is .projected from the cell from damp.A cell constructed inthe source of illumination L on to the mirror M this manner has in the dark a resistance ofof a Carpentieroscillograph(shown only ro,000 to soo,000 ohms., and a moderatein cross-section), and is reflected on through illumination will change the conductivity ofthe aperture in the diaphragm K on to the a good cell by to per cent. selenium cell Se, which is connected in series Selenium cells were for many years thewith a battery and the oscillograph. When principal obstacle in the way of the develop-a beam of light thus reflected falls on the cell ment of telephotography, chiefly on accountSe its conductivity is increased, resulting in of its high resistance, but with the adventan increased e.m.f. through the windings of the of the valve this objection disappears, andoscillograph and the movement of the mirror in fact becomes an advantage. M. As the mirror moves, the beam of light A circuit first used by T. Nemes is givenis diverted from the aperture in the diaphragm in Fig. 4.The principle of this circuit isK and the cell Se returns to its former state somewhat on the lines of a bridge.Se is theof non -conductivity. selenium cell, R1 and R2 are non -inductive Now, the frequency at which the mirror resistances of equal value.The movementwill oscillateis dependent chiefly upon the of the sliding contact on R2 the potential on the grid of the valve can be controlled so that the best point of the valve characteristic can be utilised. Now itis desired that the selenium cell should be responsive torapid changes in L light values.Glatzel, who worked with Korn, obtained lag curves when very rapid changes in light values were made.Fig.5 shows a curve obtained by Glatzel employing a selenium celland a Siemen's oscillograph, thecellbeingsubjectedtointermittent illumination, the duration of each illumination being about 0'02 second, and a similar period K 11111111111111111. of darkness. 5e As can be seen from the curve, there is a sharp riseatfirst,after which a steady Fig. 6. oscillation takes place. Some years ago I myself had the opportunitylag of the selenium cell, which can be estimated of conductingresearchalongtheselines.inthismatter, other considerations which affect the frequency, such as the intensity of illumination, or the lag of the oscillograph being calculated and allowed for. Verycriticalexperiments have notyet been conducted, but results so far obtained show- (t) That selenium cellsare capable of Fig. 5. responding to variations in light at a frequency of io,000 per second. I employed intermittent illuminations of a (2) That with an increase of speed the higher frequency, viz., o000rto oo0oo25 sensitivity of the cell is greatly reduced. second, and I endeavoured to ascertain the (3) That by the use of valve amplifiers limit of speed of change which a selenium it is possible to compensate largely for the cell was capable of recording. loss in sensitiv:ty at high speeds. NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW 201 These observations are sufficient to showso as to intercept to a greater or lesser degree that the selenium cellis applicable to thethe passage of the beam of light through the experiments under discussion in this article.drilled hole in the poles.This is illustrated We must remember, however, that the numberat P, Fig. 7. of picture elements will exceed this frequency The diagram Fig. 7 shows the arrangement of to,000 per second, and if, as in the caseof the complete apparatus, both transmitting of moving pictures, it is desired to transmitand receiving.The upper half of the picture ten pictures per second, then this may repre-represents the transmitter and the lower the sent as many as ioo,000 picture elements receiver.If, for example, itisdesired to transmit the picture seen atthe arrow A through the lens of the camera, an inverted and reduced image appears on the mirror M1, which oscillatesin two planes asalready explained.The picture elements are reflected, one after the other, on to the selenium cell Se, the conductivity of which is thereby varied. The variations in e.m.f. are amplified through the valve circuit, which should give several stagesofamplification,though only one stageis shown in Fig.7.The amplified currentsare then passed to the receiving circuits by means of the transformer T. The next step is that the incoming oscillations are passed through the fine platinum wire at P of the galvanometer, which is diverted in proportion to the amplitude of the incoming oscillations in the process already described. The mirror M2 on which the beam of light controlled by the incoming oscillations falls, must be exactly synchronised with the mirror MI F .g.7. at the transmitting end, and herein lies the greatest obstacle to a practical solution of the problem. in one second.However, itis seldom that The method of producing this synchronisa- a picture element is of a tone which standstion in experimental work was by means of out isolated from itsneighbours, the grada-synchronous motors S S2 fed from the same tions of tone being almost in every case veryA.C. supply.S3, S4, are generators supplying gradual, so that the actual number of changes the 500 cycle frequency for the oscillation in illumination to be registered are greatlyof the mirrors M1 M2. reduced.In general we can take 5,000 to In conclusion I may say that in the foregoing 20,000 frequency to be quite sufficient for thearticleI have endeavoured to indicate the transmissions. lines along which we may look for a solution At the receiving end of the apparatus,of the problem.Ifeel that it may be of in order to reconvert the variations of e.m.f.interest to other experimenters to have these backintopictureelements,thefollowing suggestions put forward. The solution of the arrangement is made. A dead beat stringproblem from a wireless point of view must galvanometer is required.Between the poles be looked for as a logical outcome of television of a powerful electro-magnet is suspended aby line wires. fine platinum thread, which carries a small Personally, I look forward with confidence and light aluminium plate at its centre.The to the time when we shall not only speak with, poles of the electro-magnet are drilled through but also see those with whom we carry on so as to provide for the passage of a beam oftelephone or wireless telephone conversations, light. A current passing through the threadand the distribution of cinematograph films diverts it at right angles to the lines of force,will be superseded by the direct transmission and consequently the aluminium plate movesfrom a central cinema. 2o2 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 11, 1922 The Effect of Underground Metalwork on Radio DirectionFinders.* DISCUSSION. Mr. A. A. Campbell Swinton. an error in bearings or deviation in the observed I think we are all very much indebted to the bearings is essentially an exploration of the elettro- readers of this paper for the very clear way in which magnetic field in the neighbourhood.What we they have brought the matter before us.I recollect are doing is to find the resulting deviation which that about a year ago there was an Italian gentle- is due to an incoming wave and secondary current man over here with some kind of apparatus whichset up in the metalwork by that wave.It is quite was intended for the purpose of finding minerals.true that we do not generate the electromagnetic I think his experiments took place in the neighbour- field ourselves, but that is the principle of the hood of Florence.There is no doubt that theremethod, and in that way I should imagine it has are people who claim to be able to find minerals,a somewhat similar relationship to any other method and not only minerals, but water also, by means ofdetectingtheelectromagneticfield.With of wireless apparatus. regard to signal strength, the mere fact that the The President. error exists as a secondary effect due to the presence Mr. Fogarty, I believe you were introduced toof the metal and currents set up in the metal the Italian gentleman who was interested in thiswork by the incoming wave, these currents neces- subject.Can you say anything about his work ? sarily mean an absorption of energy, but I must admit that this absorption was surprisingly small Mr. L. F. Fogarty. in these experiments and the range of direction The gentleman whom I had the pleasure of meetingfinding at Aberdeen was not appreciably diminished was the Hon. Umberto Bianchi, the President ofby the existence of the metal work. We were the Radio Club of Italy.He was in this country able to get Moscow (over 1,600 miles away), and for the express purpose of finding someone whothis compares very favourably with conditions would make certain special apparatus he wanted in other parts of the country. to enable him to carry on his work of locating Itisofcourse very difficult, when using an metallicmasses and metallic ores underground. amplifier, to compare signal strength in different I believe he is at present in this country, and as places and under different conditions, unless special a matter of fact, I sent him an invitation a few precautionsaretakentomaintainconstancy days ago to be present here this evening, but of amplication.Also signals may vary from day I presume he could not attend. to day from other causes. Mr. C. F. Phillips. With regard to making compensation for this With regardtoMr.Bianchi'sresearches,I error, this could be arranged in much the same might say that they ,did not in any way concern manner as the quadrantal error of a ship or aeroplane location by deviation of the bearings taken with is corrected, i.e., by the arrangement of suitable adirectionfinder.Itisan entirelydifferent coils near the D.F. set.By adjusting the position system. It involves a search for p displacement and electrical constants of these an approximate of an electro-magneticfield, and itisnota correction for the error can be obtained. question of locating any error by means of bearings In this particular case it was not considered taken on some station. worth while to make a correction because, having I should like to ask the lecturer whether in located the source of the permanent error, we were noting the deviation of bearings obtained with the not so interested in this as in the variations which, direction finding apparatus from the true bearings, compared with this error, are of much greater whether there was any really noticeable difference magnitude.The whole object ofthisresearch in signal strength, and whether he thinks that is essentiallytoget atthe variableerrorsof any considerable absorption by the mass of metalthe order of60°,andthispermanent error, took place. although it is fairly largeis not now of the first Mr. W. H. Lawes. importance. I should like to ask whether any attempt was made to correct the error in the same way thatThe President. ships' compasses are corrected. Ladies and Gentlemen, I ask for a vote of thanks to Mr. Smith -Rose and Mr. Barfield for their able Mr. R. L. Smith -Rose (in reply). enunciation of these facts.There is no doubt I was very interested to learn that a methodthat the experiments are a triumph for direction isbeing developed for the actual detection of finding.We of the Radio Research Board used hidden metal.Of course we did not start out to hear every month from Mr. Smith -Rose about with that object.We were certainly successfulthis iron, although he could not locateit, and in finding hidden metal, but whether this wouldwas informed by the surveyor that there was no be possible on a commercial scale is another matter. iron about.But at last his tenacity had the I do not know anything of this gentleman's desired effect, and the surveyor looked up his plans method, but the method we have used in detecting and it was found that the surveyor was wrong and Mr. Smith -Rose was right. It is quite likely * Discussion on a paper read before the Wireless that this method will be adopted in other cases, Society of London on October 25th, 1922. See and it is well to let people know that direction find pages 165 to 171 of issue for November 4th. ing has other uses besides the location of a station. NOVEMBER 11, 1922 THE WIRELESSWORLD AND RADIO REVIEW 203 If any of you use direction finders in London It iswellworthwhileremembering,in you will observe that you get errors in any house. using direction finders in London, that with water - When I find that Paris is about seven degrees offpipes, electric light leads, telegraph and telephone what it ought to be, I know Paris is perfectly wires and iron balcony rails you cannot expect correct, but I am perfectly correct also, becauseto get true bearings.You know the error is not I have a permanent error of seven degrees.I get no due to the stations, therefore you should plot error on Horsea, and yet on Ongar, which is almost out your curve and see what the errors are, and reciprocal, I get an error of five degrees. you will know what the correcting fact or should be.

Notes A Wired Wireless Demonstration. Messages to Aeroplanes. On Friday evening, November 3rd, a demon- Haren (OPVH) telephones frequently to aero- stration of wired wireless took place at the Regent planes flying between Brussels and Paris, Brussels Street Polytechnic as previously announced in thisand London, and Brussels and Amsterdam. Messages journal. on 900 metres are usually transmitted at twenty Mr. E. H. Shaughnessy, head of the Wirelessminutes past each hour from 11.20 to 4.20. Weather Section of the General Post Office, gave a lecture reports are given in French and English. on recent developments in radio telegraphy and telephony, when he dealt with the work which wasTelephony from Eiffel Tower. being done at Leafield.In the course of his lecture, The Eiffel Tower Station now transmits telephony he mentioned that the daily news service main-at 7.20 a.m., 11.15 a.m. and 5.10 p.m.It is an- tained from Leafield to Halifax, Nova Scotia, wasticipated that the power will be increased in the regarded by Americans as the fastest Transatlantic near future. service in existence. Belgian Meteorological Transmissions. Duringtheevening, bypermission ofthe Transmissions from the Brussels Meteorological Postmaster -General and with the co-operation ofInstitute (OPO) are made on (C.W.) 1,500 metres the Marconi Company and the British Broadcasting at so slow a rate that amateurs are easily able to Company, a demonstration of wireless telephony read the messages, which are in Morse code. was given.- Sir William Noble,speakingfrom Marconi House, introduced the Lord Mayor ofKonigswusterhausen. Bristol, who delivered an address from his own Daily transmissions of telephony from Konigs- home.This was transmitted by " wired wireless "wusterhausen, Berlin,are onawavelength to Marconi House, and thence broadcasted. of 2,800 metres, and the times are 6 to 7 a.m.. An instrumental and vocal concert was afterwards 11 a.m. to 12.30 noon and 4 to 5.30 p.m. broadcasted from Marconi House. Address of 2 ZY Required. African Stations. Receptionof2 ZY has beenreported,and Tete station, Lourenco Marques, is now almost excellent telephony recorded.We have been asked completed.Direct communication with Lisbonfor the address of this station. is to be established.Smaller stations have already been erected at Inambane and Chai-Chai on theWireless Insurance Policy. ;oast. Liverpool Marine and GeneralInsurance American Call Signal WWAA. Company,Ltd.,haveissueda comprehensive The general call signal WWAA has been assigned policy covering all risks in connection with an forallvessels operated and controlled by the amateur wirelessinstallation at a premium of RadioCorporationofAmerica.Thisgeneral 7s. 6d. ca,11 signal will be used by Radio Corporation of America ships or coast stations desiring to ascertainCanadian Government RadioDirectorin whether there is an R.C.A. ship within range, London. and any R.C.A. vessel hearing another ship or Mr. C. P. Edwards, O.B.E., Director of Radio coast station calling WWAA should answer.Also for the Canadian Government, arrived in London this general call signal will he used in broadcastingon the 30th October.He is to advise the Hon. Ernest Lapointe, M.P., Canadian Minister of Marine, messages to R.C.A. ships. in connection with the conference between the Wireless Apparatus in Aircraft. Canadian and Imperial Authorities in regard to At the first public session of the International the Imperial Chain. Commission forAerial Navigation consideration was given to the report of a Sub -Committee on theWireless at St. Bride's Institute. use of wireless apparatus on aircraft.It was agreed At St. Bride's Institute, Ludgate Circus, E.C.. as a general principle thatall aircraft engaged in a lecture and demonstration on " Broadcasting " public transport must carry wireless apparatus. is to be given on November lath.The lecturer, At present this provision is applied only to aircraft Mr. H. A. Hankey, is an ex -Fleet Wireless Officer. abletocarrytenormorepersons.Aircraft By arrangement with Marconi'sWirelessTele- carrying fewer than ten persons, and flying more graph Company, the event is being held under the than 100 miles over land without landing, or more auspices of the National Association of Supervising than 15 miles over sea, must carry wireless apparatus Engineers.Tickets are obtainable from Mr. A. within two years. Brammer, 63, Queen Victoria Street, E.C.4. 204 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 11, 1922 The New Licence?, for Broadcast Reception

BROADCAST LICENCE. A 41602 WIRELESS TELEGRAPHY ACT, 1904. 0,Licence to establish a wireless receiving station. Mir4214-3 JACe Gtehdo/fArtrre-d oft I r-tf/-6tAl-/-744-\/. is hereby (Address in autho sed (siAstz4 o§elloweivir to estabh a wireless station or he purpose o receiving messages a LICENCE MUST BE MARKED for a period ending on t The payment of the fee of ten shillings is hereby acknowledged. Dated. 3 y of frk-A3r."2-'42L.4192?- Issued kr_41lf he Postmaster -General W PR EtESSWORLD Signature of Licensee

If it is desired to continue to mailitaialestRADICkate - Licence must be taken out within fourteen days. eavy penalties are prescribed by the Wireless Telegraphy Act 1904, on conviction of the offence of establishing a wireless station without the Postmaster -General's Licence. 280. G & S 194 CONDITIONS.

1.The Licensee shall not allow the Station to be used for any purpose other than that of receiving messages. 2.Any receiving set, or any of the following parts,vizt. :-Amplifiers (valve or other), telephone. head receivers, loud speakers and valves, used under this licence must bear the mark shewn in the margin.

3.The Station shall not be used in such a manner as to cause interference with the workingof other Stations.In particular valves must not be so connected as to he capable of causing the aerial to oscillate. 4.The combined height and length of the external aerial (where one is employpd) shall .not exceed 100 feet. 5.The Licensee. shall not divulge or allow to be divulged to any person (other than a duly authorised of of His Majesty's Government or a competent legal tribunal) or make any use whatsoever, of any message received by means Or the Station other than time signals, musical performances and me sages transmitted for general reception. 6.The Station shall be open to inspection at all reasonable times by duly authorised officers of the Post Office This Licence may be cancelled by the Postmaster -General at any time either by specific notice in writing sent bypost to the Licensee at the address shewn hereon, or by means of a general notice in thg London Gazette addressed to all holders of wireless reoeiving Licences for broadcast messages. N.B.-Licences may only be beld by persons who are of fall age, and any chango of address must be promptly communicated to the issuing Postmaster. 2801 At the top will be seen a reproduction of the front of the licence. The Conditions are on the back of the form. NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW 205 Correspondence Calendar of Current Events To the Editor of THE WIRELESS WORLD Friday, November 10th. AND RADIO REVIEW. HECKMONDWIKE AND DISTRICT WIRELESS SOCIETY. Sue,-In a book of Standard Tables for Radio, At 7.30 p.m.Exhibition and Demonstration. published in London, there is given a formula for Opening by Mr. C. W. Leather, Checkheaton. findingthe distance between two points on the RADIO SOCIETY OF HIGHGATE. earth's surface.The example worked out is :- At 7.45 p.m.At the 1919 Club, South Grove. Latitude. Longitude. Lecture by Prof. E. Mallett, M.Sc. San Francisco ..37°44'40" N. 122°24'40" W. BELVEDERE AND DISTRICT RADIO AND SCIENTIFIC Choishi 35°44'08" N. 140°51'12" E. SOCIETY. and is not as simple as it could be. Lecture on " Properties of Crystals," by Mr. Compare with the following way of making the H. H. Smith. calculation, in which d.lon.is the difference of LEEDS AND DISTRICT AMATEUR WIRELESS SOCIETY. longitude, and d.lat. the difference of latitude : Lecture on " Some Gadgets of a Faddist," by lat. 37°44'40" log. cos9.89804 Mr. G. P. Kendall, B.Sc. lat.35°44'08" log. cos 9.90941 MANCHESTER WIRELESS SOCIETY. d.lon 96°44'28" log. hav9.94717 Annual General Meeting. log.hav 9 . 55462 = N. hav 0.35860 Saturday, November 11th. d.lat2°00'32" N.hav 0.00031 HECKMONDWIKE AND DISTRICT WIRELESS SOCIETY. At3p.m. Exhibition and Demonstration. Distance= 73°36'35" N.hav 0.35891 Opening byLieut.H. W. Burbury,R.N., Crigglestone. 73 x 60=4380 LIVERPOOL WIRELESS SOCIETY. 34=-44161 nautical miles. FirstmeetingofWinterSessionatRoyal Institution.Address by Prof. E. W. Marchant. Las Heras, 1960. JUAN CHRISTENSEN. Sunday, November 12th. Buenos Aires, Daily Mail Concert from the Hague, 3 to 5 p.m., Argentina. on 1,085 metres. Monday, November 13th. To the Editor of THE WIRELESS WORLD AND NORTH LONDON WIRELESS ASSOCIATION. RADIO REVIEW. Lecture on" Telephone Working :External SIR,-With reference to the Proceedings of the Routine," by Mr. A. G. Hill. Wireless Society of London, reported in your issues WIRELESS SOCIETY (HULL AND DISTRICT). of October 14th and 21st, I regret to notice the At the Signal Corps Headquarters.Lecture on apathy shown to the experimenter as distinct " Calculation of Capacity," by Mr. Hy. Strong. from the receiver of " broadcasting." IPSWICH AND DISTRICT WIRELESS SOCIETY. The prohibition of the use of reaction(which At 8 p.m.At 55, Fonnereau Road.Annual if pressed to its logicalconclusion implies that General Meeting. transmitting would not be allowed) on wavelengths FINCHLEY AND DISTRICT WIRELESS SOCIETY. from 300 to 500 metres, during the hours 5 to 10 p.m. Lecture by Mr. Wilck. on weekdays, and all day on Sundays (the very timeswhen many experimentersareobliged Tuesday, November 14th. to work) seems grossly unfair. Transmissions of Telephony by 2 MT, Writtle, I would ask why this prohibitionshouldbe as above. extended beyond the upper limit of the broadcasting band, viz., 425 metres.Itisfurther proposedWednesday, November 15th. that the experimenter shall pay an increased fee EDINBURGH AND DISTRICT RADIO SOCIETY. for an " entertainment " which is to debar him At8 p.m.AtHeadquarters.Lectureon from carrying out any experiments he may wish " Need for International Language in W.T." to do.I trust that the wireless societies, in their By Mr. A. Boyd Anderson, F.B.E.A. present prosperity, will do all in their power to maintain the privileges of those who were earlyThursday, November 16th. members. LUTON WIRELESS SOCIETY. Trinity College, " EXPERIMENTER." At 8 p.m.At Hitchin Road Boys'School Cambridge. Exhibition and Demonstration (Messrs. Radio October 24th, 1922. Instruments Co.). DERBY WIRELESS CLUB. At7.30p.m.At" TheCourt,"Alvaston. Informal meeting. Books Received Friday, November 17th. DISPOSAL BOARD RADIO INSTRUMENTS AND THEIR BRADFORD WIRELESS SOCIETY. APPLICATION TO EXPERIMENTAL TTSES.By Cinema Display. P.R.Coursey,B.Sc.(London : Messrs. BIRMINGHAM EXPERIMENTAL WIRELESS CLUB. LeslieMcMichael,Ltd.,Providence Place, At Digbeth Institute, Birmingham.Lecture by West End Lane, N.W.6.Illustrated.Price Mr.P. R. Coursey, B.Sc.(All members of Is. 6d.) Federated Midland Wireless Societies invited.) 206 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 11, 1922 The Wireless Society of London Report of Proceedings at the Ordinary General Meeting held on October 25th. An ordinary general meeting of the Society was before and since he lost his sight, made a hobby of held on Wednesday, October 25th, at 6 p.m.,the study of radio and allied sciences.He states at the Institution of Electrical Engineers. from his own practical experience that it is possible After the minutes of the previous meeting had for a totally blind person, with no more knowledge been read and confirmed, the President said :- of the subject than the average ordinary amateur, The listof members proposed for electionis tolookafterhisinstruments,accumulators, being distributed in the usual way, to be collected batteries, etc., and manipulate them with great at the end of the meeting.It is very satisfactoryaccuracy and without any sightedassistance. to note the very large increase at every meetingHe further claims that with a little more knowledge of the number of members joining us, and also theof the subject, the connecting up of instruments, lists of Societies and Clubs becoming affiliated. experimenting with various circuits, and even the Before calling upon our lecturers, Mr. Smith -building up of simple apparatus, is not outside a Rose and Mr. Barfield, to give their paper, thereblind man's reach.In his appeal to the Council are a few matters of business to go through.The Captain Fraser points out that, in spite of the first is that a letter has been received from Messrs. above, there are initial difficulties such as the fitting Bertram Day & Co., thanking our Society forup of an aerial, leading -in tube, etc., which the associating itself with the late Exhibition.We, most skilful blind man cannot undertake, and that in our turn, may well congratulate Mr. Bertram in the case of absolute beginners unusual difficulties Day on a very great success. present themselves in connection with the choice Now I have a very important announcementof suitable apparatus to purchase, learning how to to make to you, and I feel very proud that, as Presi- use it, etc. dent, I should have to do it.The announcement Since a blind man is deprived of many forms of is that His Royal Highness the Prince of Walesenjoyment which are available for those who can has graciously consented to become the Patronsee, Captain Fraser asked the Council if it would of the Wireless Society of London and the affiliatedconsider these points on behalf of its members, Societies, and he notices that we intend to changeand take steps to place them before the Councils our name to the Radio Society of Great Britain. or Committees of all associated or affiliated societies I think, ladies and gentlemen, that this is a verywiththefollowingobjects: (1) To obtainan great honour for the Society.(Applause.) indication as to whether or no the societies would There is another matter which I have to bringbe willing to make a special point of arranging for to your notice.I have had an appeal from Captain one or more of their members to make a particular Ian Fraser, who is in charge of St. Dunstan'sfriend of any blinded soldier or other blind person Hostel for Blinded Soldiers and Sailors.Captain who might qualify for membership of the society, Fraser is himself a blind man.He is interestedand undertake to give him the personal assistance in wireless, and was an amateur before the war. whichisobviouslyrequiredinthedirections He asks me to bring to the notice of those connected outlined above ;and (2) if it is indicated that the with the Wireless Society of London suggestions affiliated societies are willing to help in this way, whereby they can help individually blinded menit is suggested that a notice should be printed in all over the country, who wish to take up wireless. the St. Dunstan's Magazine, and in the Braille Press, I visited St. Dunstan's, and had a long talk withand that all other suitable steps be taken to let him, and he has written me a letter explainingblind people know that if they apply to either the what he wants.He has his own wireless apparatus, Wireless Society of London or to Captain Fraser which he practically built up with his own hands,they willbeputintouchwiththeirlocal with very slight assistance from one of our members. society, the members of which (if the blind person I will ask the Secretary to read his letter, whichqualifies inallotherrespectsfor membership) will be published later on, and I may say that will be willing to welcome him and give him special His Royal Highness wishes to associate himselfassistance. as his first act as Patron of this Society, with this It is understood that no financial assistance is appeal for St. Dunstan's.I think that alone willasked for in connection with this scheme, but be sufficient to push it.We all have sympathy merely personal service and interest, and the Council with these men in their darkened lives, and if they of the Wireless Society of London unanimously can be helped by us individually, I think we shallresolved to ask all affiliated societies to consider be glad to assist. this matter and indicate to the Council, or direct The following is the text of the letter which wasto Captain Fraser, Headquarters of St. Dunstan's then read :- Work, Inner Circle, Regent's Park, N.W., if they The Council of the Wireless Society of London are willing to co-operate. have had under consideration a request from There are 35,000 blind persons in the United Captain Ian Fraser, the Chairman of St. Dunstan's,Kingdom, of whom 2,000 are blinded soldiers. that they should bring to the notice of wirelessProbably only a relatively small number will be amateurs a direction in which they can contributeinterested,but by them thehelpasked for very materially to the instruction and entertainmentwill be greatly appreciated, and already Captain of blind people who are, or will be, interested inFraser has the names ofa few blind people radio -telegraphy and telephony.Captain Fraser whowouldwelcomeassistanceonthelines was himself blinded in the war, and has,both indicated.

NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW 207 I take it that those present here approve of It was mentioned in the minutes of the last this appeal to the members of our Society. meeting which you have just heard read that that I will now ask the Chairman to make a few matter was still only mooted and would receive remarks. further serious consideration.All I can tell you, gentlemen, is that it has received further serious Mr. F. Hope -Jones (Chairman). consideration, and practically a chorus of approval Ladies and Gentlemen :One announcement There has been, I think, no voice raised against which ought to be made to -night is that we propose theproposal,certainly none inthe provinces to call the next monthly general meeting (on theamong our affiliated Societies, who are most con- fourth Wednesday in November) a special general cerned.I will not trouble you with the precise meeting, the object being that it may be competent alterations now because you will find them with to make alterations in our constitution by certainthe notice calling the next meeting. changes in our rules.We try to keep the rules. Another matter which I am desired to mention There are very precise regulations bearing on them.is the proposal that we should institute some The last three state how the other rules can beprizes.We have had the suggestion knocking amended.Rule 42 states in effect that if the altera- at our door for some time, but the Council has tions emanate from the general body of the mem- beenso much engaged with other important bership apart from the Committee they must be matters that they have not been able to do justice signed by ten members, and must be in our handsto it.They have received an enterprising offer a month before the meeting, and it must be either from a prominent member who suggests that we an annual meeting or a special general meeting. might announce a prize for the most efficient Rule 43 states that any alterations are to be sent Armstrong Super -Regenerative Circuit.The Ameri- by the Honorary Secretary to all members at least cans are setting themselves very closely to work a fortnight before that annual general or specialon that subject, and this gentleman feels keenly general meeting.It will mean that you will getthat we should not be beaten on the other side your notices a fortnight before the next meeting,of the Atlantic, and has made a generous offer rather earlier than usual.Rule 44, the last rule of a ten -guinea first prize.The Committee pro- in our constitution, provides that no amendmentsposes to issue the conditions forthwith, and there shall be adopted unless at least three -fourths of the will very likely be a second prize. votes are in favour of such action.I will briefly The President. mention the subjects of change.One has already I am sorry to take up so much tithe from the lec- been referred to in the minutes which have justture, but itis necessary to bring these things been read, that is the new class of membership before your notice.I will now ask Mr. Smith -Rose called Associates.It may strike you as a littleand Mr. Barfield to give their lecture on " The bold that action of that kind should be taken inEffectofUndergroundMetalwork onRadio advance of an alteration of the rules, but I can Direction Finders."(See pages 165-171 of issue assure you that we only break our laws in the of November 4th, 1922. ) interest of the Society when occasion or emergency At the conclusion of the paper and discussion really demands it.In this case, as you know,(see page 202 of this issue) the President said :- broadcasting and the announcement that there All the large number of members and associate should be two classes of licences created a newmembers up for ballot have been elected, and the class that ought to be taken under our wing, and list of the Societies accepted for affiliation.(For if we had not done so,perhaps other people list see page 176 of issue of November 4th.)In would have thought it necessary to start associa- addition a large number of Associates have joined tions for that purpose. the Society. And then the change of name.Did you notice There are also several other members in addition the terms in which the President announced theto those in the printed list and passed by the great honour of our royal patronage ? Apparently Committee who will be put up for ballot next month. His Royal Highness the Prince of Wales has gone The next meeting will be on the fourth Wednesday out of his way to note that the name of the Society in November. You have heard already that it will is to be changed from the Wireless Society of London be a special one.There will also be a lecture. to the Radio Society of Great Britain. The meeting adjourned at 7.15 p.m.

Wireless in Schools. New Station at Lausanne. Mr. R. J. Hibberd, Grayswood School, Haslemere, At Lausanne a new station has been erected. is compiling a list of Primary, Secondary and Public Transmissions are on 900, 1,400 and occasionally Schools which possess wireless apparatus.Par- 2,610 metres.Telephony on 900 is transmitted ticulars would be gladly received by him as from the station to aeroplanes leaving Le Bourget. follows :-(1 )Name and typeofschool. (2) Messages are also sent to Dijon on 1,400 metres Date apparatus was installed or made.(3) Nature between 11 a.m. and 12 noon. of work carried on. Chess Played by Wireless. New Station at Phuto. An interesting experiment conducted by the At Phuto, near Saigon, the Compagnie Generale local wireless club at Guildford consisted of a de Telegraphie sans Fil has erected a new. station. chess match in which the moves were communicated Direct communication with Saint Assise, and also bywireless.The match was played by the with Tananarivo, Madagascar, is to be effected. Guildford Chess Club.

208 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 11, 1922 Wireless Club Reports NOTE.-Under this heading the Editor will be pleased to give publication to reports of the meetings of Wireless Clubs and Societies.Such reports should be submitted without covering letter in the exact form in which they are to appear and as concise as possible, the Editor reserving the right to edit and curtail the reports if necessary. The Editor will be pleased to consider for publication papers read before Societies. An Asterisk denotes affiliation with the Wireless Society of London. Correspondence with Clubs should be addressed to the Secretaries direct in every case unless otherwise stated. Willesden Wireless Society.* to Mr. Bever for the lecture and demonstration. Hon. Secretary, Mr. G. D. Wyatt, 70, CravenThanks were also expressed to Mr. Longbottom Park, Harlesden, N.W.10. who had kindly loaned the Magnavox apparatus. Several changes in the administration of the The arrangements for the Society's annual ex- Society have recently taken place, and the Societyhibition are now in hand, to be held at the end of has now settled down in its new headquarters atJanuary.TheOrganisingSecretary,Mr. N. The Harlesden Public Library, Harlesden, N.W.10. Whiteley, 8, Warrels Terrace, Bramley, Leeds, will A very interesting programme has been arrangedbe glad to hear from any firms desirous of exhibiting for the wintersession.Regular meetings areapparatus.Communications will receive prompt held every Tuesday evening from 8 p.m. to 10 p.m. attention. Owing to the kindness of several of the long-standing Aberdeen and District Wireless Society.* members who have volunteered their services as Joint Secretary, Mr. James S. Duthie, M.A., instructors, provision has been made for the less 148, Forest Avenue, Aberdeen. experienced members to gain knowledge through The Society met in new quarters at Aberdeen the medium of elementary lessons.These lessonsGrammar School, on October 20th.Dr. Fyvie, will precede the ordinary meeting on TuesdayMarischal College, occupied the chair. evenings,commencingpromptlyat 7 p.m. Lectures by well-known people will be a feature The following gentlemen being dulyelected acceptedoffice :-President,Dr.Fyvie ; Vice - of the Society's future programme and, as thePresident, Dr. McLeod ;Secretary and Treasurer, club apparatus has been enlarged, it is confidently Mr.IV. W. Inder, M.I.R.E. ;Joint -Secretary, anticipated that adequate demonstration of the Mr. James S. Duthie, M.A.General Committee : principles involved in the lectures will be possible. Messrs. John Miller, Cumming, Walker, Shearer, A new twin -wire aerial is shortly to be erected. JamesMiller,Watson.TechnicalCommittee : Hamilton and District Radio Society.* Dr. Fyvie, Messrs. Inder, John Miller. Hon. Secretary, Mr. James M'Killop, 22, Dalziel It was unanimously decided that ladies would Street, Hamilton. be eligible for membership. The above Society is now in full swing. Mr. G. W. G. Benzie was presented with a Lectures have been arranged for every Fridayleather suit -case, on his leaving for India to take evening at 8 p.m. by members and others who have up an appointment.Mr. Cumming, in making knowledge of the subject.Already lectures havethe presentation, thanked Mr. Benzie for the great been given by Mr. Jas. Brawn (Vice -President) oninterest he had taken in the Society, and wished different types of receivers for beginners ;Mr. him every success in his new sphere of work. D.Miller,on" Electricity and Magnetism " ;Mr. Benzie, in a happy reminiscent speech, thanked Mr. S. B. Becket (President ), on " Possibility ofthe members of the Society for their great kindness. Communication with Mars," and Mr. McCammond The meeting terminated with an inspection and on " Accumulators." The Vice -President has kindlydemonstration of the Society's five -valve set. loaned a three -valve transformer -coupled receiver Wireless and Experimental Association.* for use in the Society's room until the instru- Hon. Secretary, Mr. Geo. Sutton, 18, Telford ment under construction is completed. Road, S.E.22. On October 18th, at the Central Hall, Peckham, Bradford Wireless Society.* the scheme of the" Agenda Committee," was Hon. Secretary, Mr. G. Bever, 85, Emm Lane,considered.Five members were elected whose Heaton, Bradford. sole duty on that committee is to ascertain the A meeting was held in the club -room at Randall -special .needs of the other members in the various well Street, on October 20th, with Mr. A. Liardet stages of wireless progress. in the chair.The minutes of the previous meeting Should a member desire to know how to con- having been passed as correct, and three newstruct a crystal set, the committee member for the members elected, the Chairman called upon theelementary grade wouldascertainthespecial Secretary to give his lecture on " Telephony."Incircumstances of his case and report to the Secretary, an exceedingly able manner Mr. Bever dealt withwho then would take steps to ensure that at an early the variouscircuitsappertaining to telephony " elementary " meeting, that member's difficulties transmission, illustrating his remarks by numerouswould be fully gone into. diagrams.At 9 p.m. a demonstration of telephony Should an advanced member desire to know was given from the lecturer's station (2Q1C) and whether a separate heterodyne will meet his rendered audible all over the hall by means of specialneeds,thepros and cons would be his four -valve receiving set in conjunction with agone into by one of the valve specialists for the Magnavox loud speaker and poweramplifier. benefit of the whole meeting, and if the younger Reception was exceedingly good, both from 2QRmembers did not receive immediate benefit they and other stations. A vote of thanks was accorded would probably make notes for the future. NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW 209 The Radio Society of Highgate.* also resolved that a periodical should be published Hon. Secretary, Mr. J. F. Stanley, B.Sc., A.C.G.I., as the official organ of the federation. 49, Cholmeley Park, Highgate, N.6. The title and objects of the Federation have riot An informal discussion was held at the 1919 Club, been finally decided upon, this being left to a further Highgate, on October 13th, when several interestingconference which will be held shortly. points were raised by members.Mr. Andrews The proceedings terminated with votes of thanks explained the results of some experiments on theto Dr. Ratcliffe and Mr. F. S. Adams damping of an oscillatory circuit caused by the introduction of a crystal detector and pair of tele- Brighton and Hove Radio Society. phones.Messrs. Hogg and Grinstead contributed Hon.Secretary,Mr. D.F. Underwood,68, some useful remarks on the value of the ratio, Southdown Avenue. " Inductance to Capacity," in an oscillatory circuit. The first general meeting of the above Society Mr. Stanleyemphasisedthenecessity of was held on October 11th,1922, at 7.30 p.m. thoroughly insulating the units of a high tensionAfter electing a chairman for the evening, the battery when made up of pocket lamp batteries. electionof officers and committees took place. It is unfortunate that at these discussions nearly Capt. C. Hoghton (late President of the Sussex all the talking is confined to the more advancedWirelessResearchSociety)wasunanimously members. New members and novices are urgedelected President for the ensuing year.A supreme to take a more active part in the discussions. council of four and executive and technical com- On October20th,Mr.Grinstead gavean mittees of six members were elected.The Society's instructivelectureon ValveCharacteristics and Design."Mr. Grinstead is an expert on this subject, and the theory of valve design was very ably dealt with.Both transmitting and receiving valves were discussed, and the differences in their design carefully explained. All members are urged to do their utmost to ensure the success of the Radio Dance to be given at the Gate House, Highgate, on Saturday, Novem- ber 25th.There are still a number of tickets to be disposed of in order to cover expenses.Single tickets, 7s. 6d. and double tickets 12s. 6d. inclusive, may be obtained from the Hon. Secretary. Birmingham Y.M.C.A. Wireless Club. Hon. Secretary, Mr. R. Jenkinson, Y.M.C.A., Dale End, Birmingham. The winter programme commenced on October 17th, a demonstration being given by Mr. H. H. Whitfield (2 LG), of Messrs. Cook & Whitfield Wireless, Ltd. Telephony by Mr. Baynton (2 KO) was heard with remarkable clearness by about 100 people. The equipment at present consists of a three - valve receivingset.Lectures are to be given fortnightly. Demonstration at Birmingham G. A. Birmingham Experimental Wireless Club.* Wireless Club. Hon. Secretary, Mr. Frank S. Adams, 110, Ivor Road, Sparkhill, Birmingham. very energetic Secretary, Mr. D. F. Underwood, The first Conference of Midland Wireless Societieswas elected Secretary of the new Society, and Mr. convened by the Birmingham Experimental Wireless Phelp, the past Assist. Secretary of the Brighton Club, was held at the Y.M.C.A., Dale End, Birming, Radio Society, Assist. Secretary of the new Society. ham, on October 14th. A new Treasurer, Mr. Mons, was elected, and the Dr. J. R. Ratcliffe, M.B., F.R.C.S., President Brighton Society's librarian elected to the new post. of the Birmingham Club, took the chair. Smethwick Wireless Society.* ThefollowingSocietieswererepresented Hon.Secretary,Mr.R.H.Parker,F.C.S., Birmingham Experimental Wireless Club, Birming- Radio House, Wilson Road, Smethwick, Staffs. ham Y.M.C.A.WirelessClub,Burton -on -Trent A successfulmeetingofthe above Society Wireless Society, Coventry Wireless Association,was held at the Technical Institute on September Smethwick Wireless Society, Wolverhampton and 22nd, when Mr. Saunders gave his lecture on District Wireless Society. " Electric WavesandRadioActivity."The A telegram was received from the Stoke-on-Trent lecture provedto be very interesting, and a Wireless and ExperimentalSociety,regretting hearty vote of thanks was accorded to Mr. Saunders. thattheirdelegate was unavoidably detained, At a meeting on September 29th, Mr. S. D. Waltho and would be unable to attend. in the chair, after the usual buzzer practice in- A letter from the Rugby and District Wirelessstructed by Mr. Headley on this occasion, it was Club was read in which the Hon. Secretary expresseddecided to hold weekly meetings ;one week to be his regret that the Club would be unable to send given to lectures and the other week for experimental a delegate. purposes on the Society's apparatus. The formationof a FederationofMidland Mr. Headly was elected to represent the Society Wireless Societies was formally approved.It was at the Conference of Midland Wireless Societies. C 2 210 THEWIRELESSWORLD AND RADIO REVIEW NOVEMBER 11. 1922 Fulham and Putney Radio Society.* distances.The serious experimenter would,of Hon. Secretary, Mr. J. Wright Dewhurst, 52,course, have no fixed arrangement, but would North End Road, West Kensington, London, W.14. always be trying something different, or working on At a meeting held on October 20th, which wassome fresh gadget," therefore the set for him well attended, a considerable amount of businessmust be very flexible in its adaptation. was done.The Society's headquarters are being Mr. R. G. Herschel' gave a short elementary moved to Fulham House, Putney Bridge, whichlecture on " Resistance, Inductance and Capacity," is the headquarters ofthe 47th (2nd Lon.) Div.explaining the fundamental actions of these three Signal Company, and the wireless room has beenimportantpropertiesoftheelectricalcircuit. placed at the Society's disposal one evening eachAlthough the lecture was necessarily brief, quite week by the commanding officer. a deal of information was gained by beginners, and There is a very fine aerial fixed and the room iswas appreciated by all. equipped with 120 -watt and 30 -watt C.W. sets, Finchley and District Wireless Society.* also a 20 -watt spark set, and the Society has a Secretary,Mr. A. E.Field,28,Holmwood collection of apparatus of its own. Gardens, N.3. It was also arranged that a technical committee On Monday, October 23rd, a lecture on " The ofthefollowing members, Messrs. Hart -Smith,Principles of the Valve " was given by Mr. Trussler. Wooding, Calver, Houstoun and Galton be formedAt the close of his lecture, which was exceedingly to deal with the arranging and making of apparatusclear to even the absolute novice, a demonstration and most of the members present promised to assistwas given on a three -valve home-made set by by giving apparatus or component parts to the Mr.Heppel,on which excellentresultswere Society. obtained. It was proposed that the Secretary write to the Radio Experimental Association Wireless Society of London stating that the Society (Nottingham and District).* was in full sympathy with their views regarding the Hon. Secretary, Mr. F. E. Bailey, 157, Trent change of title and the amalgamation of all Societies.Boulevard, West Bridgford, Notts. The Secretary was asked to write stating the A meeting of the above Association was held Society's views regarding the broadcasting restric-in the People's Hall, Heathcote Street, Nottingham, tions. on October19th.Mr.Gill,having taken the Regarding the transatlantic tests for amateursChair in the unavoidable absence of Mr. Thornton, the Society intend to apply for special permissioninformed the meeting that the lecturer for the to transmit for these tests. evening was unable to attend through illness. Mr. Calver gave the first of a series of lectures onMr. Ford, however, stepped into the breach and the elementary principles ofwireless;the firstgave an interesting lecture on " Aperiodic Trans- lecture was entitled " Ether Waves and Rays." formers," setting forth clearly the essential points Mr. Calver treated the subject very fully and theto be borne in mind when designing such trans- members were very appreciative. formers to function efficiently over a comparatively A very hearty vote of thanks was accorded tolarge band of wavelengths. Following the lecture Mr. Calver. an interesting discussion took place. The outlook for the Society is very promising Will all members please note that commencing and with a fully equipped club -room membershipThursday, November 2nd, meetings will be held should increase. weekly at Messrs. Bennett's Garage, Shakespeare Belvedere and District Radio and ScientificStreet, Nottingham, where an ideal room, with Society.* aerial already installed, 'has been secured for the Hon. Sec., Mr. S. G. Meadows, 1, Kentish Road, use of members. Belvedere, Kent. Glasgow and District Radio Club.* The eighth general meeting of the above Society Hon. Secretary, Mr. W. Yuill, 93, Holm Street, was held at theErith TechnicalInstituteon Glasgow. October 20th. In the club -room on October 19th, Mr. W. K. The usual buzzer practice took place from 7.30Dewar presided before a very large attendance, to 8.0 p.m., members making good headway atand remarked that he thought the club would soon five words per minute. require larger premises. The Secretary informed the meeting that the After the usual preliminaries, the Chairman called Postmaster -General's receiving permit had arrived. on Mr. Yuill to open a discussion on the best He read a letter from The Wireless Society ofcircuit to use for a valve broadcasting reception set London, stating that The Belvedere and Districtto comply with the P.M.G. Regulations, and the Radio Society had been approved for affiliation,following gentlemen took part :-Messrs. Quinn, which places it as the recognised Society for ErithTodd, Wright, McDade, Nicholson and Morrisou. and Belvedere. After a show of hands Mr. Morrison was declared At 8.15 Mr. A. G. Norman spoke on the subject the winner of a M.O. " R " valve, kindly presented by of choosing a type of receiver.He classed wirelessthe General Electric Company, Ltd., 71, Waterloo amateurs in three groups :(1) The broadcaster ; Street, Glasgow, for the best reply.This was a new (2) the serious experimenter, arid (3) the man whoinnovation, and the Chairman asked for a show of was satisfied with his set, i.e., the non -progressivehands to see if the members would like a similar man, outlining the type of receiver most suitablenight later in the session, and this seemed to be the foreach group.For thebroadcaster,crystalunanimous opinion. receivers were suitable on well designed aerials The next meeting was held on October 26th, formoderate distances from thebroadcastingwhen a full discussion of the arrangements for the centres, valvereceivers beingused for longerexhibition on November 4th took place. NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW 211 Hornsey and District Wireless and Modelform, showing how theprinciplesof wireless Engineering Society. were made easily understandable by following the Hon. Secretary, Mr. H. Davy, 134, Inderwick firstprinciplesofforce,inertia and capacity. Road, Hornsey, N.8. As a measure of appreciation by his audience he was At a meeting on October, 13th, 1922, the chairprevailed upon by them to continue his lecture was taken by Mr. H. J. Pugh.' The usual business and demonstration on November 1st. was gone through and one new member was elected. An interesting discussion was entered into by The Chairman then called on Mr. H. Davy to giveMessrs. Beadle, Hon. Secretary, Hon. Treasurer, his lecture as per programme. Daniels, R. McCue, Hurst, Bruce, and the Chairman, Mr. H. Davy gave an interesting lecture on " Theintroducing" TranspositionofEnergy,Heat, Thermionic Valve as a Detector," after whichSkin effect of A.C. versus Resistance." many questions were asked which showed that the A hearty vote of thanks was accorded the lecturer. large attendance had taken particularinterest The Hon. Secretary reported a gracious offer in the subject which was so ably explained by the on the part of Mr. F. H. Haynes to describe the lecturer. building up of " An Amateur Three -valve Receiving The meeting was then thrown open, and discussion Set," to be followed by demonstration and dis- took place on the merits of high and low frequencycussion, which offer the members gladly accepted. amplification.A new programme of interestingMr. F. H. Haynes agreeing to come to the next lectures, etc., has been arranged.Particulars maymeeting, October 25th, for that ptfrpose. be obtained from the Hon. Secretary on receipt ofProposed Gorton (Manchester) and District stamped envelope. Wireless Society. Mount Pleasant Radio Society. Hon. Secretary (pro tern),Mr. G. Sykes, 13, Hon. Secretary, Mr. Walter R. Fleming, 156, Longford Street, Gorton. Upton Park Road, Forest Gate, E.7. Amateurs, experimenters and all interested in A meeting of the above Society, which was heldwireless matters within the Gorton districtof on October 19th, was opened with buzzer instructionManchester, are asked to communicate with the under Mr. G. H. Vine.Very satisfactory progress gentleman whose name is given above.Mr. Sykes, is being made. together with Mr. T. E. Rowe, 8, Fairhaven Street, This was followed by a lecture on the " Rudiments Hyde Road, W. Gorton, hopes to receive sufficient of Wireless," by Mr. W. D. Keiller, technical advisersupport to enable them to inaugurate a society. to the Society. He dealt very ably with the subject,Rhyl and District Amateur Wireless Society. explaining the molecular theory of magnetism, Hon. Secretary, Mr. C. Mitchell, 24, East Parade, electrons, atoms, positive and negative currents, Rhyl. etc.After answering several questions the lecturer At the meeting on October 18th, a lecture was was accorded a hearty vote of thanks. given by Dr. Goodwin.His subject was " In- New headquarters have been obtained at John duction. Dr. Goodwin prefaced his remarks by StreetChapel,JohnStreet,Theobalds Road,saying that although induction was his subject, W.C.1, and a splendid series of lectures will beyet he intended it to cover a very wide field, as given during the winter session. so many electrical forces came under the title of Particulars of affiliation to the Wireless Society induction.Dr. Goodwin then explained the mean- of London have been received and it is hoped to ing of the term as far as it was possible.He dealt become a member in the near future. withthemysterious happenings when certain Full particulars as to membership, etc., may beelectrical forces were letloose, no matter how obtained from the Hon. Secretary. minute,and explainedtheresult.From the scientist's point of view it might be comparatively Clapham Park Wireless Society. clear, but the lay mind had difficulty in under- Hon. Secretary, Mr. J.C. Elvy, A.M.I.E.E., standing why the universe was not a heap of dust 12, Tavistock Street, Strand, W.C.2. after listening to some of the happenings which The eighth general meeting was held at head-were possible, with limitations, which the lecturer quarters on October 18th. dealt with.But the system of electrical induction There was the usual crowded attendance whichwas so closely allied to wireless that it would be promised a lively discussion.Mr. A. E. Radburnalmost impossible to either transmit or receive was again elected Chairman for the evening. telephony without it.Why it was that we should After election of new members, the Hon. Secre- have two coils, separated by space with no con- tary reported that he was still awaiting furthernection, yet, when one is charged with electricity information to facilitate the passage of the Society to-the other takes a charge also, seemed almost wards affiliation with the Wireless Society of London. Allthesethings were Severalcopiesofflashlightphotographsof beyond comprehension. October 4th evening's proceedings were secureddealt with by Dr. Goodwin in a lecture which by members. created profound interest. Mr. C. W. Richardson opened the discussion on St. Helens Radio Club. " Aerials and Cognate Matters " by a lecturette Hon. Secretary, Mr. C. Hodgson, Crescent House, delivered in a pleasing and instructive manner Liverpool Road, St. Helens. with the aid of blackboard diagrams and apparatus Meetings of the above club will be held in the he had brought along with him. Y.M.C.A. Buildings, North Road, every Tuesday All present were ably conducted through the so-night at 7.30 p.m. called mysteries of aerials, wavelengths, inductances, Arrangements are being made to provide interest- condensers, aerial oscillations, the latter two items ing and instructive meetings. being regarded by thelectureras misnomers. Applications for membership should be made The course adopted by the lecturer was in tabloidto the Hon. Secretary. 212 THE WIRELESS WORLDAND RADIO REVIEW NOVEMBER 11, 1922 Paddington Wireless and Scientific Society. Eastbourne Amateur Wireless Society. Hon. Secretary, Mr. L. Bland Flagg, 61, Burling- Hon. Secretary, Mr. W. F. G. West, 11, Bolton ton Road, Bayswater, W.2. Road, Eastbourne. The fourth general meeting of the Society was The above Society has been formed and the held at the Institute under the Chairmanship ofSecretary will be glad to reply to and give full Vice-Bresident Dr. J. H. Vincent, and the attend-particulars of the Association's objects and terms ance created quite a record.The business of theof, subscription to all gentlemen who are interested Society included the minutes of the last meetingand desire to seek membership.Several lectures and the presentation of the monthly accounts,have already been given, and have been well after which the recommendations of the Committeeattended. were put before the members.The recommenda- A programme for the winter session is being tions included a Sale and Exchange and the electionarranged for, and members will be notified in due of the following hon. members :-Messrs. Clements, course.The Secretary would be very grateful Alexander, Sutton and Styles. to hear of any gentlemen who can give a lecture A crystal receiver was very kindly presentedor otherwise contribute to the programme. to the Society by Mr. A. Hoban, which was acknow- It is hoped very shortly to announce that per- ledged by a very hearty vote of thanks from themanent headquarters have been obtained, where chair, and endorsed by the meeting. A workingit is proposed to erect a wireless set for the use of committee of four was formed to take over themembers. erection of the new aerial, which it is hoped to see A lecture was arranged for October 31st. in service very shortly. A new section was opened under the heading Bolton Wireless Society. of " Student Membership " to cater for the second Secretary, Mr. D. Walford-Drucquer,4, Bold year day students of technical institutes and gram- Street, Bolton. mar schools in the immediate neighbourhood of At a Special General Meeting held on October 13th the Institute, particulars of which can be obtainedthe following members were elected to hold office :- from the Hon. Secretary. Chairman, Mr.C. Kershaw ;Vice -Chairman, Mr. A. L. Beak, A.M.I.E.E., read a very interest- Mr. R. C. Walch ; Hon. Secretary, Mr. D. Walford- ing paper entitled " High Frequency Amplification."Drucquer ;Hon. Treasurer, Mr. J. Waller ;Com- Mr. Beak dealt mainly with resistance capacity, mittee :Mr.J. McLeod, Mr. G.T. Woodley, coupled amplifiers,the intricaciesof which heMr. C. Andrews, Mr. C. H. Smith. elucidated very fully.A short discussion followed, The meeting was devoted to general discussions after which the meeting closed with a vote of thankson the way the Society had been run in the past to the lecturer. and many thingswere promised by the new Enquiries re membership should be addressedCommittee, and everybody looks forwardto a to the Hon. Secretary. very good season. The new Committee met on October17th, Ayr and County Radio Society. and the following business was dealt with :- Hon. Secretary, Mr. J. Blair, Rosebank, March -(1) That the Society becomes affiliated with the field Road, Newton -on -Ayr. Wireless Society of London. (2) That the subscrip- Following a public invitation, the above -namedtions be reduced to 10s. 6d. per year for full members Society was formed.The undernoted officers wereand 5s. per year for junior members.Entrance elected :-President, Mr. D.M. Sproat ;Vice - fee for junior members to be 2s. 6d.Same to come President,Mr.RichCurrie ;Hon.Treasurer,into force forthwith.(3) That membership cards Mr. W. Robertson, jnr. ;Hon. Secretary, Mr. J. beissued to all members. (4) That a dance be Blair.Committee :Miss Jean Raince,Messrs. arranged to be held the week preceding Xmas. Auld, Cassells, Headley, Oliver, Robertson, Lamont (5) That two whist drives be arranged ;one to be and Ross.Members are now being enrolled. held in the first week in November and the other The newly formed Society has six fully qualified in the first week in December.(6) That the Society holders of P.M.G.'s Certificates, and of these onegoes in for transmitting.(7) That the Society is Miss Raince. obtains a new five -valve receiving set.(8) That The Society is greatly indebted for its being tothe Society join the Relay League.(9) That the the Vice -President,Mr.R.Currie,ofMessrs. Secretary take charge of the winter entertainments Reid & Co., and also to the valuable informationand that he arranges a good programme including received from Mr. W. Yuill,Hon.Secretary, some interesting lectures.(10) That the Annual Glasgow and District Club, who honoured theGeneral Meeting be held on the last Tuesday in meeting with his presence. September each year instead of December, as at The Society wish to express their appreciationpresent.(11) Alterations were made in the rules to . Mr. M. Miller, 2MG, for his transmissions ofto be brought up at the next General Meeting. telephony which were picked up, but owing to (12) Mr. McLeod was asked to take charge of the ship stations jamming it was only heard inter-arrangementswithreferencetotransmitting, mittently.Classes will be formed for each classand he asked Mr. Andrews and Mr. Smith to form of member, viz., Morse, Construction and Technical. a sub -committee under him to carry out this work. Itisfully anticipated that a very prosperous All the above were resolved, and after about Society has been inaugurated. an hour's general discussion on the running of the The Society meets every Friday at8 p.m.,Society, the meeting was declared closed by the beginning October 27th, in the show rooms ofChairman. Messrs. Reid & Co., High Street, Ayr. The new Committee ask for new members to Communications should be addressed to thethe Society, and can promise them a real good Hon. Secretary. programme. NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW The "BROWN" Loud Speakers With NewImprovedCurvedHorns THE REQUISITES of a Loud Speaker are pure tone, clear articulation, and good volume of sound. The " BROWN " Loud Speaker possesses these qualities and they are enhancedby the newimproved curved horn. AMATEURS do not always need the full sized Loud Speaker(11.1)as used in Lecture Halls, and a small type (11.2) has been designed to meet their more modest home requirements both as to volume of sound and price. THE NEW HORN of dull blacked minium used with both 11.1 and H.2 is constructed on the logarithmic law of calu-increasing openings and isacoustically perfect. 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E.P.S.I6 NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW 213 Questions and Answers NOTE.-This section of the magazine is placed at the disposal of all readers who wish to receive advice and information on matters pertaining to both the technical and non -technical sides of wire ess work.Readers should comply with the following rules :--(1) Each questions should be numbered and written on a separate sheet on one side of the paper, and addressed "Questions and Answers," Editor, THE WIRELESS WORLD AND RADIO REVIEW, 12/13, Henrietta Street, London. W .C.2.Queries should be clear and concise.(2) Before sending in their questions readers are advised to search recent numbers to see whether the same queries have not been dealt with before.(3) Each communication sent in to be accompanied by the " Questions and Answers " coupon to be found in the advertisement columns of the issue current at the time of forwarding the questions.(4) The name and address of the querist, which is for reference and not for publication, to appear at the top of every sheet or sheets, and unless typewritten, this should be in block capitals.Queries will be answered under the initials and town of the correspondent, or, if so desired, under a " nom de plume."(5) In view of the fact that a large proportion of the circuits and apparatus described in these answers are covered by patents, readers are advised, before making use of them, to satisfy themselves that they would not be infringing patents.(6) Where a reply through the post is required, every question sent in must be accompanied by a postal order for the amount of ls., or 3s. 6d. for a maximum of four questions.(7) Four questions is the maximum which may be sent in at one time. " P.T." (Maldon).-(1) The precisedetails you have some definite theme of research in view, for converting a single valve panel into a two orand that you are fully qualified to _use wireless three -valve set conforming with the regulationsapparatus in such a way as not to cause interference. of the Postmaster -General, were given on pageHowever, why not write to the Secretary of the Post 865 of our issue of September 30th last.(2) OneOffice and obtain the necessary forms, and if you is not permitted to construct or instal wirelesshave any difficulty, then write to us. apparatus without first obtaining permission from the Post Office.We cannot advise you on the " C.G.S." (Brighton).-Circuits whichare qualifications required by the Post Office in thenot- capable of energising the aerial to a serious award of an experimental licence, but we under- extent have been repeatedly given in this journal stand that you have to satisfy them that you havefor the past six weeks. We would refer you in a serious interest in experimental wireless work. particulartothe instalment on Experimental Why not pass your question to the Post Office, andStation Design in our issue of September 30th ask them for a statement as to the qualificationslast, which has apparently escaped your notice. which they are desirous you should hold. With regard to the unit system, it must be capable " I.C.B." (W.2.).-Certainly itis possible to of being assembled in such a way that the circuit renderordinaryland -linetelephonemessages cannot be easily modified by the user.Anyhow, audible in a loud speaker, or strongly magnifiedsubmit your proposed designs to the Post Office.

Fig. 1. inheadgeartelephonereceivers. We should " G.F.P." (Hayes).-(1) Yes, but reacting recommend you to use a three -valve note magnifierback to the tuning circuits in this way is liable connected as shown inFig.1,on whichall to lead to oscillation and seriously interfere with necessary values are given.Before connecting thisthe pleasure ofother listenersinyour neigh- apparatus to your telephone, we would advise youbourhood.(2) About 2,000 metres.(3) 0.00065 to obtain permission from the Post Office. mfds. (4) You should certainly be able to get 2 MT " H.S.F."(Greenock).-Anexperimentalwith a single valve as H.F. amplifier followed by a licence authorising you to construct your own, ap-crystal, but we doubt if this arrangement will be paratus will be probably awarded by the Post-sensitive enough to give PCGG unless your aerial master -General if you make it clear to him thatis a very good one. 214 THE WIRELESS WORLDAND RADIO REVIEW NOVEMBER 11, 1922 " E.H.W." (Twickenham).-(1) The diagramexperimenters for specific purposes, and we suggest of a single valve receiver which accompaniedyou applyforalicencebeforecommencing your letter will certainly not meet with the approvalexperiments.(2) The formula, watts = volts x ofthePostOffice.Theconditionsspecified amperes,isquitecorrect. Ifthecurrentis by the Post Office are clearly stated in a recent5 amperes, and thevoltagedrop across the issue, and very many circuit diagrams of arrange-apparatusis2volts, 10 watts are being used ments which will not cause serious interferencein the circuit. have been given in our issues for the past six weeks. "S.O.H." (Eastbourne).-(1) The method of Removal of the variometer from the aerial circuitmodulating at the transmitting stations enters will in no way reduce the extent of radiationlargely into this question.Where the modulation which your proposed circuit would produce.(2) is good, no difficulty should be experienced.If the The Post Office, we understand, are preparedtransmitted oscillations are very slightly modulated to authorise the use of a set in which the reactionthe result of using reaction to hear the weak coupling is fixed, and is arranged so loosely as not signals is to cause the set very easily to oscillate, and to seriously energise the aerial inductance.How- so you hear the carrier wave.(2) We cannot ever, why not make up a two -valve set with tuned say with any degree of certainty what causes the anode high frequency amplification and coupletrouble you mention. You might try removing the plate circuit of the second valve with this the condenser, when the self capacity of the winding anode inductance, and add a third valve if necessary. will probably be sufficient to by-pass the H.F. " SPARKS " (Morecambe) asks (1) For a current.The more likely cause of the trouble, diagram of a two -valve set to meet certain conditions. however, is probably to be found in the grid (2) Parts required for this set.(3) If he will getcondenser and leak.The grid leak may have 2 LO, 2 MT and PCGG. become faulty.(3) As your aerial tuning condenser has a rather low value, we think you will have to use a larger coil in the aerial circuit than in the closed circuit when using the series connection. Try the arrangement, aerial condenser in series, No. 150 coil in aerial circuit, and No. 75 in closed circuit, and choose the most suitable value of reaction coil.(4) The arrangement for parallel working which you suggest is quite satisfactory, but it will be necessary to take care not to use too much reaction.The aim should be to alter the positions of the coils until best results are obtained. Generally the reaction coil has to be well away from the closed circuit coil.The connections of your set are quite correct and in every way are suitable. We assume the grid condenser has the correct value -0.0003 mfds. Fig. 2. " AMATEUR " (Northants) asks (1) How to make the most advantageous frame aerial with the (1) See diagram (Fig. 2 ). (2) Two variable highest efficiency. condensers.Aerialtuninginductance reaction As you do not state the wavelength range over coil.H.F. transformer.Two valve holders. Onewhich you wish to receive, we cannot give you filamentresistance.H.T.and L.T.batteries. much useful information.However, frame aerials One pair of telephones.(3) It is very doubtful are fully described in " Mast and Aerial Construction whether you will get any of these stations. for Amateurs," by Ainsley, price 1/6. " F.S." (Hants) asks (1) For a diagram of " C.L." (Huddersfield) asks (1) Why a certain connections using 2 H.F., 1Detector and 2 L.F. circuit sketched gives no better results with two valves valves with switchestocut out any valves.(2) than it does with one.(2) How to add another Whethercapacity reaction should besubstitutedvalve to the set as an H. F . amplifier with the minimum for direct reaction into the aerial circuit. alteration to the wiring. (1) The circuit given on page 883, September 30th (1) We do not know which of your two panels issue, is just the diagram you require.(2) Reactionwas the original.The L.F. panel appears to be of the type you suggest should not be used. Wequite all right, but the detector fails through not suggest you couple the reaction coil to the firsthaving a complete grid circuit.The lower end H.F. transformer secondary.There will then beof the A.T.I. shobld be connected to the filament littlepossibility of energy being radiated fromof the valve.Possibly the failure of your note your aerial. magnifying valve is due to the fact that the trans- " SPARKS " (Ilkley) (1) Proposes to installformer is incorrectly wound or introduced into the an experimental sparktransmitter. (2)Askscircuit.The windings should be about 3,000 ohms whether the formula, watts = volts x amperes, isin the anode circuit of the first valve, and 6,001) correct when applied to a circuit connected to anohms in the grid circuit of the second.(2) The accumulator. circuit might become similar to that of Fig. 5, (1) The circuit submitted will not be satisfactory,August 5th, page 608, with the omission of the and apparatus joined up as you suggest wouldreaction back to the aerial there shOwn. The seriously inteilere with other experimenters workingmethod of using transformers for part of the range on a wavelength anywhere near your own. Weand resistance capacity coupling for the rest is understand transmittimg licences are issued toshown on page 705, August 26th issue. NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVI EW XV MAGNAVOX THE WO7a,D'S F1AEST

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THE TELEPHONE MANUFACTURING CO. LTD HOLLINGSWORTH WORKS, WEST DULWICH, S.E.21 TELEPHONE :SYDENHAM 2460-1 TELEGRAMS :BUBASTIS DULCROX NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW 215 " W.G.W. (London) asks (1)Whether a set " M.E.G." (New Brighton).-The coils you ketched is satisfactory.(2) Whether it will radiate, mention would tune the circuit to about 2,000 and if so, how much.(3) How it can be preventedmetres with a 0.001 mfds.parallelcondenser, from radiating.(4) If it will receive PCGG, 2 MTbut the use of a condenser of this size would be and FL. very inefficient, and we should strongly recommend (1) Yes, except that a parallel condenser is notyou to use about four times as much inductance, at all efficient on short wavelengths.(2) This set and only a quarter of the capacity. will certainly radiate unless the reaction coilis " (Rochester) -a,s/c8(1)Whether the very small indeed.(3) The only way to stop it American short wave tuner of the June 3rd issue from radiating is to make the reaction coil very will receive C.W.(2) Whether the wavelength range small and to fix it in one position.It is not possiblecould be increased to 1,000 metres without loss of to say how bad the radiation will be as this will efficiency.(3)Whether a certain pairofcoils depend on the constants of the aerial, etc., but if thecould be used as A.T.I. and reaction coil. couplings are made at all tight the radiation may be (1) If made exactly on the lines of the article as bad as with reaction back direct on the aerial.it is probable that the set will receive C.W., but (4) The set should receive FL and 2 MT, but is if it does so it will radiate badly.(2) This could not likely to be sensitive enough to receive PCGG.be done, but if the wave were increased in this way any especial merits that the set may have would probably be lost.(3) Yes, but coils used in this

OP TO PLATE way are liable to radiate badly, and therefore IP 10 +11T are to be discouraged in the interests of others OS TO -LT receiving. IS TOGRID " DADDY LONG EARS " (Paris) asks (1) For a criticism of a set.(2) For values for some of the components.(3) If he can use honeycombs, and if so, what sizes to use.(4) If he will hear Fig. 3.Windings i11.a groove.Secondary FL, 2 MT, and PCGG. over Primary. (1) Satisfactory except that strictly speaking all the grid resistances should be connected to some " J.B." (Yarmouth). The method of connect-point which does not change in potential when the ing up H.F. transformers depends entirely upon thepolarity of the filament battery is reversed, but direction in which the coils are wound.Figs. 3 and 4 in practice this refinement is hardly likely to be show clearly, we hope, the correct method of necessary.In any case we do not think that very joining up. We cannot say how the transformersmuch gain in life of receiving valves is actually to which you refer aie wound, and we suggest youobtained by reversing the filament battery.(2) connect them up according to the manufacturer's (a) 0.0005 mfds;(b)0.0002 mfds;(c)50,000 instructions. ohms ;(d) grid leak 2 megohms ;(e) preferably 6 volts ;(f) about 60 volts.(3) Yes, but particulars will depend on the waverange required, which Iwwwwww.www-lowX53 is not specified. Turns may vary from about 50 for very short waves up to about 1,500 for long waves. EACH LAYDI WOUND N SAME OIREC110N The gauge may be about 0.5 mms., and the mean OP TO PLATE diameter about 5 cins.(4) FL certainly, PCGG IP TO +HT very likely, 2 MT not at all likely, as the resistance OS TO GR10 capacity coupling shown is very inefficient on such 1$10 - LT short wavelengths as are used by this station.For this purpose H.F. transformers should be sub- stituted. 13 " NOVICE " (Torquay) asks what would be Fig. 4.Single layer windings. the minimum requirements for a set to receive 2 MT, preferably with fixed tuning, or still better with one " A.M." (Ryde) asks (1) Whether it is possibleadjustment for throwing over to a Plymouth station. to use any other type of battery than an accumulator It is rather difficult to specify suitable apparatus for the filament of a single valve set.(2) Whetherfor use at such a distance, as at long ranges the it is better to have a long aerial lead-in, and a short local characteristics alter the question very con- earth lead, or vice -versa.(3) What he is likely to siderably.Ifwe wereundertaking the work get with a single valve set.(4) Wavelength rangeourselves we should try a three -valve set, with one with certain coils. stage of high frequency amplification and one of (1) With some types of valve, as for instance the low frequency. We should hope to get fairly good Marconi-Osram "DEV," which only takes 0.2 amps, results in this way, but we should not be very a dry cell may be used ;but we do not recommendsurprised or disappointed if we found after test the use of dry cells for any valve taking more thanthat a couple of extra valves were required.This 0.5 amps.In any case the cells used should beof course, is for telephone reception.If a loud of large size, and the cost of operation will be con-speaker were required, two or three additional siderably more than with accumulators.(2) Long L.F. valves would be necessary, but we should aerial lead-in and short earth lead is much pre-hardly expect to get very good results.We should ferable.(3) Most European high power stations, ourselves confine our activities to the new Plymouth and ships up to perhaps 250 miles, but probablystation, as 2 MT is hardly likely to continue in not 2 MT, 2 LO, or PCGG unless conditions operation after the broadcasting stations commence are particularly favourable.(4) Up to 700-800 ms. operations. 216 THE WIRELESS WORLDAND RADIO REVIEW NOVEMBER 11, 1922 T.G." (Coventry) asks (1) Questions about his (1) Detailed informationisgiven in various set.(2) For a diagram using six valves efficiently. textbooks, including Eccles' Handbook.Briefly, (1) It is unfortunate that you have not sent us aa light steel reed is supported in the field close to sketch showing the diagramof connections of the poles of a permanent magnet of roughly horse- your set and the values of the components. Without shoe shape, carrying the windings for the operating this information we can only offer suggestions forcurrents.To the reed is attached a light diaphragm the improvement of your set.Itisbetter to by which the air is set in motion, giving rise to the employ H.F.valvesthanL.F.valves when sound.(2) Nos. 34, 35 and 36, Vol IX;also therearestrayelectricfieldswhichmay May 6th, 1922.(3) No ;the adjustment and the induce voltages into the set.In addition, L.F. proportioning of the parts is very critical.Every iron coiltransformers generally cause distortion. set put up needs elaborate experimental work to It is, therefore, better to use the minimum number determine suitable values for the constants to make of L.F. stages of amplification.(2) We prefer, it function at all, and we think that no one but a when using six valves, to employ three as H.F. skilled experimenter is likely to get satisfactory amplifiers,one asdetector, and two asL.F. results with it. amplifiers.The tuned anode method of H.F. " H.E.N." (Watford) asks(1) For windings amplification is generally accepted as the best,for a telephone transformer for use with 1,300 ohms and we suggest you continue to use this method. telephones.(2) If it is possible to receive C.W . You will find the tuning critical, and there shouldwith a valveset with ordinary reaction, without be no difficulty whatever in eliminating stationsgiving out enough radiation to affect other receivers. transmitting on a wavelength which is only slightly(3) If the circuit of Fig.4, page 636, August 12th different to that which you wish to receive.When issue, is capable of receiving C.W. receiving short wavelengths, the A.T.C. should be (1) Telephones of this resistance may be used in series with the A.T.I., and a switch for connecting withoutatelephonetransformer.Transformer the A.T.C. in series or parallel would be a usefulmay consist'of open core 3" in length by i" diameter,

Fig. 5.

attachment to your set.Fig.5 shows the con- with 2 ozs. No. 44 S.S.C. for primary, and 1ozs. nections, and usual values for the parts are markedNo. 38 S.S.C. for secondary.(2) This can be done in.We suggest you see the articles on " Experi-quite easily if more than one valve is used in the mental Station Design," which appeared in ourset.It can be done in any way which involves issues of September 2nd, 14th and 30th. taking the reaction coupling back to any point " V.H.G." (Bolton).-(1) The gauge of thewhich is not nearer to the aerial than the anode wire submitted is No. 20 S.W.G.(2) Approxi-of the first valve.If only a single valve is used mately 1,500 metres without the addition of athere is no safe way.(3) Certainly. parallel condenser.(3) 0.0005 mfds., which may " WAVELET " (Keighley).-(1) You do not be obtained approximately by the use of plates give us any information about the tuning condenser, of glass 0.1 cms. thick, with an overlap of foilbut if this has a normal value for a set of this of 25 square ems., and a total of 5 plates.(4) type, say 0 0005 mfds., you should be able to Approximately 0.0008 mfds. tune up to nearly 3,000 metres, and down to some- S.E." (Southampton) asks(1) How thewhere in the neighbourhood of 300 metres.(2) Brown patent telephone works.(2) The number L.R.telephones with a telephone transformer of " The Wireless World" in which an articlemay certainly be used with a crystal set.(3) ontheJohnsen-Rahbek loud speaker appeared.0.0005 mfds. is quite big enough for the tuning (3)IftheArmstrong super -regenerativecircuit condenser, and 0.001 to 0.002 mfds. for the blocking can be regarded as a practical proposition and likelycondenser.(4) The buzzer, key, and cell should be to give good results in the hands of an average amateur. connected across a few turns of the A.T.I. NO VEMBE R 11 1922 THE WIRELESS WORLD AND RADIO REVIEW

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We Ur& Commercial Wil-eless telephone 8erv1ee in GreatY3ntain is used for Communicatthns between the offices of the Aensey Docks CI' Harbour 3oard in Liverpool and the Oar lightship beyond the mouth of the ikensey. She Atarconi apparatus in each Case is operated by the ordinary 9iarbbur23oard staff and has been in continual use since its installation over a year ago .- "Calling up" is performed by means of the- e 0 _Marconi wireless bell 0 MARCONIS WIRELESS TELEGRAPH CO.. an MARCONI HOUSE. STRAND, LONDON, IV C.2 Telephone' CITY 87/0.

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.5 xviii THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER11. 1922 " BRITWIRE " APPARATUS "BRITWIRE" Mk IV RECEIVER Now made with Radion Mahoganite panel as standard, andfitted with the very finestL.F.transformers and components. Guaranteed equal to,orbetter than,anyfour valvereceiver sold, and equalto manysixand sevenvalvereceivers. OneH.F., oneRectifying and two L.F. valves .. 21 "BRITWIRE" TUNER to match.. 18 10.. Completewith aerial equipment,accumulator and all accessories. Forty Guineas. " BRITWIRE " TUNER. 13R1 f WIPE " RECEIVER. ALL BRITWIRE valve apparatus is licensed under Marconi patents for amateur use in Great Britain List post free, 3d. Post orders to- BRITISH WIRELESS SUPPLY CO., LTD. 8, Blenheim Terrace, 18, Eldon Square, 11, Church Street, 83, High Street, LEEDS. NEWCASTLE -ON -TYNE WEST HARTLEPOOL. S aunt AMPTON Telephone -403 Telephone - 26926. Telephone-36oCity. Telephone - -373. BRANCHES AT BELFAST AND LONDON OPENING SHORTLY.

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'0003 SUPER CRYSTAL ... '00005,. .. 5'6ea. Filament Resistances ...... 3/- ea. RECEIVING SET Terminals with high base ...... 1/6 doz. completefromAerialto'Phones. Contact Studs, with nuts.- 9d. doz. Sliders, with springs and studs 9d.e.. £4 7 6 only. Ebonite Panels, cut to order 3/6lb. Guaranteed to receive Broadcasting and British Single Valve Panels made throughout. fitted with Variable Condenser, Filament Illustrated Catalogue including List of Stations. Resistance. Grid Leak and fixed Conden- etc., 6d. post free. ser,EngravedPaneland Rosewood finished Box, ready for use- - EONSWIRELESS SUPPLY CO. VulcanisedFibre and Ebonite 115, FLEET STREET, E.C. 4 Sheets, Rods & Tubes from stock. NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW 217 " W.W." (Brighton) asks(1)The number " SOLDIER " (Woodseats).-Theaddition of turns to wind in a basket coil to tune in 2,700you suggest can certainly be made; the valve or metres.(2) How many turns to tune in 360-425valves being added as low frequency amplifiers. metres.(3) How ,many turns to tune in 180-360To do this itis not necessary to alter your set metres.(4) For diagram of a single valve set usingin any way.It is merely necessary for you to a three -coil holder in his possession. introduce the one winding of an input transformer (1), (2) and (3) It is not possible to give the in front of your first valve in place of the telephones. exact number of turns to wind a basket coil to give Many diagrams of one and two -valve low frequency amplifiers will be found in recent issues. " C.A.S." (Ealing) asks (1) If itis desirable toearth -wire garden poles against lightning.(2) Should lightning arresters be fitted at point of entry of aerial wire into the house.(3) Would a vacuum type lightning arrester affect reception. (1)Poles are not generally earth -wired, but there certainly is no harm in so doing. A No. 12 galvanised iron wire should be twisted around the bottom of the pole, and run up the side of the pole. At the top end it may project 6 or 8 inches.(2) and (3) A vacuum type lightning arrester will suit your purpose very well, and should be fitted across the aerial and earth at the point of entry of the aerial into the house.A switch should be provided, so that when the set is not being used the aerial may be directly connected with earth. Theseprecautionsshouldbetaken,otherwise Fig. 6. damage to the set may result from the effect of static charges, as well as the effect of lightning. acertaininductance.TheinductancevariesSometimes a highly inductive leak is connected with the spacing, method of winding, etc.Assum- across the aerial condenser as a protection against ing you will use a 0.001 coil A.T.C. in parallelstatic charges_it this will largely be unnecessary with the coils to tune in 2,700 metres, we suggestif you adopt the other arrangements.No loss you wind five coils of No. 30, each coil havingin reception efficiency will result through the use 80 turns.With the tuning condenser in series on of the above protective apparatus. the short wavelengths, two coils in series, each " W.K.N." (Hounslow).-We cannot give you coil having 50 turns of No. 20, will tune precise windings, and it would be much more metres, and one coil with 60 turns of No. 20 will satisfactoryif you wound the coils exactly as tune in 180-360 metres.(4) See Fig. 6. described, and then experimentyourselfuntil the best results are obtained. " J.F." (Berks) asks (1) For a criticism of his circuit.(2) Whether a broadcast licensee is only " G.L.E." (Woolwich) asks (1) For a two- permitted to receive broadcast signals.(3) Can a valve circuit suitable for use with certain apparatus. holderof a broadcastlicenceusereaction above (2) For windings for a transformer suitable for use 500 metres. with 300 ohm. telephones. (1) We have examined your diagram of connections, and we are afraid you will be unable to use reaction in this circuit.We suggest you cut out the reaction coil altogether.We think you would get much better results if you added one high frequency valve.Reaction could then be provided for.The reaction coil would be connected between the anode and telephones, and would be coupled to the tuned anode of the first valve. A large number of circuits have recently appeared inthisjournal.(2)and(3) We understand that the holder of a broadcast licence is not restricted in so far that he may receive signals of any wavelength.The restrictionappliestothe useof reaction and the employment only of apparatus approved by the Post Office.The set must be so designed that under no circumstances will the aerial circuit oscillate. " F.J.W." (Leyton) asks whether he can connect Fig. 7. a transformer to his set, and so strengthen the signals. Unfortunately a transformer cannot be connected (1) See diagram (Fi7. 7 ).(2) Core i" diameter to increase the strength of signals, and we suggestof iron wires, about 4" long, primary wound with you add a valve as note magnifier, using the connec- 3 ozs. of No. 44, and secondary wound with 6 ozs. tions given in several recent issues of this journal. of No. 34. 218. THE WIRELESS %WORLDAND RADIO REVIEW NOVEMBER 11, 1922 " R.V.J." (Brixton) asks for the issues in which " H.P.H." (Herts) asks (1) The range of a appeared a description of a set which will receive crystal set.(2) For an explanation of Dead-end " broadcast. effects.(3) If he may add one L.F. valve. (4) We suggest you see the articles entitled " A Where to obtain books dealing with wireless. Broadcast Receiver," which appeared in the issues (1) We are afraid you will only receive local of August 26th and September 2nd. signals when using a crystal set. (2) " Dead-end " effect is the name given to the loss of efficiency " N.N.L." (Cheam).-(1) The diagram sub-which arises when, for example, only a small mitted is not quite correct, and we suggest you useportion of a big coil is in use.It is overcome by the circuitshown inFig.8. Care must bebreaking up the coil into sections.The proposed exercised in the selection of suitable jacks.The coil is far too large for short wavelengths, and we springs must be very well spaced and robust.(2) suggest you wind another coil making it 4" diameter, A suitable frame aerial for your purpose would be 5" long, and using No. 22 D.C.C. wire, taking a frame 4' square with 16 turns of No. 18 wire 8 tappings.The A.T.C. should be in series with with 6 tappings, the wires being spaced 4" apart. the A. T. I.

0.0004a F

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025.,E

Fig. 8.

" ENQUIRER " (Chelmsford) asks (1) The " A.B."eir (Staffs.)1 (1) Submits acircuit for number of turns of wire to wind in a 24" diametercriticism.(2) and (3) Asks the wavelength range former for use as a reaction coil. (2)Values ofof coils.(4) Whether a proposed arrangement is condensers in microfarade and inductances in micro - correct. henries to tune to 360 metres.(3) Whether his set (1) The diagram is correct, except that the plate is suitable for operating a loud speaker. andgridconnectionsarereversed.Thiswe (1) Wind 100 turns of No. 38 S.S.C. wire.(2) presume to be merely a clerical error.(2) We The aerial condenser should have a maximumcannot say without a knowledge of the size of the value of 0.001 mfds., and should be in series with coil.(3) 2,600 metres with condenser in parallel the A.T.I.The closed circuit condenser may haveand 800 metres with the condenser in series.(4) a maximum value of 0.0005 mfds.The aerialThe arrangement will work very well. coil should possess an inductance of 450 micro - henries, and the closed circuit 220 microhenries. SHARE MARKET REPORT The waverange will be from 600 metres to 2,000 metres.(3) We think your set is suitable to operate Prices as we go to press on November 3rd, are :- a loud speaker.However, if you cannot get suffi- Marconi Ordinary .. £250 cient signal strength, add one L.F. valve. 2 29 " G.A.Q." (Birmingham).-The suggested Preference coils are suitable, but it is just as well to use a single Inter. Marine.. 177 layer coil, which you can make yourself.Wind a coil 4" diameter and 5" long, of No 22 D.C.C. and Canadian .. 10104 take 8 tappings.The circuit, given on page 80, April 8th issue, will be quite suitable if you connect Radio Corporation of America ;- the primary of the transformer in place of the Ordinary .. 180 telephones, and join the telephones to the secondary 6 side of the transformer. Preference .. 13 ITOTAIMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW xx Buildyour ownset Mullard Accessories

The wireless components with a worldwide reputation of many years' standing. They will ensure your getting a set which looks well, works well and "speaks'"well. For receiving vocal and instrumental items you must have the MULLARD "ORA" Valves to get the best results. Oscillates-Rectifies-Amplifies Specially recommended where good amplificationis required. 15/. each IMPORTANT NOTICE The great demand for Mallard "ORA" Valves and other accessories hascompelled us to open much larger works. A. greatly increased, output is now available. The MULLARD "R " Valveis now reduced in price from 22/6 to17/6 Mullard Radio Valve Co., Ltd. 45, Nightingale Lane, S.W.12.

011111111111111111111111111111111111111111111milim1111

Contractors to H.M. Admiralty, Signal School, Portsmouth, War Office, Royal Air Force & Post Office.

Telephone : Codes: Telegrams: Battersea ABC (5th Ed.) "Radiovalve. 1068. Bentley's Hammer Lond."

0,01111111111

gessoow Derot :15, Woodside Terrace. Newcastle Depot :17, Sanaa xx THE WIRELESS WORLD AND RADIO RE VIEW Nt.. \-HNI BEI: 11, 1922 BULLERS' Tubular Steel Mast Sets for Broadcasting Reception and Low Power Transmission HEIGHT 35' 0" Each Set conszsts of : One Top Tube, one Bottom Tube with Shoe and Joint Socket.Six Double Swivels for adjusting the Stay Wires.One 3 -Way Stay Clip.Three Stay Pegs of Angle Iron, 2 ft. long pointed at one end and provided with a hole in each flange for independent adjustment of Stays.180 ft. of No. 12 Flexible Steel Wire Rope.Six Guy Insulators, Patt. E.A. 8760. One Aerial Halyard Pulley and Eye Bolt for securing Halyard. The whole of the Metalwork is galvanised except the Stay Pegs, which are oiled. Total weight of Tubes & Socket 59 lbs. These masts are light, strong, and the general arrangement is based on sound engineering practice. The design is as economical as is possible, consistent with necessary strength and weathering capabilities ;sufficient stay wireis provided to enable the erector to vary the staying points within a reasonable margin. These masts can conveniently be erected on a base of 20 ft. diameter. 40ft.masts can be supplied at slight extra cost. RETAIL per set PRICE :23 15 0complete. SPECIAL TERMS TO THE TRADE. BULLERS, Ltd.

1'1 6, Laurence Pountney Hill, . r,l, London, E.C.4.

Works: HAN LEY, Phone: TIPTON. STAFFS. CITY 985/6. MILTON, 11) NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW xxi. BULLERS' WIRELESS INSULATORS

Reception Weigh 6 ozs. Reception Weight 1 i ozs. Type Test 500 lb. Type Test 600 lb. E.A. 9340 E.A. 9341 Tested to 40,000 volts. Tested to 52,000 volts

RETAIL PRICES. E.A. 9340, 1/4 each E.A. 9341 2/-

E.A. 9342..2/6

Transmission Weight 18 ozs. .611.11110 ;Type Test 800 lb. 1. Fait WM. E.A. 9342 LOOK FOR OUR TRADE MARK. Tested to 52,000 volts.

These insulators, of which we are the originators, have been specially designed by us for Broadcasting reception, and Low Power Telegraphic and Telephonic Transmission. Advantages over other types : I.Very Low Capacity. II.Instant Shedding of Rain. III.Negligible Weight. IV.Highest Insulation Possible. V.Great Tensile Strength. VI.Easy to attach to Aerial or Halyard. Trade Enquiries Solicited. BULLERS LT.'?6, Laurence Pountney Hill, LONDON. Phone :City985/6 Works : TIPTON, HANLEY, MILTON, STAFFS xxii THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER11, 199t LESE MICW LTD PROVIDENCE PLACE, WEST END LANE, KILBURN, N.W.6 ServIcee 1. 8.16.. 28. 31 allpassWest End Lone Telephone HAMPSTEAD 1261 Nearest Tube Station: KILBURN PARK ( BAKERUDO)

EX DISPOSAL BOARD WIRELESS APPARATUS Brandnew andguaranteedinperfectwork'ngorder

We have published a booklet written by Coureey;B.Sc., describing fully the various Disposal Board apparatus and their applicaticn te!crreti- mental uses.We give below a list of each apparatus and their prices.

Transmitters,' Mark 3 C.W., for 2 valves, complete Amplifier. C. Mark 3, 3 -valve L.F., ccmpletc with with milliampere, platinum pointed Morse key telephone transtormer in new mahogany case.. 16 5 0 in mahogany box range 30o to 1,75o metres, Same with new mahogany case with hinged top 7 10 0 described page 14 above booklet.. f500 Townsend Wavemeters, 300 to 4,000 metre ..6 00 The same converted to 2 -Valve Detector Ampli- Brown's Telephones, new guaranteed condition, fier Tuner in new mahogany box 8 100 ex Government, guaranteed and reconditioned by the makers8,000 ohms . ..215 0 B. Mark 2 Receiver, vertical pattern, page 6 above T20 ohms .. 2 10 0 50 Same guaranteed in perfect condition, Converted to take up any wavelength.. ..65 aluminium and parchmentdiaphragms With variable air condenser.. ..75 O0 8,000 ohms ..2 39 Mark 3 Tuner (page r of Booklet), complete with 120 ohms 117 6 all spares, 8,000 ohm new Brown's telephones The Booklet .. Disposal Board instruments and Their suitable for wavelengths up to ryoo metres in its Application to 'Experimental Uses," can be supplied against present state, but can be easily altered to any wavelength for use with carborundum, Perikon Postal Order 1/6, together with Complete List otour or valve .. .. 10 100 2, 4 valve receiving sets, accessor, e c.

Are light, strong, made in sections, easily erected, and will last a lifetime. Each mast is complete with baseplate, finial, rope cleat, pulley, guy clips,'steel guy ropes, strainers, painted one coat ready for erection. Prompt delivery.Prices F.O.R. for cash with order.25 ft. 2415/0, 3o ft. £5/5/0, 4o ft. £7, 45 ft. 27/1510 5o ft. £10/10/0 6o ft. 215/1010.Other lengths supplied at equally low prices.Trade inquiries invited. The Wireless Steel Mast & Accessory 0o., Lombard St. West, West Bromwich. Telephone No. : 447. Telegrams :" Wireless Westbrommich.

BAMBOO SPREADERS 5/6 BRASSBOUND EYELET ENDS EYS 1/6 EYEBOLTS19 CLEATS 1/- ROPE GRIPS 16 LIPS 1/9 ADJUSTABLE REEW'tat- RAINERS 2/0 GUYeLIPS 2/9 N INSULATORS EGG TYPE 19 SHELL TYPE 1/9 VOLe' TUBULAR INSULATORS1/9 LEAD IN n 5/ - BEST H TE COTTON HALYARD ROPE. TINNED S L CABLE, AERIAL WIRES. AVS.?" FREE. TRADE SUPPLIED. NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW We RequireResponsible Agents Throughout the Country The demandforour WirelessApparatushasgrowntosuchan enormous extent thatweare compelledtoenlistthe assistanceofsoundAgentsall overtheCountry.EveryresponsibleWirelessDealer whoappreciatesthe businesspossibilitiesof efficientequipmentata reasonablepriceshouldget intotouchwithus withoutdelay. Thefollowingfirmshave already takenupour EdinburghandDistrict.Messrs.Robertson& Agencies:-- Hogge,29,Nicolson Street,Edinburgh. SouthportandDistrict.Messrs.T. Wainwright Manchesterand District.Messrs. A. Franks,Ltd., & Sons,Ltd..329, LordStreet,Southport. of 44. MarketStreet,Manchester;73, Oxford Street, Manchester;95 and 97,Deansgate, BrightonandDistrict.Messrs.SmithBros., Manchester. 33, NorthRoad, Brighton. BoltonandDistrict.Messrs. A. Franks,Ltd., Barnes andDistrict.Messrs.Secretan &Mallett. 30, Bradshawgate,Bolton. Ltd., 149,Lowther Parade,Barnes, SM.13. BournemouthandDistrict.Messrs.G. E. Beale, WokingandDistrict.Messrs.CapperBros., Ltd., Bournemouth. 89, ChertscyRoad, Woking. LESLIEMcMICHAELLtd. ContractorstoRadioResearch Boa,/, .Army,,firMinistry,PostOfficeEff Govt,ofEgypt. ProvidencePlace, WestEndLane, Kilburn,N.W.6 Telephone-HAMPSTEAD 1261. Nearest Tube Station-KILBURN PARK, Bakerloo

CRYSTAL BROADCAST "RADIO -WAVE RECEIVER. This Broadcast Receiver conforms to the Post Office Regulations for Broadcast Receiving apparatus.There are many receivers being offered to the public which do not conform to these requirements and broadcast licence holders may later experience the annoyance of having them condemned by the Post Office Inspectors.Apart from thisthere are other reasons why you should not hesitate to fix your choice on the " Radio Wave " Crystal Broadcast Receiver. (1) You will not be confined to the reception of Broadcast. Amateur telephony and morse code messages from ships may be tuned in. (2) The short wave switch gives ULTRA EFFICIENCY on amateur wavelengths. (3) The twelve -point inductance switch gives 100 per cent. tuning accuracy.The instrument is therefore extremely SENSITIVE to the WEAKEST OF SIGNALS. (4) Only selected Hertzite crystals are used in the detector. (5) The detector is robust, comfortable to handle, and easy to adjust, giving every possible point of contact. (6) The detector cup may be easily removedfacilitating rapid replacements. (7) Owing to the special care taken in the construction to avoid electrical leakage this instrument should give a slightly larger signal range than the average crystal receiver. (8) It is a well made handsome apparatus, metal parts being highly polished and lacquered, and the cabinet work French polished mahogany. (9) It is sent out with full instructions, under guarantee. Price, including cost of aerial wire, insulators, 4,000 10 10, ohms resistanoe headphones, with two earpieces,.4- MADE BY : THE MEDICAL SUPPLY ASSOCIATION,Ltd. 167/185 Gray's Inn Road, London, W.C.1.Works: London & Sheffield. Telephones: MUSEUM 7210, 7511,'7212. THE kVIRELESS WORLD AND RADIO liEVIEW NovEmBER 11, 1922

THE TURRET WIRELESS MAST FOR BROADCASTING ANDI ISTFNINGIN SPECIALITY DESIGNS Low Frequency Transformers 30/- each

Telephone Transformers, 22/6 Coil Holder for Two Coils,

22/6 (Patent applied for) Coil Holder for Three Coils,

27/6 (Patent applied for) High Frequency Transformers

from 5/6 to 10/6 High Frequency Transformers,

Reversible Type, from 7/6 to 12/6 (Prov. Patent)

EFFICIENCY is the essential feature of all our designs and accessories. We are stillable to give immediate delivery of orders booked NOW, why not write for details of our stocks.

TRADE TERMS ON APPLICATION DUBILIER CONDENSERS AND SPECIALITIES Appointed agents for Manchester & District Deliveries can he given ex stock, Manchester

Photo of the Patent Turret Oregan Pine Cantilever Mast designed by Naval Experts. It is rigid and does not spoil the garden, no current jump, no rusting, aluminium fittings, easily packed. Light and simple to fix.(Send for details.) 29 ft. Mastin2sections39;9 The Manchester Radio Co., Ltd. 311 ft. Mastin3sections.11),() P. H. Met REA, Managing Director 1..2 ft. Mastin3sections(1.9/11 W. R.BURNE, Directing Experimental Department SIMPSON & BLYTHE, 155, OXFORD RD., MANCHESTER (Entrance Boundary Street East) 8 & 9, Sherwood Street, Piccadilly, W.I Telephone :Central 4935 NOVEMBER 11,922 THEW WIRELESS WOELD M AN I) REVIEW XXV TUNER & CRYSTAL RECTIFIER RECEIVING SET G.P.O. Regd. No. 128 ApprovedbyPostmaster -GeneralforBroadcastingLicence.

Including Royalty to BROADCASTING COMPANY. Packing & Postage Free. CAS' INV I'M I ORDER. Delivery from Stock.

ALL on KALANITE (Moulded Ebonite)- NO WOODWORK. Wave Range on Standard G.P.O. Aerial -100 to 1,200 metres.Fitted with our new CRYSTAL DETECTOR (Registered Design No. 692248) ;Double Sliding INDUCTANCE ;001 mfd. CONDENSER ; Terminals for Aerial, Earth, and for Two Sets of Headphones. Every set stamped with the Trade Mark of The British Broadcasting Co., Ltd., and with the G.P.O. Registered Number.

100 ft. Aerial Wire, 2 Insulators, 1 Leading -in Tube, and I Pair Siemens Double Head Telephones -36/- extra the lot. Total Cost of Complete Equipment £4 15 6 including all Royalties. WE WILL SEND ON 'APPROVAL and on the distinct understanding -that if the buyer is in any degree:dissatisfied with his purchase, he can return same within 24 hours and money will be immediately refunded. ALL OUR APPARATUS is produced under the'rpersonal supervision of our Technical Director, Mr. Henry A. Machen, A.M.I.E.E. (late of Siemens Bros. and Co., Ltd.), whose experience in the design and manufacture of Wireless Apparatus extends over a period of Fifteen years. CATALOGUES FREE. TRADE TERMS AND DISCOUNTS ON APPLICATION.

Sole Manufacturers- The Wainwright Manufacturing Co., Ltd., (Members of The British Broadcasting Co., Ltd.) 25, VICTORIA STREET, LONDON, S.W.1. Telegrams :Nominatus Vic London. Telephone :Victoria 4319. xxvi THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER H. 1022

BOOKS FOR THE LIBRARY ACCESSORIES CONTINUOUS WAVE WIRELESS TELE- FOR GRAPHY. Part I. By W. H. Eccles, D.Sc. Price 25/- net.Post free 25/9.407 rages. PRIVATE WIRELESS 306 diagrams and illustrations. INSTALLATIONS THERMIONIC TUBES IN RADIO TELE- GRAPHY AND TELEPHONY. By John Scott -Taggart, A.M.A.I.E.E.Price 25/- net. Post free 25/9.424 pages.kr 344 diagrams and illustrations. THE THERMIONIC VALVE andIts Development in Radio Telegraphy and Telephony. By J. A. Fleming, M.A., D.Sc. Price 15/- net.Post free 15/9. 279 pages. 144 diagrams and illustrations. WIRELESS TELEGRAPHY AND TELE- PHONY.-First Principles, Present Practice and Testing. By H. M. Dowsett, M.I.E.E.Price9/-net. Post free9/9. 331 pages.305 diagrams and illustrations.

TELEPHONY WITHOUT WIRES. By Philip R. Coursey, B.Sc. (Eng.), A.M.I.E.E. TELEPHONE HEAD SETSspecially Price 15/- net.Post free 15/9.414 pages. designed for wireless work.Terminals en- 250 diagrams and illustrations. closedtopreventreceivingcircuitbeing STANDARD TABLES AND EQUATIONS interfered with. Earpiecesareprovided IN RADIO TELEGRAPHY. By Bertram withgroove on surfaceto minimise con- Hoyle.Price 9/- net.Post free 9/6. 159 densation of moisture. pages. VACUUM PROTECTORS(for pro- FIFTY YEARS OF ELECTRICITY-THE tecting the aerial).They secure protection MEMORIESOFPv. AN ELECTRICAL against risk of fire or damage by lightning. ENGINEER. By Dr. J. A. Fleming, M.A., D.Sc.,F.R.S.Price 30/-net.Post free Will operate many times before renewal is 31/-.371 pages, 1 1 I plates. necessary. for protecting the filament accumu- THE WIRELESS TELEGRAPHIST'S FUSES POCKET BOOK OF NOTES,FORMULAE lators and batteries in the event of a short AND CALCULATIONS. By J. A. Fleming, circuit. M.A., D.Sc.Price 9/- net.Post free 9/6. 352 pages.39 diagrams and illustrations. AERIAL WIRE & INSULATORS T.S.F. LA TELiGRAPHIE SANS FIL. EARTHING DEVICES LA TELEPHONIE SANS FIL. By G. E. JACKS, PLUGS & SWITCHES Petit and Leon Bouthillon.Price 12/6 net. 13/-postfree ;papercover,15/-net. H.T. BATTERIES, 15/9 postfree.Cloth bound.304 pages, 197 diagrams and illustrations. ETC. ETC. PREPARED RADIO MEASUREMENTS WITH SELF -COMPUTING CHARTS. Descriptivepamphlet andprices on applicationto By Ralph R. Batcher, E.E.Price 10/6 net. THE MANUFACTURERSs Post free 10/11.132 pages. SIEMENS BROTHERS & CO., LTD. General Offices and Works : The Wireless Press Ltd., WOOLWICH, LONDON, S.E. 18 Dept. W.W. Telegrams-Siemens, Woolwich. Telephone-City 6400

And at Ballast, Birmingham, Bristol, Cardiff,_Blaagow, 12-13, Henrietta Street, London, W.C.2 Leeds, Manchester, Newcastle, Sheffield, Southampton. NOVEMBER 11, 1922 THE WIRELESS WORLD AND RA1)10 REVIEW xxvii der- Caig Jrilaw°52"mr DRY CELLS and BATTERIES for High & Low Tension

No. W.19 THE STANDARD OF QUALITY 17W.1

1111111111111111111111111111111111111111111111111111111111111111111111111111111111111 I11111111111111111111111111IHIIICI.

HIGH TENSION BATTERIES THE UNIT DRY CEIL Any size or voltage with any tappings or sockets at 3 or 6 volt Build up your batteries as you build up your intervals for use with Wander Plugs can be suppliedtoorder Marconi Sets." With 13 sockets as illustrated. Unlimited flexibility in size. voltage and intermediate tappings.Each cell is fitted with brass No. W.ro. 36 volts, 24 cells, 8/6 each. Size 6f x x31. screw terminal and looped wire, and they are Weight z lb. 8 ozs. efficiently insulated to prevent current leak. WanderPlugs1/-perpair. With2 SpringContacts. No. MY. z, 7;6 per dozen.E.M.P. 4 voila. No. Wax, 25volts,IIcells, 3/6 each. Size gixI x 2}. 5/26 diem. Weight xlb. 2 OM. Weight 3i ozs.Dimensions 4 x 2

Art Catalogue of Standard Sizes and Voltagce and list of Accumulators for Valve Filament Supply sent on request.Dent. D.L. THE EVER - READY WORKS, HerculesPlace,Holloway,N. 7.

1EBONESTOS INSULATORSIIIIIIIIIIIIIIII

WHOLESALE ONLY.

----11111111EBONESTOS INSULATORS LTD., ROLLINS ST., LONDON,S.E.15.19 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 11, 1922

1. Fil. Resistance ..7/9 BUTLER'S RELIABLE MANUFACTURES. 2. 9 -Stage H.F. Trans- former . 52/6 3. Vernier Condenser.. 5/6 a 4. Grid Leak and Con- denser ..4/6 5. MultipleContact Switch .. 10/6 6. Unmounted Fil. Re- sistance . . 5/3 7. Coil Holder .. 15/6 s For 2 Coils.. 12/6 8. TumblerSwitchin Erenoid 2/6 9. SkeletonCondenser

from . . 13/9 10. Crystal Detector 4/10

`pi 11. Switch Arms . . 3/- Gt elto. Li 12. Coil Holder for basket 4 or Slabs, 38f-. With el 8 holders. Tapped S holder, extra . . 8/3 13. Multiple Valve Holders . ..3/10 Also made up for 3 or 4 valves. 14. New TypeValve Holder, no exposed 17* . . metal 1/5 15. Valve Holder ..1/4 16. On and off Switch.. 3/6 12 ! 17. 1" Radius Switch Arm 2/2 20 18.0003 FixedCon- denser .. ..5/- 2 19. Three-way Switch ..4/6 20. BrassValveLegs, each..3d.and 214. 21 Lead-inTubes,6", 2/3 12", 3/-, etc. 22 22. Tin Type Trans- formers, price aecord- ing to range. Bank Buildings, 222, Gt. Dover Street, S.E.1. NEW FULLY ILLUSTRATED H. D. BUTLER & Co., Ltd9Telephones-HOP 3029. Works, North 5838 LIST POST FREE, 4d. Works-Canonbury, London, N.1. "For theareOn ood Fellows" OP' Precision Air Condensers For series of parallel tuninguse Fellows PrecisionAirCondensers. Theyare equally suitable for separate useor panel mounting.Made in four standard sizes.

*0002 mfd. - - Price 16/- (postage 6d.) *0003 mfd. - - Price 17/6 (postage 6d.) -0005 mfd. - - Price 22/6 (postage 6d.) 00005 mfd. vernierPrice 8/6 (postage 6d.) AllFellowsradiocomponents are British Made throughout and fully guaranteed ER to FELLOWS MAGNETO Co., Ltd. LONDON, N.W.10. Telephone-Willesden zs6o.q. Telegrams-Quixmag, Phone, London. // ////// NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW ASHDOWN Condensers SEM still pre-eminent Ask Your Dealer !

Owing to to the boom in wireless goods, many firms have sprung up like mushrooms (luring thelastfewmonths, and much shoddystufffindsits way tothe, market, ASHDOWN Condensers were first made when " wireless " was thought of more as a wonderful invention than a practical business proposition, and ASHDOWN Condensers have stood the teat of time and experience.TRUST THE FIRM WITH A GREAT REPUTATION.

.titocks held by London:Rep.: Mm. J. 0. Maddock, tc. Bayham Road, Bedford Park II Agents wanted in Coloniesand ForeignCo:Hat:les. H. E. Ashdown (Birmingham), Ltd., Perry Barr, Birmingham 'Phone :Northern 859. Tel.: Segment. Cod:: A.P.C., 5th Editi3n, Wcsteru.

I I Do Yon get FL !

X701JR crystal or valve may be the best of their kind-your I aerials high as Snowdon, your tuner perfectly accurate, but unless your 'phones are O.K. you won't get maximum "sign." Signals come "ihumping in" through ERICSSON 'PHONES. They're built that way-for never -failing clarity and sensitivity.The magnets never lose their strength and " shorts " don't exist.And they're easy I and comfortable to the head. Back of ERICSSON 'PHONES isthe accumulated experience of a I generation in telephone manufacture. The BRITISH L. M. ERICSSON MANUFACTURING Co., Ltd. Head Office : 67/73, International Write for Buildings, Kingsway, W.C. Particulars

321per Pair

- 4000 ohms. All Resistances i in stock. -Telephones

MIEN SRAM MEMO - xxx THE WIRELESS NVORLD AND RADIO REVIEW NOVEMBER 11, 1922 RADIO INSULATION AS SPECIFIED AND USED BY THE BRITISH ADMIRALTY

BRITISH MADE PAXOLIN BRITISH MADE

TUBES DISCS PLATES, &c. MANUFACTURED IN ALL FORMS, SIZES AND THICKNESSES BY THE MICANITE & INSULATORS CO. LTD. EMPIRE WORKS WALTHAMSTOW LONDON,E.17 TRLDORAPAS -" MYTILITE, PHONE. LONDON." TELEPHONED -WALTHAMSTOW 738. 7310

Reliance Radio Service Co. HIGH-CLASS RECEIVING SETS AND COMPONENTS.

TliE" RELIANCE "No. 1 CRYSTAL RECEIVING CABINET. Consisting of Ebonite panel mounted in Oak cabinet with lid, Tuning Coil and Condenser.Patent Crystal Detector totally enclosed in glass.4,000 ohms. Double Headphones, 100 feet stranded copper wire, 2 shell insulators, etc. No further outlay.No batteries required. Each set has been tested and carries our guarantee, and we confidently assert that for the price it is the most compact and reliable that is obtainable. A PRICECOMPLETE INSTRUMENT ONLY £.3 15 0 £,2 2 6 We have also a complete range of Receiving Sets and parts in stock, both Valve and Crystal. Send for our .Art Catalogue, Post Free on Application. Our sets are open to inspection at our London address at any time. Demonstrations given with pleasure.You will not be urged to buy as we know you will come to ns after you have compared our goods with other makes.Call, phone or write. `Grade (inquiries Solicited. RELIANCE RADIO SERVICE Co. 283, St. John Street, Clerkenwell, London, E.C.1 PHONE-CLERKENWELL 4290. NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW

THE NATIONAL RADIO COMPANY, Carlton House, Birming- ham, offer a series of high-class instrument component parts at the following attractive prices : Filament Resistanoes .. each 3 - and 4 - 16 Pages, handsome Knobs, It", brassed bushed, 2B.A. ..each 8d. coverinthreecolours, Valve Holders, Ebonite, Matt or polished.. each L- and 1/3 gives you full information OUR NEW BIG - Condenser Dials, engraved with knob .. each 1/2 and 2! - and prices on Wireless ILLUSTRATED CATALOGUE - Condenser Dials, less knob 1,'-,1'4 Receiving Sets complete Sliders, Ebonite with plunger ..each 1/ - from £3 108. to £12 Terminals, Ebonite insulated .. .. doz. 3 - 10s. Hear allthe RADIO Crystal Galena Detectors, on ebonite base.. ..each 4,9 concerts,speeches,ser- Contact Studs, with nuts and washers doz. L - mons,news,cropand SUPPLIEST Copper D.P. Throw -over Earthing Switch.. ..each 5!6 weatherresorts, now \\NAN-7,-"--''' Condenser and Filament Scales, Ivorine .. each 1'- and 1!8 being broadcasted daily. Switch Arms, laminated Phosphor Bronze ..each 2/3 Costs you nothingafter Condenser Knobs and Pointers.. ..each 1'2 first cost.Easy to install and operate. Grid Leak and Condenser Sealed, complete with terminals, And hundreds of other Wireless articles. each 2 3 Blocking Condensers, ebonite parts and screws ..each 1 - Write to -day.FREE. De Forrest Pattern Coil Plug . . each 1 -

Twin Ebonite Coil Stand, complete with. handle,. fitted ONLY plugs, etc. 9 6 Three Ebonite Coil Stand, complete with handle, fitted CRYSTAL 7/6 plugs, etc. . . each 13 - Ebonite Bases, Matt. finish, 8;18" .. 9d.. 12 sq. inches DETECTORPost paid Ebonite Bases, Matt finish, i" . 1 12 sq. inches

Ebonite Bases, Matt finish,g" . .. 1 6 12 sq. inches Ready to attach to your set. H.F. Transformer Formers, Matt or highly polished, Greatest boon ever known to Wireless each 1/8, 1/10, 21-, 2.2 and 2 4 Experimenters. Always ready,no Variable Condensers,0014 M.F. Ebonite Dielectric, fiddlingorsearchingforapoint. mounted in lacquered brass case .. ..each 32:- Crystal always active. Largest mail- Variable Condensers, Air Dielectric, for panel mounting, brass order firm in Europe, G, Important Notice.-All our vanes,fitted with knob and pointer - u apparatus is guaranteed "your money back in full" if .001 15 - not satisfied.Write to -day. .0005 10 6 0003 8 6 00005 . odd L.F. Intervalve Transformers, Igranic .. 22'6 <000111 Intervalve Transformers, Burndept .. 25 - BRITISH RADIO L.F. Intervalve Transformers, Acme .. 27 - '\ SALES CO.LTD Telephone Transformers, Acme.. S1. TEPNEMS SUILDIIISS,GRASSE ST, 17 - .SqA11/ NATIISOK PLACE, CONDOS W I. The above are the very best workmanship throughout. Special \,", quotations for large quantities.Cash with order. Ediswan Valves. THE manufactureof Thermionic Valvesisa highly skilled operation and every Ediswan Valve has behind it the experience and operative skillof over forty years of lamp making. The A R Valveillustratedisspecially made for Amateur reception. Platevoltage3o -8ovolts. Filamentvolts3.5-6.ovolts. Filamentcurrent 0.75 amperes.High amplification-silent working. Price 15!- each. Alway ask for Ediswan Valves.If you are unable to obtain them ai your Dealers write to us for the name and address of the nearest supplier. THE EDISON SWAN ELECTRIC CO., LTD., Head Office : 123/5, QUEEW VICTORIA STREET, E.C.4. London Showrooms:553/5, Queen Victoria Street, E.C.4, & 71, Victoria Strew, S.W.r. Type A R Works :Pout:us End, Middlesex. THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 11, 1922 atCcoy.. 'ft Series No. 6. ,,111 IPIII) 13

zoemot, The Wireless Receiving Cabinet de Luxe (Model No. 1)

With gradual education of the publicof decoration, these sets appeal very to the possibilities of wireless in thestrongly to the householder of taste. home,theSeexquisitely constructedThe cabinet contains complete equip- Western ElectricReceiving Cabinetsment for the reception of wireless broad- should provideavery considerablecasting, and has a range of at least zoo source of new business and profit tomiles. No earth connection whatever is the Wireless dealer.In any periodnecessary. Simple, elegant and efficient design to harmonise with any scheme-Western Electric quality throughout. Western Makers of over Half the World's Telephones. Electric 62, Finsbury Pavement, London, E.C.2 Telephone-London Wall 7608 WORKS :- North Woolwich, London, E.16 Telephone-East 3840 (re lines)

Also at BEXLEYHEATH, KENT, and NEW SOUTHGATE, N.11 xe". copy Birmingham-Grenville Buildings, 12, Cherry St.Manchester-Northern Assurance Buildings. Leeds-Standard Buildings, City SQuare. Newcastle -20 Saville Row. Cardiff-Motor House Chambers, I, Wood St. Glaigow-49, West Campbell Street.

CONDO NOVEMBER 11, 1922 TFIE WIRELESS WORLD AND RADIO REVIEW xxxiii HaveYou heard THE BROADCASTER"? It'ssimply marvellous ! ! The advent of the Real loud speaker, not the substitute AGENTS.-Your opportunities are passing. We aregetting enquiries from your districts,and we aregrantingsolerights. Price £6 10 0 A limited number only at special reduced price, viz., £4 17 6 for advertising purposes.Presentation of one " R " Valve free until November 20th. Write at once for Terms.All orders in strict rotation. Oneofthelargest 2 valvesetManufacturerssays," A big stride inthe right direction." BRITISHMANUFACTURERS WIRELESS : CO. Incorporating MIDLAND RADIOPHONE CO. 'Plar HEARSALL WORKS, COVENTRY 63'9GCnsnity

Enormous Stocks of Ex - W.D. WIRELESS GEAR EBONITE AT ABSURDLY LOW PRICES INTERVALVE TRANSFORMER. EQUIPMENT (New Goods) 1 OR Fittedwith panel fixing plate and earthing wire for iron core. WIRELESS SETS Fullytested ; SHEETS, KNOBS, COIL Ratio 5 :I PRICE 15/ - HOLDERS, VALVE HOLDERS, Postage pd.extra ENGRAVED DIALS, SOLID

Callandinspect EBONITE HORNS FOR our enormous stock or write for particu- LOUD SPEAKERS, PANELS lars and prices of your requirements.

Terminals: 4B.A. Double, Solid Brass, special price, 2 B per doz. Phones, 4,010 Ohms, new, Price 18/6. FROM STOCK Wavemeters, WheatstoneBridges,Marconi Type 16 Crystal Sets, Model L receiving sets, Shell insulators. Electrical and J. LIPOWSKYWireless Engineer HIGHTENSITE LTD. 614, OLD FORD ROAD, BOW, LONDON, E.3 Normandy St., Custom House, E. 16 Telephone :East 3345 Near Old Ford Station. Nos. 8 or 39 'Bus 'Phone :EAST 3153. THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 11, 1922

-W1R3:14E S IiiROADCASTNG "'hisis a high grade crystaldetector especia ly designed for receiving broadcasting, and complies with all regulations. Beautiful pure clear speech and music are received, and as many as 3 pairsof Fellows 4,000 ohms double headphones can be simultaneously used. The " Fellowcryst Super " is mounted in a highly polished oak cabinet andissent out complete with100 ft.coil of 7/22 stranded copper aerial wire, two shell insulators and one 4,000 ohms doubleheadphone, andisBritish Made Throughout. PRICE COMPLETE £4 6 POSTAGE 2,'- EACH. EXTRA 4,000 OHMS DOUBLE HEADPHONES ; / - POSTAGE 1. - FELLOWS MAGNETO Co., Ltd. LONDON, N.W.10. Telephone :IV illesden 156o-1. Telegrams :Quitmag, Phone, London'

3v? -//gaycvit," rod n, NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW xxxv

Simple to Operate Engraving on eboniteis now a speedy mechanical process. The Taylor -Hobson Engraving Machine cutsquickly andaccuratelyonevery surface. No modern WirelessFactory is e fficient without this machine. Cutter at Work Send for our new catalogue.

TAYLORTAYLOIr- 0135 01\it " 74a,NewmanStreet,London,W.1 Works :LEICESTER.

....24 -HOUR SERVICE SPEARS and COMPANY We make it our boast that every FOR letterreceivedhasattention within twenty-four hours. Send your enquiry along and test our TERMINALS service for yourself. SCREWS, NUTS,WA813ERS, PLUGS and SOCKETS, CONTACT STUDS, BUSHES, VALVE LEGS, CONDENSER VANES and ELECTRICAL SUPPLY STORES, TURNED and PRESSED PARTS OF EVERY DESCRIPTION. Wireless Specialists. Actual Manufacturers to TRADE ONLY 5, Albert Terrace, King Cross, We regret we cannot supply small lotsto Amateurs. Write for Illustrated List. Halifax, Eng. CAPSTAN REPITITION WORKS, NEW LISTS NOW READY PARK ROAD, HOCKLEY, BIRMINGHAM 24 -HOUR SERVICE- Telephone : 3265 Central. Telegrams : " Firettes," Birmingham TO WIRELESS BROADCASTING Questions and Answers APPARATUS MAKERS. COUPON We solicit your enquiriesfor To accompany Questions DIESPRESS andTOOLS MACHINING - STAMPINGS offering you first -ekes work. sent induring the week CompetitivePrices. Send us year Drawings and Specifications, etc. commencing Nov. 11th, 1922. CHAS. WRIGHT, LTD., VOL. XI, NO. 6. General Engineers, Tool Makers, Stamper'. etc., EDGWARE. MIDDLESEX. See Conditions on Page 213. Established 1864. xxxvi THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 11, 1922 FOR PROFESSION OR BROADCAST. WIRE_ DAY AND EVENING CLASSES : Correspondence Classes with Instru- ment work at School if desired.Postal Course on Valves.Classes for Amateurs and Experimenters. LESS CABLE AND INLAND TELEGRAPHY. Send for Pros.Radio supplies. List A, from JAS. FRASER & CO. Telephone RadioHouse,Manor Gardens, No-th 1036 ELECTRICAL TRAINING COLLEGE, Holl oway, London, N. 7. POLISHED WIRELESS TRAINING Mostthorough trainingin Wireless Telegraphy E BONITE orTelephonygiven underidealconditions. Special Postal Course for Amateurs. S HEETS Prospectus Free. Wholesale only WIRELESS APPARATUS (Importers) Complete stocks of all WirelessInstrumentsand Accessories. Prompt Deliveries.List 1 id. stamp. PIDGEN BROS. 25, Helmet Row, Old St., WIRELESS COLLEGE LONDON, E. C.1 COLWYN BAY

SKINDERVIKEN BUTTON. The Construction of A Supersensitive Microphone. Known all over the world and patented in every civilised country.Over 60,000 Amateur Valve Stations sold.ENGLISH Manufacture. By ALAN L. M. DOUGLAS Make up your own Loud Speaker. Transmit your GRAMOPHONE music 78 pages. 55 Diagrams and Illustrations. to any room inyourhouse. The only practical Microphone for use in Detectiphone Sets. PRICE NET. Price 5,- each 1/6 Special Low Resistance Receivers (for use with Skinderviken Buttons) .. 10;- each Special Gramophone Attachments (Postage 2d.) Write for 16 page BOOKLET fully illustrated and containing much usefulinformationforallinterestedinElectrical THE WIRELESS PRESS, LIMITED Sound Transmission.6d. Post free. Dept. 117.1V, Sole Proprietors : 12-13 Henrietta Street, London, W.C.2. MIKRO LTD.,274/6, PentonvilleRd.,London,N.1 (Opp. King's Cross (Met.) Rly. Station).

III ION M MIIB lEM F. WIGGINS & SONS W. A. C. SMITH Telephone 236, Argyle Street, Avenue2 2 48 Largest Stock GLASGOW MICAin the World. are Sole Scottish Agents for the FOR CONDENSERS Famous Burndept Receivers AND ALL PURPOSES. 102,103 & 104, Minories, London, E.1 N NW 111M11111111111

THE AMERICAN MONTHLY JOURNAL OP THE WIRELESS AGE WIRELESS TELEGRAPHY AND TELEPHONY A " Go -a head " MagazineforOperators and Amateurs.

Sole European Agents : THE WIRELESS PRESS LTD., 12-13 Henrietta St.,Strand, London,W.C.2 NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW xxxvii SPECIAL OFFER FOR AMATEURS. TUBE, SHEET, YOU CANNOT GET THE BEST RESULTS WIRE, STRIP, Unless you thoroughly understand the Scientific Facts which govern the working of your apparatus.Acquiring this essential knowledge is no longer a tedious labour. ROD& CASTINGS PLEASANT LESSONS BY POST AT YOUR LEISURE. IN It duesnot matter whether you have absolutely no knowledg,. wireless or have many years' experience, our system ol individualtuition enables you to start just where desired. PHOSPHOR BRONZE, WE POSITIVELY GUARANTEEthat our course of rz Lesson - will give you a thorough knowledge of wireless. Spe,:ial fee for the Course -30:- cash, or 111- upon enrolment COPPER, BRASS,&c.,&c. and live monthly payments of5"-. THIS IS JUST THE THING YOU NEED. Write at once for full particulars to- CHARLES CLIFFORD & SON,LTD., THE NATIONAL INSTITUTE OF APPLIED SCIENCE, 3, 5 and 7.OLD QUEEN STREET, LONDON, S.W.I. BIRMINGHAM.

" EIFFEL TOWER TYPE." TO THE TRADE MASTS EBONITE - SHEETS - RODS STRONG. LIGHT. WOOD LATTICE. EASY TO ERECT. COPPER WIRE - STmelip ROT AND WATER PROOF. 20 to50 feet - - 1/3 per foot AERIALS - SLEEVING, &c.

- 55 100 - -1/9 FROM STOCK. CASH WITH ORDER. CABLES & ELECTRICAL SUPPLIES. WILKINSON, Lonsdale Road, Kilburn, N.W.6 MICA HOUSE. OFFORD STREET. Telephone: Same Address since 1900. Trade Supplied. CALEDONIAN ROAD, LONDON. N.I. North 8o5. BaNkCIS-LONDON City ANDMIDLAND, KILBURN,N.W.6.

TE/

111111! 111111111111111

MANUFACTURERS & RETAILERS apply for Illustrated List 2 and TRADE TERMS. KEEN PRICES. PROMPT DELIVERY. rihor-;,8,20RMOND ENGINEERINGCO.,199, Pentonville Rd., King's Cross, N.1. THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 11, 1922

f, _

r-2'. -7

" POLAR " Automatic Morse Instructor 1 This ingenious mechanical device-the result of many years' patient development work-makes it possible for a person to become proficient in the reception and transmission of morse signals by practisingat home during spare time, without the assistance of an experienced telegraphist. It can transmit either buzzer or sounder signals at any desired speed from a few lettersa minute up to 40 wordsparminute. It transmits in cypher groups and has tens of thousands of permutations,thus avoiding any recognisable repetitions By adjustingthelinksmarkedI, 2 and3 ontheillustrationthe instrument may be set to transmit combinations of letters and figures, figures alone, or letters alone. i When set to work very slowly it transmits a letter at a normal speed,pauses, then transmits another letter- does not draw out or distort characters when working at beginner's speed. Any number of head telephones may be connected to it, thus making it an ideal class instructor. band key is combined in the instrument for sending practice. No wireless society should fail to add one of these instruments to their club equipment for the use of members who wish to learn morse. PRICE 110 - 10 - 0 Full descriptive leaflet will be forwarded on request. RADIO COMMUNICATION C 9 HD 34 and 35, NORFOLK STREET, STRAND, LONDON, W.C.2 NEWCASTLE :z7, Sandhill. LIVERPOOL :67, DaleSt. CARDIFF : Atlas Chambers, James St SOUTHAMPTON :rg, Queens Terrace. GLASGOW Blythswood Square. NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW xxxix COMPLETE SETS JUST PUBLISHED. FOR EXPERIMENTERS Elementary Text -Book on ONE VALVE SET (complete) 11 0 Wireless Vacuum Tubes. THREE VALVE SET (complete) £25 +th (Enlarged and Revised) Edition. The prices quoted include all accessories for BY complete receiving station.(Full details on JOHN SCOTT-TAGGART, F.Inst.P. application.) This book has now been- enlarged and completely COMPONENT PARTS revised.All the latest inventions, including the Armstrongsuperregenerativecircuits,are fully for building your own set.(Price list W described, and Major Armstrong himself recommends. free on application.) this new edition to all interested in valves. Itis a large book, handsomely produced, simply CRYSTAL SETS written but complete and authoritative.It is the ideal text -book for the better class of experimenter Complete,includinghighefficient 8000 and student. ohm headphone. PRICE£4 10 0 PRICE 101- NET. NOTE.-OUR BROADCAST SETS Obtainablefrout or through all booksellers or,Iirect 10/6 will be ready shortly, ask for all particulars now ostfre*,fi.om_ Complete Sets and All Components in Stock ttabia Press, Itimittb, WIRELESS COMPONENTS Ltd. DEVEREUX COURT. TEMPLE, 16 Manette St., Charing Cross Rd.,W.C.2 (Opposite the Law Courts) W.C.2

The" HESTAVOX"I Important Notice Broadcast Receiver WE 11EltE13Y GIVE (`rype G.P.O.'Regd. No. 1007) WARNING to the trade, that WE are not to blame if, when your customer asks you for " Hestia " apparatus, you have none in stock. SPECIAL ATTENTION is being given to all trade enquiries and orders and attractive terms are offered to all dealers desirous of handling our apparatus. Our NewIllustrated Loose Leaf Catalogue will be sent, post free, on receipt of 6d. (returnable with first order). Our Showroom is also atyour disposal between 9 a.m. and 6 p.m. from Monday to Friday, and from 9 a.m. till 1 p.m. on Saturdays. CALL OR WRITE AT ONCE.

ALL VALVE APPARATUS IS LICENSED UNDER MARCONI PATENTS WHERENECESSARY. THE " HESTIA "ENGINEERING COMPANY, Offices, Showroom and Factory- 32, Palmerston Road, Acton, London, W.3. (n,Anin sth'Idlissti°." sctSin"Rys.) THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 11, 1922 The Broadway Radio Works DEVONSHIRE ROAD, BEXLETHEATH, KENT. THE MARK OF RELIABILITY

CRYSTAL SETS 1111111111111111111111111 11111111111111111111WP Every Setis thoroughly tested before it leaves our works. FittedinbeautifullyFrenchPolished Mahogany Cabinet with Lid. I to 12 volts. 1 to 35 amps. Range 200 to 3,000 metres ....., .... 610 0 Range 200 to 500 metres ...... g815 0 The second setis specially designed to give maximum efficiency on the Broadcasting Wavelength. VOLT & AMMETER CONDENSERS Combined Dead Beat Pocket Type.New and not German. SplendidInstrumentinNickelPlatedCase. leabinet Pol- Idealfor TestingCoils and Filament Current. Value Panel Panel Cabinet Cabinet Mount-ished in el Mount-Mount- Mount- Mount- ing As- Mahog- POST NUMBER M.F. ing ining As-ing ining As- sembledany PartssembledPartssembled in Cabinet PAID 5/6 LIMITED Cabinet OTHER EXCEPTIONAL VALUES. .0015.. 23/- 25/8 24/- 26/6 38/- 6/3 .001 .. 16/9 19/6 17/9 21/- 26/- 5/8 Aerial Wire.Bright Hard Drawn, 7/22's Copper, 3.6 .00075.. 13/8 16/3 14/6 16/8 22/- 5/8 per coo'.Enamelled, 7/22's, 5/- per too'. 0005.. 10/6 13/- 11/9 13/9 18/- 4/6 Aerial Insulators.Shell type, 2" x 21", 9d. each. 0004.. 10/- 12/6 11/- 13/3 17/6 4/6 Aerial Insulators.Reel type, 2" diameter, brown, 3d. each. 0003.. 9/- 11/6 10/- 12/- 16/- 4/- Filament Resistances.For panel mounting, 2/6 each. 0002.. 7/- 9/- 8/- 9/6 18/6 4/- H.F. Transformers, plug in type, 300 and 700 metres, 0001 .. 6/- 8/- 7/- 8/8 12/6 4/ - 4/6 each.',coo m. 5/6 ;2,600 m. 6/- each. Vernier.. 4/8 5/- 9/- 3/8 H.F. Transformers.Formers only, with pins, 2/- each. - - Tangent H.F. Transformers.All ranges, 8/8 each. Fitted with Bevelled Ebonite Dial 1/9 extra. Switch Arms.Complete fitted with knob, 1/- and 2/6 each. Special Sizes Made to Order. Price list on request. Dewar Switches.D.P. Change over, panel type, 2/- each. ALL SUNDRIES AND COMPONENTS IN STOCK. Lightning Arresters.Carbon block type, 1/6 each. ORDERS OVER20/- CARRIAGEPAID.. Valve Holders.Flanged "A " type, 1/-.Ebonite with 8 nuts, 13 each. TRADE ENQUIRIES INVITED. Ebonite Panel, fitted with 3 Valve Holders, complete, 3/2. Ebonite Panel, fitted with 2 Valve Holders, complete, 2/3. Valve Sockets, per set of 4 with 8 nuts, 7d. Transformer Holder.With 4 terminals and wired, 3/6 each. High Note Buzzer (Army Type), worth treble, 3/- each. Telephone Transformers (Army Type), 9/- each. VARIOMETERS Wireless Jacks, with plug, as illus., page 733, 1/- the pair. IDEAL FOR TELEPHONY TUNING. Brown's Type " A " Headphones.Guaranteed new and AMERICAN Pattern in Selected Beech, wound complete with unused.8,000 ohms, 49/6 ;12o ohms, 42/8.With terminals, can be connected as Reaction and Coupling Coil, cords, 51/6 and 44/6. optimum Wavelength approx. 200 metres when used as A.T.I., Ever Ready Batteries (all sizes).it Volt, 3/8 each. but can be wound to approx. 1300 metres. Mica.Clear Ruby, .one thick, 3" x 2", doz. pieces. Inductance Slider Rod, r square, 13" long, drilledl ed. each. Slider, complete with plunger for 1" rod, 6d. each. Contact Studs.Fitted with nut and washer, 1/3 doz. Condenser Vanes.Best Aluminium, 3:1,", 1/6 doz. pairs. Condenser Spacing Washers.Small, 3d., larg6d. doz. PRICE Condenser Screwed Rod, Brass 12" long, ." 4d., 3/16" 6d. Insulating Tubing.Assorted colours,fld'.per yard. Sheet Ebonite, )" to 1" thick, 4/- per lb. 1 8 / 6 Terminals.Mark 3 N. Plated, 4B.A. 2/6 doz. Terminals.Small pattern, 9d. doz. each Dubilier Condensers.All capacities at price; advertised. Grid Leaks.All resistances, 2'- and 5/- each. Good discount Radio Instrument L.F. Transformers, 25/- each. to Trade. Tangent L.F. Transformers, 22/6 each. Ivorine Scales.o- 18o, good quality, 6d. each. Ivorine Tablets.Set of seven, 7d. Skinderviken Microphone Buttons, 5/- each. Burndept and De ForestCoilsinstock.Advertised HIGHEST QUALITY. prices. ACCUMULATORS LOWEST PRICES. Potentiometer 300 ohms.Panel type on ebonite, 4/6 each. 44 volt 40 amp. ..18/ 6 volt40amp. ..26,3 Condenser,Cur,ps5.-Plate. Paneltype on ebonite, 4/- each.

80 ..21/66 6 80 Crystal 4 screw type, 6d. each.

4 15s. each. 100 ..80/- 6 100 ..43/6 Special L.F. Transformers. SPECIAL BARGAIN OFFER. Fellows 4,000 ohms Headphones.30/-. 4 volt, 30 amp., in celluloid cases, 13,'- each. Fellows Valve and Crystal Receivers.I.ist prices. In separate 2 volt cells cemented together. Write for Complete Supplementary Price List of Exceptional 2 volt, 30 amp., 6/8 each. GOOD DISCOUNT TO TRADE. Values, sent Post Free. WRITE FOR LISTS. All goods sent CARRIAGE PAID but with orders under 5/6 add 6d. for postage. F. YATES & SON, LTD., J. H. TAYLOR & CO., WHOLESALE ELECT It' I CI AN S, ELECTRICAL AND RADIO ENGINEERS. 144, Church St.,Kensing ton,London,W. 8 Macaulay St., HUDDERSFIELD. hone, Park 4276. One minute from Notting Hill Gate, Telephone, 331.Telegrams :" TInrmh, I " Central London and District Railways NOVEMBER 1!. 1922THF: 11.11{El.P.SS11.01{1,1) .1N1)IL\ WO It EV I ENV xli

Telephone -55. Telegrams-" ENTLEY, WHITCHURCH." ANUFACTURING JOSEPH HOPLEY & SON, WIRELESS ENQINEERS Dept. W., DODINGTON, WHITCHURCH, SALOP, ENTLEY BROADCAST RECEIVER

Designed to fulfil the requirements of the Postmaster -General, and those of the amateur, who require a simply operated, single valve receiver, on to which may he added at any time, if desired, one or more of our amplifying units. Instrument only, 7 Guineas. Instrument complete with allaccessories and instructions, as shown, 11 Guineas. Illustrated Leaflet Catalogue sent on application post free, 9d. TRADE SUPPLIED.

J. L. CARTWRIGHT & Co. 24, Variometer or Coupler London Road, Manchester. Consisting of 3" turnedMahogany Ball mounted in Phone-Central 4209. Grams-"Pladuram" Manchester. Works-Berry Street. 3k" Ebonite Former which is turned and grooved for wire.All contacts made complete with Bush,BOfs, Spindles and Knob.Mounted on Ebonite panel and base, with shorting strap and four terminals for use asVariometerorCoupler.21 /-,postage9d. CONDENSERS Instrument Finish Every Set of Parts or Complete Condensers Examined by Experiencel Inspector.

Approximate Parts ready to Price assembled capacity in No of assemble for for Panel Mfds. Plates. Panel Mounting.Mounting. .001 57 17/- 20/- .0007 5 13/- 16/- .0005 2439 10- 12/6 -0003 19 8//- 10/6 1002 13 V- 9/- -0001 7 6/- 8/- -00005 3 - 4/6 Ivorine Scale and Pointer, 1/- extra. Ebonite Dial, 1/9 extra. Sufficient Celluloid Covering with 6 B.A. x }" Rd. Bd. Brass Screw and nut for fixing, 1/- each. Sole Distributing Agents for Scotland - Scientific Supply Stores, 1. GORSTON SINCLAIR & CO., 47, Waterloo Street, Glasgow. 8,Newington Causeway, London, S.E.1 Retail Agents for Blackburn- THOS. BARTON & CO., The ElectricWorks, Blackburn. Phone -4177 Hop. xlii THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 11, 1922 Dry Batteries for Wireless Sets THE KEYSTONE No. 1 W.Standard Pohl:it-lamp siz,., volts(as illustration), with patent spiral wire terminals for connecting in series. LIGHTNING ARRESTER Insert stra,gbt terminal in spiral of next battery and bend same, no soldering required. PRICE 7/- Per doz. A device WiliCh effectually protects your NOTE.-(i doz.= 34volts). House and Apparatus from lightning and obviates the useof the usual earthing switch so often forgotten. No. 2 W. Slab. No. 4 W. Connected per- Does not interfere 15 volts(ii Reittangalar. manently between I9 with operation cells),3 screw 36 volts, I screw terminal Aerial and Earth. of your set. terminals,size and8plug holes 9" xr' x 21" with wander high. plug. Size or x 2*" X 2k". PRICE PRICE 3/ - 7/ - EACH EACH Can be fixed No. 1 W. Hermetically to wall, mast Connect as illustration. sealed and or suspended from (Patent applied for). BRITISH MADE-CARRIAGE PAID. unaffected by wet. leading -in wires. Packed in ca,dboard canons. Manufactured by- Price 1 0 / Obtainable at all Radio Stores. THE BRITISH BATTERY Co., Ltd. Clarendon Rd., WATFORD, HERTS. The Equipment & Engineering Co. (Telephone :Watford 617.) 2 & 3, Norfolk Street, Strand, LONDON, W.C.

WIRELESS Our claim tospecialised know- ADVERTISING ledgeinWirelessAdvertising - is based on Ten Years' practical 19121922 experience. This, together with ourCompleteWirelessAdver- tisingOrganization,is atthe disposalof every bona -fide Advertiser entirely free of charge. Nobusinessistoosmallor toolargeto command our BE R TRAM DAY'S promptattentionandcourtesy. (Bertram Day & Co., Ltd.) Whatever your Advertising Organisers of the First All -British problem or difficulty, it will pay Wireless Exhibition - - 1922 youtoget intouchwithus. H ireless Publicity Specialists Why buy your experience when Contractors, Printers & Publishers expert advice is yours for theasking ? 9 & 10 CHARING CROSS, S.W.1 Gerrard 8063 & 8064 BRANCHES AT MANCHESTER & GLASGOW NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW AUCKLAND'S

AUCKLAND (Igranic) DUO LATERAL COILS. Made under De Forest P PRICES from5/ - Mounted. INTERVALVE TRANSFORMERS. NOTE MAGNIFIER. Most Efficient Cores,being 1 VALVE SELF-CONTAINED builtupofStalloyandin UNIT. correct proportion. For attaching to Crystal Sets, etc. The Bobbin is Layer Wound, Mounted in Cabinet with Terminals, each LayerbeingSpaced. CONDENSER DIALS. and suitably engraved, comprising Designed togive maximum Fitted with Knob and Bush, V -Holder ;Fils. Res. ;Intervalve Amplification. Transformer. Engraved to'goo PRICE20/-each. 3/9each. PRICE 651- Without Valve. Delivery-Stock.

THE NEW A NEW UNI- WAVE AUCKLAND INDUCTANCES PRODUCT. Duo Wound. 3 Coil Holder with Range from Remote Control 300-30,000 m. InductiveValues keepingCapacity are to be found in effects from body. Catalogue. Finish as a first- PRICE per set of 8 class instrument. 1216 PRICE 22.'6 e,eh, We are also Manufacturing CompleteSets,for Broad- cast use or Experimenters. INSIST upon having AUCKLAND Products. All AUCKLAND Valve Apparatus is duly licensed under Marconi Patents for amateur use in Great Britain.

G. Z. AUCKLAND & SON, E.C.1 Faeteries-ISLINGTON, N. WIRELESS INSTRUMENT MAKERS. 'phone - - 3173 CLERKENWELL

F Nliv THE WIRELESS WORLD AN!) RADIO REVIEW NOVEMBER 11, 1922

The Experimenters ownTuner HERE is a particularly efficient Tuning Unit designed for the amateur requiring the utmost efficiency and selectivity in tuning on all wavelengths. Two double pole rotary switches are used for Series -Parallel and for Stand by -Tune. A solid Ebonite three coil Holder, of substantial construction,. is supplied ready made. It will take all 276 standard Coils. Range from 18o metres to 26,000 Mahogany metres with suitable coils-with or without reaction. Cabinet to fit, 3/6 No Coils are included, but suitable ones are in extra. stock. (See page 16 of our Catalogue.) Combines the principles 15/of the famous Mark III Tuner.

FullSetsofpartsforassembling thisexcellent Tuner include : 16 Terminals, z Rotary Switches complete REAC co GO with studs and stops, Ebonite Panel FO REAL SERIES drilled and tapped, set of engraved ebonite name plates, complete 3 coil Holder, systoflex tubing and wire. RARALLE0 Full ql(15fOtt instructions for assembling and 2 Cowana

wiring areincluded. STAND-Ell

TUNE SEC" - CONE THE PETO SCOTT CO. FEATHERSTONE HOUSE, Ready assembled, complete with Cabinet,43/6 64, HIGH HOLBORN, W.C.1 Postage 9d. extra in each case. M.A.S.

RA DCOMFilament RHEOSTATS Control. Protect. Improve. Features :PANEL MOUNTING *" to i" Positive Stops at zero and full resistance. Single Turn Control. Smooth and Quiet. Guaranteed. PLAIN TYPE for Amplifying Valves-5/ - VERNIER TYPE for Detector Valves 7/6 Radcom Coils, Tuners, Transformers, Accumulators. 12/13, HenriettaSt., LONDON, W.C.2 Telephsne: Telegrams: ror_....froke" COMPONENTS 12-13 Gerrard Radponents. 792. Rsnd. London. NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW xlv !r QUALITY EFFICIENCY - "NATIONAL VALUE You Should Come and SeeOur Works and Stocks. SATISFACTION OR MONEY BACK GUARANTEE. Coil Holders, stand for mounting on cases, 3 -plug extended handles 16! - Aerial Wire, best copper hard -drawn, 7/22 . per 100'3'6 Coil Holders, stand for mounting on cases, 2 plug extended Aerial Wire, beat copper enamelled, hard drawn. 7 22, per 100' 5,' - handles Aerial Insulators, green glazed shell type, 2f", our price . 1 - Coil Plugs, standard for above, and all honeycomb coils.. 1/6 Aerial Insulators, white reel type, 2" by 1" high] ..each2d. Basket Coils, best quality, per set of 7, our price.. set 8! - Aerial Insulators, brown glazed, pillar type, a nice thing, each9d. Tin Foil, .002 in sheets, approx. size 9" x 9", our price 3d. Aerial Pulleys, aluminium, ex -Government, 2" pulley, bronze Ebonite Sheet, best quality on market, I", any size cut, per lb..3/10 bushed .. . .. each 1/3 Aerial Strainers, ex -Government, splendid value, our price, each 4d. EX -GOVERNMENT. Filament Resistance, Panel mounting, standard size, best Fullerphones !! Ex -government. In handsome mahogany cases, finish with lid.Approx. size . Containing :buzzer and Holders, standard 4 -Pin type, highly polished .. 1/ - tapping key (less points), 1 earpiece, L.R. in leather case, 2 Valve Legs, with 2 nuts and washer, per set of 4, only .. 7d. choke coils, 1 transformer, 1 tel. jack, 1 Dewar switch. odd Valve Pins, best quality, with collar, our price, per doz. .. 8d. screws and terminals.Cost Government about £5 each. We Valves, Mullard Ora, 15,- ;51.0., 17/6 ;Dutch valves, each 11/ - only ask you price of the case.Post free, each . 9/6 Transformers, L.F., absolutely guaranteed, good value..17/6 Fullerphones I ! Ex -Government.In handsome *walnutcase Transformers, TEL, can be relied on, fully tested..each 15/ - and lid, size approx. . These are in perfect working Condensers, VAR, special line,.0005 polished box, with order, and with 1,- battery speech and Morse is perfect.Con- ebonite top and scale, guaranteed .. - 12/6 tents:1 buzzer (2 -coil type), tapping key, microphone and Condenser Dial and Knob, beautiful finish, highly polished earphone on handpiece, 1 earphone, L.R. (150 ohms), 2 choke and engraved .. 2/6 coils, 1 transformer, 1 Dewar switch, terminals, etc.Splendid Condenser Scales, ivorine, look 'fine on panels... each9d. for works or houses. Ridiculous price.Post free.. 20/ - Grid Leaks, Dubiliers, all capacities, at usual price.. 2/6 Dewar Switches, hardly used, Siemens 2 -way, 3!-, worth double ; Switch Arms, a well finished job, laminated, with knob.. 2/8 Contact Studs, best quality only, with nut and washer, 5;16 Buzzers, less points, Siemens, new condition, 2 coil.. each1 6 diameter .. 1/- Condensers, Manabridge, 1 mfd. and 2 mid., unused, only- 2 - Choke Coils, 500 ohms.Wire alone worth more, our price 1 - Ivorine Tablets, set of 7 for panels . ..per set 11 - Knobs, best quality 2 B.A., bushed and tapped, polished, each5d. Phones, L.R. single earpieces, 150 ohms, very sensitive.. 3,6 Insulation Sleeving. The best in yard lengths.. ..each 5d. Terminals, large double 2 B.A., worth 6d., our price only, doz. 2,' - Terminals, 2 B.A., just right size for valve panels.. doz. 2/ - IF THE ITEM YOU REQUIRE IS NOT HERE, WRITE US, Terminals, smaller for smaller sets, crystals, etc... doz.1/6 WE CAN SUPPLY. Crystal Cups, with 3 screws, each 6d., or 1 screw..each 4d. COME AND LISTEN IN ON OUR VARIOUS SETS AND SEE Crystal Detectors. A fine job on ebonite, with terms, each2/9 OUR BROADCAST INSTRUMENTS. Sliders, complete with plunger, highly polished .. 6d. ALL GOODS PER RETURN-POST FREE ON ORDERS OVER Ebonite Switches, tumbler type, look fine on panel..each2/6 10'-.CASH WITH ORDER, PLEASE. THE NATIONAL WIRELESS & ELECTRIC CO.,7a, CHURCH ROAD, ACTON, LONDON, W.3 WHDLESALE AND RETAIL. 20 Yards from High Street.

IF YOU WANT A JUST RECEIVED FROM AMERICA GOOD BOOK ON RADIOTELEPHONY GET An Introduction TELEPHONY to Radio WITHOUT WIRES 2 VOLUMES BY Size 3i x 5 inches - 96 pages in each volume PHILIP R. COURSEY, B.Sc. (ENG.), A.M.I.E.E. FullyIllustrated - Flexible Leather Covers Price 15 Nett (Postage 9d.) TWO VOLS. It contains a complete collection of information on the PRICE,6/- various schemes, proposed and tried, relative to the electrical transmission of the sound of voices through (Postage 3d.) space without wires. An excellentlistof references to papers and articles, forms a complete bibliography of the whole subject. The Wireless Press Ltd. THE WIRELESS PRESS, LTD. Dept. W.W. Dept. W.W. 12-13, Henrietta St., London, W.C.2 12/13 Henrietta St., London,w.c.2 x THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 11, 1922 THE WIRELESS WORLD EXCHANGE AND MART

TARIFF. Advertisements are accepted for FORSALE. this Section at the rate of twopence per word, with a minimum charge of two shillings.The advertiser's name and address will be charged for, SterlingCrystalSet, No.1,condition a, - Electradix Radios and single letters and single figures will be countednew.Cost £7I2S. 6d.,accept £6. -Call after aswords.Compound wordswillbe counted7 o'clock, 55, Calboume Road, Balham, S.W.x2. Telephones In stock as two words. Telephones. 4,000 ohms, new, 18s. per pair. SterlingMarconi, Postage extra.znew intervalve transformers, 2,000 ohms, 49/- ; DEPOSITS. Alladvertisements must be each.-M.L., 16, Bridge Street, Mile End, E.3. 4,000 ohms, 50/- ; prepaidinthe formofPostalOrders,the King Radio Two -Valve Panel, H.F., complete 8,000 ohms, 57/ - remittanced being forwarded to Messrs. Bertramwith separate variometer tuner.What offers? per pair, complete Day & Co., Ltd., 9 & 10 Charing Cross, S.W.r. -Box F.7, BERTRAM DAY'S ADVERTISING OFFICES, with cord and tag. Intending purchasers may deposit the purchase9 and to, Charing Cross, Sullivan's L.R. money of any articleadvertised or sold by Aerial Masts and Spreaders. -Over iclo perfectly Head 'Phones with advertisers with Messrs. Bertram Day & Co., Ltd.,clean and straight bamboo poles, 24'-25' long, cord, 14/6 per pair. who will acknowledge its receipt to the vendor3,4" diameter.ma ditto spreaders, 6' 6" long, NewL.R.Head and the depositor, the full addresses of whom1" diameter ;ditto Tonking canes, very strong. Sets, 12/- per pair should be given.Subject to special agreementCarriageforward. Whatoffersthelot ?- with cords. New between the parties,itis understood that allADVERTISER, Whitehayes, Christchurch, Hants. 1,500 ohm Head goods are sent on approval, each party paying Diddy-da-da-Diddy.-The Morsophone gives Setswithcords, carriage one way in the event of the goods beingcorrect Morse at any speed.Learning the Morse 20/-perpair. returned.The depositwillbe retaineduntilcode made apleasure.25s.carriage paid.- SingleReceivers due advice of the completion of the purchase hasBOW,TON, Oxley Bank, Wolverhampton. and Cord, 4/6 e.Sh. been given or until the articles have been retained Five -Valve Receiverbyreputablemaker, Large stocks of and accepted.In order to cover postage, etc.,practically new, including tuner, very good tele- Ammeters and a fee of 6d. in respect of sums of £x and under,phonyset.What offers. -ADVERTISER,226, Voltmeters,Milli -ammeters and hot Wire and is. for sums in excess of kr, must be paidMartin Road, Grove Hill, Middlesbrough. Ammeters, 10/- to 60/,Morse Inkers, 45/-. at the same time as the deposit.For persons Maximum High Resistance Headphones, magnets ReceivingSets.MarkIIB. 2 valve,in not resident in the United Kingdom these feesWolfram steel, adjustable earpieces, very sensitive, polished mahogany case, new and guaranteed, are doubled. We cannot undertake to receivewithcordsandtags.On approvalagainst 27 5s. CrystalSets,variable condenser y deposit less than 25. 6d. P.O. 225., money returned if not satisfied.Price detector, and fixedinductance, mahogany 25s., after first 3,000 sold.-PINKERTON, I, Dukes case, 45/-.5o D.C. Sets for Crystal and Two Lane, Kensington, W.8. Valves,£7Si.,inslopingdeskpattern, Variometers.-Wide range,registereddesign. polished mahogany cabinet, calibratedfor No. 1 size in circuit, with average P.M.G. aerial broadcastwavelength.SwitchArms,1/6 willtuneapproximately 350-60ometres.No and 1/9 each. condenser required.For Panel mounting, 22S. 6d., Buzzers.2/6, 8/6 and 5/- each.Terminals, in cabinet, 27s.Postage is.Special engraved 2/6 and 3/- per dozen.Valve legs, 14. each. bevel dial, 3s. extra. -MARTIN, Dryburgh Works, Studs, 1/8 per dozen. Dryburgh Road, S.W.i5. Condensers.2M.F.,1/8each.4M.F.,51 - Two -Valve Panel, I H.F., I detector, resistance each.VariableforPanel,6/6,11/8and coupled (less valves), £3 15s.L.F. Transformer, 13/9.men Cabinet,$2/6Murdoch Rheostats 6d. -H., 74, Primrose Mansions, Battersea for panel, 7/8, with vernier extra lever 8/-. Park, S.W.1 1. Our make, 3/9. Connecting up wire, 23's/4o's, Mark 8 Star Tuner, Marconi, brand new, 14. per yard. Insulated Sleeving, 5d. per yard Complete, 3 valves set, unit system with valves, in four colours. tuner,condenser,batteries,telephones,£15. Aerial Wire. -7/22 enamelled copper, 5/6 per Burndept 3 dills tuner, latest design with set of too';hard -drawncopper,5/6permo'. 8 coils, £9.-W. H. GARDAM, 7, Poultry, London, Aerial Down Leads, 12 yd. lengths, 1/- each. Voltmeters Ammeters E.C.2. EarthClips,8d.each.Earth Mats, 10/ - 0- 3 0- 3 Valves,Superior French R.3 and 9.5, with each. 0- 6 1 9/6 0- 6 9/6 certificate of characteristique by Radio Telegraph, Transformers.Intervalve Transformers, 20/ - 0-10 .. Postage0-10 1 Postage France, guaranteed.Post Free, its. 6d.Quota- each. Telephone, 15/-, all brand new and 0-15 3d. 0-15 ' 3d. tionstothetrade. -GEORGE & GEORGE, 134, guaranteed.Lightning Arrester parts, M. ALL OTHERREADINGS IN STOCK. Market Place, nr. Broughton, Manchester. Switches.AerialtoEarth,2/9.Dewar Telephones.-Sullivan's 8,000, 28s.Murdock's Flush type, three-way lever switches, 8/6 each. 2,000,215.C.Q.,2,000,20S.Sullivan's24o Eight -way A.T.I. Switches, 8/-.3o amp. and Transformer, 205.Polished mahogany valve D.P.,16/-.R.A.F.LightWeight In- panel, 15s.All good condition. -RHODES, Histon, sulators, Ebonite, 4d. each. E Cambs. K.T. BatteryUnits. volts,Sd. each ; Morse biker, Marconi xo,000 ohm relay.P.O. 15 volts, 8/2 each. relay,2 -valve panel, including 3 variable con- All Wireless Components can be Supplied from A densers and z potentiometers, etc., also plug-in Stock.Write for Catalogue, 44.Call and type H.T. transmitting condenser. Photographs inspect our Huge Stocks. D and prices on application.- LAWRENCE, 19, Ashburton Road, Southsea. TheHandiestDepotforCityBuyers. Y Valve Panel, unused, double slide tuner large, Near Aldgate Station, Metropolitan Railway. L Mark IV tapper and buzzer, and camera, all £i First on the left in Minories. each.Stamp, DAWSON, 81, MidlandRoad, E Rotherham. LESLIE DIXON & CO A Bargain I -For sale.Hand press with dies for fixed and rotary vanes.Perfect order, 412 cos., 9. COLONIAL AVENUE, MINORIES. LI. lessthanhalfcost.Writeorcall. -2304., A.E.G.and SiemensEfalskeValves.Ex- Hermitage Road, London, N.4. ceptionally good for Rectifying and Amplifying. LoudSpeakerHorns. -Guaranteedperfect Filament I Volts.Plate 60/80. acoustics.Allsizesfrom4s.6d.,complete PRICE 7/6 Each.Poet M. with polished aluminium receiver base.Usual Adapter as shown for "R " Type Holders. trade terms. -MIDLAND RADIOPHONE Co., Hearsall PRICE 8/- EachPoet 2d. Works, Coventry. All Wireless Accessories in Stock.Is your Wireless amts. -Improved girder type, light RESULTS Whether as a source of practical information name on Mailing Listfor New Illustrated and strong.Up to 5o ft. at is. 3d. per ft.Over for the Amateur or as a valuable medium for Catalogue ? so ft., Is. 9d. per ft.Cash with order.Carriage every Advertiser, thebest resultsare forward. -F. ARMSTRONG, Weybridge. invariably obtained it B.A. Screws, Nute and Washers, assorted gross through the Wheless Grafton Electric Company 2S.,lists2d. -J. H. BENNETT, Station Road, For 7511,0artruodors and advrrnw:rt, '-"aptly le Showrooms -5 4.GRAFTON STREET, Willesden Junction. BERTRAM DAY & CO., LTD. TOTTENHAM COURT ROAD. Aerial Equipment is Useless without Masts. - LONDON, W.1.Telephone -Museum 24x. We supply from is. 8d. each.Stamp.-DowNEs, Complete Advertising Service, W ough. Arthur Street, Derby. 9 and 10 CHARING CROSS. S.W.1 NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW xlvii THE WIRELESS WORLD EXCHANGE AND MART

TRADE ENQUIRIES. HEATH & Co., Ltd. Working Drawings supplied for wirelessap- A.S.A. Guaranteed Instrument Works, New Eltham, S.E.9 paratus.Motors, generators,etc.,designed. Informationandadvice.-Puclux,Buckhurst WirelessProducts are prepared to undertake in their fully Hill, Essex. equipped works-Wireless Apparatus Wireless Dealers throughout Great Britain are Best Filament Resistances .. - 3/- and Parts for thetrade. Quotations given strongly advised to stock parts for making up 15v. H.T. Batteries ---The Best.. .. 3/ - wireless sets.Buy your parts direct from the Grid Leaks and Condensers .. .. 2/6 to Blue Prints Immediate attention. factory at wholesale prices.-NEWTON1A WIRELESS Fixed Condensers, -002...... 2/ - Phone-Lee Green:3ot. Polarir, Lomion., FACTORY, 13 and 15, Whitcomb Street, W.C.2. Laminated Switch Arms and Bush- 2/ - Insure your Set against Lightning fromis. Condenser Vanes, the best .. doz. 1/ - yearly.-Write for full particulars to F LICHFIELD Vernier Condensers, 0001 .. .. 4/6 & CO., 12, Great Castle Street, London Variable Condensers in Cabinet, .0005.. 18/6 Inventors.-Consult firm with 35years'ex- 100' 7/22 Aerial Wire.. .. - 4/- perience ;models, ideas ;advice free ;references 4,000 ohm Headphones (good) I Buy Wireless Gear 25/ - to clients.-E. DORCET CO.,14, Augusta Mill, Crystal Receiving Sets .. - .. 25/ - of every description. Warstone Lane, Birmingham. Sets of Parts for 2 -Valve H.F. Amplifier30/- 2 -Valve L.F. Amplifier ...... 40/- Send your particulars to : BUSINESS OPPORTUNITIES. 3 -Valve H.F. and L.F. Amplifier .. 60/- ;.- Cabinets,10" x 6" 4", polished 5/ - WILKINSON, Exceptional Opportunityoffered by recently Condenser Boxes, polished .. .. 2/8 Lonsdale Rd., Kilburn, N.W.6 established manufacturers of Wireless Apparatus, 3 -Coil Honeycomb Holders .. .. 18/8 viz., half-share and salary in return for investment H.F. Transformers, for Broadcast .. 3/8 SAME ADDRESS SINCE 1900. of £300.Active partner with technical knowledge Honeycomb Coils from .. .. 1/6 desired.Apply Box 27, BERTRAM DAY'S ADVER- Concert Coils .. . .. per pair 2/ -

TISING OFFICES, 9 and ro, Charing Cross, S.W.i. Coil Holders, for same . . 5/ - OUR LIST BEATS THEM ALL. ENGRAVING WANTED. Mark LIP Tuner,alsocoilsfrom same or Amateur SuppliesAssociation for every style of instru- other parts.-H.R., Sowerbutts, Highfield, Ashton - ment on any material. on -Ribble, Preston. 134, Coteford Street, Tooting, S.W. StandardWirelessShipInstallation,work- Works :196,HighStreet,Merton,S.W. ingorder. Particulars.-HAY,Enfield, Ash - F. OSBORNE & CO., LTD. vale, Aldershot. 27, Eastoastle St., Oxford St., London, W.1 Est. 1874. Museum 2264 SITUATIONS VACANT. Your Case Work Let us quote you for your wireless Wireless.-Assistant required in sales depart- casework. We are specialists in this ment, must have good technical knowledge of class of work and feel sure our work- wirelesstelephoningandpossesscommercial manship and prices will interest you. COIL, WINDING, WIRES. experience and selling ability.Excellent prospects Prices per lb. for bright young fellow.State full particulars of Phone-L.W. 2720. S.W.G. S.C.C. D.C.C.S.S.C. D.S.C. Enamd. education, experience, also age and remuneration CARRINGTON &NEWBERY LTD., 20 2/2 2/3 4/0 5/8 2/4 expected.-EGERTONS(Ipswich),LTD., North - 22 2/6 2/11 4/6 6/0 2/8 gate Street, Ipswich. 18:29, Normans Buildings,Old Street, E.C. 24 3/0 3/8 5/0 6/6 2/8 26 3/7 4/1 5/4 8/0 3/2 SITUATIONS WANTED. 28 4/4 4/8 5/8 9/0 3/6 ONE OF OUR SPECIALITIES 30 5/0 5/8 6/8 10/0 8/10 Young Man, well up in wireless set construction 5 5 32 8/0 7/3 8/0 12/6 4/2 and demonstration,seekssituation.Wages 34 7/0 8/3 10/0 13/6 4/4 week.-GODDARD, Norwood Court, Southall, 36 8/8 10/0 13/0 "SIDLEY 15/8 4/8 Middlesex. 38 11/3 13,0 16/0 19/0 5/3 High -Frequency Transformers. 40 15/0 17/6 20'0 22/8 7/8 7/22AerialWire, plain, 4/- per 100'. MACHINERY FOR SALE. Double -Grooved. Highest Efficiency. 7/22 Aerial Wire, enamelled, 5/- per 100'. Loreh Lathes, all sizes in stock, send for list.-- No. 1-300/530 1 6/.. EACH Bobbins Free. Postage extra. DGEN BROS., 25, Helmet Row, OldStreet, 2-500/920 / Reels 3d. extraif under llb.of any size. E.C.I. ,3 -900/1500 Postage 3d. Extra. Intervalve Transformer Coils Wound ,,4-1450/2600 Complete Set of Five with best Silk Covered Wire ready MISCELLANEOUS. 5-2400/4000 Poet Free. for Assembling. East Ham, Wanstead, Ilford, Manor Park and We also manufacture in-between Price complete with Core 10/- Forest Gate. Amateurs should not failto come sizes la, 2a, 3a at same prices. A typeValveHolders,1,-.Knobs, 5d. to the RADIORENDEZVOUS, 709, Manor Park COIL WINDERS TO THE TRADE. Broadway (over Lipton). Club open till so PH JNE-HOP 6030- nightly. G. R. MARSON, LTD. G.GILLIVER & CO., If you require a full experimental receiving and Electrical and Radio Engineers, transmitting licence you must satisfy the G.P.O. 16, Lorrimore Buildings, Lorrimore Street, that you have a sufficient knowledge of W/T HALES STREET, COVENTRY. London, 8.E.17. science to warrant the issue of such a licence.The London Telegraph Training College, Ltd., will SINGLE RECEIVERS, 150w., 3/6 ;2,000 w.,6; 6 give you the necessary qualifications in 12 lessons. Dittowith Headband and Strap,150w., Write for full particulars of evening lectures to 5 - , 2,000w., 7,6. Secretary(Dept.A.T.), 262, Earl's Court DOUBLE HEADPHONES fittedwith.fight AGENCIES WANTED Road, S.W.5. adjustablesteelbands, 300 ohms series, 8,6 ;4,000 ohms, 14/-. inWireless Supplies BOOKS. Mahogany Baseboards, suitable crystal set, 3/3, TEAK BOXES,121" x10" x 4r,suitable and Accessoriesfor RadioMagazines,allthelatest," Radio valve set, 6'-. World,"ioid. ; 11 PopularRadio,"told. ; 'PHONE PLUG and JACK, perpair,1/6. LONDON " Radio Broadcast."is.6d. ;" Radio News," 'PHONE CORDS, single, 1/3 ;double,2/6. is.6d. ;" Science andInvention,"is.9d. ; SUPPLIES PLL POST FREE. MACRADIO WIRELESS CO., " Scientific American,"2s.6d. Post free.- ROBERTS, 89a, Walworth Road, London, S.E. INTERNATIONAL NEWS COMPANY, LTD., 15, 2, MIDMOOR ROAD, BALHAM. Bream's Buildings, London, E.C.4. xlviii TILE VIII ELES8 VOR LD ANI) RADIO RRVIEW N(o. EMBER II, 1922 THE WIRELESS WORLD EXCHANGE AND MART

GRIFPHONES To the Trade Only WE SPECIALISE IN Condenser plates and 4,000 Ohms Guaranteed.Wonderful Value, Make washers, switch parts,resistanceclips,and 22/6.Postage 9d.Exchange if not abso- otherstamped orpressedwork.ALSO lutely satisfied. Capstan lathe work, such as terminals, con- tactstuds,plugs andsockets,valvelegs. bushes, spindles, etc. Your Own WILKINS & WRIGHT, LTD., VALVE PANEL KENYON STREET, BIRMINGHAM. To build yourself, containing- DrilledEbonitePanel,Fil.Resistance. Grid Leak and Condenser, Tele. Condenser, Set ESTABLISHED TWENTY-FIVE YEARS. Valve Holder, Terminals, Insulated Wire, 17/-.Postage 6d. The excellent series J.W.B. BUZZER SETS of articlesentitled ACCUMULATORS RESULT OF OVER 40 YEARS' EXPERIENCE. Fittedin Teak Case with L.R.'Phone, EXPERIMENTAL Buzzer,Morse Key, Terminals, Head Band,etc. 4v. 40a. 18 -6v. 40a. 26 - 4v. 60a. 21 -6v. 615. 31 - Don't MissThese.8,6.Carriage 1,13. STATION DESIGN which commenced in the PLATES,SETS, BOXES, SEPARATORS, CONDENSERS REPLACEMENTS, EXPERT REPAIRS. Variable Cir. Type, Cell Case.- Wireless World .001 0005 0003 and Radio Review J. W. BARNARD 24!- 19 '6 16J - MAY 27,1922,No.9, Vol. X, WORKS 45, GT.ORMOND STREET, Vernier Type for Panel Mounting LONDON, W.C.1, and 4, GT. WINCHESTER 00005 0003. '0005 .001 STREET, LOND E C.2 6/6 9,6 12'6 15 - should be in the possession of all experimenters. HOW TO MAKE YOUR OWN WIRELESS RECEIVING SET. ACCESSORIES Only a few complete sets Amplifiers and Detectors.No marking out. Aeriel Wire 7 22, 100' 3/9 Full-sizeDiagrams andallwiringdetails of the parts containing accuratelygiven ;successguaranteed.In Ebonite, Cut to size, per lb. 4'6 two Series, 2 6 each.Publisher, T. Appleby, Coil Holders, 3 -way . . 17 6 these articles to date are 109, High Street, Boston, Lincs. :or London Coil Holders, 2 -way .. 15 - Agents :Messrs. W. & G. Foyle, Ltd., 121, available, price 7d. each, CharingCross Road, London, W.C.2. and Crystal Detectors 46 and 7'6 Economic Electric, Ltd., 10, Fitzroy Square, Switches, D.P.C.O. . 29 post free. London, W.1. Write for L st. Nos. 9,11,13,15, 17, 19. 21,23, WIRELESS 25,27, Vol. X. 165,167,Vol. XI. TO MANUFACTURERS OF GRIFFINSUPPLIES CRYSTAL SETS, Etc. 80,Newington Causeway We canquoteyouattractivepricesfor The WIRELESS PRESS, Ltd., STRAWBOARD INDUCTANCE TUBES. LONDON, S.E.1 12/13, Henrietta St., London, W.C.2. All diameters frcm 2" to 6". Enquiries solicited. A. EATON I.EE & CO., 4, LIME COLLEGE ST.. LONDON, E.C.4. Central, 4839. Near cannon Street Station, With Good Apparatus you canGetGoodResults Cheapest house in the Trade for TO THE TRADE. Nearly allthe principal dealers stock OUR Condenserswhile most ofthebig manu- The facturersareincorporating themintheir sets.There'sareason. Wireless L Exceptionaly Liberal Discounts.Write. "W W. P." Morse FALLON CONDENSER MANUFACTURING Supplies COMPANY, Practice Key 230a, HERMITAGE ROAD, LONDON, N.4. Well Made-Well Finished " DACO " STEEL TAPERED MASTS. Thoroughly Reliable Equipment One-third the weight and twice as strong as 1.4C) ordinary tute masts. Price 7/6 Post Free (Wholesale only) PRICES COMPLETE WITH ALL FITTINGS. 4, Little Titchfield Street, 20' 30' 40' 50' 60' Oxford Circus, 55/- 75;'- 110'-160'- 240:-each THE WIRELESS PRESS, LTD., LONDON, W.1ASK FOR E. HILL ALDAM & CO., LTD., 12/13, Henrietta St., London, W.C.2 Telephone - Gerrard 6123OUR LIST 93, STAMFORD STREET, LONDON, S.E.1. Agents Wanted). NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW xLx

SIMPLIFIED WIkEIESS

JUST OUT ! " PRACTICIL WIRELESS VALVE CIRCUITS."A well produced of circuits with critical notes. 2/8 (2/8post free).Cloth8/.. (8/3post free). " WIRELESS FOR'ALL."For thegeneral publicand absolute novice. ed. (7*d. post free). "7-ELEDIENTARY'TEXT-BOOKrON WIRELESS VACUUM TUBES."Beauti- fully bound in cloth.The standard book on the subject. 10/- (10/8 post free).

" CONSTRUCTION OFWIRELESS RECEIVINGAPPARATUS." Gives complete instructionsfor making all the components of crystal and valve sets. 1'8 (1/7*post free). " WIRELESS VALVES SIMPLY EXPLAINED."A very cheap but authoritative book on valves. 2/6 12/8 post free).Cloth3/- (8/3post free).

"SIMPLIFIED WIRELESS."A sequel to " Wireless For All." Gives elementary technical instruction with details of home-made broadcast receivers. 1/-(1/11post free). `RADIO PRESS WIRELESS DIRECTORY."Absolutely up-to-date list of land,ship and amateur call signs. 2/8 (2/8post free).

THESE athotitativeademBook are obtainable from or throughallbooksellers or direct, by return post, from DEVEREUX COURT, TEMPLE, W.C.2. atria Vress fth. Opposite Law Courts. NOVEMBER 11, 1922 1 THE WIRELESS WORLD AND RADIO REVIEW

HEADPHONES British and Best

The Finest Headphones Procurable for 30/- This priceisforone pair of either TYPE F." Featherweight." 120 or 4000 ohm 'phones, including Actual weight, including cords, cords of good quality. is 6ozs. only. Catalogue Post Free. Head Office and London Works: Showrooms : Victoria Road, 19MortimerSt., North Acton, W.3S. C. BROWN, Ltd London, W.1

TRY OUR GREAT CRYSTAL " HERTZ ITE " Simple to use.No battery required Price 2/6 post free With our Patent Detector 5/9 post free VALVES "ORA," " XTRAUDION," " R.M.R." Post free 15 -each VALVEHOLDERS, 1/6,1/9, & 2/3 H.T. BATTERIES, tapped :- 36 volts, 8/-60 volts,14/6 An absolutely up -to -Gate and complete list of all 15 volts, 4/-

land, ship and amateur call signs. 30 7/950 13 -75 16/6 It is as much a necessity to the real experimenter 4 Volt BATTERIES,1 doz.6;'9post free as a telephone directory is to a telephone subscriber. PRICE 2/6 NET. Set of Eight BASKET COILS, 16/6 post free (Post free zi8). Best Wholesale Terms for all Crystals. Orderyour cop) at on,through the trade or direct from RADIO PRESS LTD. RUSSELL AND SHAW, Devereux Court, Temple, W.C.2 38, Great James St., Bedford Row, W.C.1 NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW 1i The Perry The Wireless Auto -Time Morse Telephone System Whatitis,and How it works. By Philip R. Coursey, By F. W. Perry. B.Sc. (Bog.), A.M.I.H.E. Crown 8vo. 16 Pages. 128 Pages. 78 Diagrams and Illustrations. PRICE NET. (Postage Id.) PRICE2/6NET. (Postage 4d.) The author sets out in a simple manner, not An aid to the rapid acquirement of speed in only the essentials of the radiotelephone, but the transmission and reception of the Morse how it operates and how its parts are built Code.Learn Morse and you will never get up, including directions for building a simple tired of wireless.Far more interesting even than the wonderful broadcasting telephony valve receiver for wireless telephone broadcast. concerts and events. Contents.-Introduction.Wire and Wire- 0111111111111111111111111111111111111111111111111111111011111101111HL less Speech Trans- The constantly changing mission. The Funda- personal messages sent by mental Principles of wireless telegraphy open up a vast field of interest, Radiotelephony. The = Radiophone Trans- amusement andknow- USEFUL mitter. TheReceiver. ledge.The Perry system Some usesforRadio- teaches you Morse inter- telephony. A Simple estingly so that its study; LIBRARY Radiotelephone Receiver is a real hobby. for " Broadcast " Trans- I ADDITIONS missions.

fi THE WIRELESS PRESS, LTD. Mast and Dept. W.W. Crystal 12-13, HENRIETTA ST., LONDON, W.C.2

Aerial 1111111111111111111111111101111111111111111111111111111111111111111110 Receivers Constructionfor for Broadcast Amateurs Reception By F. J. Ainsley, By Percy W. Harris. A.M.I.C.E. 80 Pages. 75 Photographs and Diagrams. 88 Pages. 70 Photographs & Diagrams PRICEII. / 6 NET.(Postage2d.) PRICE1 /6NET.(Postage t2d) This book is one which the amateur will read This book includes directions for building a with gratitude to the author who has ren- simple crystal receiver for wireless telephone dered agreatservicein removing the broadcasting. difficulties of mast and aerial construction. Contents.-General Principles of Wireless With the use of a few ordinary tools and by Reception.CrystalRectifiersand their following the instructions given in the book Properties.Tuners for Crystal Receivers. this will be found a simple matter. PracticalCrystalDetectors. Telephone Contents.-Various Types Masts.General Headpieces.Aerials and Earth Connections. Information.Scaffold -pole Masts. Plank What you may Expect to Hear. How to Masts.Stayed Lattice Mast.Self -support - Adjust a Crystal Detector.Making Signals Mast.Tubular Mast.Aerial System. Louder. Iii THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 11, 1922 BEFORE YOU CAN STUDY WIRELESS TELEGRAPHY AND TELEPHONY YOU MUST HAVE A KNOWLEDGE OF MAGNETISM AND ELECTRICITY

Dear Sir, A HFADMASTPR'S APPRPCIATION. Enclosed please find cheque for 6 -in payment for book, " Magnetism and Electricity for Home Study," which you sent me on approval. It is a book for which I have been seeking for quite a long time.The lucid way in which the author puts the matter before the reader ; the sequence followed (proceeding from the known to the unknown) ; the numerous analogies and associations with ordinary everyday things and the excellent sketches and diagrams, together with test questions and summaries make the work admirable for self study or as a book for school use.As a schoolmaster I am using it as a base for the science scheme in my school.

To many who are anxious towellgrounded. Inthisway gain a knowledge of Magnetismhewillknow thathisfuture and Electricity some text booksstudyofWirelessTelegraphy on the subject have a very forbid-andTelephonywillbebased ding appearance. upon a solid foundation. The formulae and equations too A copy of the book willbe frequently haunt the non -mathe-sent ON APPROVAL toall matical reader and cause him towho complete the request form abandon his intention. - below. Such fears, however, need no longer deter anyone from acquir- The Manager, Mail Order Dept., ing the knowledge desired as inTHE WIRELESS PRESS, LIMITED, MAGNETISM & ELECTRICITY12-13, Henrietta St., LONDON, W.C.2 FOR HOME STUDY By H. E. I enclose 6d. for postage. PENROSE will be found FIFTY COMPLETE LESSONS prepared Pleasesend me acopyof in such a form that the readerMAGNETISM ANDELECTRICITY FOR HOME STUDY. ByH. E. ceasestoregard themasaPenrose. study. The various facts and theories If IretainitIwillremitthe are elucidated subtly but surely.sum of 6/-. Otherwise I will return No effort has been spared by thethe book ingood condition within Authortoexplainthesubject5 days of its receipt. so clearlyand thoroughly that no one can misunderstand him. Name...... AttheconclusionofeachPostal Address ...... lesson isplacedaseries of questions which enable the reader to test his progress and assure himselfthathisknowledgeis Date...... 1922 W W.11/11/22 NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW Perfectyour NOW READY Morse BINDING CASES AT HOME VOL. X. with the assistance of the The Marconi Official Gramophone Records Wireless World For Self-Vuition in receiving aCorse Signals. & Radio Review Price per record - - - 5/ - (INCLUDING INDEX) (Packing and postage 9d. extra.) Set of Six 10 -inch Double -sided Records30/ - (Packing and postage free.) Price nett. SERIES L RecordI.One Side.-TheMorseCode, 2/6 including full figures, abbreviated figures, and punctuation signs, as printed in the Postmaster -General's Handbook. Reverse.-Difficult letters which experience has shown give most difficulty to learners ,also a sentence sent slowly. (Post free 2/11.) Record 2.One Side.A Press message sent at a speed of approximately so words per minute.Reverse.-A similar message at a speed of 5o per cent. faster. Record 3.BothSides.-Dummymessages, properly numbered, timed and counted, as exchanged between ships and stations, and vice versa. INDEX(IF PURCi I ASED SEPARATELY) Record 4.One Side.-Difficult business message, containing figures, fractions, Stock Exchange terms, etc.; one or two mistakes have been introduced and then corrected in the accepted style.Reverse.-Code words Pricegd Post free. and cipher transmitted at a normal rate of zo words per minute. Record 5.One Side.-Various messages, such as would be met with in an ordinary day's transmission, sent at the rateof25 words per minute.Reverse.-Messages in French, Spanish and Italian. Record 6.One Side.-Signals from two distinct transmitters on different notes ;Press message transmitted at A limited number only of 25 words per minute jammed by similar matter at slower speed.Reverse.-Mixedmessagesjammed - byPress messages. COMPLETE BOUND VOI,. X SERIES II.Record 1.One Side.-Morse Code, including (April-September, 1922) full figures, abbreviated figures, and punctuation signs, as printed in the Postmaster -General's Handbook (Sounder Record).Reverse.-Simple Press, sent slowly (Sounder Record). Record 2.One Side.-Italian Press, 25 words per minute. Price nett. Reverse.-French Press, 25 words per minute. R cord 3. 25b One Side.-Spanish Press, 25 words per minute. Reverse.-Portuguese Press, 25 words per minute. Record 4.One Side.-Figures and fractions at moderate (Post free 26/-) speed.Reverse.-PoldhuPress,with interruptions by voices, whistles, and various noises, to teach the reception o signals in conditions of difficulty from interruption. Record 5.One Side.-" Distress Record " in which two ships working are interrupted by a third which sends the SOS signal.The traffic of the ship in distress is then For the benefit of those of our readers who expeditiously handled.This is a very dramatic record, exactly reproducing the wireless conditions at sea when a desire to have their parts bound, we shall be cry of distressis sent out.Reverse.-Ship and shore working withcorrect" T.R.s "andproperlycoded glad to undertake this for them upon receipt messages. of the copies and remittance of 8/6 which Record 6.One Side.-Messages from ship to shore at 25 words per minute, with jamming from French Press. includes cost of Binding Case, Index and Reverse.-Messsages from shore to ship at 25 words per minute, jammed by similar Press. return postage. The Wireless Press, Ltd., The WIRELESS PRESS Ld. 12-13. HENRIETTA ST., LONDON, W.C.2 1 2-1 3, Henrietta St., London, W.C.2 liv THE WIRELESS WORLD AND RADIO REVIEW NovEmBER 11, 1922 DON'T WORK IN THE DARK. SEA, LAND If you have a Wireless Set and and AIR know but little of the principles of its working, you are missing THE AUSTRALIAN a great amount of the interest and pleasure which the man ob- MONTHLY JOURNAL tains who has this knowledge. ofAviation, Radio -Tele- It is nice to get good results graphy &Radio -Telephony but where is the satisfaction if you know not how they are obtained ? Price Annual 1/9 Subscription The Elementary Post Free 21/ - Principles of THE WIRELESS PRESS LIMITED 12/13, Henrietta St., London, W.C.2 Wireless Telegraphy By R. D. BANGAY, To all who mention the "Wireless World" and send 6d.for. postage, we will send six back copies of the tells in the simplest possible manner, the theory and practice of wireless. The Author makes the subject intelligible to persons who do notpossess much technical knowledge, and at the same time it is brief and accurate. free. This will prove to you that the PHILATELIC MAGAZINE is the best Stamp Collectors' Newspaper. The book isso arranged as to be useful as All the newsfor3d. afortnight. Currentissue a reference book for students and amateurs. from your newsagent3d., or4d. post free from: It is published in two parts HARRIS PUBLICATIONS LTD., Balham atalogue of Stamp Albums and Accessories free.

PRICE4/mEACH (post free .1/3) MY or combined in one volume ELECTRICAL WORKSHOP A BOOK for the ELECTRICAL EXPERIMENTER By FRANK T. A DDYMAN, PRICE NETT 7/6 PRACTICAL & INTERESTING. (post free 8/3). 249 pages. 169 diagrams, etc. PRICE 1/- NET. The Wireless Press, Limited (Postage 9c1.) Dept. W.W. THE WIRELESS PRESS, LIMITED Dept. W. W., 12-13 Henrietta St., Strand, London, W.C.2 12-13 Henrietta Street, London, W.C.2. NOVEMBER 11, 1922 THE WIRELESS WORLD ANDRADIO REVIEW lv

JIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIL ._= =Hoyle's Book Saves Time !THE ONLY BOOK= The tables and equations are compiled in book form andreference to the GIVING FULL DETAILS detailed indexspeedily puts onein ION THIS SUBJECTE possession of the information desired. .. . is _.=. NO OTHER COMPLETE BOOK ,-.. EXISTS FOR THE USE OF RADIO WORKERS.

Direction.,_._ Send at once for a copy of = AND -__-. 1--- = _ = STANDARD . TABLES & EQUATIONS Positiom= IN = .._. ... = RADIO TELEGRAPHY = By indin BERTRAM HOYLE, M.Sc., Tech.. A.M.1.E.E. BY Price 9/.nett. Post free 919 The Wireless Press, Ltd. !Wireless; Dept. W.W. By R. KEEN, B.Eng.(Hons.) Sheffield, 12-13, Henrietta St., Strand, London, W.C.2 A M.I.C.E. =- 363 pages, 254 Photographs & Diagrams. THE RADIO EXPERIMENTER'S HANDBOOK PRICE91_NETT. --.= By PHILIPR. COURSEY, (Postage 9d.) B.Sc. (Eng ), F.Inst.P. This book deals not only with the principles /13 pages. 99 'Diagram and Illuaralions. = of the subject but with the constructional details of direction finding installations.It PRICE NETT. describes the principles ofDirection and 316 -LA Position Finding in this country in such a (Postage 6d.) way that the subject may be grasped easily L=-.= by engineers tackling this fieldof wireless THE WIRELESS PRESS, LIMITED, = work for the first time. Dept. W.W., 12'13, Henrietta St., Strand, London, W.C.2 CONTENTS. = Introduction ;Theory of the Wireless Direc- tion Finder ; Valve Amplifiers and Detectors ; Maps ;Position Finding ;Night WIRELESS APPARATUS Effect and other Freak Phenomena ;The OF EVERY DESCRIPTION ShoreD.F. Station;TheShip D.F. At lowest possible prices.Send P.C. for het. Station ; AircraftD.F.Station ;Fault Experiencedradioengineerinattendance. Clearing and Maintenance ;Notes on Field :7-7 Expert advice free to all clients.Accumulators and NauticalAstronomy ; Bibliography. charged. Instruments repaired. Quotations for complete installations.Specialists in aerial equipment. Allparts instock forsuper - regenerative sets. The Wireless Press, Ltd

-=_ Dept. W,W. JOHN BANKS & SONS E.7.= 12/13, HENRIETTA ST., LONDON, W.C.2 14-18, DUKE STREET, TELE. ; ROYAL 4424.LIVERPOOL lvi THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 1I, 1922 Just Received from America. Elgie's Weather Book DO YOU KNOW FOR THE GENERAL READER. -the proper proportionofgrid and plate By JOSEPH H. ELGIE. currents in a transmitting tube ? Author of -the proper proportion of plate current when THE STARS NIGHT BY NIGHT," "THE COMPLETE not modulating to the normal full -load current STAR GUIDE." "STAR AND WEATHER GOSSIP." when modulating ? -how toeliminateexcessiveplatecurrent when no adjustment of the circuits will do it ? PRICE45/m NET.POST FREE 5/6 -the percentage of increase in output to be expected by the addition of one or mote tubes to a transmitter ? CONTENTS: -the advantages and disadvantages of trans- The Atmosphere ; Wind ;Rain ;Clouds ;Snow. mitting circuits employing direct current on the Had and Dew ;Fog ;Depressions ; Thunderstorms ; plates ;A.C.,with half -wave rectification ; Anticyclones ;Frost and Thermometers ;Evapora- A.C. withfull -wave rectification,kenotron- tion ;Haloes and Coronas ;Supposed Weather rectified A. C. ;and which type of circuit is Signs ; Climate ;Weather Vocabulary ; Index. the most economical and at the same time most efficient ? " Mr. Elgie is not tiresomely technical, as experts commonly are :he writes in a well-read readable IF YOU DON'T way. Anyone who wants to know more about weather will find him a pleasant aswellasa competent guide."-The Daily Mail. "There isnota dull moment."-The Dundee Modern Advertiser. THE WIRELESS PRESS, LTD. Radio Operation 12.13 Henrietta St., London, W.C.2 DuJ. 0. SMITH Price 10 6 Nett Post free 11/ - RADIO & MODEL WILL TELL YOU ENGINEERING in plain language that you will enjoy reading. Edited by M. B. SLEEPER.

LIST OF CHAPTERS. Price 7d. monthly. Post free 8d. I.The Radio Telephone. 2. Transmitting Equipment Used in Radio Subscription 7s. per annum. Telephony and Its Operation. 3. Typical High Power Broadcasting Stations. 4. Receiving Equipment for all Purposes and THE WIRELESSPRESS, LTD., Its Operation. 12-13 HENRIETTA ST., LONDON, W.C.2 5. Spark v. Continuous Wave Transmission. 6.Vacuum Tube Fundamentals. 7. Operating Characteristics of Vacuum Tubes. 8. Methods of Obtaining PlatePotentials, THISY8It IWANT WHA r and Types of Continuous Wave Trans- AMATEURS mitters. 9.Continuous Wave Transmission by THE VEST POCKET Amateurs. so.Tube Transmitters in Commercial Work. Dictionary of Technical II. Advantages of a Counterpoise Ground in Connection with Tube Transmitters. TERMS USED IN WIRELESS WORK. 150 Pages. Over 50 Illustrations. Over1,500 definitions. Price 2s. 6d. net. Post free 2S 9d. The Wireless Press, Ltd. Dept. W .W THE WIRELESS PRESS, LTD., 12/13, Henrietta St., London, W.C.2 12-13 Henrietta Street, Strand, London, W. C.2 NOVEMBER 11, 1922 THE WIRELESS WORLD AND RADIO REVIEW `the OHMER INSULATION TESTING SET (cox's PATENT) This is the lightest, cheapest and best instrument of its kind on the market. It consists of an Ohmeter and Generator mounted in one case.The Ohmeter is of the Electrostatic type, giving extreme lightness.Absolutely unaffected by externalfields.Itreadsdirectly in Megohms and is independent of the voltage or speedofthe generator. NALDER BROS. & THOMPSON, LTD., 97a, DALSTON LANE, LONDON, E.8.

The YEAR BOOK of WIRELESS Telegraphy and Telephony 1922 1476 Pages. Price 151- Nett. Derry 8vo. Postage Inland1 /-. Abroad 114.

CONTENTS :- Record of the Development of Wireless Telegraphy-National and International Wireless Laws and Regu- lations-Directory of the World's Land and Ship Wireless Stations-International Allocation of Call Letters-Alphabetical List of Call Letters-Meteorological Section-International Time and Weather Signals-National Resumis of Progress in Wireless Telegraphy-Particulars of Wireless Telegraph Patents, 1921-Aviation Section-Tabular List of Aviation Stations-.Useful Data Section-Wireless Terminology-Conventional Signs used in Wireless Diagrams-Companies Engaged in the Commercial Development of Wireless Telegraphy-Biographical Section-Literature on Wireless Telegraphy and Telephony-Directory of the World's Wireless Societies-Directory of Wireless Colleges and Schools-List of Licensed Amateur Transmitting Stations-Code Section-Special Articles on " The Earthing Resistance of Antennie," by Dr. Miessner-" The Recording of Wireless Signals," by Dr. Abraham-" The Birth and History of Long Distance Wireless Telegraphy "-" The Rectification Effect in its Reaction to the Composition and Structure of Crystals." A valuable feature of the present issue is the specially drawn map, which gives, for the first Gime, a simple means of finding the distance and true direction of Wireless Stations in all parts of the World, from London as the centre.

L130 NHDBONNR. I EwT Tc A2 THE WIRELESS PRESS, LIMITED, ;$ s TWRND

Registered NIPHAN-Trade Mark. As used by H.M. War Office, Electric Supply Companies, Railway Companies. Marconi s Wireless Telegraph Company WATER-TIGHT PLUGSSIMMONDS BROS.. LTD. and CABLE COUPLINGS 4.6 & 8. NEWTON STREET. HOLBORN, W C. TO MEET HOME OFFICE REQUIREMENTS

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COUPLING CONNECTING CABLES Phones: Telegrams: ,r -a! 2600 Gerrard 120b1 Caatral Niphon. London:. SIX WAY TEE CONNECTORS Patented 'n England and Abroad. THE WIRELESS WORLD AND RADIO REVIEW NovEmma 11, 1922

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GET THE BEST OUT OF YOUR SET BY USING

(,)Any standard telephone plug can be usedbutpreferably thespecialspiral Elwell plugs which are fitted with self - THE ELWELL tightening connection grips. JACK SYSTEM Once connected up on the Elwell Jack 411.- (b) The Jacks fit neatly on the panel and System your receiving set becomes far beingheavilynickelplatedaddcon- more convenient to use both for broadcast siderably to its appearance. reception and for experimental purposes. The following operations become quite automatic :- 1. Filaments switched on. 2.Telephones or loud speaker 'put (c)They are easily fixedto any panel up to thick.No fixingscrewsare across any desired number of valves. required. 3.Intervalve transformers disconnected atpointofinsertionsoensuring maximum efficiency. 4.Only the required number of valves light 'up.The remainder stay out of ( d) Five types of jacks are available from circuit. a simple telephone jack to one controlling 5. Removing Plug completely switches telephone, transformer and filament battery. off set.No errors can afterwards be madeinconnectionsorswitching. Loose contactsand broken leads are permanently prevented.Comparative tests of telephones and loud speakers (c) Insulation tested up to 1000 volts. can be made with ease and accuracy.

Write for descriptiveleaflets. C. F. ELWELL, LTD.,RadioEngineers, CRAVEN HOUSE,KINGSWAY, LONDON, W.C.2 Telephone :REGENT 421.

Printed by Sanders Phillips & Co., Ltd., Chryssell Road, London, S.W.9,for the Proprietors and Publishers, The Wireless Press, Ltd., 12-13, HenriettaStreet, London, W.C.2 ;Sydney, N.S.W., 97, Clarence Street ;Melbourne, 422-24, Little Collins Street ; New York, 326, Broadway. 18th NOVEMBER, 1922. THE PRICE 6DNET. WIRELESS WORLD AND RADIO REVIEW

No. 170.r No. 7. 7 LVOL. Xl. Registered at the G.P.O. 18th NOVEMBER, 1922. as a Weekly Newspaper.

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HART ACCUMULATORCO- LTD., STRATFORD LONDON, E.15 BRANCHESBELFAST, BIRMINGHAM, BRISTOL, GLASGOW 1 MANCHESTER, WESTMINSTER & YORK. THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18, 1922 STERLING No. 1 CRYSTAL RECEIVING SET Specially designed for use in connection withthe Wireless Telephony Broad- casting Scheme, and is suitable for a rangeofabout 25 miles. PRICE £7-12-6 TO BE OBTAINED FROM ALL DEALERS OR DIRECT FROM: - STERLING TELEPHONE & ELECTRIC CO., LTD. 210-212, Tottenham Court Road, LONDON : : : W.1 Telephone No. 4144 Museum (7 lines)

Telegrams : Cucumis, Wesdo, London." Works :DAGENHAM, ESSEX. BRANCHES: NEWCASTLE -ON -TYNE: 9, Clavering Place. IMMEDIATE DELIVERY CARDIFF:8, Park Place. "Wireless for all" Before you decide on the construction of your set. It will pay you to have particulars of- Condensite Celoron For PANELS and OTHER PARTS. This material is waterproof, immune to atmospheric and climatic conditions, will not warp, has high surface and volume restivity, high di -electric strength, low specific gravity. LET US QUOTE YOU SEND P.IRTICULJRSOF YOUR EXICT REQUIREMENTS TO THE MANUFACTURERS

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crhe Instruments advertised on thispage are approved by the P.M.G. under seal and registerednumbers. Vhey may be used to receive British Broadcastingunderlicence which may now be obtained at any Post Office. very Instrument is thoroughly tested and guaran- G. P.O. Registered No. 1008 teed to be scientifically perfect and entirely British. The Simplex enables you to hear Broadcasting Music, Telephony, etc. Itisas simple as a gramophone, butinfinitelymore fascinating. Hilophone 1 H.F., Det., 1 L.F. Speciallydesignedto pickupBroadcasting in anypartof Great Britain.

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Full particulars of these and many other instruments of convenience forexpert, andnovicealikemaybe haduponapplication. H.P.R. WIRELESS, LTD. Pioneer Designers and Makers of Fine Valve Receiving Instruments for Amateurs. Head Office and Demonstration Room : CARI,TON HOUSE, GREAT QUEEN STREET, KINGSWAY, LONDON, W.C.2 Tel. : REGENT 1;19. (Opposite Kingcoo. I heat, e)

5 iv THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18, 1922

An unprecedented offer !

4000 Ohms 7 DAYS' FREE TRIAL in Series The " SENSIFONE isthefinestvalue -for - EVERY SET TESTED money Headphone onthe marketto -day- and AND GUARANTEED you can prove it in your own home at no risk to yourself.If your dealer does not stock, simply remit the purchase price (27/6) and the SENSIFONE 2716 will be sent you by return.Test it at home, and if Complete you do not find itall we claim, return it within 7 with days and we refund your money in full without question Flexib!e This is a genuine offer that only supreme confidence in the efficiency of the SENSIFONE would enable us to make THE Write to -day. If I SENSIFONE `the extremesensitivityof Free desalt, ive leaflet on application to the sole makers : The SENSIFONE ERNEST STREET TOWNSHEND'S LD. BIRMINGHAM is due to the fact that the very powerful magnets are so arranged that the pull on Agents and Showrooms : the diaphragm is in exactly the correct spot. LONDON : Coward & Co., Sr, Charlotte Street, W.I. A really first-class instrument. MANCHESTER :Coulston & Co., 5, Cross Street. NEWCASTLE :R. F. Sunderland, Milburn House. TRADE AGENTS REQUIRED. GLASGOW :Clarkson Hood & Co., 45, Hope Street.

THROUGH THEIR EFFICIENCY, THESE TRANSFORMERS, HIGH AND LOW, HAVE EARNED A REPUTATION FOR THEM- SELVES, AND ARE NOW INLARGE DEMAND BY EVERY CLASS OF USER. The " Discol" H.F. Transformer ASK YOUR DEALER FOR :- PRICE 6;8 Each GENTS' "TANGENT" L.F. TRANSFORMER N D GENTS' "DISCOL" H.F. TRANSFORMER 1 he 'Tangent" L.F Trans( °ruler GENT & Co., Ltd. "FARADAY WORKS" LEICESTER LONDON :- 25, VICTORIA STREET, S.W.I. NEWCASTLE -ON -TYNE:- "TANGENT HOUSE," BLACRETT STREET. 0 0 NOVEMBER 18, 1922 THE WIRELESS WORLD AND RADIO REVIEW

111191111111111111111111111111111111 111111111111111111111111191119111111

A Rheostat of Quality.

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Receiving Apparatus. ALL Burndept Broadcast Apparatusissold under the name" ETHOPHONE." Four models can now be supplied from stock.Prices from £4 10s. to 34 guineas. All Ethophones have been approved by the Postmaster -General and bear the B.B.C. badge. BURNDEPT Intervalve Transformer. THESE Transformers ensure maximum amplification with minimum distortion.They are tested ata pressure of 500 volts, winding to winding and frame, and also with a current of 10 milliamperes flowing through the windings. Minimum insulation resistance 250 megohms.Guaranteed against breakdown. Price.g1 :5:0 (E) boxed. (With diagram.)

A fullyillustr ted catalogue containing muchusefulinformation anddetails ofourapparotuswill be sent postfree 1 I-.

AllI BURNDEPrValve Apparatus is duly licensed under Marconi Patents for Amateur use in Great Britain. London OfficeAetShowrooms :15, Bedfod.3 Street, Strand. BURNDEPT, LTD., arTirst Works, Blackheath, vi THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18, 1922 ESLIE IC LTD. PROVIDENCE PLACE, WEST END LANE, KILBURN, N.W.6 B,,18 Servlcee1.8.16.. 28.31 allpeasWeal. EndLane TelephoneHAMPSTEAD 1261 Nearest Tube Station: KILBURN PARK ( BAKERLOO) Single Valve Detector Receiver Panel. Type M.H.1.-This panel is fitted with :-Valve Holder: Fil. Rheostat ;'0005 M,F.D. Variable Condenser,;Series Parallel Switch and all necessary Terminals. The Ebonite Panel is highly polished and fully engraved, being mounted ina well finished case of polished mahogany. A coil holder can be mounted on the side, the unit then beinga complete receivingsetrequiring only the usual additions of Aerial Batteries and Phones. Price £5 5s. Pricesforaccessoriesto make completestation,including Aerial,Insulators, Tuning Coils, Coil Holder, Head Phones, Valve,High Tension Battery, and Accumulator. 12s. NOTE.-Other M.H. Sets, 2 to 4 valves, of similar design and unsurpassed efficiency, are mentioned in detail in our NEW Booklet, 6d. post free. All applying for same will alsoreceive our x6 page,tooillustrations, GENERAL CATALOGUE. (Ail our valve apparatus is menu/at:lured under Marconi Licence.)

PLEASE NOTE CHANGE OF ADDRESS. W. J. HENDERSON, 351 FULHAM ROAD, S.W.10 (Nearest Stations-Earl's Court or South Kensington.)('Bus Routes. Nos. 14 & 96 pass the door.)(Two minutes from old address.)

SPECIAL OFFERS-SUBJECT UNSOLD Items listed below are guaranteed in BRAND NEW condition, in every instance complete, and in perfect working order.(Valves and Batteries are not included.) TRANSMITTERS. Tuners, Short Wave, Mk. III* complete in every respect, with Transmitters, Mk. for two valves, range 500-2,000m., spares each£9 easily altered for 440 m. and telephony, complete with C.O. Switch, milliammeter, key, spares, etc., etc. .. each£8 AMPLIFIERS. Transmitters, C.W. 80 w., comprising inductance 2,000-5,000 m., with tappings to rotary switch, anode tap, reaction coil, and Amplifiers, C.Mk. IV, 3 valve, H.F., intended for use in con- variometer coil, thermal milliammeter, mounted on r ebonite junction with 80 watt tuner above, but can be altered for use base carrying key, valveholders, etc., etc... .. price£4 on other wavelengths, complete with three slot -wound H.F. Transformers,potentiometer,filamentRheostat,etc.,etc., RECEIVERS. price each£3 Receivers B.Mk.If (Front and Rear), for two valves (one Rect., Amplifiers, C.Mk.IV, 3 Valve L.F. (or 1 rectifier and 2 L.F.) 1 L.F.), wavelength 85 and 80 metres ;easily altered for other complete with telephone transformer, etc., etc... each£6 wavelengths (see W.W. 10%12;21), complete with intervalve and Amplifiers,C.lWk.1II,3Valve,L.F., same components as telephone transformers, each £4 10s.(if fitted with variable C.Mk.IV above each£8 A.T. Condenser, extra 7/8). Receivers, Mk. III*, 30 watt, C.W., for two valves (one rect. WAVEMETERS. and one L.F.), wavelength 350-1,800 m., complete ready for use .. eachf8 Heterodyne Wavemeters, calibrated, 500-3,000 m.,complete This instrument is arranged to interconnect with the Mk. with charts.. . each£4 III* Transmitter above, and together form a very useful portable Transmitter and Receiver. CONDENSERS. TUNERS. Condensers, Mk. III Type, complete with bevelled scale and Tuners, C.W. 60 watt, wavelength 2,000-5,000 m., complete knob, and ebonite case-

and in case with two .0015 variable condensers, C.O. switch .0015 mitts. . each 40- (SW. by and Tune), etc., etc. (see Amplifiers below).. each £5 each 15 - Complete lists on request. Goods above £2 in value carriage paid. Terms, CASH WITH ORDER. NOVEMBER 18, 1922 THE WIRELESS WORLD AND RADIO REVIEW vii RADIO INSULATION AS SPECIFIED AND USED BY THE BRITISH ADMIRALTY

BRITISH MADE pA3DDLIN BRITISH MADE

TUBES DISCS PLATES, &c. MANUFACTURED IN ALL FORMS, SIZES AND THICKNESSES BY THE MICANITE & INSULATORS CO. LTD. EMPIRE WORKS WALTHAMSTOW LONDON, E.17 TSLOSPAM -" MYTILITE. PHONE, LNOON." TELEPHONES,-WALTHAMSTOW 73S, 7111 Ediswan Valves. THE manufactureof Thermionic Valvesisa highly skilled operation and every Ediswan Valve has behind it the experience and operative skillof over forty years of lamp making. The A R Valveillustratedisspecially made for Amateurreception. Platevoltage30-80volts. Filamentvolts3.5-6.ovolts. Filamentcurrent 0.75 amperes.High amplification-silent working. Price 15/- each. Always ask for I:list:van Valves.If you are unable to obtain tiem at your Dealers write to us for Lis name and address of at nearestsupplier. THE EDiSON SWAN ELECTRIC CO., LTD., Head Office :123/5, QUEEN VICTORIA STREET, E.C.4. ;London Showrooms:123/5, Queen Victoria Street, E.C.4, & 71, Victoria Street, S.W.r. Type A R Works : Ponders End, Middlesex. viii THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18, 19:22 The Perry The Wireless Auto -Time Morse Telephone System Whatitis,and How it works. By Philip R. Coursey, By F. W. Perry. B.Sc. (Eng.), A.M.I.E.E. Crown 8vo. 16 Pages. 128 Pages. 78 Diagrams and Illustrations.

PRICE NET. (Postage ld.) PRICE 2/6 NET. (Postage 4d.) The author sets out in a simple manner, not An aid to the rapid acquirement of speed in only the essentials of the radiotelephone, but the transmission and reception of the Morse how it operates and how its parts are built Code.Learn Morse and you will never get up, including directions for building a simple tired of wireless.Far more interesting even valve receiver for wireless telephone broadcast. than the wonderful broadcasting telephony Contents.-Introduction.Wire and Wire- concerts and events less Speech Trans - The constantly changing 11111t11 personal messages sent by mission. TheFunda- wireless telegraphy open mental Principles of up a vast field of interest. Radio telephony.The amusement andknow- THE Radiophone Trans- ledge.The Perry system mitter. TheReceiver. teaches you Morse inter- Some usesforRadio- telephony. A Simple estingly so that its study NEW Radiotelephone Receiver is a real hobby. for " Broadcast " Trans- FOUR missions.

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Aerial ,i111111111111111111111111111111111111111111111111111111111111111111111111. Receivers Construction* for for Broadcast Amateurs Reception By F. J. Ainsley, By Percy W. Harris. A.M.I.C.E. 80 Pages. 75 Photographs and Diagrams. 88 Pages. 70 Photographs do Diagrams PRICE 1 / 6 NET. (Postage2d.) PRICE1/6NET.(Postage2d) This book is one which the amateur will read This book includes directions for building a with gratitude to the author who has ren- simple crystal receiver for wireless telephone dered agreatservicein removing the broadcasting. difficulties of mast and aerial construction. With the use of a few ordinary tools and by Contents.-General Principles of Wireless following the instructions given in the book Reception. CrystalRectifiersand their this will be found a simple matter. Properties.Tuners for Crystal Receivers. PracticalCrystalDetectors. Telephone Contents.-Various Types Masts.General Headpieces.Aerials and Earth Connections. Information.Scaffold -pole Masts. Plank What you may Expect to Hear. How to Masts.Stayed Lattice Mast.Self-support. Adjust a Crystal Detector.Making Signals Mast.Tubular Mast.Aerial System. Louder. ix I I 1:1;\* In. 1922 : \ 11;I:I.FSSVORLU .Y.\-1)I t. \ 1)1(

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Thisinstrument, as illustrated, isone of the most efficient and powerful valve receivers ever designed.It can be operated bya child and is self-contained except for batteries. Iminetli'areDelivery. pis [Price £24: 10: 0 oriComplete-with Batteries-and:Telephones,.Aerial,Accessories, but without valves £30: 15 : 0 In addition to the above, 12 ofour valve sets up to 7 valves have been passed by the G.P.O. for Broadcasting.

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AUCKLAND (Igranic) DUO LATERAL COILS. Made under De Forest Patents. PRICES from5/- Mounted. INTERVALVE TRANSFORMERS. ,11,1,1111,11 NOTE MAGNIFIER. Most Efficient Cores,being 1 VALVE SELF-CONTAINED builtupof Stalloyandin 41.? UNIT. correct proportion. ass viis For attaching to Crystal Sets, etc. The Bobbin is Layer Wound, Mounted in Cabinet with Terminals, each LayerbeingSpaced. CONDENSER DIALS. and suitably engraved, comprising Designed togive maximum Fitted with Knob and Bush, V -Holder ;Fils. Res.;Intervalve Amplification. Engraved to 18o° Transformer. PRICE20/-each. 3/9each. PRICE65/-Without Valve. Delivery-Stock.

THE NEW A NEW UNI-WAVE AUCKLAND INDUCTANCES PRODUCT. Duo Wound. 3 Coil Holder with Range from Remote Control 300-30,000 M. InductiveValues keepingCapacity are to be found in effects from body. Catalogue. Finish as a first- PRICE per set of 8 class instrument. 12/6 PRICE 22/6 We are also Mannfacturin* CompleteSets,for Broad- cast use or Experimenters. INSIST upon having AUCKLAND Products. Al! AUCKLAND Valve Apparatus is duly licensed under Marconi Patents for amateur use in Great Britain.

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Every electric lampholder can now be used with safety for picking up radio signals," Broadcasting,"etc. The DUCON " forms a perfect attachment between the radio receiver and the electric light wires. Every " DUCON " is tested at 2000 volts A.C., and has the highest possible insulationresistance. Shocksand short-circuits are thus rendered impossible. The " DUCON " fits directly into any standard B.C. electric lampholder, and is provided with terminals for connections to the radio receiver. Simplicity with Perfect Safety is the Keynote of the " Ducon." Price 10/- each DUBILIER CONDENSERS FOR ALL PURPOSES

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Silk and Cotton Covered H.C. Copper Wire, Resistance P. ORMISTON & SONS Wires, Fuse Wire, Binding Wires, Charcoal Iron Core (P. H. ORMISTON) ::ESTABLISHED 1793 Wire, Asbestos Covered Wire, Braided and Twisted 79 Clerkenwell Rd., London, E.C. Wires, Bare Copper Strand and Flexibles of any Con- struction, Wire Ropes, and Cords(fine "01.n:won, London." sizes)in :: 13 2 59Central. Galvanized Steel, Phosphor Bronze, 1.4c. THE WIRELESS WORLD AND RADIO REVIEW THE OFFICIAL ORGAN OF THE WIRELESS SOCIETY OF LONDON A MAGAZINE DEVOTED TO WIRELESS TELEGRAPHY AND TELEPHONY CONTENTS

The Amateur Position :How Broadcasting Affects the Experimenter- - - 219 A Separate Oscillator for the Transatlantic Tests.By Philip R. Coursey, B.Sc., F.Inst.P., A.M.I.E.E. ------221 Signal Rectification------227 Contents continued on next page.

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L E SS AmateursCABLE ANDand INLAND Experimenters. TELEGRAPHY. Send for Pros.Radio supplies, List A, from JAS. FRASER & CO. Telephone Radio House, Manor Gardens, North 1036 ELECTRICAL TRAINING COLLEGE, Holloway, London, N.7.

CONTENTS(Continued) Electrons, Electric Waves and Wireless Telephony.By Dr. J. A. Fleming, F.R.S. - 229 Some Recent Developments of Regenerative Circuits.By Edwin H. Armstrong - 234 Notes ------._ - - - 241 Correspondence ------242 Calendar of Current Events ------242 Wireless Club Reports ------243 Questions and Answers - - - .. ------249

THE WIRELESS WORLD AND RADIO REVIEW is published weekly on Saturdays. All correspondence relatingtocontributions should be addressed to THE EDITOR, THE WIRELESS WORLD AND RADIO REVIEW, 12-13, Henrietta Street, Strand, London, W.C.2. No responsibility can be taken for MSS. or photographs sent without stamps to defray .cost of return postage. Editorial and Publishing Offices :12-13, Henrietta Street, Strand, London, W.C.2. Telegraphic Address :" Radionic, Rand, London." Telephone No.:Gerrard2807. Advertisment Managers, Bertram Day & Co., Ltd., 9 and to, Charing Cross, S.W.': Telephone No.: Gerrard 8063 and 8064

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1 The London Telegraph Training College, Ltd. Telephone: WESTERN 2696. Morse House, Earl's Court, S.W. ESTABLISHED 25 YEARS. OFFICIALLY RECOGNISED BY THE WAR OFFICE AND POST OFFICE AUTHORITIES CABLE AND WIRELESS TELEGRAPHIC. PARENTS desirous of placing their sons in either of the above Services and of affording them the best training facilities should apply for particulars of Courses and the methods of instruction which place this Institution in the first rank.Cable Telegraphy offers at the present time excellent prospects to youths from 15 years of age and upwards, and the College has exclusive facilities for obtaining posts for qualified students in the leading Cable Companies at commencing salaries of Li5o to 30o per annum, with yearly increments of gaa to gas, aiu3 ultimata possibilities of obtaining positions as Supervisors, Assistant Superintendents, Managers, etc. In the Wireless Telegraph Service the commencing remuneration at the present time is approximately 1:15o per annum, and Operators, when qualified by obtaining the Postmaster -General's Certificate of Proficiency, are nominated by the College for appointments. No CorrespondenceDAY Classes ANDor Branches. EVENING CLASSES. Prospectus containing all information will be forwarded on application to THE SECRETARY (Derr. H.), 262, Earl's Court Road, Earl's Court, London, S.W.5. Sole Proprietors of the " Scott " Training Disc, which contains useful formula and other information for Wireless Telegraph Operators and is invaluable to Army Signalling Officers for range finding, etc. Price. complete with instructions for use, 1/-.Postage 2d. NOVEMBER 18, 1922 THE WIRELESS WORLD AND RADIO REVIEW xvii VALVES DELIVERY FROM STOCK.

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Call andseethis Receiving Set Demonstrated.

No intricate adjustments are necessary with this highly efficient Broadcast Receiving Set to obtain Telephony and Telegraphy signals with remarkable clarity.All the adjustment necessary to receive any particular wavelength is the movement of one switch arm. Its dimensions are 9" x 9" and 8i" high, the Hertzite crystal is enclosed in glass, one adjustment being almost permanent. Supplied complete in highly polished mahogany case together with Sterling R1258 Head 'Phones (4,000 ohms), 100 tt Black 7;22 Aerial Wire, 2 " Econ " Aerial Insulators, 1 Aluminium Aerial Pulley.It costs but BS 5s. Everything can be enclosed in the case for packing away. In additionto complete Receiving Sets we also manufacture all Component Parts. honeycomb Inductance Coils from . .. 5,- " Ideal " Valve Accumulator, 4 -volt .50 amp. per set 25/ - (Carriage, 2/-) " Ideal " Valve Accumulator, 6 volt 50 amp. per set 35/ - (Carriage, 3/-) .. Filament Resistances ...... each itt: Variable Condensers (of various capacities) from.. Fixed Condensers from ...... 2/6 H.T. Battery Case .. .. 15/- H.T. Battery Case, with 60 volt battery .. 29/ - Three Coil Holder, complete unit.. 20/ - Baal 8d. stamps for our Illustrated Catalogue.List of H.T. Batteries or Accumulators tree. 13-14, Great Queen Street, WATES BROS Kingsway, LONDON, W.C.2.

VARIOMETERS. Formers made from finest selected Beech and supplied in four parts as illustrated.A. Outer formers (one showing winding).B. Ball former.C. Former for winding coils to be placed inside A. Diameter / EBONITE AND of ball 2r .. Price per Set, VULCANITE

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No. 170 [VONL.°. 7)(i.] NOVEMBER 18TH, 1922. WEEKLY The Amateur Position. HOW BROADCASTING AFFECTS THE EXPERIMENTER. IT has already been mentioned in theseupon or modified without some sign of a columns that no surprise should be feltstruggle to resist any such attempt. atthefactthat many new situations A well established precedent in law is often have arisen with the introduction of the pro-as good as a statute, and undoubtedly the posed schemes for broadcasting, but we dostatus of the amateur has been very well not think that at the time thatstatementestablished within the last two years. was made it was realised that the problems Perhaps before going any further it would arising therefrom would present themselvesbe well to emphasise that in writing these so rapidly and forcibly as has been the case.lines there is not the least intention to adopt And in this connection reference is made onlyan antagonistic attitude towards broadcasting. to the amateur problems, by which is meant On the contrary, the amateur wants broad- the matters which affect in particular those casting.and would have been verydis- who were experimenters before broadcastingappointed if it had not come.If any support was talked of, or who will join the ranks ofof thisstatementisnecessarythe reader the experimenter proper in the future. Thereneed only be referred to the fact that it was is not space in this issue to make reference entirely through the agency of a very forceful to the other problems, which have confronted petition to the Authorities from the amateurs the Postmaster -General and those who haveof this country as a body that broadcasting been responsibleforbringing theBritishfirst came into being, when the Postmaster - Broadcasting Company into being. General authorised the regular weekly trans- Only a year or two ago practical amateurmissions from Writtle. wireless was illegal in this country, and for Broadcasting is a very good thing indeed, some time the authorities would not give wayand should receive every encouragement from on the question of the re -issuing of licences everyone concerned, but at the same time after the war. The struggle to win back forit should be remembered that it is possible to the amateur some of his pre-war rights andhave too much even of a good thing, and if generally to reinstate the wireless experimenter there is any danger of the amateur and ex- was a long and arduous one which requiredperimenter being " crowded out," so to speak, much hearty co-operation on the part of allof hisrights, then there must and certainly amateurs throughout the country and manywill be objections raised. interviews and petitions to the Post Office Broadcasting,itisunderstood, will take Authorities.Theseconcessions,orrights place from 5 p.m. to t t p.m. daily, and through- (it is of no material importance by which name out the day on Sunday, and the official regula- they are described) having once been obtained tions state that reaction must not be used at all are not likely to be permitted to be encroached during these times over the range of wavelengths 220 THE WIRELESS WORLDAND RADIO REVIEW NON EMBER 18, 1922 covered by the broadcastingstations.Thisfeel, however, that it should be possible to means that no reception of continuous wavearrive at some happy medium when those who telegraphy may be conducted between thesegenuinely desire to join the ranks of the ex- times on the amateur wavelength of 440 metres.perimenter should be allowed to do so provided Since the hours to be covered by broadcastingthat reasonable guarantees could be given areliterally the only times during whichthat the recipients of licences would conduct the true experimenter (unless he is engagedtheir experiments in a proper manner, with on commercial experimental work, orisa due respect for other users of the aether, person of leisure) can conduct his experiments,and would not earn for themselves the title the regulationisequivalenttobanishingof " aether hogs."There must be some hun- the amateur to the shorter wavelengths belowdreds, though still a small proportion of the the broadcasting band, and depriving himtotal future users of wireless, who are attracted altogether of the use of the 44o metre wave-to the scienceentirely on account of its length as soon as broadcasting commences.fascination as a hobby, in the practice of which The chief danger that threatens the amateurthe construction of their own apparatus and position is that in the near future he mustthe possibilities which -experiment with all expect to find himself in the minority as farkinds of circuits may present, would form the as the general users of wireless are concerned,chief interest. and a minority may often be overruled by a There is yet another side to this question. We majority vote however well established andrefer now to the development of the industry just may be the claims of the minority.Per-of manufacturing wireless apparatus which haps the position of those amateurs who havehas taken place as a result of the proposals transmitting licencesiseven lessenvious,for broadcasting, and the stimulus which this since their work on 44o metres will apparentlyhas given to public interest in the subject. have to cease altogether, although many ofThe retailing of wireless apparatus parts is them are pioneers in amateur work, and maynow confined to those users who will con- be regardedas some of the most seriousstruct apparatus for themselves or conduct investigators in this country. experiments, whilst the broadcast licensee is So much consideration then for the im-accommodated with complete sets of approved mediate situation which confronts the amateur design.The majority of those firms who and experimenter who has already establishedundertake to provide complete sets for the his claim to consideration in so far as he hasbroadcast licenseewillproduce their own obtained an experimental licence.There isparts for incorporation in their sets, and this also to be considered the position of thoseleaves to the manufacturer of parts only, no would-be experimenters, who, on accountoutlet for the disposal of his goods except of the unhappy accident of the date of theirthrough retail sales to the experimental licence applicationsforexperimentallicencesfind holder.The net result is that many manufac- that their applications are turned down, andturers who would otherwise have been content they are recommended to content themselvesto leave the manufacture of the complete sets withabroadcastreceptionlicence.Un-to the larger firms, are finding themselves fortunately, the number of these disappointedccmpelled to assemble complete sets in order enthusiasts is increasing daily, and it is there- to come into the field and share in the industry. fore not altogether surprising that, in spite Some readers, perhaps, are reminding them- of the fact that as a whole we are a law-abiding selves that broadcasting has as yet scarcely nation, rumours should reach us of the possi-started, and that these questions are therefore bility of the illegal establishment of unlicensed brought forward prematurely. To this we receiving stations, despite the very seriouswould reply that it is better to face the facts penalties that are risked in so doing. beforehand and look for a remedy. We feel It is of course appreciated that the wholesure that the delay in broadcasting is due to question is a very difficult one for the Authori-the honest desire on the part of the Authorities ties, who could not under any circumstancesand the Broadcasting Company to present be expected to issue experimental licencesbroadcasting to the country with as many to all and sundry without any guarantee thatas possible of the problems whichithas the shrieks and howls of radiation would notbrought withitsolvedtothesatisfaction compel every sane experimenter and broadcastof all parties. listener -intoclose down indisgust. We H.S.P NOVEMBER IS, 1922 THE WIRELESS WORLD AND RADIO REVIEW 221 A Separate Oscillator for the Transatlantic Tests. (Wavelength Range, 170-440 metres.) By PHILIP R. COURSEY, B.Sc., F.Inst.P., A.M.I.E.E. AS was mentioned in last week's notereducing radiation from the receiving aerial. on thesubject of the forthcomingThe most practicable method isto keep the Transatlantic tests which are to takeseparate heterodyne unit as far away as possible place in conjunction with the American Radiofrom the aerial circuit, and also from the tuned Relay League, it is essential that a separatesecondary circuit coupled to the aerial, and heterodyne be employed when listening forto couple it on to some other part of the C.W. signals, in order to avoid interferencereceiving circuit, so that there is at least one between the various stations listening -in in this valve between the aerial and the part of the country. circuit to which the heterodyne is coupled. The mere employment of a separate hetero-The best arrangement is to couple the separate dyne unit, however, is not of itself sufficientheterodyne oscillatorto the detector valve unless proper precautions are taken in its use.itself, either to its grid or to its plate circuit. For instance, in many receiving stations direct It will generally be found sufficient for this coupling between the aerial circuit and thepurpose to place the separate heterodyne unit heterodyne is used, with the result that onnear to the detector valve, although if preferred, it may be placed much further away 1 (but not near the aerial circuit) and coupled to the detector valve by means of an aperiodic circuit consisting of a coil of a few turns of wire, placed near the heterodyne and con- a/e nected by a pair of leads close together to a similar coil coupled to either the grid or the anode circuit of the detector valve. To couple the heterodyne in this way to the anode circuit of the detector valve of the 4 J receiving set a special coupling coil may be 7/6 4/4"4. 741 built up consisting of some six or eight turns of No. 22 S.W.G., D.C.C. copper wire, Fig. 1.The coils for the separate oscillator. wound on an insulating tube about three inches shortwavelengthstheradiation from thein diameter.In the centre of this tube a aerial is practically as strong as if an autodyne similar smaller tube abouttwo inches in receiver were employed.The conditions arediameter, and having wound on it about six slightly improved if the heterodyne is coupledturns of the same wire, should be pivoted in to the secondary circuit of a loose -coupledsuch a way that it can be rotated so that the receivingtuner,butforshort wavestheplanes of the two coils can be placed at any improvement is not great, because the hetero-angle to one another between o and 90 degrees. dyne has to be so slightly detuned from theBy this means the coupling between the two frequency of the incoming signal in order tocoils can be varied from zero up to a maximum keep the beat note frequency within the audiblevalue. A fixed condenser of about oboi limits that to all intents and purposes the hetero-microfarad should be joined across the primary dyne and the aerial are in tune as regards theofthe intervalve transformer coupling the transfer of energy between them.On longdetector valve to the first L.F. valve when this wavelengths the much larger frequency differ-arrangement is employed. ence between thetwo circuits limits very The receivingsetsforuseduringthe considerably this transfer of energy, so that theTransatlantictests are preferably built up heterodyne radiation is reduced by this method.with atleastone or two stages of H.F. For the short waves to be used during theseamplification, the intervalve coupling of these tests some other means must be employed forstagesbeing tuned, as only by this means 2 22: THE WIRELESS WORLD AND RADIO REVIEWNOVEMBER18, 1922

04"

TAP4BA,- TERMINALS

TAP 6 BA

TAP 6BA

k We/ CENTRE FOR MINATURE TUMBLER SWITCH SWITCH SHOULD NOT EXCEED tY4:

FIXING HOLES7/64 DIA. C SK.

HOLE TO FIT BUSH ON CONDENSER 1

TAP 4 BA,- TERMINALS

11/4.-±- --7- -.4-

.5/5- I 5A. ft 54* Fig. 2.Drilling diagram for ebonite top. can efficient amplification of the short wave-variable condensers for tuning them to the lengths be secured.High frequency inter-desired range of wavelengths (which is approxi- valve transformers of the plug-in type, withmately i8o to 40o metres), may be employed, NOVEMBER 18, 1922 THE WIRELESS WORLDAND RADIO REVIEW 223 or the anode circuit of each H.F. valve may bethen put on, using the same wire. A variable tuned by a variometer or fixed coil with a condenser,havingamaximum valueof variable condenser in parallel with it, using a approximately 0.00025microfaradisused fixed condenser to couple the successive stagesfor tuning purposes, and should be connected together, as is customarily done in the well-across the grid coil G.For convenience the known tuned -anode -reactance -capacity -coupledwhole instrument may be mounted in a wooden method of H.F. amplification.When either of these arrangements is employed some means .3A6 HOLE CSK of stabilising the whole receiver is necessary to 10 Va ON urr- prevent self -oscillation.This can be effected rtANO SURFACE either by providing a definite reverse coupling 6BA between the plate circuit of the detector valve acAss,4-W1DE and the input or grid circuit of the first H.F. valve,thiscoupling being in thereverse direction to that normally required to produce Fig. 4.Fixed end clips for valve holder. oscillations,and being adjustedtosuch a box, with an ebonite top on which the valve holder, and the terminals for the H.T. and L.T. batteries are mounted.Convenient dimensions are indicated in Fig. 2, which also gives the positions of holes for drilling.This ebonite top should be -136- in. to 4 in. thick. The outside dimensions of the box are 94 ins. by 6 ins. by 44 ins. deep, and it is constructed of wood 4 in. thick.Any con- Fig. 3.Details of side clips for valve holder. venient wood may be used, although, of course, the appearance of the instrument is improved value that oscillations just cease, or by damping the H.F. valves by applying a positive potential Iht'DIA. HOLE to all the grid circuits by means of a suitable potentiometer connected across the filament battery. The separate heterodyne can be fed from the .:_r,_HOLE same filament battery as is used for the main receiving set, but it is better to employ com- 1.- 3 613A CLEAR pletely separate L.T. and H.T. batteries for the separate heterodyne, especially since only 7A; four volts is required for the filament of the Fig. 5.,S'pringyjend;clip for valve holders. heterodyne and six volts for its H.T. supply. A convenient heterodyne unit for use inby using a hard wood such as mahogany or 200 -metre reception, such as is required for theteak. arrangements outlined above, may be con- The ebonite top is fastened in place with structed in the following manner. The anode in. brass screws (size No. 4), using the outer and grid coils may be wound on the sameholes, marked in Fig. 2.These are shown former, closely adjacent to each other,as as,r7iin.diameter,andaresuitablefor indicated in Fig. t, in which G represents theNo. 4 countersunk or raised head brass screws. grid coil and A the anode reaction coil.IfThey should be countersunk so that the bevelled the diameter of the winding former-whichparts of the screw heads sink in flush with may be a waxed cardboard, or an ebonite tube-the surface of the ebonite. is 24 ins., and its length 24 ins. as shown, the Details of the dimensions of other parts grid coil G should have 45 turns of No. 28required for the construction of the instrument S.W.G. double silk -covered copper wire, wound are given in Figs. 3 to 8.It will be noted with the turns touching so as to occupy a length from this that provision is made for using of 4 in.A space of 4 in. is left between the a V 24 type of valve, which is a very convenient windings, and the anode coil A of 38 turns one to use for an instrument of this type,since 224 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18. 1922 /32 made of thin brass strip about lo in. thick. --I r- Fig. 8 indicates the dimensions of the brass stripusedtoshort-circuitthe" phone " terminals when telephones are not required connected to theset.This, of course,is usually the case when the instrument is used purelyasaseparate heterodyne, but the terminals are very convenient in some cases since the instrument can also be used for many other purposes, such as a C.W. wavemeter, andforcarryingout many simple high - frequency measurements. eEtA CLEAR In Fig. 9 will be found a diagram of the layout of the top of the instrument, with the Fig. 6.Supports for coil former. lettering of the variousterminals, and in only a low value of H.T. voltage is necessary. Fig. 10 a diagram of the connections of the When completed with one of these valves theinstrument between these terminals, the label- instrument will usually oscillate with onlyling of the terminals in this diagram corres- six volts in the high tension battery.If preferred, a holder'for a four -pin valve of the standard French or " R " type may be fitted, instead of the spring clips for the V 24 valve, so that an " Ora " type of valve may be used %INA. with buttriflingalteration to the general Fig. 8.Short-circuiting link. layout of the apparatus.The low capacity of the V 24 valve, however, is advantageousponding with that in Fig. 9.In Fig. 9 it will for this short wave instrument. be noticed that a miniature tumbler switch Fig. 3 gives the details of the side -clips foris shown, to provide a filament switch for the the V 24 valve.They are bent up from thinset.The position of the centre only of this springy phosphor -bronze strip, I in. wide, toswitch is indicated in Fig. 2, as the exact the dimensions shown in that sketch.Theseposition and size of the holes necessary for are the clips marked A and G in Fig. 9. fixing this switch in position, and for allowing The end clips for the valve are shown inthe connecting wires access to its terminals, Figs.4 and5, the former being of h in.will depend upon the particular pattern of brass strip, I in. wide, and the latter, theswitch used.The position of these holes flexible one, of thin springy phosphor -bronzeshould thereforebe marked out after the purchase of this switch.Its outside diameter A jrsif should not exceed about It ins. The terminals used (4 BA) should be screwed [0 °I into the ebonite, and provided with washers r.- and nuts on the underside for the connections. The wiring is most conveniently carried out Fig. 7.Pointer for condenser scale. with bare No. 18 copper wire, covered with insulating sleeving where necessary. strip.The thickness of this strip should not The former on which the anode and grid muchexceedabout5a in.These twocoils are wound is supported from the under clips are those mounted on the right and left-side of the ebonite top by means of the brass hand ends of the valve in Fig. 9 respectively.brackets, of which the dimensions are given In Fig. 6 will be found details of the two brass in Fig. 6. angle brackets used to support the former on The variable condenser has a maximum. which the coils (Fig. 1) are wound.This iscapacity of approximately o00025 microfarad. made of 132 in. brass strip, / in. wide. Two A suitable condenser for this purpose is most are required to the dimensions given. conveniently purchased ready made, but if it is The pointer for the condenser scale (shownpreferred to build it up from standard com- mounted on the right-hand side of the con-ponent parts which are purchaseable at some- denser, in Fig. 9) is shown in Fig. 7.This iswhat cheaper rates than the complete article, NOVEMBER18, 1922 THE WIRELESS WORLD AND RADIO REVIEW 225 The negative lead of the H.T. battery is joined to the positive of the filament battery so that the two combine together in the plate circuit of the valve, giving an effective voltage of ro in that circuit.With this arrangement A care must be taken to keep the grid circuit joined up to the negative end of the filament. This will be the case if the wiring diagram given in Fig. 10 is adhered to.With such an instrument a tuning range of about 170 to 44o metres should be obtained.Care should be taken that the two windings are put on in the same direction, and that the outer end of the 45 -turn coil is joined to the grid of the valve, and the outer end of the other coil to $147,1ABLE the anode-thus making the anode and grid CONDENSER 0-00025g connections to the two extreme ends of the MAXIMUM coils.When in use as a normal heterodyne unit the telephone terminals are not required and should be short-circuited by the link provided.They are only fitted to the instrument to enable telephones to be joined in circuit as a help for calibration purposes, and for other measurements. The two terminals marked " capacity," in Figs. 9 and to, are connected directly across the ends of the variable condenser. A very small single plate or vernier condenser can be TELEPHONES CAPACITY joined across these terminals when desired to aid in fine adjustments of the wavelength. Fig. 9.Luy-out of instrument top. Such an addition is particularly desirable when it will be found convenient to use six fixed and heterodyning these short wavelengths, as the five moving plates of diameters of 2+ ins. andtuning range for maintaining the beat note 2+ ins. respectively.If the plates are L in.within the audible limits is very restricted at inthickness the spacing washers usedto these high frequencies.Such an addition, separate both the fixed and the moving plateshowever, will, of course, alter the calibration should be about it, in. thick. of the instrument should it bedesiredto The fixed bypass condenser of ooi micro -use it as a wavemeter. farad capacity shown in Fig. ro, may be built The readings of the instrument may be up of tinfoil with paraffined paper, or mica,calibrated against a standard wavemeter, so for the dielectric.More conveniently a small astoobtaintheapproximate wavelength Dubilier Type 577 condenser of this capacity corresponding to any scale reading of the con- may be employed, and fixed in place on the denser.Such acalibration,however, will underside of the ebonite top by two smallvary slightly with all changes in the filament screws. and H.T. batteries, and will usually also vary If a four -volt accumulator is connected tosomewhat when the valveischanged.It the L.T. terminals of this heterodyne set nomust be carried out, of course, without any filament resistance will be necessary for the additional fine adjustment or vernier condenser V 24 valve, but if preferred, a six -volt accumu- connected to the " capacity " terminals, as such lator may be employed with a fixed resistancean addition, although very convenient for use, of about r a ohms, mounted inside the hetero- would constitute a serious disturbing element. dyne box. An important point to note when joining An instrument constructed on these linesup the leads inside the instrument is that the with a V 24 valve should oscillate readily overwire from the grid of the valve should be the whole range of the condenser scale withjoined to the fixed platesof the variable six volts connected to the H.T. terminals. condenser, the movable vanes being connected 226 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18, 1922 to the filament of the valve.The potentialoscillator of this kinditisverydesirable of the movable vanes will then be lower,to fit a long handle to the condenser so as to and the presence of the hand when makingenable the hand to be kept further from the

-I- 4V - -I- 6V - LT HT-

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' -) 0.01µ,F

r -1 I FIXED I I I CONDENSER FO )4-4- - t - I

TELEPHONES. -t-CAPACITY

Fig. 10.Wiring Diagram. adjustments will be less serious.This pre-instrument.Any convenient form of such caution will be found of particular value whenhandle can readily be added to this instrument, calibrating the in ;trument. and willaidconsiderablytheeaseof its When accurate work is necessary with an operation. NOVEMBER 18, 1922 THE WIRELESS WORLD AND RADIO REVIEW 227 Signal Rectification A CONSIDERATION OF THE METHODS OF DETECTION. IT is the purpose of these notes to discusstypes of valve will, for a given input voltage, thepossiblemethodsofrectification, produce a larger strength of signal than others. using the three -electrode valve. A suitable choice should be made The high frequency energy input to the Since the apparatus in the anode circuit detector is always modulated, that is, high fre-is an energy operated device, its impedance quency and audible frequency componentsat the simal frequency should approximate are present together in the signal. to that of the anode -filament circuit of the The function of the detector is to transform valve. high frequencyenergytolow frequency Sometimes, when damping is not objected energy :therefore the circuit connected toto, the upper bend of the plate current grid the input of the detecting apparatus is tunedvoltagecurveis used.The meangrid tothe wavelength of the high frequencypotential isfixed, and the filament current energy, and the output circuit is tuned to theis charged until maximum response is secured. low frequency energy.But the output powerA low plate potential is necessary in this case. is not entirely in the signal.A high frequency Now that hard valves are easily procured, component ispresent.The output circuitthe method of rectification which employs of the detecting valve must, then, contain aa grid condenser and leak is used.In this capacity whichwillcarrythiscomponentmethod the grid voltage-grid current charac- of the signal.This capacity is present in allteristic of the valve is made use of, and the output circuits-sometimes in the form ofinputcircuitisproportioned so thatgrid self -capacity, but generally in the form of a currents flow. shunt condenser which has a reactance high Considering the grid condenser connected toaudiblefrequencies,but lowtoradio to the grid without the leak resistance, the frequencies. A condenser of crow mfds. isnegative half wave of a signal will produce suitable.Itsreactanceata frequency ofa positive potential on the plates of the con- r,000,000cyclesper second, correspondingdenser joined to the grid. A current will to a wavelength of 30o metres, is 16o ohms,flow from the filament to the grid, and will and its reactance to a frequency of i,000charge the condenser plates negatively.The cycles per second is 16o,000 ohms. positive half cycle of the signal will further The method of rectification which is mostreduce the negative potential of the grid and easily understood makes use of the curvaturesucceedingpulsesof energywilllikewise of the plate current curve.The grid potentialincrease the negative charge held on the con- is adjusted roughly by connecting small cellsdenser plates connected to the grid.This in the grid circuit, ora finer adjustment isreduction of grid potential causes a reduction made possible with the aid of a potentiometer.inthe normal filament anode currentat Arising from the fact that any appreciable gridaudio frequencies, and the instrument in the current causes damping and a lowering ofplate circuit responds.The grid condenser the input voltage, the grid is usually madeshould, then, have a small capacity, in order negative, and adjustments of anode potentialthat the energy which it receives may result and filament current are made to bring thein the largest possible voltage fluctuations, mean grid potential to the point on the bottomwhich inturnwillgive maximum signal of the plate current grid voltage curve where aenergy in the anode circuit.On the other given signal impressed across the input circuithand, it should not be so small that an ap- produces the greatest mean increase in thepreciable radio -frequency voltage drop takes filament anode current. The rectifying actionplace across it.When " R " valves are used, takes place because a given positive potentialonoo3 mfds. is suitable. To restore the grid incrementtothegridproducesalarger potential to its normal value, a leak is provided increase in anode filament current, than anwhich will allow the charge to leak away equalnegativepotentialcausedreduction,to the filament during the intervals between and it is this balance of energy which is availablesignals.Obviously the leak should have no to operate the instrument connected in thelower resistance than is necessary for it to anode circuit.It is to be expected that someperform its function properly. THE WIRELESS WORLDAND RADIO REVIEW NOVEMBER 18, 1922 Two methods of connection are available.portion of the anode current grid volt curve The leak resistance may be joined directlywill be utilised.The latter adjustments may across the grid condenser, or it may be joinedalso be made to give a steep grid -current grid from the griddirectly with the filament. voltagecurve. Maximum signalstrength The latter method is preferable. will then be secured. Several adjustments for maximum audible Using hard valves, the grid leak and con- energy are possible.The grid potential shoulddenser method of rectification gives results be adjusted so that input potentials will causesuperior to any other. the largest possible filament grid current to Adjustments based upon conclusions reached flow, and the anode potential and filamentafter a study of the static characteristic curves current should be chosen so that the steepestwill not be far wrong. W. J. The Size of Accumulator to Buy Critical Adjustment of WHEN buying an accumulator there Condensers areseveralpointsto which due consideration must be given if the battery is to give satisfactory service.First, one must decide whether one prefers a small and comparatively light affair which must be frequently charged, or a large and ponderous one which will hold a month's supply.This question must be settled by such individual considerations as distance to charging place, strength of one's arms, and so on. Supposing that a small cell is decided upon, the point to be settled next is the safe minimum size, and this demands a knowledge of the current required by valves, and also of the meaning of the term " ampere hour capacity."This last may be best understood from an example.If a battery is said to have a capacity of 20 ampere hours it means thatitwill give a current of 1 ampere for 20 hours, 2 amps. for to hours, 4 amps. for 5 hours, and so on, before requiring recharging.The matter is complicated somewhat by the common practice of rating accumulators at " ignition " capacity, which TYPEWRITER istwicethe" actual "or" continuous " INDIAPUBSER capacity.Thus, if the cell is said to be ofAn easily fitted device for critically controlling the 6o A.H.capacity,baseyourcalculations setting of a condenser.The typewriter rubber upon i amp. for 3o hours, not 6o, unless it makes a friction contact on the bevel of is definitely stated to be " 6o A.H. actual." the condense^ scale. To find the minimum size for a given number of valves allow / amp. of current for each valve, Aerial Insulators and an eight hours discharge rate, since that is the shortest time in which an accumulator should be discharged, whether in one spell of eight hours or in separate shorter ones totalling eight in all. Example :-What is the smallest capacity to supply 4 valves satisfactorily ? Four valves require 3 amps. 3 x 8 = 24 amp. hours. A Novel type of Aerial Insulator with screw cap, Answer :-24 A.H. actual, or say, 5o A.H. providing a convenient method of terminating ignition. G. P. K. and adjusting length of aerial. NOVEMBER 18, 1922THE WIRELESS WORLD AND RADIO REVIEW 2 2 t Electrons, Electric Waves, and Wireless TelephonyVII. By Dr. J. A. FLEMING, F.R.S.

The articles appearing under the above title are a reproduction, with some additions, of the Christmas Lectures on Electric Waves and Wireless Telephony given by Dr. J. A. Fleming, F.R.S., at the Royal Institution, London, in December and January, 1921-1922.The Wireless Press, Ltd., has been able to secure the serial rights of publication, and any subsequent re -publication. The articles are therefore copyright, and rights of publication and reproduction are strictly reserved.

IV -ELECTROMAGNETIC FIELDS, FORCES AND RADIATION.

.-LINES OF ELECTRIC AND MAGNETIC FORCE. In the case of an electrified sphere the lines Before dealing at greater- length with theof electric force radiate from the sphere as problem of atomic structure, it will be necessaryfrom its centre, being equally distributed in to enter into certain elementary expositionsall directions, provided the sphere is at rest. of the nature of electromagnetic fields andFaraday showed by numerous experiments forces and of electromagnetic or so-calledthat itis impossible to createa charge of electric waves. electricity of one kind without creating also Theory showsthat when anelectrified an equal quantity of the opposite kind.Hence sphere or electrically charged body is set inwe must consider that a line of electric force motion in any direction it not only exerts amust be either an endless line or, if not, must force on otherelectrifiedbodiesnearit, have its ends terminated by charges of electricity called electric force, but also when moving,of opposite sign, say, by ending on positive acts on magnets or exerts a magnetic forceand negative electrons respectively, or else along certain directions.In the case of amust start from an electron and be extended small charged sphere in uniform linear motion,to an infinite distance. the lines of electric force are radial and the Thereis,however,aninterconnection linesof magnetic forcearecircles whosebetween lines of electric and lines of magnetic centres lie on the line of motion and planesforce which may be explained as follows are perpendicular toit.The regions near If a line of electric force is moved parallel to electrified bodies or magnets are called electricitself or in a direction at right angles to its or magnetic fields, and in these fields forcesown direction it creates a line of magnetic of attraction or repulsion are exerted on otherforce which runs in a direction at right angles electrified bodies or magnets which are called to that of the line of electric force and to that electricandmagneticforcesrespectively.of the motion of the latter. These forces are exerted along certain straight The relationof thedirections may be or curved linescalledlines of electric ormemorised by means of a " hand rule," as magnetic force.Faraday considered that these follows :Hold the thumb, forefinger and lines of force are not merely ideal lmes likemiddle finger of the right hand in positions lines of latitude and longitude, hut that theymutually at right angles like three co-ordinate have some actual physical existence and are axes.Then let the direction of the forefinger regions in which some special actions in adenote the direction of a line of electric force, universallydiffused medium callednether, and that of the thumb the direction of the are taking place. motion of thislineatright angles toits Hence we may saythat an electricor own direction. Then the direction in which magnetic field has a certain discreteness orthe middle finger points will be the direction atomic structure, and that the space within aof the magnetic force produced by its motion. small tubular region surrounding a line ofIt should be remembered that by usual con- force is in some w' different from the spaceventions the direction of an electric line of outside. force is the direction in which it would cause 230 THE WIRELESS WORLDAND RADIO REVIEW NOVEMBER 18, 1922 a free positive electron or positively chargedwith a velocity v, it has energy called kinetic particle placed on it,to move.Hence foror motional energy associated with it, which anegativeelectronthelinesof electricis in amount equal to ,1,-.mv2 or to half the mass force are directed towards the electron. multiplied by the square of the speed.It If then we consider an electron carrying itscan be proved, though the proof is somewhat system of radial lines of electric force to bedifficult, that when an electrified sphere moves in motion, we see that the result is to surroundwith velocity v it has energy associated with the electron with a family of circular lines ofit measured by magnetic force which all have their centres 4 e21 on the line of motion and all have their planes -3d)v2 perpendicular to it (see Fig. 41). where eis the electric charge, which in the

1 / \ i / I ...\ \ I I I I \ / 1 , \ I 1 / , ... N. \/ N/ 1 II \ I 1 / i c ' i , 1 I N 1 y .... /` / 1 / 1 I 1 \ . I I I / , ''I I 4.. / c I I \ I I '' I i I -I- v 1 I .... I \. I ,/, I II 1 1 I / \ 'I / \r / I I ,',; V ..A- , /I, / \ -"" ..../ / I // \ I / \ ,. I / / -1-"" / I / I Fig.42.Lines of Electric and Magnetic Farce ' 1 around an Electron moving with high velocity.

Fig. 41.Lines of Electric and Magnetic Force roundcase of an electronis1.6 x 10-20 electro- an Electron. magnetic units, or 16/102° Coulombs, and d is the diameter of the sphere or electron. The magnetic force at any point is propor-The letter m signifies the ordinary mass and tional to the velocity and also to the resolved4e2/3d is called the electrical mass. part or component of the electric force which 2.-SIZE AND MASS OF AN ELECTRON. is at that point perpendicular to the direction of motion.It can be shown mathematically The question has been much discussed that when the velocity or speed of the electronwhether the electron has any mass other than approaches that of light, viz., 303,000 kilo-the electrical mass, and certain experiments metres per second, the radiating lines of electricby Kaufmann strongly indicate that it has not. force all crowd up into the equatorial plane, If this is the case then the whole mass m of which is a plane through the centre of thethe electron is represented by the value of 4e electron and perpendicular to its direction of4e2/3d and the diameter d is equal to- -e. motion (see Fig. 42). 3m The radiallinesofelectricforceandBut now we have seen that the ratio of charge embracing circularlines of magnetic forceto mass or elm for an electronisnearly then form a sort of spider's web pattern in1.774 x 107 electromagnetic units and that the thatequatorialplane.Thisiscalled theelectric charge e is 1.6 x 10-2° electromagnetic electromagnetic field of force of the electron.units.Hence the diameter of an electron is 4 This electromagnetic field represents a store- X 1.774 x 1.6 x 10 -"of a centimetre of energy.If a substance of mass m, whether 3 a bullet or a railway train, to be in motionor 0.38 x 10-12 cm, that is about one-third NOVEMBER 18, 1922 THE WIRELESS WORLDAND RADIO REVIEW 231 of a billionth of acentimetre. A millionsixth of an inch. A negative electron is there- times a million electrons, put in a close row, forevery small compared with an atom, would only extend a distance of about one -about one hundred thousandth part of the diameter of an atom.Small however as is the negative electron,the positive electron is probably still smaller. We have seen that ina Hydrogen atom,consisting probably ofasinglepositiveandsinglenegative electron,thenegativeelectroncontributes only 1/1,700th part of the mass.This implies thatif the charge of the positive electron is the same as that of the negative the diameter of the former is only 1/1,700th part of that of the latter. We see, therefore, that the negative electron has a diameter of only about a hundred thousandth part of that of the whole atom and thatthepositiveelectronisperhaps 2,000 times smaller. We are now able to make a pretty clear mental picture of what an atom of matter is like according to the above theory. Imagine a cricket ball suspended in the air. At a distance of 100 or 200 feet or so from it let there be a few dozen grains of dust each not more than 1/100 inch in diameter.Let these grains, representing electrons, revolve round the cricket ball, representing the nucleus in circular orbits, the grains being arranged Fig. 43.A golf ball with radial wires in it to repre- in shells or groups of 2, 3, 4 to 8, in various sent an electron with its electrolines. orbits, up to say 100 feet would suggest what an atom would look like if it

tg. 44.A golf ball with radial wires in it to represent an electron in motion.7 he electrolines crowd up into the equatorial plane. 232 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18, 1922 could be magnified a billion times and be thenelectromagnetic pulse or solitary wave and is viewed from adistance of several hundred also called electric radiation. yards. The same kind of electric radiation will be produced if an electron in uniform motion 3 -ELECTROMAGNETIC WAVES. is suddenly stopped or has its velocity changed Before considering the problems of atomicor suffers acceleration.There are, however, structure at any greater length it may be welltwo kinds of acceleration.Velocity may be at this stage to outline our present views onchanged in amount, but not indirection, the nature of an electric or electromagneticas when a stone is falling towards the earth, wave. We have seen that from an electron we consider lines of electric force to radiate. These lines may for the sake of brevity be calledelectrolines,and we maytherefore picture to ourselves an electron as something like a golf ball in which have been stuck very long straight wires radiating equally inall directions, which wires represent the electro- L_1 lines. These electrolines possess an elasticity of a certain kind.They resist stretching and endeavour to make themselves as short as possible. Infacttheattraction between positive and negative electrons may be regarded as the result of the endeavour of these lines to shrink up in the direction of their length. Also these lines possess a quality equivalent to mass or inertia and the so-called electric mass of the electron to which we have already referred is merely the mass of the entirety of theseelectrolines and of the magnetolines produced by their motion. Suppose then that an electron at rest is caused to make a sudden jump forward. It carries with Fig. 45.Kinks produced on radial electrolines of an it the ends of the electrolines which terminateelectron B when the latter suddenly jumps forward. on it, but the inertia of the line causes the The dotted lines denote the electrolines. rest of the line to be left behind for a moment and the resultis the production of a kink ordislocationinthelines(seeFig.45).or the velocity may be continually changed This kink, however, travels outwards alongin direction but not in magnitude as when the lines as the whole electroline picks upa mass revolves with uniform speed in a circle. the motion. We have, however, seen that theIt appears, for reasons too long to give at this lateral or sideway motion of anelectroline point, that an electron whenrevolving with gives rise to a magnetic force at right angles to constant speed in a circle round a nucleus, itself and to the direction of its' motion. Hence,although in one sense of the term experiencing as the " kink " in the electroline travels out-an acceleration towards the nucleus, isyet wards it is accompanied by lines of magneticnot radiating electromagnetic waves and there- force or magnetolines created by the motionfore not losing energy. On the other hand if of the electrolines. an electron jumps backwards and forwards These two sets of lines are at right anglesin a straight line it does radiate, although the to each other and to the direction of motion.direction of its motion is always in one line. Experimentshowsthatthiskinktravels If then we imagine a number of electrons to outwards with a velocity of 300,000 kilometres be placed in a row in one line and allto per second in empty space or with the velocityjump to and fro in that line through a small of light in any medium in which the electronrange simultaneously, the whole lot of them is placed. would radiate and would produce an electro- This movement of electric and magneticmagnetic wave, the wave surface of which lines of force in the same plane is called anwould be a co -axial cylindricalsheathor NOVEMBER 18, 1922 THE WIRELESS WORLD AND RADIO REVIEW 233 surface to the line of electrons.We shall tionofthe problem of electricradiation see, when we come to discuss the subject ofby the atoms and electrons, it will be necessary wirelesstelephony,thatthisisjust whatto return to the discussion of a few more happens in the case of the aerial of a wirelessmatters connected with the architecture of telephone transmitter. atoms. Before proceeding further with the considera- (To be continued.)

The Switching of L.F. Valves.

By G. P. KENDALL, B.Sc.

yvHEN a set includes one or morenectedtotheplateandtheotherto stagesof low frequencyamplifi- the H.T. positive, and the two inner ones cationitisextremelydesirabletotheintervalvetransformerprimary,it to use just the necessary number of valvesis clear that ifthe phones are connected to toproducethedesiredsignalstrength.a plug we have the desired system of switching. The switching arrangementsto permit ofWhen the plug is inserted in a given jack the

Fig. 1.L.F. Valves.Four -point break jack and plug. this being done must be designed with somephones are connected into the plate circuit care to avoid loss of efficiency from dead-of the valve, while the intervalve transformer end effects and interaction between circuits.is disconnected, thus cutting off the succeeding In most cases the best solution of the problem(unused)valves.When the plugiswith - is the use of two -pole plug and four -spring break jack, provided that they are correctly used. Fig. t shows the arrangement of plug and jack. The four spring -strips of which the jack is composed may be conveniently referred to as the outer and inner springs,two of each.The outer ones are of unequal length and have their ends bent in such a way as c> c> c> to facilitate the introduction of the plug, and c> 401. to cause one of them to make contact with the c> ball, and the other with the tubular part. c> The inner springs make contact through two corre- pairs of platinoid points withthe Fig. 2.Method of connecting jacks in L.F. sponding outer ones when the plug is out of Amplifier Circuit. the jack.When the plugisinsertedthe outer springs are pushed apart and thusdrawn theintervalvetransformerprimary disconnectedfromtheinnerones. If,is brought back into the plate circuit and the then, a jack isplaced in the plate circuitnext valve comes into action.This will be of each valve, with one outer spring con -readily understood from Fig. 2. 234 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18, 1922

Some Recent Developments of Regenerative Circuits.*

By EDWIN H. ARMSTRONG.

IT is the purpose of this paper to describe a In the second case the negative resistance is method of amplification which is based funda-equal to the positive resistance, and the resultant mentally on regeneration, but which involveseffective resistance of the circuit is therefore zero. the application of a principle and the attainmentWhen an E.M.F. is suddenly impressed in this of a result which it is believed is new.This new case, the current in the circuit starts to increase result is obtained by the extension of regenerationat a rate which is directly proportional to the im- into a field which lies beyond that hitherto con-pressed electromotive force and to the square sidered its theoretical limit, and the process ofroot of the ratio of the capacity to the inductance amplification is therefore termed super -regeneration.of the circuit (for a given impressed frequency). before proceeding with a description of thisIf the forceis impressed for an infinite time, method it is in order to consider a few fundamentalthen the current in the circuit reachesinfinity. facts about regenerative circuits.It is well knownIf the E.M.F. is impressed for a finite time, then the that the effect of regeneration (that is, the supplyingcurrent reaches some finite value.When the im- of energy to a circuit to reinforce the oscillations existingtherein)isequivalenttointroducing a negative resistance reaction in the circuit, which neutralises positive resistance reaction, and thereby reduces the effective resistance of the circuit. There are three conceivable relations between the negative and positiveresistances :namely-the negative resistance introduced may be less than the positive resistance, it may be equal to the positive resistance, or it may be greater than the positive resistance of the circuit. We will consider what occurs in a regenerative circuit containing inductance and capacity when an alternating electromotive forceof the resonant Fig. 2. pressed E.M.F. is removed, the current in the circuit at that instant continues indefinitely with unchangedamplitudeasafreeoscillation. Theoretically, this is the limiting case for regeneration ; practically it is always necessary to operate at some point slightly below this state at which the circuits have a definite resistance. It is important to note here that although the circuit of this case has zero resistance, oscillations I will not start unless an E.M.F. is impressed upon Fig. 1. frequency is suddenly impressed for each of the three cases.In the first case (when the negative resistance is less than the positive), the free and forced oscillations have a maximum amplitude equal to the impressed electromotive force over the effective resistance, and the free oscillation has a damping determined by this effective resistance. The steady state is attained after the initial free oscillation dies out and continues until the impressed E.M.F. is removed, when the current dies out in accordance with a second free oscillation.The maximum amplitude of current in this case is always finite ;it reaches this maximum amplitude in a finite time, and when the impressed E.M.F. is removed the current dies away to zero.This is the action of the circuits which are now in everyday practical use. Fig. 3. the circuit;furthermore, that oscillations once * Abstract ot a paper read before THE INSTITUTE startedcontinue with undiminished amprtude OF RADIO ENGINEERS, New York, June7th,indefinitely.This state cannot be attained in 1922. practice, because the negative resistance furnished NON -EMBER 18, 1922 THE WIRELESS WORLDAND RADIO REVIEW 235 by the tube is dependent on the amplitude of the It is important to note that although the nega- current and for stable operation decreases with tive resistance of the circuit exceeds the positive, increasing amplitude. t and the effective resistance of the circuit is negative, In the third case the negative resistance intro-oscillations will -not occur until some E.M.F.is duced into the circuit is greater than the positive impressed.Once an E.M.F. is impressed, however, resistance, and the effective resistance of the circuit no matter how small it may be, the current in the circuit is therefore negative. When an E.M.F. is impressedbuilds up to infinity regardless of whether or not the upon a circuit in this condition, a free and a forcedexternal E.M.F. is removed. oscillation are set up which have some interesting The fundamental difference between the case properties.The amplitude of the forced oscillation in which the resistance of the circuit is positive is determined by the value of the impressed E.M.F.and the case in which the resistance of the circuit divided by the resultant resistance of the circuit.i- negative may be summed up as follows :in the The freeoscillationstarts with an amplitudefirst, the forced oscillation contains the greatest equal to the forced oscillation, and builds up toamount of energy and the free oscillation is of very infinity regardless of whether or not the externalminor importance: (after a short interval of time), in the second, it is the free oscillation which contains the greatest amount of energy and the forced 1,1VVv\ANINV oscillation which is of negligible importance. Itisof course impossible, owing to practical limitations,toset up a system in which the negative resistance exceeds the positive without the production of oscillations in the system, since any irregularity in filament emission or impulse produced by atmospheric disturbances is sufficient to initiate an oscillation which builds up to the carrying capacity of the tube.Itis,however, possible, by means of various expedients, to set up systems which avoid the production of such a paralysing oscillation and which approximate the theoretical case in the use of a free oscillation to produce amplification. The first use of the free oscillation in a regenera- 6 tive system for the amplification of signals appears to have been made by Turner§ in his valve relay system.Briefly, Turner prevented the regenerative 1N\f, <1 circuit from producing oscillations when no signals

Fig. 4. E.M.F.isremoved. This freeoscillationstarts with an amplitude which is proportional to the impressed force, and this proportionality is maintained throughout any finite time interval (with constant impressed electromotive force).

Fig. 6. were being received by placing a negative potential on the grid of sufficient value to hold it just below that point on the characteristic curve at which Fig. 5. self -oscillation would start.The impressing of a small electromotive forceofsufficient value t It is very important at this point to distinguishwould carry the potential of the grid over the between this purely theoretical state and the state which exists in oscillating tube circuits.In the" threshold " value and a free oscillation would various forms of self -heterodyne circuits a freestart which would build up to the limiting value oscillation of constant amplitude is maintained This is strictly true when dealing with continu- in the system and the circuit may be consideredous waves which we have been considering.It as having zero resistance, but only for that particularis not true in the regenerative reception of spark amplitude of current. An external E.M.F. impressedsignals,particularly of short wavelength, large on the circuit always encounters a positive resultantdamping, and low spark frequency.In this case resistance, assuming, of course, that the existingthe energy in the free oscillation exceeds the energy oscillation is stable.This is due to the non-linearin the forced oscillation. characteristic of the tube. § British Patent, 130,408. 236 THE WIRELESS WORLDAND RADIO REVIEW NOVEMBER 18, 1922 of the tube.The system was returned to its initialfree oscillations which are set up during the periods sensitive state by means of a relay operated by theof negative resistance are directly proportional in increase in the plate current of the tube.This amplitude to the amplitude of the impressed relay short-circuited the feed -back coil, therebyE.M.F.The variation in the relation between the cutting off the supply of energy and permittingnegative and positive resistance may be carried the potential of the grid to drop back below theout by varying the negative resistance with respect " threshold "value.As Turner explains,theto the positive, by varying the positive resistance device is a relay with a low limit (as distinguishedwith respect to the negative, or by varying both from an amplifier), but it appears to be the first simultaneously at some frequency which is generally device in which the free oscillation set up by anrelatively low compared to the frequency of the impressed electromotive force produced the magni- current to be amplified. fied result. These three methods of producing the super - Bolitho* contributed an important improvementregenerativestateareillustratedrespectively by replacing the mechanical relay of Turner which by Figs. 1, 2, and 3, which figures indicate the general operated only upon the receipt of a signal by a valvescheme of the system and the methods of varying relay which was continuously operated by indepen- the relation between the negative and positive dentmeans.Briefly,thiswasaccomplished resistance.Fig.1 shows a method of varying by connecting a second valve to the oscillatingthe negative resistance produced by the regenerative circuit of the Turner arrangement with a reversedsystem by varying the voltage of the plate of the feed -backconnection and supplying the plateamplifying tube by means of a second tube, the circuit of this second valve with alternating current. grid of the second tube being excited by an E.M.F. When the" threshold " value of the first tube of suitable frequency. was overcome and a free oscillation started in the Fig. 2 illustrates a method of varying the positive system, the reversed feed -back of the second tuberesistance of the circuit with respect to the nega- comes into action and at that time when the voltage tive.This is accomplished by connecting the plate supplied to the plate is positive, damps out the free oscillation and permits the grid of the first tube to return below the " threshold "value. This represents the second step in the utilisation of the free oscillation for the production of amplification. It is the purpose of this paper to describe a principle of operation based on the free oscillation which is quantitative and without a lower limit. This new method is based on the discovery that if a periodic variation be introduced in the relation between the negative and positive resistance of a circuit containing inductance and capacity,in such manner that the negative resistance is alternately greater and less than the positive resistance,

Fig. 8. circuit of a vacuum tube in parallel to the tuned circuit of the regenerative system and exciting the grid by an E.M.F. of suitable frequency.Fig. 3 illustrates a combination of these two systems in which simultaneous variations are produced inboth the negative and positiveresistances and provision made for adjusting the relative phases of these two variations. A general idea of the phenomena occurring in these systems when an E.M.F. is applied to the input circuit will be obtained from the diagram of Fig. 4, which applies specifically to the circuit of Fig.1. This figure illustrates the principal relations existing in the system in which the positive resistance is constant and the variation isintroduced into the negative resistance.It ig. 7. will be observed that the frequency of variation but that the average value of resistance is positive,appears as a modulation of the amplified current then the circuit will not of itself produce oscillations, so that the output circuit contains currents of the but during those intervals when the negativeimpressed frequency plus two side frequencies resistance is greater than the positive will producediffering from the fundamental by the frequency great amplification of an impressed E.M.F.The of the variation. Oscillograms of the essential current and voltage * British Patent, 156,330. relations existing in the systems of the type illus- NOVEMBER18, 1922 THE WIRELESS WORLD AND RADIO REVIEW 237 trated by Figs.1 and 2 were obtained with thephenomena involved will be analysed in a later apparatus connected as shown in Figs. 5 and 6,part of the paper. respectively.InthearrangementofFig.6, The rate of variation in the relation between in order to produce sufficient variation in thethe negative and positive resistance is a matter positive resistance of the tuned circuit, which wasof great importance.It may be a sub -audible, of large capacity and low inductance,itwas audible, or super -audible frequencies.In radio necessary to use a two -electrode tube in series with the auxiliary E.M.F. Figs. 7 and 8 are oscillograms respectively for a negative resistance variation and a positive resistance variation.The signalling E.M.F. was impressed about half way along the film, the exact point at which the key was closed being indicated by the arrow.These oscillograms show phenomena which are in accordance with the explanations already given, but, in addition, show evidence of self excitation.It has been stated in the preceding pages of this paper that the basis of super -regeneration was the discovery that a variation in the relation between the negative and positive resistances prevented a system which would normally oscillate Fig. 11. violently from becomingself -exciting.An ex-signalling,for the reception of telephony, the amination of the oscillograms will show that thisvariation should be at a super -audible frequency. is not strictly true, as a free oscillation starts everyFor modulated continuous wave telegraphy and time the resistance of the circuit becomes negative.spark telegraphy, to retain the tone characteristics It will be observed, however, that this free oscilla-of the signals, it must be well above audibility ; tion is small compared to that produced by thefor maximum amplification a lower and audible signal, and therein lies the complete explanationrate of variation should be used.In continuous of the operation of the system. The free oscillationswave telegraphy, where an audible tone is required, produced in the system when no signalling E.M.F.the variation is at an audible rate ; where the opera- is impressed, must be initiated by some irregularitytion of an indicating device is required, a sub - of operation of the vacuum tubes, and must startaudible frequency may be best.The choice of at an amplitude equal to the amplitude of thisfrequency is a compromise, particularly in telephony, disturbance.This initial value is of infinitesimalsince obviously the lower the frequency the greater order, and hence, in the limited time interval inthe amplification, and the higher the frequency which it can build up the locally excited oscillation,the better the quality. never rettches an amplitude comparable to the Some practical forms of circuits are illustrated oscillation set up by a signal of any ordinaryby Figs. 9, 10 and 11, which illustrate respectively working strength. the three types of variation.Fig. 9 shows a method

Fig. 9. There is a second point of interest which isof varying the plate voltage of the amplifying tube most evident from the curves of Fig. 7.It willR by means of the vacuum tube oscillator 0 coupled be observed that there is a decided lag in the maxi-into the platecircuit.In this arrangement a mum value attained by the free oscillation setthird tube D acts as a detector.This is essential up by a signal and maximum value of plate voltagewhen an audible frequency is employed ;when a (negativeresistance)oftheamplifyingtube.super -audible frequency is used the telephones can This is most evident from the plate current curve.be placed directly in the plate circuit of the ampli- Itisa point of considerable interest, and thefying tube. Fig. 10 shows the second case in which the varia- tionisintroduced into the positive resistance of the tuned circuit.This is done by means of an oscillating tube 0, the grid circuit of which is connected through the tuned circuit LC of the amplifying tube R.The variation in the resistance of the circuitis effected through the variation in potential of the grid of the oscillating tube. During that half of the cycle, when the grid of the oscillating tube is positive, energy is withdrawn from the tuned circuit in the form of a conduction current from the grid to the filament of the oscillating tube, thereby increasing the effective resistance Fig 10 of the circuit.During the other half of the cycle, C -a 238 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18, 1922 when the grid of the oscillating tube is negative,in the tuned circuit to insure the dying out of the no conduction current can flow through the grid freeoscillationduring theinterval when the circuit of the oscillating tube, and hence no resistance resistance of the circuit is positive.This is most is introduced into the tuned circuit of the amplifying effectively carried out by means of the arrangement tube.In this case the amplifying tube servesillustrated in Fig. 13, in which a secondary coil also as the detector for any frequency of variation, L1 of large inductance and high resistance is coupled as the tuned circuit forms a sufficiently good filterto the tuned circuit LC and the energy withdrawn even for an audible frequency to prevent a dis-thereby from the oscillating circuit stepped up turbing audible tone in the telephones. and applied to the grid of the tube.In the opera- Fig. 11 illustrates the case of a simultaneoustion of this system, a curious phenomena is en- variation in both positive and negative resistances. countered.This is the manifestation of an induc- This is accomplished by providing the amplifyingtive reaction by the plate circuit of the amplifying tube R with a second feed -back circuit L1C1 andtube to the auxiliary frequency E.M.F. supplied L202 adjusted to oscillate at some lower frequency, the plate circuit by the oscillating tube, which thereby introducing a variation in the negativecomes about in the following way :When the resistancethrough thevariationoftheplate auxiliary E.M.F. is impressed upon the plate of the potential of the amplifier and a variation in theamplifying tube, a currentis produced in this positive resistance by means of the variation of theLube in phase with the E.M.F. across the tube. grid of the amplifier.The proper phase relationsNow suppose the plate voltage is at its maximum betweenthenegativeandpositiveresistance positivevalue.This means that the negative are obtained by adjustment of the capacity of resistance of the circuit is a maximum in amplitude. condensers C1 and C2 and the coupling between This in turn means that the average value of the grid is becoming more positive and the current in the plate circuit is likewise increasing.Since the free oscillation in the system will increase in amplitude as long as the resistance of the circuit is negative, it will reach its maximum amplitude after the maximum positive voltage is applied to the plate. Hence the component of current corresponding to the frequency of the variation set up in the plate circuit by the rectification of the radio frequency - oscillations lags in phase behind the auxiliary E.M.F. impressed on the plate.Hence the plate circuit of the tube manifests an inductive reaction to Fig. 12. the auxiliary E.M.F.It was found that this inductive reaction could be tuned out by means of the L, and L2. In operation this system is very critical, parallel condenser C1 with a great improvement and extreme care is necessary in order to obtainin the stability of the operation of the system and the super -regenerative state. increase in the signal strength.The resonance In each of the preceding cases the detectingpoint is pronounced, and once the other adjustments function has been carried out either by a separate of the system have been correctly made is as tube or by means of the amplifying tube.When readily found as any ordinary tuning adjustment. a super -audible frequency of variation is employed, The problem of cascade amplification with these it is sometimes of advantage to perform the detect- systems is a rather involved one on account of a ing function in the oscillating tube, and an arrange- great number of effects which are not encountered ment for carrying this out is illustrated in Fig. 12. inordinary methods ofcascade amplification. The operation of this system is as follows :in- The principal trouble is the reaction of the second coming signals are amplified by means of the regenerative action of the amplifier tube R and the variationsof potential across the tuned wave frequency circuit LC impressed upon the grid of the oscillating- tube 0.These oscillations are then rectified, and two frequencies are produced in the circuits of the amplifier tube.One of these frequencies corresponds to the frequency of modulation of the signalling wave.The other corresponds to the frequency of the variation and contains Fig. 13. a modulation in amplitude corresponding to the modulation of the transmitted wave.This second amplifying system on the first, and the difficulty frequency is then impressed upon the circuitsof preventing it in any simple way on account of of the oscillating tube with which it is in tune, thehighamplificationperstage.Whilethis amplified by the regenerative action of the systemdifficulty is not insuperable, a simple expedient LiCIL,O, and then rectified.The amplificationmay be employed which avoids it.On account obtainable with this form of system is considerablyof the large values of radio frequency energy in greater than thatofthesingleamplificationthese amplifying systems, the second harmonic circuits, butis naturally more complicated tois very strong in the plate circuit of the amplifying operate. tube and is of the same order of magnitude as the When a super -audible variationis employedfundamental if the tube is operated with a large in a system such as illustrated in Fig. 1, it is generallynegative voltage on the grid.Hence by arranging necessary to introduce a certain amount of resistancethe second stage of a cascade system to operate at NOVEMBER 18, 1922 THE WIRELESS WORLDAND RADIO REVIEW 239 double the frequency and to amplify this harmonic, million times greater than that obtainable with a the difficulty is avoided.The general arrangementsimple self -heteorodyne circuit is readily secured. of such a system is illustrated by Fig. 14, in whichWhere a super -audible frequency is used for the the positive resistance of the circuits LC and L1C1reception of telephone signals,amplificationof of a two -stage amplifier are varied synchronouslyfifty thousand to one hundred thousand times by a single oscillator.The circuit LiC, in this energy can be obtained. case is tuned to the second harmonic of the circuit In a practical way the relative amplication of LC, but the combinations of circuits which may bethe new system with respect to the standard arranged on this principle are very numerous. One of the curious phenomena encountered with the super -regenerative system is found when it is attempted to secure sharp tuning by the use of tuned circuits placed between the antenna and the amplifying system.The free oscillations set up in these circuits by the reaction of the amplifying system continue in these circuits during the interval when the resistance of the amplifier circuitis positive, re -excite the amplifier when the resistance becomes negative, and hence the entire system is kept in a continuous state of oscillation.The effect is most critical, and may be produced with most extremely weak couplings between the amplifier circuit and the second tuned circuit.The simplest solution of the difficulty is to perform the function of tuning at one frequency and amplification at another, and thisisbest accomplished by means of the super -heterodyne method illustrated Fig. 14. by Fig. 15.This may be adapted to work on either the sum or difference frequencies, but when theregenerative system for reception of telephone higher frequency is used, care should be taken signals may be visualised as follows.With a signal that it is not near the second harmonic of the local so extremely weak that only the faintest of beat heterodyning current.In the particular arrange-notes can be heard in the ordinary regenerative ment illustrated, LCD represents, together with thereceiver, the super -regenerative receiver will give heterodyne, the usual agency for changing the clearlyunderstandablespeech.Forsignalsof incoming frequency, and A represents the super - sufficient strength to be understandable with the regenerative amplifier which may be of any suitable ordinaryregenerativesystemwithzerobeat type. adjustment but not audible without local oscillations, Some of the results obtained in practice with the super -regenerative receiver will produce signals super -regenerative systems compared tosimple loud enough to be heard throughout the room. regenerative systems may perhaps be of interest. Perhaps the most surprising characteristic of the In general, it may he stated that the amplificationsystem, apart from the amplification, is its selec- which can be obtained varies with the frequencytivity with respect to spark interference when a of the incoming signal and with the radio of the super -audiblefrequencyofvariationisused. wave frequency to the auxiliary frequency.The The explanation of this selectivity with respect, higher the signalling frequency and the greater for example, to the ordinary regenerative receiver, the ratio of this frequency to the auxiliary frequency, lies in the periodic suppression of all free vibrations A

.,010Erna Fig. 15. the greater the amplification.Other things being in the system.In the ordinary regenerative system equal,it appears that the energy amplificationspark interference approximates a form of shock varies as the square of the ratio of the signallingexcitation setting up a free vibration in the system frequencytotheauxiliaryfrequency. Hencewhich, because of the low damping existing therein, itfollows that for telegraphic signals where an continues for a long period of time.An examina- audible auxiliary frequency is used, much greater tion of the character of the oscillation set up will amplification can be obtained than in the case show that the energy existing in the free vibration of telephony, where a super -audible auxiliary fre-after the initial impressed electromotive force is quency must be employed.Using the arrangement removed, is far greater than the forced vibration. of Fig. 11 for a signalling frequency of five hundred In the ordinary system this free vibration may thousand cycles, an energy amplification several exist for a thousandth of a second or more.In the 240 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18, 1922 super -regenerative system this free vibrationis with the arrangements of either Figs.11 or 12 damped out before it has proceeded more than oneare still heard loudly if the loop is discontinued twenty thousandth of a second as a maximum. from the receiver, the coils and wires of the receiver Hence the interference from spark signals is greatlyitself collecting sufficient energy to produce response. reduced.This phenomenon opens up a new field While the new system does not amplify the for the suppression of interference produced byordinary spark signal with anything approaching shock excitation. its efficiency on continuous wave signals, one ex- At the present time, on a three-foot loop antenna ample of spark reception may be ofinterest. located twenty-five miles from the station WJZDuring the past winter an amateur spark station at Newark, New Jersey, and a system of the typelocated at Cleveland, Ohio, and operating on a illustrated in Fig.12 with one stage of audio -wavelength of about 340 metres was received frequency amplification (three tubes inall) thenightly at Yonkers, New York, on a three-foot announcements and musical selections are clearly(1 metre) loop, and the arrangement of Fig. 13 audible five hundred yards from the receiver.Withwith sufficient intensity to enable the signals to the same loop at the same distance, using thebe read throughout the room. arrangementofFig.11 without the separate In conclusion, I wish to express my very great detector tube, that is with the telephones directlyindebtedness to Professor L. A. Hazeltine for much in the plate circuit of the amplifier tube, it is possiblevaluable aid in connection with the theoretical to 'operate a loud -speaking telephone so that theside and to Mr. W. T. Russell for his assistance programme from the Newark station is plainlythrougholt the experimental side of this develop- heard through a large size room.The signalsment. Broadcasting Commences. The followingstatementwasissued by the Broadcasting Committee on Monday, November 13th. " Pending the formation of the British Broadcasting Company, which will be completed in a few days, the Broadcasting Committee has decided to commence a limited nightly programme from the London Station.This will consist of two copyright news bulletins and official weather reports, broadcast at 6 and 9 p.m. on a wavelength of 36o metres. " The first two bulletins will be broadcast to -morrow, Tuesday evening. Special messages indicating the progress of the General Election will be broadcast asreceived on Wednesday and Thursday; evenings."

Broadcastingand the Lord Mayor's Show. The accompanying photograph ' shows the interiorofa Daimler car fitted with wireless receiving apparatus by the Marconi Com- pany.This car took part in the processionofthe Lord Mayor's Show on Thursday, November 9th. During the procession communi- cationsweresentfrom2 LO (Marconi House) and being received on the car were broadcasted from a loud speaker in the car. We understood from reports of the reception of these transmissions in different parts of this country that the band music of the procession was also distinctly audible during the time that the procession was passing in the neighbourhood of Marconi House. The Receiving Set, which was connected to a frame aerial carried on the roof of the car. NOVEMBER 18, 1922 THE WIRELESS WORLD AND RADIO REVIEW 241 Notes. Manchester Society and Transatlantic Tests.An Interesting Photograph. Manchester Wireless Society is conducting four The photograph on this page shows Dr. Charles special tests during November with a 1 kW. spark P.Steinmetz,chief consulting engineer of the set.The times are from 1 a.m. to 7 a.m. G.M.T. General Electric Company, with Mr. Thomas A. each Sunday morning, the actual transmissions Edison.Dr.Steinmetzisshowinghisfellow being for the duration of the first 15 minutes in each hour.5 MS is the call sign. Six New Canadian Stations. With the primary object of keeping Federal officials in touch with one another, six new wireless stations are proposed to be erected by the Govern. ment of the Dominions of Canada.The following sites are mentioned :Fort Smith, Fort Resolution, Fort Simpson, Fort Norman, Fort Macpherson (all Mackenzie River), and Dawson City. Messages from Amundsen. It is -reported that the arrangement with Captain Amundsen and a chain of wireless stations for the transmission of daily messages has not been carried out.Amundsen'sship,the" Maud," wasto transmit via Nome, Alaska, and the East Coast of America, to the Eiffel Tower.Messages were to bereceivedby the Norwegian Meteorological InstitutefromOctober15thonward. A few messages were received, and have been duly passed on by the Eiffel Tower.Investigation is being carried out with a view to finding the break in the chain. Glasgow Exhibition. A highly successful exhibition was held by the Glasgow and District Radio Club, in the McLellan Galleries, Sauchiehall Street, Glasgow, on Saturday, DrCharles P. Steinmetz and Thomas A. Edison November 4th.The special features were the large examining a shattered High Tension Insulator. Trade Show, the latest apparatus being exhibited by about twenty firms, the local firms being very scientist some broken porcelaininsulators and prominent.The Club Members' Show was also broken pieces of a tree limb which a few minutes fairlylarge,alltypes of ancient and modern before he had shattered during special high voltage apparatus were on view, and the workmanshiptests.The demonstration took place on October of some was of high order. 18th, at Schenectady, during Edison's firstvisit Specialtransmissions from Paris and Northolt in 25 years. were received at 4 and 7 p.m., both wishing the Club every success.The set used for the receptionRoyal Air Force Wireless School and Squadron. of these messages was built by one of the Club A Re -Union Dinner for Past and Present Officers members who is totally blind.It is in the form of the Wireless School and Squadron will be held of a bureau with lid, and has a three -valve setat the Holborn Restaurant, London, at 7 p.m. containing one H.F., one detector and one "L.F. for7.30 on Wednesday, December 6th,1922. The workmanship and general finish of the set Full particulars and tickets,price 15s., may be is splendid, and gives particularly good signals. obtained from F/0 E. Taylor, Electrical and Wire- Concerts were transmitted at regular intervalsless School, R.A.F., Winchester, Hants. all day from an adjoining hall, and received in loud speakers and head phones at a number ofPublic Demonstration at Birmingham. the exhibitors' stands in the main hall.By 3 o'clock At the Solihull Public Hall, Birmingham, on the hall was so packed that it was found necessary November 18th, a public demonstration of telephony to stop admitting visitors for a short time.Pro- is being given in aid of Solihull Allotment Holders' fessor Howe's lecture on " Wave Transmission " Association and the Birmingham Mail Christmas was a great success. Tree Fund. During the day about 100 names were taken, practically doubling the Club membership. Mr. A. P. M. Fleming at the Manchester The office bearers and Committee beg to thank School of Technology. all members and others who contributed to the Mr. A. P. M. Fleming lectured before an audience success of theexhibition, especially the artistesof over 600 on November 3rd at the Manchester who so kindly gave their services in the transmitting School of Technology.His subject was " Radio room. Telephony, with Special Reference to Broadcasting." 242 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18. 1922 Calendar of Current Events BROADCASTING.-An important announcement concerning thecommencement of Broadcasting appears on p. 240. Friday, November 17th. Thursday, November 23rd. BELVEDERE AND DISTRICT RADIO AND SCIENTIFIC LUTON WIRELESS SOCIETY. SOCIETY. At 8 p.m.At Hitchin Road Boys' School. Lecture on " Valve Control," by Mr. W. F. Ellis. Practical Work and Experiments. SUTTON AND DISTRICT WIRELESS SOCIETY". NEWCASTLE AND DISTRICT AMATEUR WIRELESS At the Sutton Adult School, Benhill Avenue. ASSOCIATION. Demonstrationinaidof London Hqgpitals. At 7.30 p.m.At Armstrong College.Lecture on Transmissions by Marconi House, at 5 to 7 p.m. " The Singing Arc," by Dr. Thornton (Members LEEDS AND DISTRICTAMATEUR WIRELESS of other local societies welcome). SOCIETY. DERBY WIRELESS CLUB. At 7.0 p.m.At the Grammar School.Lecture At7.30p.m.At" The Court,"Alvaston. on Inductance and Capacity," PartI,by Lecture on " H. F. Currents," by Mr. F.J. Mr. W. G. Marshall. Allen. BRADFORD WIRELESS SOCIETY. Cinema Display. Friday, November 24th. LEEDS AND DISTRICT AMATEUR WIRELESS SOCIETY. Sunday, November 19th. At 8p.m.Demonstrationof" Burndept Daily Mail Concert from the Hague, 3 to 5 p.m. Apparatus," by Messrs. Townend and Phillips. on 1,085 metres. WIRELESS SOCIETY OF HULL AND DISTRICT. Monday, November 20th. At 7.30 p.m.Sale of Surplus Apparatusat ILKLEY AND DISTRICT WIRELESS SOCIETY. the Signal Corps H.Q., Park Street. At 7.30 p.m.At Regent Café. Lecture on " Maritime Wireless Communication," by Mr. D. E.Pettigrew. Correspondence NORTH LONDON WIRELESS ASSOCIATION. To the Editor of THE WIRELESS WORLD Lecture on " Telephone Headgear :Construc- AND RADIO REVIEW. tional," by Mr. H. Norman Wilson. SIR,-I believe the simple circuit shown will be Tuesday, November 21st. helpful to many of your readers who possess Transmission of Telephony at 8 p.m. on 400 powerful receiving sets. metres, by- 2 MT Writtle. PLYMOUTH WIRELESS AND SCIENTIFIC SOCIETY. V At the Technical School.Lecture on " The ArmstrongSuper -RegenerativeCircuit,"by Mr. P. Arberry. RADIO SOCIETY OF BIRKENHEAD. At 8 p.m.At 36, Hamilton Square.Opening meeting and Demonstration. LOWESTOFT AND DISTRICT WIRELESS SOCIETY. Lecture and Demonstration on the " Armstrong Super Circuits," by Messrs. Burcham and Garrood. Wednesday, November 22nd. WIRELESS SOCIETY OF LONDON. At 6p.m.At the InstitutionofElectrical Engineers, Victoria Embankment, W.C.Special Meeting to consider change of name, and other business.Following, Mr. G. G. Blake will give ashortpaperon" A MechanicalModel Illustrating the Action of the Three -Electrode Valve."Mr. Maurice Child willalso give a short paper on a " Five -Valve Selective Amplifier." MANCHESTER WIRELESS SOCIETY. At 7.30 p.m.In the Council Chamber, Houlds- worth Hall.Discussion. REDHILL AND DISTRICT Y.M.C.A. WIRELESS SOCIETY. At111,Station Road,Redhill.Lecture on " Operating," by Mr. Ross. Capt. Wood Smith also shows the leak circuit con- HALIFAX WIRELESS CLUB AND RADIO SCIENTIFIC nected between the aerial and earth leads. SOCIETY. These multivalve sets, admirably adapted for the At 7.30 p.m.Lecture. receptionof weak signals and telephony, are MALVERN WIRELESS SOCIETY. hard to reduce in tone volume (and sometimes Lecture on " Electro Magnetism and Inductance," oscillation) when receiving powerful transmissions by Mr. H. J. B. Martin. at short distance. R. F. WOOD SMITH, F.C.S. NOVEMBER 18, 1922 THE WIRELESS WORLD AND RADIO REVIEW 243 Wireless Club Reports NO T E.-Under this heading the Editor will be pleased to give publication to reports of the meetings of Wireless Clubs and Societies.Such reports should be submitted without covering letter in the exact form in which they are to appear and as concise as possible, the Editor reserving the right to edit and curtailthe reports if necessary. The Editor will be pleased to consider for publication papers read before Societies. An Asterisk denotes affiliation with the Wireless Society of London. Correspondence with Clubs should be addressed to the Secretaries direct in every case unless otherwise stated. Fulham andChelsea Amateur Radio and the Chairman made a rough blackboard sketch of Social Society.* this circuit.Other questions were satisfactorily Hon. Secretary, Mr. R. Wood, 48, Ramble Street, dealt with.Two new memberswereelected Fulham, S.W.6. during the evening, bringing the present member- The attendance on October 24th was very ship to over 80.The Society consider that the satisfactory.New members continue to enroll. number should be at least 200, and that it would The Secretary gave the members a diagram of a pay every experimenter to join. single valve circuit that produces louder signals Members are specially asked to note that on and is devoid of all " howl," the oscillations them- November 24th a sale of members' surplus apparatus selves being hardly audible. will be held at 7.30 p.m. A short but interesting lecture was given by Mr. In view of a suggestion of the Wireless Society of Hubbard, a member, on " Elementary Electricity." London with regard to a change of name and The remaining part of the evening was devoted to constitution, the question of obtaining a supply of humorous wireless stories ranging from " Firegrate printedrulesandmembershipcardsis in Aerials " to " Dustbin Earths." abeyance pendingfurther information onthis Total membership now numbers 87. point. HALIFAXEXHIBITION.

A corner of theExhibition Room. Wireless Society of Hull and District.* The Belvedere and District Radio and Scientific Society.* Secretary's Address, 79, Balfour Street, Hull. Hon. Secretary, Mr. S. G. Meadows, 1, Kentish There was only a fair attendance at the monthly Road, Belvedere, Kent. Questions and Answers evening, October 27th. At the Erith Technical Institute on Friday, Mr. Hy. Strong (acting Vice -President) was in the October 27th, the ninth general meeting was held. chair.Routinebusinesswastransacted,and Morse instructionandpracticeprecededa matters arising from written questions discussed. short lecture on " Graphs and their Application," The question of the restriction of reacting circuits by Mr. T. E. Morriss.Mr. S. Burman also spoke directly coupled to the aerial was considered, and on " The Detector and Low Frequency Unit." the opinion of most members was that the Phillips giving many valuable hints on the practical con- rejector circuit was a good one to use.By request structionofthisunit. 244 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18, 1922 North London Wireless Association.* Wolverhampton a District Wireless Society.* Assist. Hon. Secretary, Mr. Frank S. Angel, Hon. Secretary, Mr. J. A. H. Devey, 232, Gt. Northern Polytechnic, Holloway Road, N. Brickkiln Street, Wolverhampton. On October 23rd, a lecture was delivered by At the meeting on October 25th, a most instruc- Mr. Power on " Microphones." tive lecture was given by Mr. Harvey -Marston Commencing with a description of the earlyon " Transmission. The lecturer brought forward instruments such as the Bell type and thosemany interesting points and covered a wide area making use of loose contacts between metal rodsin the limited time at his disposal.Mr. Marston or carbon pencils, he proceeded to describe themade a special feature of small power transmission, various improvements which had led up to thewhich proved of great value to the many experi- instruments of to -day. menters present.Very lucid diagrams were used, Mr. Power had brought with him several kindsand thediscussionfollowingwas exceedingly of modern microphones, including inset and solid - beneficial. back types, which he took to pieces and passed The Society hopes to secure the services of round for inspection, at the same time explainingMr. Harvey -Marston again in the new year. their construction and action. Several questions were asked by members and Sheffield and District Wireless Society.* answered by the lecturer, who received a vote of Hon. Secretary, Mr. L. H. Crowther, 18, Linden thanks. Avenue, Woodseats, Sheffield. At a meeting on October 30th Mr. Reading The second meeting was held on November 3rd, delivered an interesting lecture on Short Wavewhen an exhibition of cinematograph films, kindly Aircraft Sets in use at the time he was in the Airlent by The Western Electric Co., Ltdwas shown Force. in the Mappin Hall at the University, Sheffield,' to The speaker divided his lecture into three partsa large audience. -Transmitters, Receivers and Amplifiers-each of The films, which were of an educational character, which he treated very fully, giving diagrams of allwere entitled" The Audion " and " Telephone circuits used and details of the results obtainedInventors of To -day." with them. The meeting was presided over by Mr. F. Lloyd, The transmitters described were all of the sparkthe new President, and a vote of thanks was passed type, some being excited by batteries and some byto Messrs. The Western Electric Co., Ltd. alternators.In many cases tuning was effected by Fulham and Putney Radio Society.* fixed condensers. Hon. Secretary, Mr. J. Wright Dewhurst, 52, The receivers demonstrated wereallcrystalNorth End Road, West Kensington, London, W.14. receivers in which provision was made for the On October 27th Mr. Calver described his visit addition of L.F. valve amplifiers. to the meeting of the Wireless Society of London, Two types of amplifiers were shown by Mr.and pointed out the benefits derived by affiliation. Reading-a three -valve L.F. resistance capacityHe also drew attention to the appeal from St. coupled amplifier, and one using iron -cored trans- Dunstan's for assistance to the blinded soldiers formers.The latter was found to be the mostin matters relating to wireless.It was proposed efficient. that the Secretary write to Capt. Ian Fraser, and The following lectures have been arranged :-also the local Secretary, offering to assist any local Monday, November 27th, " Elementary Principlesmember of St. Dunstan's in wireless matters by of Radio Telegraphy and Telephony III," Mr. F. S.putting him in communication with one of the Angel.Monday, December 4th, The Mark IIImembers residing nearest, also the Society offers Tuner and its Adaption to Various Circuits," free membership. Mr.G.D.Meyer.Monday, December11th, Mr. Houstoun had on view a very compact " A CompactReceiver,"Mr.L.Hirschfeld. three -valve set, and during the interval of winding Monday, December 18th, " Elementary Principles a frame aerial Mr. Calver gave a graphic description of Radio Telegraphy and Telephony," IV, Mr. F. S. of the daylight signalling apparatus used during the Angel. war. He also explained a code system, and went on A special section of the Association has been to give a few of his experiences of wireless work formed for juniors up to the age of 18, the annualduring the war. subscription to which is 5s. per annum. The membership is still on the increase, and now Wireless and Experimental Association.* the Technical Committee has been formed itis Hon. Secretary, Mr. Geo. Sutton,18, Melford hoped in a very short time to have an experimental Road. S.E.22. unit set of such a design that members can try out At the Central Hall, Peckham, on November 1st, any wiring scheme they wish. the Vice -Chairman, Mr. Sam Middleton, opened Stoke-on-Trent Wireless and Experimental the proceedings with buzzer instruction.The new Society. * members showed commendable progress. Hon. Secretary, Mr. F. T. Jones, 360, Cobridge Mr. Chapman, of the staff of Amateur Wireless, Road, Hanley. gave some exceptionally good hints on the erection At the Y.M.C.A., Hanley, on October 26th, and useof shortaerials and direction findingdetails of an interesting competition were announced. apparatus, and other members joined in the debate.Mr. Be w, a member, offered a prize of wireless Mr.Voigt,member,discoursedoneboniteapparatus to the value of £1.Latest date for dielectricsin variable condensers and chargingreceiving entries is November 16th. batteries off direct current mains.The Chairman It is proposed to form a buzzer class from 7 p.m. and the Secretary took part in the latter part ofto 7.30 p.m. on Thursdays. the debate. A variable condenser was constructed, and some Many new members are joining. coils wound the following week. NOVEMBER 18, 1922THE WIRELESS WORLDAND RADIO REVIEW 245 Finchley and District Wireless Society..* Mr. McPherson,B.Sc., Chairman, introduced Hon. Secretary, Mr. A. E. Field, 28, Holmwood Mr. Bartle, of Blackheath (2 LT), who lectured on Gardens, Finchley, N.3. " Broadcast Reception."First taking aerials, he The socialevening on October30th, whensaid that the most efficient aerial for broadcast about 140 people were present, was a great success. reception was a single wire 60 ft. long for earth; The M.C. was Mr. Macdonald Brown.The dance a counterpoise wire strung round the garden band was excellent, a special vote of thanks beingfence was even better than the usual waterpipe given to them as they had given their services earth. Healso showed how the gaspipes or entirely free, and also to several excellent artistselectric lighting wires could be used, and were whose services made the evening the success itextremely efficient-second only to an outdoor was.There were several musical transmissions aerial.Then simple valve circuits were touched received on a four -valve set kindly brought up by upon, the lecturer insisting upon the necessity of Mr. Cannon, music from 2 OM -2 OM being clearly amateurs preventing their sets from oscillating heardalloverthe hall-transmittedspecially while receiving telephony, and showing how one to the Society and his music was excellent.Mr. could tell if their set was oscillating or not.Then Heppel arranged refreshments, the service of which the Armstrong Super -Regenerator was dealt with, was excellent.Another social evening is beingillustrated by a very beautiful and neat set that arranged.An Experimenter'sLicenceforthe Mr. Bartle had constructed and brought with him. Society has now been obtained, and the work of He showed on the blackboard the current employed, making a set and of erecting a permanent aerialand gaveconstructional details and figures for is being started at once. the various components. He used with it a frame Leeds and District Amateur Wireless Society.*aerial -9 turns of spaced wire on a 26 -in. loop. Hon.Secretary,Mr.D.E.Pettigrew,37, Thoughthehigh-pitched whistlecharacteristic Mexborough Avenue, Chapeltown Road, Leeds. of this circuit was easily obtained, it completely At the Grammar School on October 20th, a refused to amplify telephony, and it was not possible lecture entitled" Diagram Interpretation " wasto form any idea of its power.Later, telephony was delivered by the Hon. Secretary.The lecturer obtained on an Ethophone II, kindly lent by Messrs. explained the numerous difficulties that beset a Burndept.Questions were answered by Mr. Bartle, beginner where circuit diagrams were concerned, who was then accorded a hearty vote of thanks. and how these could be greatly reduced by strict Weekly meetings of the Society are held at head- standardisation of symbols.Symbols were sketched quarters, Y.M.C.A., Thomas Street, every Wednes- and explained, and combined to form simple crystal day evening at 7.30. and valve receiving circuits.The diagrams were Mr. Houghton's elementary talks to beginners then extended to valve and crystal combinations, on the construction and manipulation of simple two and three -valve sets, etc., the function of each crystal and valve sets are being continued weekly component being briefly explained. A diagram from 8 to 8.30 p.m. submitted showed a five -valve set, four different The recent sale of surplus gear was very satisfactory. typesofintervalvecoupling,with a separateNewport and District Radio Association.* heterodyne for beat reception of C.W. Discussion Hon. Secretary, Mr. Edward R. Brown, 92, followed, and the Hon. Secretary was accorded a Corporation Road, Newport. hearty vote of thanks. On October 26th, Mr. H. W. Winslow (Newport) A general meeting was held on October 27th, gave illustrations of the various methods of jointing. Mr. T. Brown Thomson taking the chair.Six He showed that although " soldering " and " joint- new members were then elected.Mr. H. F. Yardley, ing " seem somewhat elementary, it is surprising M.I.R.E., Managing Director of the British Wireless how different they appear after being carried Supply Co., Ltd., gave a demonstration of " Brit - out by a practical hand, and how easy it is to throw wire " apparatus. out of gear a whole instrument by the lack of Mr. Yardley was received with loud applause.knowledge or care upon some very small matter Music was received from the amateur experimental in this respect. station (2 LA) on a multi -valve set and a Mag- It was clearly indicated to the members that navox loud speaker.The music, etc., was clearlyother evenings could be well spent by similar audible up to 100 yards distance away.Duringdemonstrations. theintervalsofthetransmission,numerous This Association has now been affiliated with " Britwire " products were submitted to the meetingthe Wireless Society of London. forexamination.The apparatusincludedthe Ilkley and District WirelessSociety.* Mark I tuner, the Mark III three -valve receiver, Hon. Secretary, Mr E. Stanley Dobson, " Lorne the Mark IV four -valvereceiver," Britwire " House," Richmond Place, Ilkley. L.F. magnifiers, coils, etc. A well attended meeting of the above Society Mr. A. M. Bage (President) proposed a votewas held on October 23rd, at the Regent Café, of thanks to Mr. H. F. Yardley and his assistants, Ilkley.The minutes of the previous meeting were this being duly carried, after which Mr. A. F. read, and a new member enrolled. Carter, A.M.I.E.E., was elected Chairman at the Mr. L. E. Overington addressed the meeting next general meeting. on the subject of " Electro-Magnetic Induction." Woolwich Radio Society.* The assembling of the Society's receiving set Hon. Secretary, Mr. H. J. South, 42, Greenvale is well in hand, and it is hoped to have it in working Road, Eltham, S.E.9. order by next month. At the Woolwich Polytechnic on October 27th, A good programme of lectures has been drawn in a lecture room kindly lent by the Governors,up for the next few months, and a particularly the monthly meeting was held, there being a good interesting announcement will be made in the near attendance, including several welcomed visitors. future. 246 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18, 1922 Halifax WirelessClub and Radio Scientificstrides which have since been made. Pioneer Society. apparatus, coherers, crystals, etc., were exhibited. Approximately 800 people visited the exhibition An excellent demonstration was given with the held last month.Thanks are due to the Stewards,help of another member, Mr. M. Jeynes, on Mr. especially Messrs. L. H. Carter and H. Alroyd,Mansell's five -valve set and loud speaker. also to 2 QK, 2 AW and 2 YF. Mr. R. Green then gave a talk on the easiest Mr. H. W. Sullivan sent a splendid collection ofway of learning - Morse.Great interest was dis- high-class components.Exhibits were sent fromplayed by the lady members present. the following firms :-Radio Instruments,Ltd., Mr. Mansell-Moullin, F.C.S., the Society's Vice - The Mainwright Manufacturing Co., Wates Bros.,President, was heartily welcomed. The Barlow Engineering Co., Hart Accumulator The Societyhas had an aerial and fittings Co., E. E. Rosen & Co., The General Electric Co., presented to them by Messrs. L. H. Mansell and MarconiOsram Lamp Co., Western Electric Co.,M. Jaynes, and hopes to have the set of apparatus S. G. Brown, Ltd., Burndept, Ltd., The Wireless at an early date. Press, Ltd., and the Radio Press, Ltd.Two local Meetings are to be held each Wednesday evening dealers, The Electrical Supply Stores and Denisonat 8 p.m., at the Society's headquarters at the Bros., also exhibited. Drill Hall, Albert Road. Membership of the Club is conditional on abiding Membership to date totals 57. by the terms of the P.M.G.. licences as amended The second meeting was held on November 1st, from time to time when Mr. R. Green lectured on " Wave Motion in Mr. P. Denison is preparing diagrams of receiving Air, Water and 'Ether," illustrated with blackboard sets which do not contravene the regulations anddiagrams. HALIFAX EXHIBITION.

The Short Wave Receiver specially built for the Exhibition by Mr. J. R. Clay, Treasurer of th,t Club.Received the Marconi House Transmission perfectly at 200 miles away. (The two coils in the coil holder are not primary and resistance.) these are to be circulated among the members Dewsbury andDistrictWirelessSociety. A lecture is to be given by Mr. J. R. Halliwell on Hon. Secretary and Treasurer, Mr. A. Horsfall, November 22nd, at 7.30 p.m. Willow Grove,34,LeeStreet,Ravensthorpe. Malvern Wireless Society. The winter session first lecture took place on Hon. Secretary, Mr. N. H. Gwynn Jones, Burford October12th. Mr.F.Dransfield,B.Sc., of House, Gt. Malvern. Dewsbury,spoke on" Capacity."I, Discussion A good attendance marked the opening of the followed. Society's first meeting on October 25th at the On October 19th, Mr. J. Bever, of Bradford, Drill Hall. A lecture was given by Mr. L. H.(2 QK) lectured on " The Electron Theory and Mansell on " The History and Progress of Wireless." the Thermionic Valve." He touched upon theearliestdiscoveries of On November 4th, 6th and 7th, a Wireless Ex- Hertz, Marconi's early experiments and the rapidhibition and Demonstration was held in the Moot NiEMBE it 18, 1022 THE WIRELESS WORLD AND RADIO REVIEW MAGNAVOX THE IFOWLD'S FInCEST

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THE TELEPHONE MANUFACTURING CO. LTD HOLLINGSWORTH WORKS, WEST DULWICH, S.E.21 TELEPHONE :SYDENHAM 2460-1 TELEGRAMS :BUBASTIS DULGRO NOVEMBER 18, 1922 THE WIRELESS WORLD AND RADIO REVIEW 247 Hall. Various wireless receiving sets, both pro- The Society has a membership of nearly 40, fessionaland amateur made,wereexhibited. and it is desired to still further increase this number. Mr. Skinner, of Batley, lectured on November 9th, Clapham Park Wireless Society. on " Inductance." Hon. Secretary, Mr. J.C. Elvy, A.M.I.E.E., Nottingham and District Radio Experimental3, Fontenoy Road, Bedford Hill, S.W.12. Association. The Ninth General Meeting was held at Head- Hon. Secretary, Mr. D. F. Robinson, 99, Mustersquarters, 67, Balham High Road, at 7.30 p.m. on Road, West Bridgford, Notts. Wednesday, October 25th,1922. On October 26th, the Chairman, Mr. J. Thornton, The Hon. Secretary made a very interesting announced the resignation, for business reasons, announcement to the effect that he had received of the Hon. Secretary, Mr. F. E. Bailey.Thedefinite acceptance of the Presidency of the Society members expressed their regret, and a very hearty by Sir Alfred Butt. vote of thanks for his services was proposed and Members present vociferously manifestedfull carried with enthusiasm. appreciation, and expressed confidence as to the The following appointments were made :-Hon. welfare of their Society in such able hands, and Secretary, Mr. D. F. Robinson ;Assist. Hon. Secre-look forward to the time when general election tary, Mr. Old. activities will allow of their formally installing Three short papers were given by Messrs. Ley,Sir Alfred in the Chair. Gill and Thornton on" The New Method of Mr. J. H. Daniels is to present to the Society a Reception." single valve panel, and Mr. M. P. Prout a valve Great stress was laid upon the point that amateurs for same, together with head -phones. must follow the P.M.G.'s new regulations. The Hon. Secretary reported that he had been Mr. N. Jackson Ley showed a method of reacting intelephonic communicationwith Mr.Leslie upon a novel type of plug-in H.T. transformer,McMichael, of the Wireless Society of London, and gave full particulars as to windings, etc. regardingexpeditingofaffiliation. Mr. J. H. Gill explained his method of H.F. The Chairman then called upon Mr.F. H. aperiodic coupling using a reaction coil, and sug- Haynes, who gave a description, illustrated by gested an interesting line of experiment. diagrams and apparatus he had brought for the Mr. J. Thornton gave full particulars of a circuitoccasion, on " The Building of an Amateur Three - which he was using with excellent result.An Valve Receiving Set." interesting discussion followed. Mr. Haynes dealt very fully with the operation The Chairman announced that the receivingand construction of every component, and ex- set was practically complete, and reminded members plained in detail the reasons for recommending that the new headquarters were Bennett's Garage, the circuit arrangement he described.A keen Shakespeare Street, from November 2nd. interest was taken in certain types of apparatus Proposed Society at Lee. employed.The lecturer connected up a set to Mr. A. H. Kidd, A.M.Inst., R.E., " Woodlands,"the particulars he gave as he proceeded with the 39, Burnt Ash Road, Lee, S.E.12, asks for corrres- explanation of the action of the various parts. pondence from amateurs in his district who areThe circuit embodied a loose coupled aerial circuit willing to co-operate in the formation of a Society. with tuning condensers, high frequency amplifier, East Ham and District Amateur Radio Society. using the " tuned anode " arrangement and detector Hon. Secretary, Mr. W. Vice, 5, Thorpe Road,valve, followed by a low frequency amplifier. East Ham. The discussion that followed was entered into A meeting was held at 709, Manor Park, Broad- by the Chairman, Mr. Beedle, Mr. Daniels, the Hon. way (over Lipton's shop) with the result that a Secretary, the Hon. Treasurer, Mr. R. H. J. McCue, new Society has been formed to take the place ofMr. C. D. Richardson, and Mr. Hurst. the club previously held at that address. A very hearty vote of thanks to the lecturer Mr.Judge waselectedDeputy Chairman ; concluded. Mr. Vice was unanimously elected Secretary. A An interesting impromptu discussion arose at Committee was elected, and business was discussed the conclusion of the evening's programme, which with encouraging results. affects all wireless enthusiasts, namely, the forma- It was decided to hold a meeting at the sametion of a Society distinct from the Wireless Society address on November lst to discuss the Club set.of London, but promoted probably by manufac- The membership is at present about 25. turers and others having commercial interests, The Committee wish it to be known that thisand likely to bring into conflict the interests of club has no connection with the Radio Supplythe true experimenter and the manufacturer. Shop at that address. Southwark Wireless Telephony Association. The club -roomsare open each evening from Hon. Secretary, Mr. W. Helps,King's Hall, 8till10 p.m. Meeting night every WednesdayLondon Road, S.E.1. at 7.30. The first meeting of the month was held at head- Watford and District Radio Society. quarters, on October 1st, when Messrs. A. 0. Gib- Hon. Secretary, Mr. F. A. Moore, 175, Leavesden bons and Winstone gave a very instructive lecture, Road, Watford. illustrated by slides, on " Elementary Wireless." Pi. This newly -formed Society commenced activities Interesting discussion followed.A vote of thanks on October 30th. to the lecturers concluded the meeting. An aerial has been erected at the Society Room, The second meeting of the month was held on the National Schools, Watford, and apparatusOctober 15th, when Mr. Dibben gave a lecturette loaned lay members was used for demonstrationon the functions of a condenser, also aerials and purposes. theirfaults,followed by discussion. 248 THE WIRELESS WORLDAND RADIO REVIEW NOVEMBER 18, 1922 Portsmouth and District Amateur Wireless . The agenda included adoption of rules for .con Society. stitution of Society and election of officers for the Hon. Secretary, Mr. R. G. H. Cole, 34, Bradford year. Road, Southsea. A very interesting and enthusiastic time passed Mr. Gull, on October 25th, gave his lectureall too quickly.The winter programme is now on " Broadcasting."He dealt with the present being carried out. The Club hope shortly to get regulationsmade bythePostmaster -General, a receiving licence and install a club set. and various diagrams were drawn to demonstrate The Hon. Secretary will be pleased to get in touch therequirements.Mr.Gullfurtherexplained with wireless amateurs in the district. the various American methods of receiving, and drew diagrams to illustrate how a first-class set Bromley Radio and Experimental Society. could be made, although keeping within the re- Hon.Secretary,Mr.J.Fergusson-Croome, gulations.Aninterestingtalkfollowed,and " Gowrie," Wendover Road, Bromley, Kent. an animated discussionarose as to the various The Society now holdsits weekly meetings methods that could be employed should any person at the Ex -Services Club, London Road, Bromley, have the intention of defrauding the P.M.G. orwhere an aerial has been erected. his inspectors. A further discussion arose with A meeting was held on Monday, October 23rd, regard to licences, and it was gratifying to notewhen a four -valve set designed by Mr. L. R. the number of members who preferred experiment- Stephens was demonstrated.Music was received ' ing licences, and were not merely taking up the by a " Brown " microphone amplifier and loud cult of wireless forthe sake of the long -delayed speaker. broadcasting concerts. A Morse class was conducted by Mr. L. F. Allen. The Society's membership is 50 strong. Hornsey and District Wireless and Model Engineering Society. York Wireless Society. Hon. Secretary, Mr. H. Davy, 134, Inderwick Hon. Secretary, Mr. A. E. White, The Grand Road. Hornsey, N.S. Buildings, Clarence Street, York. A meeting of the above Society was held on At a Committee meeting held on October 17th, October16th, and was largely attended.One it was proposed to run a series of lectures on " Wire- ofthe members brought hissettothe club lessTelegraphy and Telephony "on thefirst for the purpose of demonstrating the possibilities Tuesday of each month during the winter. ofasingle valve receiver.The meteorological A lecture was . given on " Wireless Telegraphy, report from GFA at 8 o'clock was utilised as practise its History and Development," by Mr. V. 0. Newton, in Morse reception, and later some musical telephony York,at 7.30p.m., intheGrand Café, from 2 ON and 2 KT was received, this beingClarenceStreet,on November 7th. particularlyenjoyedby new andprospective Taunton School Radio Society. members. Hon. Secretary, Mr. H. W. Hamblin, Taunton At 9 p.m. the club " went intocommittee " School, Taunton. for the purpose of general business.It was decided An inaugural meeting ofthe above Society to raffia a crystal set made by one of the memberswas held at Taunton Schoolon October 17th. in order to raise extra funds for the purchaseThere were about 40 people present. oftheclub'sset.Aninterestingdiscussion Thefollowinggentlemen weredulyelected followed on the subject of " Broadcasting and itsfor the coming session :-Chairman, Mr. D. Pean, relation to the Amateur Experimenter." B.Sc. ;Hon. Treasurer, Mr. A .E. Viccars, B.Sc. ; Several new members were enrolled.Applica- Hon. Secretary, Mr. H. W. Hamblin. tions for membership are cordially invited by the The first formal meeting of the Society was held Hon. Secretiry, who will be pleased to send fullon October 24th ;there was an attendance of 42 particulars on receipt of stamped addressed en- members. velope. TheHeadmaster,Mr.H.Nicholson,M.A., Meetings were held on October 20th and 23rd. kindly accepted the position of President.Mr. J. C. Both meetings were well attended.On the 20thTyler was duly elected ViceChairman; a Committee Mr. H. J. Pugh lectured on " Magnetism andof five members was also elected. Electricity as Applied to Wireless."On the 23rd The proceedings terminated with a lecture upon a short lecture was given by Mr. Hunting on " The " Waves," by the Hon. Secretary. Morse Code," dealing in detail on its many and varied uses. Eastern Enfield Wireless and Experimental Afterwards members practised in sending and Society. reading.Several new members were elected. Hon. Secretary, Mr. Arthur I. Dabbs, 315, High It is not necessary to be in possession of a licence Road, Ponders End. or wireless apparatus, or have a good knowledge of The question of affiliation to the Wireless Society wirelessbefore joining this Society. A stampedof London was discussed on October 26th, and it envelope should accompany request for furtherwas decided to take a referendum of every member particulars. of the Society on the subject. Members are making good progress in Morse Felixstowe and District Radio Society. practice, and the Society's three -valve set is now Hon. Secretary, Mr. E. Cork, 3, Highfield Road, installed and is in good working order.Most of the Felixstowe. evening was spent in working and experimenting on This recently -formed Society held its first annualthe set and discussions on items of general interest. general meeting on November 4th at Headquarters, The Society has been of assistance in helping St. Andrews' Hall, Gainsboro' Road. members over licence questions. NOVEMBER 18, 1922 THE WIRELESS WORLD AND RADIO REVIEW xxi The "BROWN" Loud Speakers With NewImprovedCurvedHorns THE REQUISITES of a Loud Speaker are pure tone, clear articulation, and good volume of sound. The" BROWN "LoudSpeaker possesses these qualities and they are enhanced by the new improved curved horn. AMATEURS do not always need the full sized Loud Speaker (H. I) as used in Lecture Halls, and a small type (H.2) hasbeendesignedtomeettheir more modest home requirements both astovolumeofsound andprice. THE NEW HORN of dull blacked aluminium used with both H.1 and H.2 is constructed on the logarithmic law of increasing openings and is acoustically Visit Our perfect. London PRICES : Showrooms: 19, MortimerH.1 (Large)LowResistance, Street, W.1 120 ohms, height 21" £6 5 0 H.2(Small)LowResistance, 120 ohms, height 12" £3 0 0 (High Resistances for either size --2, 6 to 5/- extra) H.2 (Small Size) Height 12- CATALOGUE POST FREE THE" BROWN "MICROPHONE AMPLIFIER THIS AMPLIFIER magnifies signals, is muchmore robust than otherrelays. speech, or music, without distortion, and is of This instrument satisfies the urgent demand for considerable interest to amateurs and scientific a reliable, inexpensive amplifier, which the most investigators. Thismagnification is much inexperienced amateur can use, and which the greater than that obtained from a two -valve mostexperiencedrequires. The necessary amplifier. Inconstruction,thisinstrument transformers are included in the base. PRICES :Low Resistance (120 ohms input) High Resistance (2,000 ohms) input SOLE MANUFACTURERS- S.G. BROWNLTD. Head Office and Works- Telegrams-" S,dbrownix,London." VICTORIA ROAD, NORTH ACTON, LONDON, W.3. Telephone-Chiswick 1469. Lon Ion Showrooms - Sole Agent for the Argentine- Horacio D. Guerrero, 19, MORTIMER STREET, LONDON, W.L Las Heras 2480, Buenos Aires. xkii THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18, 1922 :The1111111111111111111111 111111 I 11 J. LTD. Ideal Full Range BURNS, WangyeWorks, RECEIVING SET. ChadwellHeath,Essex. A Valve Set complete for workingX7 10 _-=== We are actual manufacturers and For the successful reception of concerts, telephony can offer special advantages to and continuous wave " Morse," the following set can be enthusiastically recommended. It includes the trade-send us your enquiries. all the very latest approved advancements of wire- willgive most less science-itisthesetthat CONDENSERS. retail price pleasure to the expert as well as the newcomer. As '001 mfd. ... you will see from the particularsbelow the equip- 0005 ...... 12/6ea. ment is complete, and we shall '0003 .. ... 11/6ea. 516es. 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Questions and Answers

NOTE.-This section of the magazine is placed at the disposal of all readers who wish to receive advice and information, on matters pertaining to both the technical and non -technical sides of wireless work.Readers should comply with the following rules :-(1) Each question should be numbered and written on a separate sheet on one side of the paper, and addressed "Questions and Answers," Editor, THE WIRELESS WORLD AND RADIO REVIEW, 12/13, Henrietta Street, London, W .C.2.Queries should be clear and concise. (2) Before sending in their questions readers are advised to search recent numbers to see whether the same queries have not been dealt with before.(3) Each communication sent in to be accompanied by the Questions and Answers " coupon to be found in the advertisement columns of the issue current at the time of forwarding the questions. (4) The name and address of the querist, which is for reference and not for publication, to appear at the top of every sheet or sheets, and unless typewritten, this should be in block capitals. Queries will be answered under the initials and town of the correspondent, or, if so desired, under a " nom de plume."(5) In view of the fact that a large proportion of the circuits and apparatus described in these answers are covered by j atents, readers are advised before making use of them, to satisfy themselves that they would not be infringing patents.(6) Where a reply through the post is required, every question sent in must be accompanied by a postal order for the amount of ls., or 3s. 6d. for a maximum of four questions.(7) Four questions is the maximum which may be sent in at one time.

" DOLLY TREBOR " (Cornwall) asks(1) circuit is not permitted, we suggest you couple Number of turns required for honeycomb coilsto the reaction coil to the tuned anode coil.No' tune with 0.001 mfd. condenser from 1,000-30,000electrical connections need be altered, only the metres. (2) Size of wire.(3)Wavelength range coupling need be shown.The circuitis to be of coils.(4) Which is most efficient method of H.F. thoroughly recommended for wavelengths in the amplification (a) for short waves ;(b) for long waves. neighbourhood of 400 metres, and we would advise (I) and (3) You will require 6 coils.Wind the you to use the tuned anode arrangement up to smallest coil with 40 turns, and the largest coila wavelengthofabout2,000metres.Above with500, and theothersinproportion. Wethis wavelength use the resistance capacity con- cannot say exactly, because the method of winding nection.We do not recommend the use of re- spacing,etc.,are deciding factors.(2) No. 28sistance capacity for wavelengths so low as 500 D.C.C. wire is rather fine for the smaller coils, but metres.The values of the condensers in your you should try it.(4) Reactance capacity coupling diagram are correct.The anode resistance should will be found most efficient for all wavelengths, be of the order of 70,000 w. but it is more convenient from the point of view " F.A.P." (Walton).-The connections shown of minimum adjustments to use resistance capacityin Fig.8, page 812, September 16th issue, will or wavelengths above 2,000 metres. meet your requirements.

Fig.1. " SOTTO VOCE " (Dartford) asks for a " C.O.B." (Manchester).-The anodecoil three -valve circuit with loose coupler. will have to -be a little larger than the aerial coil See Fig.1. The H.F. amplifying valve has abecause the anode tuning condenser issmaller tuned anode, and you will find the three -valve than the aerial tuning condenser.If you are using combination shown very effective. the A.T.C. in series with the A.T.I., the anode " V.H.B." (Hampstead).-We have examinedcoil will probably be about the same size as the the diagram submitted, and we consideritis A.T.I. coil.The reaction coil will be a little smaller quite suitable.We suggest you apply for anthan the A.T.I. generally, but you should find by experimenter's licence,submitting the diagram,trial whichcoil gives most satisfactory results which we think will meet with approval.If thewhen connected in the reaction circuit. D 2 250 THE WIRELESS WORLDAND RADIO REVIEW NOVEMBER 18, 1922 " G.F.W." (Windsor).-(1) You could try " (Ilkley).-(1) The crystal arrange. and use the coils suggested, but it is better to keep ment shownisuseless,this should be asin to the values given in the article.(2) We cannot Fig. 2.(2) X, 0.0005 mfds. and V, 0.0005 to name any particular manufacturer who will supply0.001 mfds.(3) The complete circuit including a variometer, and we suggest you look through X and N would have to be tunable, but if this the advertisement pages of the journal.(3) We could be done by the condenser only, there would be think you will find your queries with regard to the no need to tune the coil as well.(4) No, the present super -regenerative circuit answered in the issue arrangementispreferable.Thetypeofset of October 28th. suggested is (mite good. "IKANOPIT " (Bedford) asks (1) For criticism of his circuit.(2) What length of No. 25 Eureka wire to use in a filament resistance.(3) Whether to rewind a L.R. earpiece.(4) Particulars of a telephone transformer. (1) The diagram isquite correct.You will not magnify the signals much with a single valve ; in fact a single valve detector without reaction is little better than a crystal.(2) Use four yards, and take evenly spaced tappings.(3) It is difficult HT+ to advise whether to rewind the receiver or not Fig. 2. without all dimensions of the receiver.However, " RED ALMOND " (Leicester) asks range you could rewind, using No. 36 S.S.C.The sample or wavelength variometer most suitable for a Super - of wire submitted is No. 30 S.S.C.(4) The tele- regenerative receiver. (2) How many plates, average phone transformers could be made as follows :- thickness 24" diameter, moving plates, 1i8" washers, Core of iron wire i" diameter and 3" long ;primary should be used for 0.001 mfd. condenser.(3) If winding, 3 ozs. of. No. 42 (sample wire is No. 42) there is any advantage in having a large number and secondary winding, 4 ozs. No. 34. of turns on a frame aerial instead of 12 or so. " VALVES " (Regent's Park)(1) and (2) (1) We suggest you make the rotor about 5" in dia- has a former 44" diameter and 44" long, and meter and the stator sufficiently large for the rotor wishes to tune from 300 to 5,000 metres, using ato revolve.Wind with No. 22 S.W.G., D.S.C. tuning condenser of 0.0005 mfds.capacity.(3) (2) If the moving plates are 24" diameter and 23 The number of turns to wind for a reaction coil. mils. thick, and the spacing washers are 1/8" thick, (4) Whether diagram submitted is correct. about 93 plates will be required to give a capacity (1) and (2) We suggest you wind the former of 0.001 mfds.(3) There is no advantage in having full, using the two -pile method of winding described a large number of turns on your frame aerial ; recently in this journal.If you wind with No. 26 15isusually sufficient, and about 5 tappings D.S.C. wire, and take 10 tappings, you will cover should be made. the wavelength range desired.(3) The reaction " " (Hong Kong).-(1) The variometer coil could be 100 turns of No. 28, with a meanreceiving transformer you suggest could undoubtedly diameter of24".(4) The diagramiscorrect, be used for the A.T.I. and reactance coil of a set, and also the method of connecting the transformer. but if this were done we do not think you will be We suggest, however, you increase the capacityable to get good results except at comparatively of the H.T. by-pass condenser to 0.02 mfds. short wavelengths.(2) We should not recommend using finer wire than about No. 38 for rewinding " D.H.B.McC."(Leicester)asks(1)For these coils, and if this were done we do not think particulars of basket coils.(2)Whether thereis that the wavelength reached would be in excess any difference in the coupling schemes submitted of 2,000 metres.(3) The same tappings as on the (3) How to construct a L.F. choke coil.(4) How to original windings might be used.(4) Use about use the formula wavelength =1885 LC when there 8 ozs. of No. 30 for the L.R. winding, and 3 ozs. is no condenser.* of No. 44 for the H.R. winding. (1) We suggest you make use of the No. 22 S.W.G. wire and wind 40 turns for the smaller wavelength, " W.S." (Wembley) asks for winding for a and other coils of 80 and 130 turns, connecting coil with Litzendraht wire totune upto about them in seriesfor the larger wavelength. (2) 450 ma., and if it is possible to use a former 3" x 6" The two schemes are identical.(3) You couldfor the purpose. make use of an old L.F. transformer, or you could There is not a lot to be gained by the, -use of wire build one to the following particulars :-Core, iron of this type for receiving on short wavelengths, wire i" diameter, 3" long.Winding, 2 ozs. No. 40 as under such conditions the resistance of the coil S.S.C. wire. is in general considerably less than that of the (4) The formula cannot be applied aerial.There is no objection to its use, however, unless there is capacity.Coils do not possessif desired.We do not know the exact gauge of capacity inany useful sense, and you cannotthe wire which you propose to use, but you will very well predict the natural wavelength of a probably find that 60 turns will be sufficient on the coil you construct. former you suggest, if you use the 0.0005 mfds- " A.L." (Liverpool).-You shouldusean condenser in series with the coil to tune the aerial.. ordinarythree -valveL.F.amplifier,the inputIt is not possible to predict the exact points for sideof thefirsttransformer being tapped for tappings for particular wavelengths, but if you put adjustment purposes. We cannot help you much,three or four taps in, evenly spaced, you should without information as to the particulars of the be able to tune all wavelengths up to your maximum. experiments you propose to conduct. without difficulty. NOVEMBER 18, 1922 THE WIRELESS WORLD AND RADTO REVIEW xsiii

vlAKCON I GIVES UNRIVALLED WIRELESS SE KV I C E

qfie MARCON IINTERNATIONAL MARINE COMMUNICATION CO LTD. MARCoNi HOUSE, STRAND, LONDON. THE WIRELESS WORLD AND RADIO REVIEW N EMBER IS, 1922' " BRITWIRE " APPARATUS "BRITWIRE" Mk.IV RECEIVER Now made with Radion Mahoganite panel as standard, andfitted with the very finestL .F.transformers and components. Guaranteed equalto,orbetter than,anyfourvalvereceiver sold, and equalto many sixand sevenvalvereceivers. OneH.F.,one Rectifying andtwo L.F. valves .. £21 "BRITWIRE" TUNER to match...... £8 10.. Completewithaerialequipment, accumulator and all accessories, Forty Guineas. RI rwi RE " RECEIVER. BRITIVIRE " TUNER. ALL BRITWIRE valve apparatusislicensed under Marconi Paints for amateur useitsGreat Britain, List post free, 3d. Post orders to- BRITISH WIRELESS SUPPLY CO., LTD. 8, Blenheim Terrace, 18, Eldon Square, 11, Church Street, 33, High Street, 8, Corporation Street, LEEDS. NEWCASTLE -ON -TYNE WEST HARTLEPOOL. SOUTHAMPTON. BELFAST. - Telephone - 6926. Telephone - 36oCity. Telephone - 373 Telephone -403 BRANCH AT LONEON OF ENING SHORTLY.

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HEAD OFFICE : (651jterELECTRICAL STORAGE 4COMPANY LIMITED. Clifton Junction, Nr. Manchester LONDON SHOWROOMS Prices and Particulars on Application 219 229, Shaftesbury Ave., London, W.C.2 NOVEMBER 18, 1922THE WIRELESS WORLDAND RADIO REVIEW 251 " A.G.P." (Swinton).-(l) We cannot give (1) We do not think that there is any restriction you a single valve circuit with reaction which will as to the amount of wire that may be used on a meet with the approval of the Post Office.We frameaerial.For short wavelengths the100' suggest you use the valve as a H.F. amplifier, andallowed for an open aerial is quite sufficient for a use a crystal for rectification.See Fig. 3.(2) The frame, but for long waves a greater length of wire A.T.I. could consist of a coil 5" diameter, 6" long, is generally used.(2) This coil cannot be used ' full of No. 22 D.C.C. with 10 tappings, and theas it stands, as the windings will certainly not be A.T.I. could be a coil 4" diameter and 6" long, full correct.It might be made some use of by rewinding of No. 26 D.C.C. with 6 tappings. with a new primary of about 6 ozs. of No. 30, covered with a rewinding of the older thin wire. Whether this would be satisfactory depends on whether the old winding could be stripped without damage, and whether there is sufficient quantity of wire in it. " H.F.C." (Wimbledon) asks for details for a frame aerial for use with an Armstrong super - regenerative circuit with a range of 300-10,000 metres, and whether loading coils can be used with such a frame. Your proposaltouse an Armstrong circuit over such a range of wavelengths indicates that you have not grasped the principles under which it works, in which case you are extremely unlikely to obtain any useful results whatever with this exceedingly tricky circuit.Itisonly intended for and suitable for the reception of signals over a restricted band of short wavelengths, and we can Fig. 3. assure you that the difficulties to be overcome aresufficiently (1)Whose call undereventheseconditions " D.H." (Nottinghhm) asks formidable.The frame should be that normally lettersare2 GR. (2)For particularsofthe suitable for say 300-600 metres, e.g., 12 turns of " spade " method of tuning by means of a fixed coil. about 3" diameter.No loading coil will be neces- (1) We regret we have no particulars of this See the articles by P. W. Harris in the issues station.(2) The method of tuning to which you sary. refer makes use of a fixed coil, and a movable piece of November 21st and 28th, 1922. of copper plate.Changing the position of the plate " W.S.B." (Daisy Bank).-(l) Zincite and changes the inductance of the coil. copper pyrites in combination isa well known " A.B." (Manchester) asks(1)Whetherit and quite satisfactory variationof the perikon is possible to hear the Dutch concerts on a three - type of crystal.The term perikon is generally valve set in his district.(2) If not, what we recom- applied to the combination zincite-bornite.(2) mend. The arrangement of your apparatus is quite correct, (1) and (2) The reception of this station is alwaysand we have no fault to find with the set, except rather uncertain at such distances, and can onlyperhaps that you would find it easier to tune on be done by the use of critical reaction adjustment, short wavelengths with coils of a less diameter. with its attendant risksofradiation. Inany (3) The aerial circuit will tune to about 2,300 metres case the results are not often good.If, as you say,with the condenser in the parallel position, and you can get weak signals we should recommend probably about 1,000 metres with it in series with you to add another L.F. valve, and at the samethe A.T.I.The closed circuit willin any case time take every possible precaution to increase tune to at least 3,000 metres. the efficiency of your aerial. " C.L."(Huddersfield)asks(1) Certain " W.V.H." (Walthamstow) askswhethera questions with regard to the permitted dimensions certain three -valve set sketched is correct and suitable of an aerial.(2) The reason why on a certain occasion for the reception of the Dutch concerts. he heard European C.W. stations with his set adjusted The circuit sketched is correct inits general in such a way that it could not possibly have been lines, but is not likely to be efficient enough to give oscillating.(3) The best all-round valve for H.F. results with the Dutch station.Firstly it would be amplification with a filament battery of not more bettertouseastageof H.F.amplification. than 4 volts. Secondly, the use of a parallel A.T.C. is unnecessary (1) Post Office Form No. 43 states that the com- and undesirable on such short wavelengths.And bined height and length shall not exceed 100 feet. thirdly, the use of reaction coupled directly back (2) This was evidently due to your set having on to the aerial circuit in the manner shown leads picked up some continuous oscillation all the time, to serious trouble from radiation, and is to be either from a local receiver in a state of oscillation, strongly deprecated. or possibly from a harmonic of the spacing wave " B.M.G." (Paddock Wood) asks (1) Whetherof some arc station standing by at the time.(3) he is allowed to use more wire for a frame aerial Impossible to say.Most valves by the foremost than he is for an outdoor aerial. (2) Whether -he makers have some specially good points, and we can use a 1" spark coil for a transformer with acannot undertaketodiscriminate between the 200 ohm loud speaker. brands. 252 THE WIRELESSWORLD AND RADIO REVIEW NOVEMBER 18, 1922 " H.W.C.M." (Clapham).-(1) With " Q " " D.C.R." (Egham).-(1) All right, but we valves the plate voltage should be about 40 fordo not think that you will get permission to use detecting with a potentiometer, without extrareaction in this way.(2) See Fig. 3, page 738, volts, 60-200 for most purposes of amplification, September 2nd issue.(3) Yes ;both windings and about 200 in an oscillator.(2) There is very are intended to be of the same wire.(4) Gauges littleto choose.Personally we have a slightare approximately No. 36, 44 and 42 S.W.G. preferencefor the potentiometer method with " J.W.W." (Essex) asks for a diagram of a these valves.(3) For the inductance of lattice valve and crystal combination. wound coils the following rather formidable looking formula gives fairly good approximations to the See Fig. 4. correct result.In actual practice its use will not be_found to present any great difficulty :- L mhd = 1 x 4r2a3 N x F1 x F, 1,000 b+c +R where a = mean radius of the winding') b = axial length of coil c = thickness of winding } all in ems.

R = outer radius N = total number of turns 10b ± 12c ± 2R 10b+10c± 1.4R and F2= 0-5 log (100 14R2b \

" IMI "(Huddersfield).-(1)Almostany valve in use at the present time will detect efficiently with 60 volts on the plate. A French type valve would, among others, be very suitable.(2) The Fig; 4. circuit of Fig. 4, page 739, September 2nd issue, " H.H.S." (Yorks).-You will require several is of the type specified.This circuit has a switch basket coils to use in conjunction with a tuning for cutting out the note magnifier valves ;this condenser of maximum value 0.0003 mfds. We may of course be omitted if desired.(3) At present suggest you use 8 coils, making coils of 40, 80 and 150 we do not think you will get anything, but youturns for the shorter wavelengths, and then adding should get Manchester and probably Newcastlecoils in series for the longer wavelengths.The when the stations in these towns come into opera-exact values cannot be given, as the inductance tion.(4) We do not understand the results youof basket coils varies greatly with the method of describe. Itisquitelikelythat signals frommaking, and tightness of winding. A resistance ships will be less strong than those from the of 50,000 w. is quite suitable for use in the anode higher powered long wave stations.The cracklingcircuit of a H.F. amplifying valve, but you may effect may be due to tram interference, which issecure a little greater amplification if you use a often found to be troublesome on some wavelengths 70,000 w. resistance.The H.F. voltage should be and not on others. increased to allow for the voltage drop in the resistance.The potential variations which occur " FUZZ " (Glasgow) asks for data forthe at the anode of the H.F. amplifying valve should construction of a five -valve set, saying nothing about be applied to the grid of the following valve by the purpose he wishes to use it for or giving anyjoining a condenser between the anode and grid. other information. A grid leak is connected between the filament and grid of this valve to provide the grid with a mean These columns are intended foil helping readers potential which is suitable for the best operation with specific difficulties, and lack of space, etc., of the valve. We suggest you use basket coils prevents us from undertaking the complete designfor the reaction coil, and you will probably find of complicated sets for individual readers.You a coil a little smaller than the anode coil is quite will find a diagram of a very good type of set insuitable. Fig. 4, page 706, August 26th issue.For details Whenreceivinglongerwavelengths, of the construction of the various parts see recent inductance should be connected in series with the articles on the construction of sets, as the construc- reaction coil. tion of condensers,coils,transformers,etc.,is very much the same whatever set they are to be used on. SHARE MARKET REPORT Prices as we go to press on November 10th, are :- " K.D." (Manchester).-The wiring of the Marconi Ordinary .. 2249 four -valve set as shown in the issues of July and Preference .. .. 23

August to which you refer is correct, and the replies Inter. Marine.. .. 1 73 to which you draw our attention are answers Canadian .. 106 to meet therequirementsofcorrespondents. The diagram in Fig. 4, page 508, is also correct, Radio Corporation of America :- and if you wire your set according to this diagram Ordinary .. 199 you may be sure the connections are correct. Preference .. 140 NOVEMBER 18, 1922 THE WIRELESS WORLD AND RADIO REVIEW XXV

7ritj1-111111 lb 114 141 Aildi" 111111111101 , ituiyANTOtris I s A The Valve Periecr Forreceivingvocal and instrumental items you must have Mullard " ORA " Valves to get the best results. Oscillates - Rectifies - Amplifies Specially recommended where good detectionandamplificationare required. 15/- each IMPORTANT NOTICE.

The greatdemand forMullard " ORA " valves and other accessories has compelledusto open much larger works. The " ORA " Valve requires about 3'8voltsonthefilamentand 30 volts or over between the anode and filament forefficientresults. Mullard Radio Valve Co., Ltd. 45, Nightingale Lane, Balham, S. W.12.

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A Complete Line Wirelessrnponents ItEe We stock a complete line of wireless accessories and the following are a few examples of the good value offered. Telephone Transformer, as illustrated, 15/6 each, or mounted in a box, with 4 terminals, 18/6 each 111111111111111',. (postage 4d.) Valve Holders-best quality Ebonite and Brass, 1/9 each (postage 3d.) Switch Arms, as illustrated, 3/6 each (postage 4d.) Ebonite Slabs-best quality, matt or polished, 5/ - each (postage 6d.) Size 6" x 12" x I" thick. Send for fully illustrated Catalogue. You will appreciate the values offered. lzr aoei4Y°"(.7s#" FELLOWS MAGNETO CO., LTD.,

LONDON, N.W.10 Telephone ; Willesden 1560-1-TelegramsQuinnag, Phone, Lou ion. NOVEMBER 18, 1922 THE WIRELESS WORLD AND RADIO REVIEW xxvii

THREE INDISPENSABLE BOOKS ON WIRELESS. Crown 8v0. Price 7 6postatTe Pd. THE COMPLETE RADIO BOOK. By Raymond F. Yates and Louis G. Pacent. Preface by A. A. Campbell Swinton, F.R.S THE TIMES :"The work is commended by Mr Campbell Swinton, F.R.S., one of our most di,- tinguishcd electric engineers. . . . The book excellent." DAILY GRAPHIC: "In simple language even a boy can understand.It explains in complete detai how to make your set, and is packed with other practical information."

Price6'- (postage 5d. Crown8vo. FullyElustrated. Price6'-. Crown 8vo. (postage 4d.) AMATEUR RADIO Wireless Telegraphy and How and Why ofWireless, with Telephony complete instructions on Operation Simply Explained of Receiving Outfits. By A. P. Morgan. By Maurice J, Grainger, One ofthe most complete and comprehensive treatiseson thesubjecteverpublished.A Radio Expert, formerly with the Westinghouse study ofitspages will enable one to master Electric and Manufacturing Co. all the detailsofthe wireless transmission of over 15o DLit:ram. and Illustrations. messages.

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NOTE. GENUINE The Condensers we list here mustNOTbe confused HELLESEN with some of the cheap and inferiorinstruments DRY BATTERIES that are on the market to -day. The FINEST WORKMANSHIPandthe BEST QUALITY material is embodiedinthem, and ALL customers can rest assuredthatthese two points will be MAINTAINEDin allour goods. FILAMENT RHEOSTAT. Finest on themarket.Guarantee. Fitted with Knob and Pointer-4/. , BevelledEboniteDial5/9 CRYSTAL SEA. Fist -Class InstrumentforBROADCASTING WAVELENGTH 1315 0' Cabineto,,,. I Panel PanelCabinetCabinetlIdount-.shed Value Mount-Mount-Mount-Mount-mg As -mmahOg. my. inginnagAs- mg ining As-sembled PartssembledPartssembledCabinetin Cabinet SPECIAL'TRADE AND \\ lloLLsALE TERMS 0015.. ; 23/- 25/8 24/- 28/8 33/- 6/3 001 .. I 18/9 19/6 17/9 21/- 28/- 5/6 , drword. Volts. Details. Price.

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-0002 7/- 1 9/- 8/- 9/6 13/6 4/- .. WanderPlugs and Terminals are included in the .0001.., 6/- 8/- 71- 8/8 12/6 4/- priceofthe Battery and are NOT AN EXTRA. I 3/8 Vernier ..' - I 4/8 - 5/- 9/- Fittedwith Bevelled Ebonite Dial1/9extra. KNOWN THE WORLD OVER AS Stateial Sines Made to Order. Pries list on request. THE BEST. ALL SUNDRIES AND COMPONENTS IN STOCK. ORDERS OVER 20/- CARRIAGE PAID. LL LISTS FREEON APPLICATION. TRADE ENQUIRIES SOLICITED. A. H. HUNT, LTD. The "Broadway" Radio Works H.A.H. Works, Tunstall Rd., Croydon. Surrey DEVONSHIRE ROAD, BEXLEYHEATIi, KENT xxviii THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18, 1922

21111111111111111111111111111111111N111111111111111111111111111111111111111111111111111111111111111111111111111111 11111 111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111IE ADVERTISING PAYS Ifyouusetherightpaper The following extracts are typical of letters being constantly received testifying to the wonderful advertising value of the "WIRELESS WORLD" " 52, Linver Road, London, S .W .6 3rd .Nov.,1922. " illthough I have only had two small advertisements in the Wireless World,' they have more than proved the wonderful results of which your paper is capable.In my case it has been thousands of orders from 4/6 for ifelvertising. " You are quite at liberty to make use of this,should you so desire. B. G. CALVER. Ifyou Advertise the right way rl UR claim to specialised knowledge in Wireless Advertising V is based on Ten Years' practical experience.This, together with our Complete Wireless Advertising Organization, is at the disposal of every hona fide Advertiser entirely free of charge. No businessis too small or too large to command our prompt attention and courtesy. Whatever your Advertising problem or difficulty, it willpay you to get in touch with us.Why buy your experience when expert advice is yours for the asking ? BERTRAM DAY & CO., LTD. OrganisersoftheFirstAll -British Sole Advertising Agents for the " Wire- WirelessExhibition, 1922. Wireless Publicity Specialists. less World."Full particulars and rates Contractors, Printers and Publishers. on application. 9 & 10, CHARING CROSS, S.W.1 Gerrard 8063, 8064 and 8065. BRANCHES AT MANCHESTER AND GLASGOW.

N11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111 111111111111111111111111111111111111111111111111111111111i11111111111111111111111111111111111111111111111E, NOVEMBER 18. 1922 THE WIRELESS WORLD AND RADIO REVIEW The" Autoveyors 3 -ELECTRODE VARIABLE CONDENSER (British Patent 17703122) is the most efficient precision controller of oscillations in radio circuits.It comprises three sections, each consisting of a tier of parallel plates of one-third disc area.The centre section is spindled and knobbed, and permits a variation of capacity over 36o degs.Both side sections are spindled and knobbed and permit Verniercontrolof extreme precision.Thus, whilst providing all the essentials of the ordinary 2 -Electrode Variable Condenser, it affords the added advantage of the coupling of the third electrode, which may be applied in a thousand and one ways. In Aerial Circuits the 3-E.V.C. permits the application of capacity from Zero Series to Maximum Parallel by asingleoperation.Additional switchesareun- necessary, and detuning from Series to Parallel is avoided. In Closed Circuits it provides a precision -controlled static coupling for synchronous super -regeneration or relay radiation choke of unbounded possibilities. In Grid Circuits it permits the employment of regenerative static influence upon the input. An absolutely up-to-date and complete list of all In A_ode Circuits it affords definite control of by-pass, stability and regenerative applications. land, ship and amateur call signs. InOscillatorCircuitsthe3-E.V.C.ensuresprecision It is as much a necessity to the real experimenter control of synchronism. as a telephone directory is to a telephone subscriber. Full particulars from the Sole Patentees :- PRICE 2/6 NET. ( BLUE COVER) (Post free z/8). AUTOVEYORS, LTD. Order your copy at once through the trade or direct from Radio Engineers and Contractors RADIO PRESS LTD. 84, Victoria Street, London, S.W.1 Devereux Court, Temple, W.C.2 'Phdite :Victoria 309. We/write/1d Las Buildup aREINARTZ TUNER TUNER THE REINARTZ -You would be surprised how simple itis.

ONE of the most remarkable discoveries of 1922 was the 0°0.o^ 000 Reinartz Tuner.Fully described in the Wireless World 000% for May 13th,1922,itpermits very critical tuning with tit almost unbelievable selectivity.By its aid you can largely eliminate jamming andatmospherics. Tuning employs new principles-the inductancebeingdivided into three portions-Aerial, Grid and Plate.If you aim at the absolute limit of efficiency, you need a Reinartz Tuner. Make one up on your own kitchen table with no other tools than a screwdriver and a pair of pliers. All drilling and tapping has been done by us.

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Wireless Transformers to 15,000 Volts . £1 Dubilier Condensers for 25,000 volts, in cases.. 10 - Transmitting Coils oneboniteformers, with 10 -way Switches on ebonite with engraved dial and pointer 5'6 2 -Way and Off Position Switches mounted on ebonite base with terminals (Tucker Switches) 4,6 A.T.M. Co. Telephone Transformers, in teak cases with 5 - 120w. Watch Type Receivers with cords.Single.. .. 4 - 1-2MF. Condensers .. 1 6 8' 4 -Way Telephone Colds, outer covering easily removed 16 Microphones with Replaceable Insets .. 26 3d. Marconi Slate Charging Boards, with ampmeter to 20 amp. Main, Switch, Fuses, etc. - Solid Dovetailed Mahogany Instrument Cases with brass

lock and key, etc., 13 x 1 x 6.. . 7/6 Hand Combination Telephones, less receiver, with good Microphones .. ,c Sul', H.T. Battery Boxes, with double way switch and fuses with lid .. .. 5 - ti;s1 H.T. & L.T. Battery Box Plugs . per pair 1 - Magneto Generators, 3 Magnet Type .. .. 5 - THE POPULAR 3 -COIL Power Buzzers in Cases, less ampmeter and key.. .. 10 - TUNER. For Baskets, Slabs Head Combination Telephones, complete...... 6 - Mark DI Crystals in Cups .. .. per doz. 3 - or Lattice Coils this 3 -coil tuner Mark III* Crystals in Cups . . per doz. 3 6 complies with P.M.G.'s restric- Ditto, Mixed .. per gross30 - tioncombiningthehighestefficiency with Dozens of other lines in stock, all ex Government. New Wireless Apparatus of all kinds in stock. cheapness and practicability.With a set of Send for requirements, reply by return. Baskets this makes the most perfect Telephony Carriage Paid on Orders over £1. tuning unit from150-4,000 metres on the market. Tuning Stand with 3 coil holders, 12/6, post 9d. C. extra. Coil Holders, 1/3 each. Tuning Stand with S. SWAN, 7 coil holders and set of Baskets, 21'6, post 1/-. 191, Bishopsgate, E.C.2 Scientific Supply Stores, (Under Brandon, Tailors), and 65, Windsor Road, Layton, E.10. 8,Newington Causeway,London,S.E.1 'Phone, Bishopsgate 1156. Phone-Hop 4177.

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YOUR crystal or valve may be the best of their kind-your aerials high as Snowdon, your tuner perfectly accurate,

I but unless your 'phones are O.K. you won't get maximum "sigs." Signals come "thumping in" through ERICSSON 'PHONES. They're built that way-for never -failing clarity and sensitivity.The magnets never lose their strength and " shorts " don't exist.And they're easy I and comfortable to the head. Back of ERICSSON 'PHONES isthe accumulated experience of a I I generation in telephone manufacture. The BRITISH L. M. ERICSSON I I MANUFACTURING Co., Ltd. Head Office : 67/73, International Writs for

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NOVEMBER 18, 1922 THE WIRELESS WORLD AND RADIO REVIEW

SK1NDERVIKEN BUTTON. " EIFFEL TOWER TYPE." A Supersensitive Microphone. Known all over the world and patented in every civilised country. Over 80,000 sold.ENGLISH Manufacture. Make up your own Loud Speaker. MASTS Transmit your GRAMOPHONE music STRONG. LIGHT. to any room in your house. WOODLArFICH. EASY TO ERECT. The only practical Microphone for use in Detectiphone Sets. ROT AND WATER PROOF. Price 5/. each 20 to50 feet - - - 1/3 per foot Special Low Resistance Receivers (for use with

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Send for Nearly all the princip,1 dealers are stocking OUR Variable Condensers, while most of the Complete Lists big manufacturers are incorporating them in their Sets.There's a reason ! WRITE FALLON CONDENSERCOMPANY 230a, HERMITAGE ROAD, LONDON, N.4 TheESSEXAccumulator Co., Ltd. 499, Grove Green Road, Leytonstone, E.11 Telephone Wanstead 749 No Waiting. Delivery from Stock Everything for Wireless Perry Head Phones 4,000 per Ohmsn CI pair IN STOCK Specially designed for Wireless _Make use of our 24 hour Service Telephony. Receivers arranged inseries, Aluminium Cases ::if you are tired of delays :: and fitted with extremely light and efficient Head Bands, and Complete Lists Two Stamps. Twin Connecting Cords. Illustrated Wireless Catalogue now ElectricalSupplyStores ready,postfree 3d. 5, Albert Terrace, King Cross, The JEARY ElectricalCo.,Ltd. Halifax, Eng. 8, LAMBETH HILL & 87, Queen Victoria St., London, E.C.4 FREE SERVICE Manufacturers' Models. Have you any queries ? Do you require any advice ? Do you wish to know the most economical method of Those about to manufacture either Crystal making your set ? Write to us, we will answer all your queries free of charge. or Valve Sets and desire excellent models A FEW OF OUR BARGAINS, to work from can procure several well con- Parts to make a first-class Crystal Receiver, 35:-. Complete, 50 - Parts for 2 -Valve Low Frequency Panel, 45 ; Cabinet 5,- extra. structed, highly efficient Low Frequency Transformers, 12,1 each ;ratio, 5-1. popular American VARIABLE CONDENSERS. 0003, 16 plates, panel mounting modelsatspecialterms parts, 7 4 ;cabinet parts, 1114 ;panel mounting complete, by applying to : 8 10.Cabinet complete,12/10. VARIABLE CONDENSERS..0005, 27 plates, panel mounting Mr. MONTAGUE ADAIR, parts, 8 8 ;cabinet parts, 12;8.Panel mounting complete, 11,'- ;cabinet complete, 16!2. 30, Bedford Place, London, W.C.1 Aerial Erection and Maintenance. 15 years' wireless experience. Dept. W., SIMPOLIA WIRELESS CO., 170 West Green Rd.; N.15 XXXII THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18, 1922

ELWELL Hi hPowar Wireless Stations

F) Ho r seal Island No needto spend time making the se connections.The Elwell note magnifier Eiffel contains them ready made. AMPLIFYING Tower

The intervalve transformer is contained MADE EASY inanironcaseallowing units to be placedclosetogetherwithout howling. When building a ValVe set, do not buy intervalve transformers. Tapped holes in two sides and base make Use Elwell Amplifying Units.They fixingeasy. The unit will also'tent save time, money and trouble. alone. When buying a ValVe set, All connections are embedded in compouid select one using these units.They and brought out to terminals.No solderi ig 0 necessary.The perfect insulation of the enable the manufacturer to give you grid connection ensures silent operation. a better job at a lower cost. The unit featured is a note magnifier. Thevalveholderhasspeciallylong leakage paths and an earthclip. A similar design of unit is available This patented amplifying unit, when provided with a as an oscillation amplifier and a third valve and connected as marked on the terminals, is all that is necessary to give:one stage of note magnification design as a rectifying unit. to your existing set. Two, three or more units may be coupled as shown, to give as many stages of note magnification as required. PRICE 39'6 each. WRITE US OR CALL. C. F. ELWELL, LTD., RadioEngineers, CRAVEN HOUSE, KINGSWAY, LONDON, W.C.2 Telephone :REGENT 421._ _ NOVEMBER 15, 1922 I' LIE WIRELESS WORLD AND RA 1)1 a REVIE

BRITISH MADE. HIGH CONDUCTIVITY COPPER WIRES The I K- 11 I Precision Best Quality Coverings. CONDENSER. Per lb. A HIGH-CLASS INSTRUMENT, designed and Yds. Ohms S.W.G. per lb. per 1,000 S.C.C. D.C.C.S.S.C.D.S.C. En'ld. constructed on Scientific Principles, mechanically yds. and electrica ly perfect. 12 10 21 1/10 1/11 3/0 1 SPECIFICATION. 14 18 41 1/11 2/0 3/2 4/28/ 1 9 16 28 7.52/0 2/1 3/4 4/4 1 10 VANES of hard rolled aluminium, dead flat. 18 48 13-32/1 2/2 3/8 4/8 1 11 BEARINGS of special design and adjustable. 20 84 24 2/2 2/3 4/0 5/6 2/4 OPERATING tension device. 22 140 39 28 sal 4/6 6/0 2/6 SPACING WASHERS gaugedto 24 230 63 3/0 3/8 5/0 6/6 2/8 plus or minus 001". 26 340 95 3/7 41 5/4 8/0 8/2 MOUNTED on high-grade Ebonite. 28 530 140 4/4 4/8 5/8 9/0 3/6 30 716 200 5/0 5/8 6/8 10/0 3/10 CABINET MOUNTED. 32 950 262 6/0 7'3 8/0 12/6 4/2 Complete in Polished Solid Mahogany Case, 34 1,300 362 7/0 83 10/0 13/6 4/4 with Ebonite Top, and fitted with graduated 36 2,000 530 8/8 100 13/0 15/6 4/8 rotating Dial and Knob. 38 3,000 850 11,3 130 18/0 19/0 5,18 40 4,8001,330 15 0 176 2D/0 22/8 7/6 PANEL MOUNTING. Per oz. Complete with graduated rotating Dial and 42 7,000 - 1/0 1/4 1/9 2/0 8d. Knob, also necessary fixing screws. 4411,000 --- 3/0 3:8 1/0 Each Instrument is carefully tested for accurate 4727,000 - - 6/0 7;6 2'6 Pro Rata. Allow- for Spools3d. extra. rapacity and electrical efficiency, before despatch. Please remit ample postage.Balance will be returned. Cabinet Mounted 101 mid.-- IT 6 Have you got our price lists, 3d. post free. Prices Panel Mounting '001 mfd.-- If not you are wasting money.Liberal discounts to the trade. Delivery from Stock. Trade Enquiries Invited. J. L. CARTWRIGHT & Co. Sole Manufacturers : New Offices and Showrooms THE DINE - RADIO CO., 24,London Road, Manchester. Scientific- and Wireless Instrument Makers, Works;BERRY STREET. 'Phone :Cent. 4209. 'Grams.: Pladuram, Manchester. Wholesale Distributing Agents for Scotland- 146 Sunbridge Road, BRADFORD. I. CORSTON SINCLAIR & CO., 47, Waterloo Street, Glasgow. ale.: Bradford, 5966. C EC HIGH TENSION DRY BATTERIES for WIRELESS SETS

NORMAL SIZE, No. W 70 V, 55 Volts W 71 V, 50 Volts GIANT SIZE, No. W 73, 55 Volts Price5/- Price15/ - Price 6/6 SUPPLIED IN TWO SIZES FOR15,50or60 VOLTS andwith Tappingsin3VoltSteps. ALL BATTERIES FITTED WITH PLUG SOCKETS ANDMOVABLE TERMINALS. Complete Illustrated Price List on Application. THE EFANDEM CO., LTD., FALLINGS PARK WORKS, DRY BATTERY MANUFACTURERS WOLVERHAMPTON xxxiv THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18, 1922

"RADIO -WAVE" Broadcast Valve Receiver This instrument has been approved for universal use by the Postmaster -General.It bears the P.O.Serial Number, and purchasers quoting same on applying for a licence will not fail to get one. PRICE £10 : 10 : 0 SPECIFICATION. Supplied with genuine Marconi Valve. Fitted with Filament Current Control.This enables user to work at most sensitive temperature of filament and also prolongs the life of the valve. Provided with Series Parallel Condenser Switch ensuring efficiency on both broadcast and amateur telephony and telegraphy. Tuning Inductance tapped in 12 places.This in combination with the low capacity tuning condenser ensures roo per cent. tuning accuracy, thereby promising abnormal signalling distances. The Grid Leak and Condenser, embodied by special arrangement with the Marconi Co., ensure that perfection of rectification essential to the purity of speech and music received. The top panelisof matt surfaced ebonite suitably engraved to indicate functions of all knobs etcInstruc- tion card is also supplied. All brass fittings are precision made, highly burnished and, being treated with lacquer, will not tarnish. Price with 2,000 ohms Sterling Brown Telephones,60 -volt variable H.T. Battery, 4 -volt Accumulator, 7/22 enamelled aerialwire,4 insulators- £15: 15 : 0 Illustrated Catalogue Post Free. THE MEDICAL SUPPLY ASSOCIATION, LTD. 167/185, Gray's Inn Road, London, W.C.2. Works: LONDON & SHEFFIELD. Telephones:MUSEUM 7210, 7211, 7212.

Laboratories and Factories : All communications to Reg. Offices I King's Rd., St. Pancras,

265, STRAND, W.C.2 LONDON. ANODE Tele. Nos.: City 4887; Cen. 3722 I WIRELESS AND SCIENTIFIC INSTRUMENTS LTD. Members oftheDritishOroadcasting Company

ANODE POPULAR SETS. Variometer "C" (simplified model) I These Sets Receive Two Bands of Wavelengths - 150-600 metres... 150I 353 -600 metres (for British Broadcasting) Fitted with coupling coil ... 1 17 6 2,003-3,6)0 metres (for Paris Time Signals and Concerts, also NAIIEN. POPULAR CRYSTAL SET ...£4 116 ANODE PATENT VARIOMETERS I (7i" x 5r x2)" with Renewable Crystals). (New Type) Patent Condenser Tuning. Improved pattern employing Two Lattice Wound Coils I POPULAR SINGLE VALVE SET... 7 100 only, so keeping both Resistance and Self -capacity low (3" x 8" x 8" with Fixed Reaction). Patent Condenser Timing Model 'A" 350-3,600 metres ...£3 18 6I "B" 2,500-25,000 metres... 3 18 6 ANODE VARIOMETER SETS.

Employing our New Type of Patent Variometer 350- "A" or "B" fitted with Vari- 3630 me.res continuous. able Reaction Coil ...... 4 150 CRYSTAL SET ...... 676 I (7r x 5}" x 51" Renewable Crystals). The above Variometers are complete in Cases. SINGLE VALVE ... 8 196

(9" x 6" x 51" with Fixed Reaction). Also supplied for Panel Mounting.Same price The above ReceivingSets all conform to the Manufacturers to Post Office design of Receiving Sets now in I Postmaster -General's latest Regulations. operation at " Leafiel I " " Cairo " " Northolt " etc. I

NOW is the Time to Order. Your Final Choice.Why Not Your First? Trade Enquiries Invited.

in= NOVEMBER18, 1922 THE WIRELESS WORLD AND RADIO REVIEW

re:. The Consult Our GREAT BARGAIN OFFER LargeIllus- World" Universal Electtic Supply: tratedCata- To Readers of the " Wireless 4 BROWN STREET logue for For a short time only 2elephonc: ONE WOO FRON IAIARKFT5*11,649,19Ohise 3409 CITY 1892 Best Value in -while the stock 1MANCHESTER allWireless lasts. G.P.O. Box No.519. Supplies and Our Wide Range of" Wireless Supplies " Complete Affords the Best Selection. Sets. Post 2,000 Free 6d. Pairsonly Audio Frequency Trans- 67, 4,000 ohm former. Remarkablycient- 27/6 PHONES Competition Type, Reli- able quality - (NEW) 22/6 at TelephoneTransformers 22/6 and 20/- High Frequency Trans- former, VariableType, 1 7 /6 35/ - PER PAIR. Plug -in Type, unwound, 3/ - Postage1 - Wound for various wave- extra. lengths from 6/-. HoneycombCoils Fitted headbands and cords, beautifully finished, thoroughly Best Finish. Excellent efficient.Each pair carefully packed inbox.Satisfaction Results- guaranteed. Metres Price Metres Price A wonderful bargain, never before offered and cannot 1804/6 1,5007/- be repeated.Readers of the " Wireless World " are 3004/62,0007/10 urged to take advantage of this astonishing offer im- 4505/- 2,500 mediately. All orders will be executed in strict rotation. 60o5/-3,500 9/ - Boo5/2io,600 11/10 Great Saleof our enormous stock of 1,0005/6 i8,00o 14/ - Prices forother wave- TERMINALS lengths on request. Coil Holder - 3 -Coil Type 21/ - Mountedon polished Base .. 27/ - DOUBLE BEAD RECEIVERS. Finest Quality.

2 B.A. Double Solid Brass or Plated, 2/- per doz. (postage extra)

2 B.A. Single 96. 91 Of Of 9* SpecialOffer at Reduced Prices of our W Inter valve Transformer 1J.E.S.Lond Speaker, Owing to the unex- superior to pectedlylargesale thosesold of these instruments, atdouble we areenabled to theprice, reduce theprice to 88/-. " WirelessWorld " readers to- Complete with Cords, 4,00o 141- Postaeiv.m. ohms, 22/8 ; 8,000 ohms, 27/6 Fittedwithpanel Wireless Cords for Double fixingplate and Head Receivers 2/3 earthing wire for iron Condenser Vanes, 3i" diameter, thickness core.Fully te,ted. 040" Fixed and Movable 1/6 doz. Ratio 5:1. Centre Rod, 4fr" overall, complete 4/6 To obtain goodsat Threaded Brass Rod 744.ft these special bargain Special High prices, please mention Grade Accu- the "Wireless World " mulators for Wireless Ser- We have ENORMOUS STOCKS OF EX-W.D. WIRELESS vice: 4 -Volt GEAR, too numerous to mention, at absurdly low prices. 40 Amp .,21/- Write for particulars of your requirements or, better still, 6Volt40 call and see our enormous stocks. Amp.,80/ - Terminals to fitPocket J. LIPOWSKY & CO. LampBat- 614, Old Ford Rd., Bow, London, E,3 teries .. 11d. Telephone-East 3345. Neat Old Ford Station, N.L.Ry. Nos. 8 or:39 'Bus Make up your own H.T. Batteries.

E2 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18, 1922 ill //Nil/,j 01 (5(

POLAR "CONDENSERS AN APOLOGY.

The immediate successofthisoriginaldesignofvariable condenser withitsextremecompactnessandefficiencyhas had twooutstandingresults :-

1. Ithas demonstrated thatalargesection of the wireless public are.looking for something better than the usual multi -plate Condenser. 2. Ithas exhausted our stocks. We offeranapologytothose whom we are havingto keep waiting for delivery and would assure them that every effort is being made by our works to accelerate production. Allorders willbedealtwithinstrictrotationin the meantime, and we donotanticipatethatthedelay will inany case exceed A FORTNIGHT FROM RECEIPT OF ORDER To avoid a similar disappointment in the case of " POLAR " BROADCASTING SETS you should apply at oncefor your copy of our new catalogue, " POLAR " RADIOPHONES & ACCESSORIES, and thus be in a position to secure precedence by an early order.

RADIO COMMUNICATION C 9 Lin) 34 and 35, NORFOLK STREET, STRANDLONDON, W.C.2 NEWCASTLE: :7, Sandhill. LIVERPOOL :67, Dale St. CARDIFF : Atlas Chambers, James St. S31J FHAWTON :zn, Queens Terrace. GLASGOW :to, Blythswoxl Square. NOVEMBER 18, 1922 THE WIRELESS WORLD AND RADIO REVIEW xxxvii BROWN'S

HEADPHONES British and Best

The Finest Headphones Procurable for 30/- This priceisforone pair of either TYPE F. " Featherweight." 120 or 4000 ohm 'phones, including Actual weight, including cords, cords of good quality. is 6ozs. only. Catalogue Post Free. Head Office and London Works : Showrooms Victoria Road, 19MortimerSt., North Acton, W.3 S. BROWNy Ltd. London, W.1

`-he Wireless World Wireless World POCKET DIRECTORY DIRECTORY OF () Amateur & Experimental Regular Transmissions OF TransmittingStations Wireless Stations.

pricee- post free. PRICE 6D' POST FREE.

Giving particulars of 380 Amateur Trans- Containing full particulars of over 350 of the mitting Stations. Chief Stations of the World. The Wireless Press, Ltd. The Wireless Press Ltd. 12 13, Henrietta St., Strand, London, W.C.2 12/13 Henrietta St., London, W.0 2 xxxviii THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18, 1922

OP Ser es No. 7 Elegant Receiving Cabinets to meet a new Public Demand

(Model No. 2) Chippendale. The graceful lines and perfect finish of is as efficient as any produced.It has a this Chippendale Cabinet appeal very minimum range of 200 miles, and under strongly to the Wireless enthusiast who quite ordinary conditions its range is wishes to install a Receiving Set that appreciably greater.It contains a Valve will really take its place as part of the Detector and Tuner, a Low Frequency furniture and equipment of the drawingAmplifier, andthe Loud Speaking room.The equipment it contains, forEquipment. The Batteries are external. the reception of wireless broadcasting,Western Electric Quality throughout. Western Makers of over Half the World's Telephones. Electric 62, Finsbury Pavement, London, E.C.2 Telephone-London Wall 7608 WORKS :- North Woolwich, London, E.16 Telephone-East 3840 (xo lines) Also at BEXLEYHEATH, KENT, and NEW SOUTHGATE, N.11 Co Birmingha m-Grenville Buildings, is, Cherry St. Manchester-Northern AssuranceBuildings. Leeds-Si. ndard Buildings, City Square. Newcastle -20Saville Row. yCW Cardiff-li otor House Chambers, /, Wood St. Glasgow -49, West Campbell Street. Cas5 VS,. 1U

ZONDO'' NOVEMBER 18, 1922 THE WIRELESS WORLD AND RADIO REVIEW (Ibis is ljaur Altu Devereux Court, on the ancient site of the headquarters of the Knights Templar, is the origin of our authoritative wireless publications. Emerging into the world amidst the traditions of Law and Order, of Chivalry and Truth, they carry with them the House -mark of the Radio Press-the heraldic shield - so so that all men shall know their origin and feel confident,

" PRACTICAL WIRELESS VALVE CIRCUITS." By Jou,:SCOTT-TAGGART,F.Inst.P. 26 net (post free 2'84 Cloth 3 - net (post free 3,1). " WIRELESS VALVES SIMPLY EXPLAINED." ByJOHN SCOTT-TAGGART,F.Inst.P. Cloth 3 - (post free 313). Paper 2 6 (post free 2 8). " CONSTRUCTION OF WIRELESS RECEIVING APPARATUS." ByPAULD.TYE RS. 1(6 (post free 1171).

lOrtsz Xitnitrb Devereux Court, Temple, W.C.2 (Opposite Law Courts) linessiiiiiiiiiimmionimineniiiiiiintinimiiiiiiiiimmiliiiiiimmilisiminuiliiiiiiiiiininimilliffiliiiiiiiiiiiiiiiiiiimmat

_____, Having over 13 Years _-_-- ._-_

Experience in Wireless :=--- --_.

I offer to those interested in installing a receiving E -- set in their homes every assistance possible,and am ready to supply promptly justthe apparatus =---:- In my showrooms you can inspect they desire. .--.. and purchase any of the following :- .

--_-_= Alltypes of MARCONIPHONE receiving F.--.._ sets.PARLIPHONE and other high quality --= LOUD SPEAKERS, CRYSTAL and --1.- VALVE DETECTORS & AMPLIFIERS. ....- reception. ..= Severaltypesof VALVES for -=, HEADPHONES byvariouswell-known --_. manufacturers. ACCUMULATORS of z± - '417) -0 reputed make and efficiency. -..- Ialso haveinstock ALL WIRELESS _... ACCESSORIES AND PARTS. .7.77 --_-_, ---=- `Demonstrations at all times. ..--_-: I p.m. "=--- 1' Business Hours : 9.3t to 6.30 p.m., Thursdays 9.30 to --=. = . AL,13Ftcovv, -= H. V. Experimental Yacht "6lettra," = . Late Chief `rechnica! Assistant on the _..- PORTMAN SQUARE, LONDON,W.1 =- 56, GEORGE STREET, Mayfair 5842. xl THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18, 1922 WIRELESS TRAINING COLLEGES, LTD. MARKET BUILDINGS, CARDIFF, & ALBERT RD.,BOURNEMOUTH The above Colleges are amongst the Most Successful in existence. We are NOT A BOOM FIRM but have 10 years reputation for not only Passing our students, but what is most vital, GETTING THEM BERTHS WHEN QUALIFIED. This past three months we have placed over 30 Youths in Permanent Berths. We instruct on Valves, and 11 kW. Marconi Sets.We have NOT a Qualified Student out of berth to -day. Also Wholesale Distributing Superintendent for Messrs. Stuart Wireless Telephone Co.,the Valve Set which NEVER FAILS YOU. Agents, ,Wanted. Wholesale Only. Principal : HON. LT. COMMANDER J. R. SCHOFIELD, M.B.E., R.N.V.R. (C). P.S.-Students taken individually, so can enter any day suitable.

WIRELESS TRAINING HighFrequencyTransformers Interchangeable Plug-in Type. Most thorough trainingin Wireless Telegraphy Former turned from best quality ebonite, fitted with pins to take standard valve socket. orTelephonygiven underidealconditions. Ranges as follows with a 0002 variable condenser connected across primary winding. Special Postal Course for Amateurs. No. 1. 150- 300 metres .. 3/6 Prospectus Free. No. 2. 300- 600 metres . 3/6

No. 3. 500-1,000 metres.. .. 3/9 No. 4. 900-1,800 metres.. .. 4/ - WIRELESS APPARATUS No. 5.1,700-3,000 metres.. 4/6 Thousands of these have been sold and are giving every satis- Complete stocks of all Wireless Instruments and faction, the efficiency being equal to those offered elsewhere at Accessories. Prompt Deliveries. List lid. stamp. much higher prices. Buy from the actual makers and save money. ELE CTRI C AL ENGINEER WIRELESS COLLEGE A. WOODAND MANUFACTURER 44 BRA CEBRIDGE STREET, NUNEATON COLWYN BAY TRADE SUPPLIED. Special Tuning Stand for EBONITEuse with BasketCoils. EQUIPMENT FOR WIRELESS SETS SHEETS, KNOBS, COIL HOLDERS, VALVE HOLDERS, ENGRAVED DIALS, SOLID EBONITE HORNS FOR LOUD SPEAKERS, PANELS Simple and efficient.Movement givesclose and accurate adjustment. Coils are rigid, being mounted on ebonite formers, fitted with FROM STOCK sockets for plug mounting. PRICES.-Tuning stand as illustrated on Ebonite Base.. 12/ - Complete set of 5 coils and stand, 220-1,300 metres.. 22'- NOTE.-Coils can now be supplied for wavelengths up to 4,000 metres (prices on application). IIIGHTENSITE LTD. Formers only, with ebonite socket .. ..each 1,6 Normandy St., Custom House, E. 16 REYNOLDS & BRADWELL, 'Phone :EAST 3153. 41,ChurchStreet,Birmingham. Ni/VF:31131,:lt ISI 922 TH E Will 'MESS,N VOlt 1,I) AND HA DIO REVIEW xli .QUALIIY " NATIONAL99 EFFICIENCY Approved ONE OF OUR BROADCAST RECEIVERS Guaranteed by P.M.G. TYPE N. Mk.II. by Us.

ALL INSTRUMENTSareTested THIS INSTRUMENT has been and Calibrated by usbefore leaving designed by us to meet the demand works.Our Finish and Workman- foragood,yetinexpensive,set, ship is the best. which will always be ready to re- The cases are very handsome, being ofaSpecial EboniteFinish.No ceive - Amateurs, Broadcasting, inferiorpartsareusedinmanu- Croydon andParis Time Signals, facture. etc. It may be used either as a PRICK xr lulling A,essories Crystal Set only, or in connection with the Valve, which amplifies ally weak signals, rendering them easily £5:5:0 ofyour Complete with Best Quality Accum. audible.Intheevent Battery, Accumulator or H.T. Battery giving 4v.6oamp.,36v.H.T. 'Phones,4,000ohms, R.Valve, out, you can still go on " listening Aerial and Insulators- in," by simply changing over your 'Phones to Crystal Terminals. Tuning £8:15:0 iseffected by studded switch and CRYSTAL largevariablecondenser,and aSize of case DETECTOR, SUBJECT TO ROYALTY 1 VALVE Calibration Cardissuppliedwith sr CARRIAGE FREE x 31t" AMPLIFICATION. each instrument. TRADE SUPPLIED We stock everything and are genuine manufacturers. Come and see our works and stock. THE NATIONAL WIRELESS& ELECTRIC CO. 74, CHURCH ROAD, ACTON, LONDON,W.3 NATIONAL WIRELESS CO. ACTON. Telephone:CHISWICK 2266. Telegram; :

Genuine Radcom Duolateral InductanceCoils " DE FOREST PATENT " Thesecoilsaredesignedtoreducetheself capacity of a receiving inductance to a minimum. RADCOM RHEOSTATS, TUNERS, TRANSFORMERS ACCUMULATORS. ORDERS VALUE £2, NOT EXCEEDING 11-LBS. WEIGHT, CARRIAGE PAID 12'13, HenriettaSt., PRICES LONDON, W.C.2 Telegt amp : M)UNTED COMPLETE, FROM Ter, ne : adioCOMPONENTS LT Gerrard Radponents. 5, - 792. Rand,London. E.P.S. 3) Triple Test rilulti-Crystals Sensitive -Galena(G), Radio -Pyrite(P),Aero-Silicon (5), Tellurium IT), Zincite (Z), Zinc Oxide (0). Questions and Answers

Radio Sextet P.G.S.T.Z. & 0. . 3 - Radio Triplets G.P. & S. . Radio Twins G. & P. .. 2 6 COUPON Radio Twinlets, G. & P... Radio Singles, G. or P. or S. .. 1/6 To accompany Questions All crystals tested for sensitiveness three times, and guaranteed " live." sent in duringthe week Mounted for fitting standard t" cups. If you want reliable crystals to get the best results from your cvmmencing Nov. 18th, 1922. receiving set, obtain the above from your dealer, or send P.O. plus 2d. postage, to- VOL. XI, NO. 7. J. H. COLLIE & CO. 8 HARRINGTON STREET, LIVERPOOL See Conditions on Page 249. Sole disttibut n7, azt nts for the Foote MineralCo., U S.A. Trade Terms for mounted and unmounted crystals on application THE WIRELESS WORLD AND RADIO 'REVIEW NovEMBER 18, 1922 BUTLER'S MAST SERVICE Reliable Manufactures. ONVIINIZED At NIA( 'Witt r

- TUBULAR STEEL- -RADIO MAST-

40HearFEW 10 1,1, Ste' Maus(lat./Al" mar IV uI

MKT CAICYANII(P frret WIT YS

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1. Fil.Resistance ..7/9 13. Multiple Valve 2. 9 -Stage H.F. Trans- Holder .. . . 3/10 former .. 52/6 Also made up for 3 or 4 valves. TYPE -13- MAST 3. Vernier Condenser.. 5/6 STAY INSULATORS 14. New Type Valve 4. Grid Leak and Con- Holder, no exposed denser.. . . 4/6 metal 1/5 5. Multiple Contact 15. Valve Holder ..1/4 Switch .. 10/6 16. On and off Switch ..8/8 6. Unmounted Fil. Re- sistance ..5/3 17. 1" Radius Switch Arm 2/2 TY4L2'...°4" 7.( oil Holder, 3 coils 15/6 18. -0003Fixed Con- denser .. 5/- 2 Coils 12/6 19. Three-way Switch ..4/6 8. TumblerSwitchin sIrro:gfeeits 20. BrassValveLegs, ....ouvrzo Erenoid . . 2/6 JrAr moo each .. 3d.and 21d. TYPE 'A' SASE 9. Skeleton Condenser from.. .. 13/9 21. Lead-inTubes,6", 2/3 12",3/-,etc. 10. Crystal Detector 4/10 22. Pin. TypeTrans- 11. Switch Arms ..8/- formers, price accord- 12. Coil Holder for basket ing to range. or Slabs, 36/-.With Made of best quality solid drawn steel tubes, 8 holders. Tapped New Fully Illustrated holder,extra ..8/3 List to aircraft specification for strength and Post Free, 4d. lightness.Designed for EASY ERECTION. H. ]). BUTLER Sc. Co., LTD. PRICES. Bank Buildings, 222 Gt. Dover Street, S.E.1 Complete in every way, ready for erection and Carriage Paid Telephones-Hop 3029. Works-North 1838. any railway station, England or Wales - Works-Canonbury. London, N.1 30 ft. 8 stays40 ft. 8 stays50 ft, 12 stays /3 15 0 24 10 0 15 10 0 Carriage Paid, Scotian]. : Above Prices plus 6 per cent. Mast Completely Insulated (Type B) 21/- Extra. WITH GOOD APPARATUS YOU Full specificationsent on request, CAN GET GOOD RESULTS also for larger and smaller masts. THE " W.P. " ERECTING GEAR. Specially Designed Erecting Gear for use with these Masts loaned against 20/ - Morse Practice Key deposit.With this gear a 50 ft, mast can Well Made. First-class Finish. Thoroughly Reliable. be erected by one man in 4 hours. Price7/6 Post Free TRADE ENQUIRIES INVITED. Manufacturer- THE WIRELESSPRESS,LTD. H. LONGTON, A.M.I.Mech.E. 12-13, HenriettaStreet, London, W.C.2 43, Johnson St., WESTMINSTER, S.W .1 NOVEMBER 18, 1922 THE WIRELESS WORLD AND RADIO REVIEW

JUST PUBLISHED. ..41111 I6Pages. handsome FREE coverinthreecolours, Elementary Text -Book on gives you full information \ OUR NEW BIG - and prices on Wireless ILLUSTRATED CATALOGUE Receiving Sets complete Wireless Vacuum Tubes. from £3 10s. to £12 10s. Hearallthe 4.6 (Enlarged and Revised) Edition. concerts,speeches,ser- mons. BY news. cropand SUPPLIEST weatherreoorts, now being broadcasted daily. JOHN SCOTT-TAGGART, F.Inst.P. Costsyou nothingafter first cost.Easy to install and operate. And hundreds of other Wireless articles. This book has now been enlarged and completely Write to -day. FREE. revised.Allthe latest inventions, including the Armstrongsuper -regenerativecircuits,arefully PERMANENTONLY described, and Major Armstrong himself recommends this new edition to all interested in valves. CRYSTAL 7/6 It is a large book, handsomely produced, simply DETECTOR written but complete and authoritative.It is the postpaid ideal text -book for the better class of experimenter Ready to attach to your set. and student. Greatest boon ever known to Wireless Experimenters. Always ready,no fiddlingorsearchingfor apoint. PRICE 101- NET. Crystal always active. Largest mail- order firm in Europe. (I, Important Notice.-All our appa, atm is guaranteed your money back in fullif Obtainable from or through all booksellers or direct /0/6 net satisficd. post free, from_ Write to -coy. Until° Puss, itttnitrb, BRITISH RADIO SALES CO. LTD STEPHENS IhNlITOGS.C.ItASSI ST. DEVEREUX COURT, TEMPLE, RATHPO. PIACI, LONDON W.I. (Opposite the Law Courts) W.0 2

MARCONIPHONE V.2. PRICE £25 : 0 : 0 RECEIVING MODELS FOR BRITISH BROADCASTING Incorporate unique features which ensure perfect reception Fullcompliancewith Government Regulations. THE MARCONIPHONE DEPARTMENT, MARCONI'S WIRELESS TELEGRAPH CO., LTD. MARCONI HOUSE,STRAND, LONDON. W C. 2. xliv THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 1§?, 1922 THE WIRELESS WORLD EXCHANGE AND MART FOR SALE. TARIFF. Advertisements are accepted for this Section at the rate of twopence per word, Fibre Sheet.-Besthard vulcanised, at greatly with a minimum charge of two shillings.Thereducedprices.Per squareft.,2',25. txl. ; advertiser's name and address will be charged for.3/8',4s. Ss. ; 06", 6s.6d.Stripsfor Electradix Radios and single letters and single figures will be countedpanels, by 3" by 3/8", is. 6d. each, other sizes in- Telephones instock as words.Compound wordswillbe countedpro rata.Postage extra.Trade enquiries Sterling Marconi. as two words. vited. -F. NV. Hour, 120. Arbor Vale, Slough. and 2,000 ohms, 491- All advertisements must he Two -Valve Telephony Transmitter (New), 4,000ohms, 50/-; DEPOSITS. complete.Ampmeter, variometer, prepaidinthe formofPostalOrders,themicrophone, 8,000 ohms, 57/ - remittance being forwarded to Messrs. Bertram400 to 5ooh., wound Lizendraht wire, oak cabinet, per pair, complete Day & Co., Ltd., 9 & to Charing Cross, S.W.s. £9. Three -valve amplifier.Ex -Government, £6. with cord and tag. Three -valve detector amplifier, £5.Both perfect Sullivan's L. R. Intending purchasers may deposit the purchaseorder.Marconi Mark 16 crystal receiver, com- orsoldby Head 'Phones with money of anyarticleadvertised plete,£7. All above can be seen working.- cord,14/8per pair. advertisers with Messrs. Bertram Day & Co., Ltd.,TELFORD. 2, Park Hill. Moseley, Birmingham. NewL.R.Head who will acknowledge its receipt to the vendor " L.B." Morse Senders. -200more at 6s, each, and the depositor, the full addresses of whom Sends any message any speed from Sets, 121- per pair post free. with cords. NOW should be given.Subject to special agreement2 to 8o words per minute.Will last a lifetime. 1,500 ohm Head between thepartiesitisunderstood that allandisspeciallyrecommendedforamateurs particulars Setswithcords. goods are sent on approval, each party payingrequiring homepractice.Further 20/- per pair, carriage one way in the event of the goods beinghalfpenny stamped envelope. -GRIALSHAVY'S willbe retaineduntil Single Receivers returned.The deposit (Dept. W.), Legh Street, Golborne, Lancs. and Cord,4/8each. due advice of the completion of the purchase has Three -ValveReceiverinMahogany Case, been given or until the articles have been ret linedsplendid for telephony, Hague, Croydon, Paris, Large stocks of in Ammeters and and accepted.In order to cover postage, etc.etc.,£1o. Mark IIIthree -valveamplifier, Voltmeters.Milli -ammeters and Hot\ a fee of 6d. in respect of sums of £1 and under,case, nearly new, £7.-FRAIN, Snainton, Yorks. Ammeters, 10 - to 60/-.Morse lnkers. 45 -. and Is. for sums in excess of £I, must be paid To Liverpool Enthusiasts,Detector and two - For persons Receivin ;Sets.MarkJIB. 2 -valve, in at the same time as the deposit. stage L.F. amplifier panels. complete with three polished mahogany case, new and guaranteed, not resident in the United Kingdom these feesvalves, unit system, also set N.E.I. Cos. inductances 675s. CrystalSets,variable condenser are doubled. We cannot undertake to receiveanddoublecolmounting, £11.--EUSTANCE, detector,andfixedinductance, mahogany any deposit less than 2s. fid. 92, Briardale Road, Mos12y Hill. Liverpool. including valves, case, 4.51-.50 D.C. Sets for Crystal and Two Seven -Valve Amplifier, R.A.F., Valves,275s.,illslopingdeskpattern, in perfect order. £18.--D.MMVBY. Wykeham, polished mahogany cabinet,calibratedfor Spalding. broadcastwavelength.Switch Arms,1/6 Earpieces, Earpieces, Earpieces, Western - 111/04 11.22MARK surplus, 15o Ohms, 3s. 6d. each, and 1/9 each. Electric G.P.O. Buzzers.2/6,8/6 and 5 each. Terminals, 63. pair.Postextra.Youcannotpurchase price.Catalogues. 2/6and 3,- per dozen.Valve legs,16.each. bettertelephonesatany Studs, 1,11 per dozen. NOTE THESE PRICES ! 6d. each, post free,43 pages.300illustrations. Condensers,2M.F., 1/8each. 4M.P., 5,f - Wavelength 150to 4,500Metres.-ELECTRICAL & MECHANICALSUPPLIES CO., each. VariableforPanel,8/6,11/3and 24. Leytonstone Manufacturing Electricians, 13/9.oot Cabinet,32/6,Murdoch Rheostats Road, London, E.15.Established 1904. for panel, 7!3, with vernier extra lever 8/-. Dewar Switches,2 -way double pole, 3s. each, Our make. 3'9. Connecting up wire, 23'5/40's, new.Telephone indicatorrelays,1,000 ohms, Newton Meatus, ld.per yard.Insulated Sleeving,ficl. per yard 3s. new.-LAMBIE, Waterside in four colours. Scotland. enamelled copper, 5/6 per G. Z. Auckland & Son,395, St. John Street, Aerial Wire. -7:22 E.C.I. have for disposal 3 7 -valve R.A.F. amplifier, too' ; hard -drawncopper,5/6pertoo'. T.F. receiver, 150-2,5oom. and r 1,500-v. Mackie Aerial Down Leads, 12 yd. lengths, 1/- each. EarthClips,6d.each. Earth Mats, 10 - Generator.All ill excellent condition, and offers for the whole or part invited.Write or call as each. Transformers. Intervalve Transformers, 20' - above. each. TelephOne,15/-,all brand new and Single Valve Receiving Set,everything complete, Lightning parts, £5 cos,- FIRTH, 275, Park Lane, Bradford. guaranteed. Arrester 8d. 15s. ; two -valve, 35s. ; Switches.AerialtoEarth,2/9.Dewar V el% e Panels,Single, Flush type, three-way lever switches, 3/6 each. EXCELLENT FOR TFJ.F.PHONY. three -valve,55s.; tested,guaranteed.Trade 3o amp. Per set of 7, 5 -.Post 3d. supplied. - BUDD. Wireless Depot, Dartford. Eight -way A.T.I. Switches, 8/-. Amateur has for Sale-Twosingle -valve panels D.P., 3.13/-.R.A.F. Light Weight Insulators, CONDENSERS. Ebonite,4d.each. in mahogany cabinets. £210S. each.Complete 6d. COMPLETE SETS OF PART new, £m cos.,nearest H.T.BatteryUnits.44volts, each ; single -valvereceivers, 15 volts, 8,2 each. Approx. No. offer.Three -valve set, complete with tuner, £m. los.H.P.R. All Wireless Components can be Supplied from capacity of Price C.mk,IV 3 -valve amplifier, £4 Stock.Write for Catalogue, 4d.Call and Urof'ds. Plates. complete single -valve receiver, range 400-30,000h, cost £42, take £1S.Three Sullivan now. tele inspect our Huge Stocks. oor 58 phones, iris. each.Two telephone transformers TheHandiest DepotforCityBuyers. .00075 43 61 with condenser,ros.each.Brown large loud Near Aldgate Station, Metropolitan Railway. '0005 30 56 speaker, £4.Two -valve L.F.amplifier, £3. First on the left in Minories. '0003 19 4 Magnavox, £8 cos-Marconi 50 -Watt transmitter L032 13 6 and receiver, less condenser, £4.8" X-ray coil, LESLIE DIXON & CO., .0001 7 3 - with tube£8. Marconi ceor mf. variable condenser. After 7 p.m.telephone Putney, 131. 5, COLONIAL AVENUE, MINORIES, E.1. Postage1.- per set extra. -MULHOLLAND, 73, UpperRichmondRoad, Will makeup asillustrated Putney, London. each Best Tumbler Switches,is. each.Post fn, FLAMM', RESISTANCES 4 - HIRONS, 51, Brook Street, Warwick. 7/6 A.E.G. VALVES, TESTED For Sale.-Two-valveReceiver, including coil 10 MARCONI " D " TYPE stand, set of 7 coils, 150 to 4,00o metres, 2 variable PostageExtra. ALL AMATEUR WIRELESS SUNDRIES condensers, r fixed, 2 pairs of telephones, r Brown's, (4,000 ohms each), 1 inter -valve IN STC LK. Sullivan's To Radio Firms. ILLUSTRATED CATALOGUE IN COURSE transformer, switches, etc.Six -volt accumulator (Exide), 6o -volt H.T.. all mounted, brand new. Gentleman with office"and aerial central Leeds OF PREPARATION. Shroggs, Hebden Price £18.-H.7, SUTCLIFFE. requiresAgency for progressive firm. Good Bridge, Yorks. Grafton Electric Company Mark 3 Star Tuner, Marconi,brand new, £8. connectionthroughoutYorkshire.Address Stoic rooms -5 4 . GhAF1ON STARE], Complete, 3 valves set, unit system with valves, particulars to T01 I ENHAMCOURTROAD tuner,condenser,batteries, telephones, £x5. A. C. DIXON, A.M.I.R.E., LONDON. W Telephone-Museum 241. Burndept 3 coils tuner, latest design with set of Works-Slough. 8 coils, £9.-W. H. GARDAM. 7, Poultry, London. 6, THE DRIVE, ROUNDHAY, LEEDS. E,C.2. lv NOVEMBER18, 1922 THE WIRELESS WORLD AND RADIO REVIEW THE WIRELESS WORLD EXCHANGEAND MART FOR SALE-continued. ExperimentalGearforSale.-Morsehiker, Cheapest house inthe Trade for £5.Relay, damaged, 7s. 6c1.Navy type tuner, 3os.Three -valve set, £6.Lot of chokes suitable fortransformers,5s.each.Mark IIITuner, converted, £3 los.Sparktransmitter, £1. Graham 2,000 ohm loud speaker, £4 15s., new. Wireless Buzzers,5s.each.Accumulators,2 x 6 volt, 42 amp. actual, pair, £5 ;2 X 4 volt too amp., pair 10S. Brown's 8,000 telephones, £2 5s. Supplies LIVERPOOL MARINE French telephones, new, La pair.Crystal sets, 25s. each.Quantity terminals, etc.Whetstone AND GENERAL Bridge, Li nas.-GAsroN, 1, Tugla Street, Catford, S.E.6. INSURANCE CO.,LTD. B.A. Screws, Nuts and Washers, assorted gross Equipment 2S.,lists 2d.-J. H. BENNETT, Station Road, London Office : 7,Angel Court, Willesden Junction. (Wholesale only) Throgmorton St., E.0 2. Wireless Masts.-Improved Girder Type, Light and strong, 3o to 5o ft. at is. ft., 5o to too ft. 4,LittleTitehfieldStreet, at Is. 6d. ft. Cash with order, carriage forward. - Oxford Circus, FIRE. ACCIDENT. MARINE.F. ARMSTRONG, Weybridge. ASK FOR Agate Cylinders, etc., for loud speaking apparatus LONDON, W.1 Write fo, particulars of our SPECIAL from JAMES R. GREGORY & Co., Mineralogists, T,leatone- Gerrard 6113OUR LIST 139, Fulham Road, S.W. WIRELESS POLICY (Aunu41 LoudSpeakerHorns.-Guaranteedperfect Premium 7 6) which covers fire and acoustics.Allsizesfrom4s.6d.,complete other damage ,o the complete %. ireless with polished aluminium receiver base.Usual EBONITE "A" TYPE 4 PRONG Set and also indemnifies the Owner trade terms.-MIDLAND RADIOPHONE CO., Hearsall Works, Coventry. VALVE HOLDERS against claims arising from damage to Wireless Amateur going abroad wishes dispose property or persons through the break- of new Marconi Unit Set, comprising plug coil 1 - each, post free. down of outside aerial and its supports. tuner, oI condenser, three -valve panel,r H.F., dect.,t magn., telephone trans.Every wavelength covered.Allinstrumentsmadeby WILKINSON. Marconi Co., cost over £35.Will sell £27 IOS. LONSDALE RD..KILBURN, N.W Box Q5, BERTRAM DAY'S ADVERTISING OFFICES, 9 TRADE l.1/I'Llr D. Established 1900 and to, Charing Cross, S.W.I. HEATH & Co., Ltd. BUSINESS FOR SALE. Instrument Works, New Eltham, 5.E.9 Small completely equipped workshop in S.W. To the Trade are prepared to undertake in their fully district, until recently engaged on production of wireless work.Gas engine, lathe, muffle, presses, CONNOLLY'S (Blackley) LTD. equipped works-WirelessApparatus grinder, charging plant, etc., etc.All in absolute and Parts for the trade. Quotations given running order.Must be sold owing to dissolving Blackley, Manchester. of partnership.Seen any day by appointment. to Blue Prints. Immediate attention. Noreasonableofferref used.--ComeroN, 17, ENAMELLED WIRES for Phone-Lee Green3oz. Polat-h, Loonier Fernshaw Road, Chelsea. AGENTS WANTED. MAGNETS and AERIALS Old -established London Firm, making one to London Office ;18, Victoria St.. S.W. 1 five -valve broadcast receivers, desires provincial TeL Vic 6368. Telegrams : Lifehold, Vic ENGRAVING agents.Every assistance and good terms offered. for every style of instru- -Box76,c/oF. ALDRIDGE, 26,Paternoster ment on anymaterial. Row, E.C.4. SITUATIONS WANTED. A.S.A. Guaranteed Advertiser (25) seeksprogressiveposition, F. OSBORNE & CO., LTD. nine years practical experience wireless, designing, WirelessProducts 27, Eastcastle St., Oxford Bt., London. W.1 erecting,testing,maintenance,demonstrating, Est. 1374. Museum z 64 two First P.M.G. Certificates.-Write Box H.7, BERTRAM DAY'S ADVERTISING OFFICES, 9 and ro, B,st Filament Resistances .. 3/- Charing Cross, S.W.I. 15v. H.T. Batteries-The Best.. .. 3/- Grid Leaks and Condensers.. 2)6 SITUATIONS VACANT. Fixed Condensers, -002.. 2/- Your Case Work Wireless Firm has opening for gentleman with Laminated Switch Arms and Bush.. 2/- Let us quote you for your wireless good technical knowledge to take complete charge Condenser Vanes, the best .. doz. 1- casework. We are specialists in this of amateur section.Investment, i30o to £500. Vernier Condensers, -0001 4//6 class of work and feel sure our work- Genuine opportunity. Box H.6, BERTRAM DAY'S Variable Condensers in Cabinet, -0005.. 18/6 manship and prices will interest you. ADVERTISING OFFICES, 9 and in. Charing Cross 100' 7/22 Aerial Wire.. 4/- Phone-L.W. 2720. S.W.I. 4,000 ohm Headphones (good).. 25/- Crystal Receiving Sets .. - . 25/- CARRINGTON & NEWBERY LTD., TRADE ENQUIRIES. Sets of Parts for 2 -Valve H.F. Amplifier30- 2 -Valve L.F. Amplifier .. 40//- 1023, Normans Buildinrs,Lid Street, E C ManufacturersofReceiverSets,Partsand accessories, are invited to send full catalogues, 8 -Valve H.F. and L.F. Amplifier . etc., to the Wireless Service Co., Ltd., 2, Lower Cabinets, 10" x 6" x 4", polished .. 60/- STEEL TUBULAR MASTS. John Street, Golden Square, Piccadilly, W. Condenser Boxes, polished .. 2/6 These mastsarelight,strong andeasily 3 -Coil Honeycomb Holders 13//138 Working Drawings supplied for wireless ap- H.F. Transformers, for Broadcast .. 6 erected and lowered by one man, and are paratus.Motors, generators,etc.,designed, 1/6 fitted up complete with Halyard and Pulley, Informationandadvice.-PrciccE,Buckhurst Honeycomb Coils from Baseplate, 4 G o mid AngleSteel Ancho's Hill, Essex. Concert Coils -PerPair fitted with ring for fastening guy lines, flexible Wireless Dealers throughout Great Britain are Coil Holders, for same . . 5/- steel guy lines with insulators and strainers, strongly advised to stock parts for making up OUR LIST BEATS THEM ALL. painted ready for erection, 10', 15/- ;20', 25/- ; wireless sets.Buy your parts direct from the 80', 35/- ;40', 50 - :50', 70/-.Any height factory at wholesale prices.-NEwTONIA WIRELESS quoted for and extra sectionssuppli(d,all FACTORY, 13 and 15, Whitcomb Street, W.C.2. Amateur SuppliesAssociation sectionsinterchangeable.Prompt delivery, Inventors.-Consult firm with 35years'ex- Freeonrail. Cashwith order.-ABBEY perience ;models, ideas ;advice free ;references 184.Cotelord Street, Tooting, S.W. ENGINEERING t LWORKS, WA TTO N, to clients.-E. DORCET CO.,14, Augusta Mill, Works:198.HighStreet,Merton,S.W. NORFOLK. Warstone Lane, Birmingham. xlvi THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18, 1922 THE WIRELESS WORLDEXCHANGE AND MART

FOR SALE - continued. Reputable House R. Valves 10/- each, £5 per dozen.B. Valves 12/- each, k6 per dozen.All new and tested. ELFCTRADIX WIRES Post free.B. CALVER, 52, Linver Road, London, Highest Conductivity at Lowest Prices. inBuenos Aires S.W.6. Gauge. D.C.C. S.S.C. D.S.C. 16.. 1 7 .. - 36 is interested in Radio Telephones and 18 1 91 . - 39 20 111 40 46

Accessories-particularly apparatus 22 25 . 46 50 for amateurs.Letters and Cata- RESULTS 24 3 0 .. 50 59 Whether as a source of practical 26 logues should be addressed to 28 42 .. 5 9 810 information for the Amateur or 11 R. & L., c/oC. W. HARTRODT as a valuable medium for every 32ao 661 . 82 90 Advertiser, the best results are 34 79 96 107 & CO., LTD., invariably obtained through the 36 92 113 1231 9/10,ST. MARY -AT -HILL, 38 1110 136 173 40 1624 . 17 0 235 LONDON, E. C.3. "WIRELESS WORLD" Prices at per lb.Postage Extra.Earth Clips. 6d. each.7/22 Aerial Wire, 5!6per 100 ft. Trade references will be submitted parlvtula, e. adr

Reliance Radio Service Co. HIGH-CLASS RECEIVING SETS AND COMPONENTS.

THE " RELIANCE "No.1 CRYSTAL RECEIVING CABINET. Consisting of Ebonite panel mounted in Oak cabinet with lid, Tuning Coil and Condenser.Patent Crystal Detector totally enclosed in glass.4,000 ohms.Double Headphones, 100 feet stranded copper wire, 2 shell insulators, etc. No further outlay.No batteries required.Each set has been tested and carries our guarantee, and we confidently assert that for the price it is the most compact and reliable that is obtainable. PRICE COMPLETE INSTRUMENT ONLY £.3 150 £2 2 6 We have also a complete range of111,., icing Sets and parts in stock, both Valve and Crystal. Send for our A rt Catalogue, Post Free on Application. Our sets are open to inspection at our London address at any time. Demonstrations given with pleasure.You will not be urged to buy as we know you will come to us after you have compared our goods with other makes.Call, phone or write. `Grade (enquiries Solicited. RELIANCE RADIO SERVICE Co. 283, St. John Street, Clerkenwell, London, E.C.1 PHONE-CLERKENWELL 4290. NOVEMBER 18, 1922 THE WIRELESS WORLD AND RADIO REVIEW xlvii

0J11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111: -_THE ONLY BOOKS.Just Published. GIVING FULL DETAILS =ON THIS SUBJECTEACHIEVEMENTS = Is =_---. & LIMITATIONS Direction OF WIRELESS AND Position FindingTELEGRAPHY BY BY L.B. TURNER,M.A.,M.I.E.E.

Wireless t8 Pages 57 Diagrams BY 9D. R. KEEN, B.Eng. (Hons.) Sheffield, PRICE NETT. A M.I.C.E. = (post free iod.) 363 pages, 254 Photographs & Diagrams. --=-_= '-----.-=.. 1-_- --=..--- PRICE NETT. --- This book is a reprint of a Lecture _--=- 91.

.=. .--=- ,.. deliveredat the S.M.E., Chatham, a.' (Postage 9d.) by Mr. Turner. ---&-- - -=_.-This book deals not only with the principles .,_-_-... of the subject but with the constructional -."-- details of direction finding installations.It -M .._-. describes the principles ofDirection and ---- CONTENTS : --_. Position Finding in this country in such a ---- _-*_-. way that the subject may be grasped easily The Three Processes of Wireless Telegraphic by engineers tackling this fieldof wireless ---=_-.. Signalling. Radiation. Propagation. Wave --=..-- work for the first time. -.. -L=-. LengthCompromise. High Frequency CONTENTS. =.-- Generators. Reception. Interference. Introduction ;Theory of the Wireless Direc--'.---- tionFinder ; Valve Amplifiers and ff. Interference from other Stations.Atmos- --=. Detectors ; Maps ;Position Finding ;Night --,- pherics. Methods of Reducing Atmospheric Effect and other Freak Phenomena ; The ..---- -.-- ShoreD.F. Station ;TheShip D.F. E. Interference. Atmospheric Balancing. --.' Station ; AircraftD.F.Station ;Fault Atmospheric Limiting. Directive Reception. Clearing and Maintenance ;Notes on Field P. ---._.- and NauticalAstronomy ; Bibliography. P_ ==... . --=- -_-- -- ..-.

hill The Wireless Press, Ltd., The Wireless Press, Limited 7=------,-_-- Dept. W.W. = DEPT. W.W. -.....- = _._-..- ..._= 12/13, HENRIETTA ST., LONDON, W.C.2 12-13 Henrietta St., London, W.C.2

111111111E11111111111111111111111111111111111111111111111111111EMMI11111111111111111111111112 xlviii THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18, 1922 BOOKS FOR THE LIBRARY The Standard CONTINUOUS WAVE WIRELESS TELE- GRAPHY. Part I.By W. H. Eccles, D.Sc. Wireless Text Book Price 25/- net.Post free 25/9.407 rages. 306 diagrams and illustrations. which has the THERMIONIC TUBES IN RADIO TELE- GRAPHY AND TELEPHONY. By John LARGEST SALE Scott -Taggart, A.M.A.I.E.E.Price 25/- net. Post free 25/9.424 pages.344 diagrams and illustrations. Usedinpracticallyevery THE THERMIONIC VALVE andIts Development in Radio Telegraphy and SchoolandCollegeinthe Telephony. By J. A. Fleming, M.A., D.Sc. Price 15/- net.Post free 15/9. 279 pages. United Kingdom where Wire- 144 diagrams and illustrations. less is taught. WIRELESS TELEGRAPHY AND TELE- PHONY.-First Principles, Present Practice and Testing. By H. M. Dowsett, M.I.E.E.Price9/-net. Post free 9/9. 331 pages.305 diagrams and illustrations. The Elementary TELEPHONY WITHOUT WIRES. By Philip R. Coursey, B.Sc. (Eng.), A.M.I.E.E. Price 15/- net.Post free 15/9.414 pages. Principles of 250 diagrams and illustrations. STANDARD TABLES AND EQUATIONS Wireless Telegraphy IN RADIO TELEGRAPHY. By Bertram Hoyle.Price 9/- net.Post free 9/6. 159 By R. D. BANGAY, pages. tells in the simplest possible manner the theory FIFTY YEARS OF ELECTRICITY-THE MEMORIES OF AN ELECTRICAL and practice of wireless. ENGINEER. By Dr. J. A. Fleming, M.A., The Author makes the subject intelligible to D.Sc.,F.R.S.Price 30/-net.Postfree persons who do not possess much technical 31/-.371 pages, 111 plates. knowledge, and at the same time it is brief and THE WIRELESS TELEGRAPHISTS accurate. POCKET BOOK OF NOTES,FORMULAE The book is so arranged as to be useful as AND CALCULATIONS. By J. A. Fleming, M.A., D.Sc.Price 9/- net.Post free 9/6. a reference book for students and amateurs. 352 pages.39 diagrams and illustrations. It is published in two parts T.S.F. LA TELEGRAPHIE SANS FIL. LA TELEPHONIE SANS FIL. By G. E. PRICE 4/- EACH Petit and Leon Bouthillon.Price 12/6 net. 13/-postfree ;papercover,15/-net. (post free 4/5) 15/9 postfree.Cloth bound.304pages, 197 diagrams and illustrations. or combined in one volume PREPARED RADIO MEASUREMENTS PRICE NETT WITH SELF -COMPUTING CHARTS. 7/6 By Ralph R. Batcher, E.E.Price 10/6 net. (post free 8/3). Post free 10/11.132 pages. The Wireless Press Ltd., The Wireless Press, Limited Dept. W.W. Dept. W.W. 12-13, Henrietta Street, London, W.C.2 12-13 lIenr:etta St., Strand, London, W.C.2 NOVEMBER 18, 1922 THE WIRELESS; WORLD AND RADIO REVIEW WIRELESS BROADCASTING 3coed tecet;/eftd Fellocryst A simple and reliable crystal receiver for all wavelengths from 30o to 150o metres. Complete with one pair 4000 ohms doubleheadphones, Too ft. aerial and insulators. : 7 : 6 (Postage : Fellocryst £ 3 lftlextra Super For fine tuning for all broadcasting wavelengths from 300 - Soo metres. Mounted in oak cabinttandhighlyfinished, complete with one pair 4000 ohms doubleheadphones, zooft. aerial and insulators.

£4 7 : 6 (postage 2/. extra) Fellophone 2 VALVE RECEIVING CABINET For all broadcasting wavelengths from 300-500 metres. In solid oak cabinet complete with H.T. battery,6voltaccumulator, 4000 ohms double headphones, zoo ft. aerial and insulators, but without valves. (carriage 21- extra) £9 : 0 : 0 2 Mullard "ORA" valvesfor Fellophone - - 30/- extra Extraheadphonescomplete. 80/- per pair.

FELLOWS MAGNETOCO., LTD. Feltgrains Telephone Quilanag,.Phone, London, Willesden xj6o-x LONDON, N.W.10 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 18,1922 H. W. SULLIVAN(LTD.) FORMERLY H. W. SULLIVAN, FOUNDED IN1900. One of the oldest established manufacturers in this Country of RadioTelegraphy and Telephony apparatus ;the pioneer in the systematic design, construction and supply of Amateur RadioSets and Components, and infurnishing users withpracticalelectro-technicaladvice,e.g.inter alia the Sullivan Book of Working Diagrams of Valve Amplifying ReceiverCircuits. 10,000 copies of this book, the first and most complete of its kind, have been issuedto all parts of the World. Improved " Broadcast " CrystalReceiver (PATENTS APPLIED FOR) THIS Set has been specially designed for - Broadcasting " and witha view to simplicity, efficiency and reliability.Bymeansof a switch itis adapted for use on aerials varying in dimensions and shape ;it has only one adjustment-for tuning. A sensitive and robust type of crystal, and one which requiresno extreme delicacy of adjustment, is employed.

SULLIVAN PATENT TWO:VALVE ALTERNATIVE SINGLE CRYSTAL RECEIVER. NOTE MAGNIFIER. VALVE NOTE MAGNIFIER. Beautifully made and remarkable for itsappearance and finish, this receiver forms a miniature nucleus cabinet complete in itself, to which Note Magnifierunits of similar appearance may be added at will to increase the strength of reception and to enable many telephonereceiversto be simultaneously used. The special advantage, so usefulin practice, of this arrangement lies in the fact that by simply adding further small units to the system, any desired degree of magnificationcan be inexpensively obtained. IMPORTANT NOTICE. We find that false reports have been and are still being spread to theeffect that we have restricted, and propose to abandon, the manufacture of Amateur Wireless Instruments.The very reverse is the case. During the past six months we have continued to increaseour manufacturing facilities and output in order to expeditiously cope with the growing demand for Radio Crystal andValve Sets and Components of every description for Broadcasting reception.The same remarks apply to Wireless Experimental generally. Instruments We regret any inconvenience that these false reportsmay have caused in some cases to our customers and friends, and we hereby offer a reward of £100 for information whichwe may be advised is sufficient to enable us to trace such reports to their source and to successfullyprosecute our rights at law against the originators thereof.

.71(ew :Book of 34 Valve Diagrams (4th edition), and NewCatalogue W4, Price 1/- each, post free within the United Kingdom, the British Dominions and theCrown Colonies and Dependencies.

DEMONSTRATION AND SHOWROOMS: Liverpool House, Middlesex Street,E.1 rwo minutes walk from Liverpool Street and Broad Street Stations.) TRADE TERMS ON APPLICATION. Work `LIVERPOOL, Offices : MIDDLESEX ST., LONDON,HOUSE,"INCHESTER E,1HW Sullivan,uvan Ltd HOUSE, Phone-Avenue4871 LONDON, E.0,2, ENGLAND Telegrams-" Deadbeat.Stock, London.'' None-London Wall 3518

Printed by Sanders Phillips & Co., Ltd., Chryssell Road,London, S.W.9, for the Proprietors and Publishers, The Wireless Press, Ltd., 12-13,Henrietta. Street, London, #rTriFf %V.( ,.2 ;Sydney, N.S.W., 97, Clarence Street ;Melbourne, 422-24, Little Collins Street ; New York, 326, Broadway. 25th NOVEMBER, 1922. THE PRICE 6D. NET. WIRELESS WORLD AND RADIO REVIEW

No. 8. -1 No. 171. Registered at the("P.O. [VOL.XI. 25th NOVEMBER, 1922. as a Weekly Newspaper.

L3URNDEPT ill11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111 4PCrf 4 / zirep ,"

All 1111ERNDEPT IValoe!Apparatits.'is dulirlicensed under Marconi Patents for amateur use in Great Britain LONDON OFFICE & SHOWROOMS: BITRNDEPT _ IATI1). 1 7,IIEDFORI) STREET, STRAND. Aerial & Eaitnor Works, Blackheath, S.E.3. al, Bridge Street, Manchester. 238, Argyle Street, Glasgow. London Assurance House, Bond Place, Leeds. Exchange Buildings, 133, New Street. Birmingham. Western Counties Electrical & Engineering Co., Midland Bank Chambers:Middle' Street, Yeovil.

111111111111[1111111111111111111111IT THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922

ELECTRIC AL MEASURING INSTRUMENTS THE WES'FONT MODEL 280 VOLT -AMMETER Triple Range. 150/15/3 Volts. 15/1'510'15 amps.

ThisPrecisionInstrumentisespeciallysuitableforWireless Research Work, i.e. 3 Volt Range. -Testing accumulator cells, dry batteries measuring fall of potential across potentiometers. 15Volt Range. --Testing 6 or 12 volt accumulator supplying voltage to valves, etc. 150 Volt Range.Testing H.T. Batteries, etc. 0.15 Amp. Range (150M.A.) -Measuring H.T. Current to transmitting valves,determiningresistanceofTransformers,chokes, telephones, rheostats, etc. 1.5 Amp. Range. -- Adjusting filament currents, etc. 15 Amp. Range.- -Measuring output or charging current of accumulators. etc. NOTE.- - The 3 volt range may be used as a sensitive low range Milli -Ammeter, SEVEN INSTRUMENTS IN on CASE. PRICE £ 1 0, Leather Case 1 5' - Writefor further particulars. WESTON ELECTRICAL INSTRUMENT CO., LTD. Audrey House, Ely Place, Holborn, E.C.1 MODEL 280 Telephone :Holborn 2029. Telegrams : Pivoted, Smith, London The YEAR BOOK of WIRELESS Telegraphy and Telephony 1922 1476 Pages. Price 15/- Nett. Demy 8vo. Postage Inland1 /-. Abroad 1.14.

CONTENTS :- Record of the Development of Wireless Telegraphy-National and International Wireless Laws and Regu- lations-Direotory of the World's Land and Ship Wireless Stations-International Allocation of Call Letters-Alphabetical List of Call Letters-Meteorological Section-International Time and Weather Signals-National Résumés of Progress in Wireless Telegraphy-Particulars of Wireless Telegraph Patents, 1921-Aviation Section-Tabular List of Aviation Stations -Useful Data Section-Wireless Terminology-Conventional Signs used in Wireless Diagrams-Companies Engaged in the Commercial Development of Wireless Telegraphy-Biographical Section-Literature on Wireless Telegraphy and Telephony-Directory of the World's Wireless Societies-Directory of Wireless Colleges and Schools-List of Licensed Amateur Transmitting Stations-Code Section-Special Articles on " The Earthing Resistance of Antennae," by Dr. Miessner-" The Recording of Wireless Signals," by Dr. Abraham-" The Birth and History of Long Distance Wireless Telegraphy "-" The Rectification Effect in its Reaction to the Composition and Structure of Crystals." A valuable feature of the present issue is the specially drawn map, which gives, for the first time, a simple means of finding the distance and true direction of Wireless Stations inall parts of the World, from London as the centre.

PTST HRONNR I R wT Tc A2 THE WIRELESS PRESS, LIMITED, ST.. WR :N1312- L130ND NOVEMBER 25, 1922 THE WIRELESS WORLD AND RADIO REVIEW iii Wireless Needs Cost You Less at

FIRST IN FOREMOST 1908 GAMAGES TO -DAY THE PIONEERS OF WIRELESS APPARATUS FOR AMATEURS Upon the quality and design of your apparatus depends the success lowest in London.Gamage's vast experience is at your service- of your experiments. Gamage instruments are of the best and have all orders and enquiries, whether in person or by post, are dealt set the standard of quality throughout, while the prices are the with by Wireless Experts. Gamage Variable Condensers RICRINTON TYPE as illustration.This pattern is intended for the 1 t who are constructing their own sets, being expressly designed for mounting behind Ti1,14 panels.This condenser is of very robustconstruction,the moving vanes being clamped at one side and the whole element firmly held together by means of alluniniulli castings. An engraved ivorine Also supplied scale and handleisfitted with capacity of a) as shown. Capacity, 000762 0004. mid. - mfd. PRICE, postfree, PRICE, post free 201- VERNIER TYPE. An exceedingly usefullittlecondenser, designedexpressly for the purpose of connecting in parallel with an instrument of larger rapacity in order to obtain very fine tuning for telephony, and it is really essential that one of these should be added to receiving sets, using a variable condenser of ordinary type. Capacity, -000087 mfd. PRICE, post ffil., VariableNos. 1 & 2 Air Dielectric Type Condensers (FARADAY HOUSE THE CALIBRATION). This instrument is one of the neatest "PARLIPHONE" obtainable.It is of the best workmanship,electrically and mechanically LOUD SPEAKER perfect.Ithas lo fixed and 9 moving vanes, and a maximum capacity of (Prop. Palest No.21957) 43003 mfd.Top and bottom panels of matt ebonite and polished rounded ECONOMICAL. NO METAL edges.Fitted with engracr.t ivorine USED IN ITS CONSTRUC- scale, as shown. A TION. EQUAL INEFFI- handsome andeffi- CIENCY TO THOSE THREE cientcondenser. I- TIMES THE PRICE. PRICE,No.r, This Loud Speaker com- No. 2, .0045 mfd.,33 6. priseshornaridstand mouldedinonesolid pieceofEbonite. It contains no receiver, but Brown's the interior is screwed and made to receive a Brown's PatentStandard Re- 'Phones ceiver.In this way by Not to be confused with simplyunscrewingone the "reconditioned" ear -piece from the exist- 'phones at present on the ing Headphones and in- market. These 'phones were serting it in the " Parli- supplied to His Majesty's Write now fora phone " an efficient Loud Government,andevery Speaker is obtained at a has Copy of Gamage's small cost.The remain- instrument therefore ing ear -piece can still be passed the strictest test. utilised for tuning in the BROWN'S HEADPHONES, WIRELESS ordinary way. As no ' A " Type, Reed Pattern, metal is used in its con- Aluminium diaphragm, struction, the objection- 120ohms. CATALOGUE able metallic " ring " so common to most Loud PRICE,OUR4216 Profusely illustrated Speakers is entirely ob- 8,000 oh and giving full viated, the result being a PRICE 49/6 rich mellow note without OUR P ICE, details and prices. the slightestdistortion. SULLIVAN 'PHONES, Post Free on request Packingand Postage, 8,000OUR ohms' PRICE,366 3 extra. Carriage paid. Cords 2 aextra. GAMAGES HOLBORN LONDON E.C.1 i v THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922

1. Fil. Resistance ..7/9 BUTLER'S RELIABLE MANUFACTURES. 2. 9 -Stage H.F. Trans- former .. ..52,'6 3. Vernier Condenser .. 5 6 4. Grid Leak and Con-

denser . . . . 4/6 5. MultipleContact Switch .. 10/6 8 Unmounted Fil. Re- sistance 5/3 7. Coil Holder.. 15/6 For 2 Coils.. 1216 8. Tumbler Switchin Erenoid 2/6 9. SkeletonCondenser from 18/9 10. Crystal Detector..4/10

11. Switch Arms 3/- 12. Coil Holder for basket or Slabs, 36/-. With 8 holders. Tapped holder, extra ..8/3 13. Multiple Valve Holders 2. ..3/10 Also made up for 3 or 4 valves. 14. New TypeValve Holder, no exposed metal .. 1,5 15. Valve Holder ..1,4 16. On and off Switch.. 3/6 17. 1" Radius Switch Arm 2/2 18. .0003Fixed Con- denser .. ..5/- 19. Three-way Switch..4/6 20. BrassValveLegs, each..3d.and nd. 21. Lead-inTubes,6", 2/3 12", 3/-, eto. 22. Pin Type Trans- formers, price according to range. H. D. BUTLER &Co., Ltd. Bank Buildings, 222, Gt. Dover Street, S.E.1. NEW FULLY ILLUSTRATED 9Telethones-Hop 3029. Works, North 1838 LIST POST FREI, war v-conmlberv. Yondon, Ediswan Valves. THE manufactureof Thermionic Valvesisa highly skilled operation and every Ediswan Valve has behind it the experience and operative skillof over forty years of lamp making. The A R Valveillustratedisspecially made for Amateur reception. Platevoltage30-80volts. Filamentvolts3.5-6.ovolts. Filamentcurrent o.75 amperes.High amplification-silent working. Price 15/- each. Always ask for Ediswan Valves.If you are unable to obtain them at your Dealers write to us for the name and address of the nearest supplier. THE-EDISON SWAN ELECTRIC CO., LTD., Head Office :123/5, QUEEN VICTORIA STREET, E.C.4. ,London Showrooms :123/5, Queen Victoria Street, E.C.4, & 7r, Victoria Street, S.W.r. Type A R Works :Ponders End, Middlesex. NOVEMBER 25, 1922 THE WIRELESS WORLD AND RADIO REVIEW

Radio Music fromevery Electric Lampholder

Every electric lampholder can now be used with safety for picking up radio signals," Broadcasting,"etc. The " DUCON " forms a perfect attachment between the radio receiver and the electric light wires. Every " DUCON " is tested at 2000 volts A.C., and has the highest possible insulationresistance. Shocksand short-circuits arc thus rendered impossible. The " DUCON " fits directly into any standard B.C. electric lampholder, and is provided with terminals for connections to the radio receiver. Simplicity with Perfect Safety is the Keynote of the " Ducon." Price 10/- each DUBILIER CONDENSERS FOR ALL PURPOSES THE DUBILIER CONDENSER CO. (1921), LTD., DUCON WORKS, Goldhawk Road, Shepherd's Bush, London, W.12 Telephone- Hammersmith 1084. Telegrams-Hivoltcon, Phone, London. Code-Marconi International

2 vi THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922

Ebonite Panels are quickly and accurately engraved by TAYLOR - HOBSON the Taylor -Hobson Engraving Machine. Itcuts letters and figures either sunk or ENGRAVING MACHINE in relief on almost any surface from soft wood to cast steel. No modern Wireless Factory is complete EARTH without this machine. Send for our latest catalogue.

TAYIATAYLO1 &110135014.11P 74a,NewmanStreet,London,V1 Works :LEICESTER.

LESE We'SIC PROVIDENCE PLACE, WEST END LANE, KILBURN, N.W.6

Telephone. HAMPSTEAD 1261 Nearest Tube Station: KILBURN PARK ( BAKERLOO) Two Valve Receiver Panel. Type M.II.2 This instrument isa highly sensitive detector -amplifier operating as a Radio Frequency Amplifier,theHighFrequency Transformer being plugged into a socket provided for this purpose.A tuning condenser is incorporated to work in conjunction with the High Frequency Intervalve Transformer which, by a special circuit arrangement, can be either the Transformer, Reactance -Capacity (Rejector Circuit), or Resistance Capacity type.Independent filament control is fitted to each valve, and a -0005 mfd. Aerial TuningPrice Condenser is fitted. £8 : Prices for accessories to make complete station, including Aerial, Insulators, Tuning Coils, Coil Holder Head Phones, Two Valves, High Frequency Transformers, High Tension Battery & Accumulator We 0 NOTE.-Other M.H. Sets, one to four valves, of similar design and unsurpassed efficiency, are mentioned in detail in our NE W. M.H. Booklet, 6S. post free.All applying for same will also receive our GENERAL CATALOGUE, with 16 pages and too illustration;. Wholesale Distributors for Mews. The Igranic Electric Company. COILS.Same trade discounts allowed as by manufacturers. All our ValveApparatus is manufactured under Marconi Licence. NOVEMBER 25, 1922 THE NVIRELESS 1VORLD AND RADIO REVIEW vii E7C.PRIEIVC4

The Lyrian. All prospective purchasers of Wireless Receivers should see " THE LYRIAN," the latest and most efficient Table Cabinet Receiver for broadcasting. This portable cabinet of classic design is a 4 valve Amplifying Receiver, comprising one high - frequency, one detector and two note magnifiers. A powerful Loud Speaker giving the clearest reproduction, sufficient tofill a drawing -room or small concert hall, is contained inside the cabinet with a concealed type of horn. Everythingisself-contained except the accumulator battery. The Cabinet is designed to close up without removing any wires so that it is always ready for use (see small illustration). In flats and places where the erection of an aerial is not suitable, it can be used in conjunction with our approved frame aerial.The price includes 45 Gns. the accumulator battery and broadcasting royalty... ORDERS BOOKED NOW FOR EARLY DELIVERY. RADIO INSTRUMENTS LIMITED Managing Director :J. Joseph, M.I.E.E., late Manager to Mr. H. W. Sullivan.Chief Designer: W. A. Appleton, M.B.E., M.I.R.E., late Admiralty Technical Research Officer. to. ONLY ADDRESS. Works, Offices and Showrooms: 12a, Hyde Street, NEW OXFORD ST., W.C.1 Telephone :Regent 1908. Telegrams :Instraclio, London. (E.P.S.101 viii THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922

COMPLETE CATALOGUE UPON APPLICAT/ON. 6 a

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1 BOOKS i s r(ELESS

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' 9 11) 'Oil It ' t ,1*

E WIRELESSPRES SLTD. - -

12 -13, HENRIETTAST., STRAND,_LONDON,W.C:2. NOVEMBER 25, 1922 THE WIRELESS WORLD AND RADIO REVIEW ix

ICIi1111llll I11101IIIIUIillll111111lllll11111111111111111111111111111111111111111111111111rfr DIRECTION AND POSITION FINDING BY WIRELESS Price By R. KEEN Post B.Eng. (Hons.) Sheffield, A.M.I.E.E. 9," Demy 8 vo. 363 Pages 9f 9 Nett Over 250 Photographs and Diagrams Free

This bookdealsnotonly with the principles of the subjectbutwith the constructional detailsof Direction Finding Installations. ItdescribestheprinciplesofDirectionandPosition Finding inthis country in such a way that the subject maybe grasped easily by engineers tackling this field of wireless work for the first time. CONTENTS. The Theory of the Wireless Direction Finder ; ValveAmplifiers and Detectors ; Maps ;Position Finding ;Night Effect and other Freak Phenomena ; The Shore D.F. StationShip D.F. Station ;The Aircraft D.F.Station ;FaultClearing andD Maintenance ;Notes onFieldandNauticalAstronomy ; Bibliography. The Wireless Press, Ltd. 12-13, Henrietta Street, London, W.C.2

1 111111k 411111 1111111111111111 II 11111111111 "" 111 111111111111 11111 THE \VI \VOli1,1) AN1)rt.\ DI() REVIEW NOVEMBI-:1; 25, [922

fg;11(reiess

T.M.C. 3 -VALVE BROADCASTING SET A Revelation in Wireless Sets employing one -valve detector,two valves for low frequency amplification.Apparatus mounted includes Variable Filament Resistance, three Valve Sockets, Grid Leak and Condenser, two highly efficient Transformers, Grid Potential Blocking Condenser, Variable Condenser, Series Parallel Switch, Switch for using Loud Speaker or Headphones, Tuner and Reactance.Complete with Three Valves, Loud Speaker and set of " De -Luxe " Headphones. Mounted in polished Walnut. Size 9 X 7 X ioi inches high. THE MARVELLOUS 3 -VALVE SET THAT WAS THE FEATURE OF THE EXHIBITION.

THE LONDON TELEPHONE (NEW SYSTEM) CO., LTD. DONINGTON HOUSE, NORFOLK ST., STRAND, W.C.2. TELEPHONE : CITY 8612. TELEGRAMS : OAKMENT, ESTRAND. NONEMBER 25, 1922THE WIRELESS WORLD AND RADIO REVIEW xi TINGEY UNIVERSAL RECEIVER

All " Tingey " Valve. Apparatusisduly licensedunderMarconi Patents ft)) Amateur use in Great Britain.

Offices and Showrooms : 92, Queen Street, Hammersmith, London, W.6. Offices and Works : Phone- HAMMERSMITH 1916 (REGISTERED DESIGN) Telegs.-" TINGOIDAR LONDON."

ROYAL CORPS OF SIGNALS, TERRITORIAL ARMY. The 48th (South Midland) Divisional Signals, Birmingham.

THERE are a number of vacancies in the Wireless Sections of this Unit for men possessing an elementary knowledge of Wireless. The training includes instruction in Operating and Procedure and practical work with 30 and 120 watt C.W. Sets. Friends joining together will be posted to the same section whenever possible. 4' For further particulars apply personally,orinwriting,tothe Orderly Room, 48th Divisional Signals, T.A., Great BrookStreetBarracks, Birmingham. zii THEWIRELESSWORLD AND RADIO REVIEW NOVEMBER 25, 1922 J. L. CARTWRIGHT & Co. 24,'LONDON ROAD, MANCHESTER. Phone-Central 4209. Grams-" Pladuram," Manchester. Makers fit I Works-Berry Street. LSomebut 43 vanes to their ooi condensers, certainly not enough togive thefull mfd. capacity stated.Buyersshould alwaysdemandthat thecapacity Reductions ! is as specified. To be absolutelysure,buythe CONDENSERS. Instrument Finish. Every Set of Parts or Complete Famous ASHDOWN Condensers Examined by ExperiencedInspector. Condensers Our '001 Condensers, for instance, contain51vanes, GUARAN- Approximate No. of Parts ready to Price assembled capacity in Plates. assemble for for Panel TEED TO GIVE FULL Mfds. Panel Mounting. Mounting. CAPACITY.All ASHDOWN Con- .001 57 12/- 14/- densersare throughlytested before .00075 43 10/- 12/- leaving the works, and all are guaranteed .0005 29 9/- 11/6 correct. 0003 19 8/- 10/- Stocksheld by London Representaiive: .0002 18 7/- 9/- Mr. J. 0. Maddock, xx, Bayham Road, 0001 7 5/ - 7/- Bedford Park, W.4. PPOP5 8 4/6 Agents wanted in Coloniesand Foreign Ivorine Scale and Pointer, 1/- extra. Ebonite Dial, 1/8. Countries. Sufficient Celluloid Covering with 6 B.A. x Rd. Hd. Brass Screw and nut for fixing, 1/- each. Sole Distributing Agents for Scotland- [111H. E. ASHDOWN(Birmingham) Ltd. J. GORSTON SINCLAIR & CO., 47, Waterloo Street, Glasgow. Retail Agents for Blackburn- Perry Barr Birmingham THOS. BARTON & CO., The Electric Works, Blackburn. ,Phone :Northern S59. 'Grains : Segment:

°HOLLOW STEEL MASTS Are light, strong, made in sections, easily erected, and will last a lifetime. Each mast is complete with baseplate, finial, rope cleat, pulley, guy clips,Lsteel guy ropes, strainers, painted one coat ready for erection. Prompt delivery.Prices F.O.R. for cash with order.25 ft. 141510, 3o ft. 15/510, 4o ft. £7, 45 ft. 17/1510 5o ft. 210110/0 6o ft. £15/10/0.Other lengths supplied at equally low prices.Trade inquiries invited. The Wireless Steel Mast & Accessory Co., Lombard St. West, West Bromwich. "Celephone No.: 447. "Celegrams :" Wireless Westbromwich. 00 BAMBOO SPREADERS 5/6 BRASSBOUND EYELET ENDS EYS 1/6 EYEBOLTS 19 CLEATS 1/- ROPE GRIPS -/6 LIPS1/9 ADJUSTABLE TRAINERS 2/0 Guyeu PS 2/9 IN INSULATORS EGG TYPE -/9 6 SHELL TYPE 1/9 TUBULAR INSULATORS 1/9 LEAD IN 5/ - BEST W,H TECOTTON HALYARD ROPE. TINNED S A L CABLE, AERIAL WIRES. Par, FREE. TRAD SUPPLIED .

66 NOVEMBER 25, 1922 THE WIRELESS WORLD AND RADIO REVIEW

A111111111111111111111111MIUMB1111111111111111111111111111MINIMIIIIIIMMI ACCESSORIES The Ideal Full Range FOR RECEIVING SET. PRIVATE WIRELESS A Valve Set com- 10 plete for working X.I INSTALLATIONS For the successful reception of concerts, telephony and continuous wave " Morse." the following set can be enthusiastically recommended.It includes all the very latest approved advancements of wire- lessscience-itisthesetthatwillgive most pleasure to the expert as well as the newcomer. As you will see from the particulars below the equipment is complete, and we shall at all times be pleased to an- sweranyqueriesthatany enthusiast might desire to raise. AGENTS WANTED. VACUUM PROTECTOR VACUUMPROTECTORS(for protecting the aerial).They secure protection against risk of fire or damage by lightning. Will operate many times before renewal is necessary. SWITCHESfor series -parallel switching of condensers, adding to or reducing the number of valves in simultaneous use, etc. FUSES for protectingthefilament DESCRIPTION. accumulators and batteries in the event of a Single valve, mounted short circuit. on polished 1 -in. ebonite panel, withvariable TELEPHONE HEAD SETS condenser, smooth act- specially designed for wireless work. Terminals ingresistance, grid leakandcondenser, enclosed to prevent receiving circuit being and all terminals clear- interfered with. ly engravedin white, in a mahogany polished AERIAL WIRES & INSULATORS, cabinet,9in. bySin. by 5in, EARTHING DEVICES, JACKS & ACCESSORIES INCLUDED. Siemens 54 volt high tension Battery with plugs PLUGS, H.T. BATTERIES, for altering the voltage. etc.etc. 4 -volt 50 amp. hr. low tension Accumulator in case with carrying strap. ALS() MANUFACTURERS OF One pair of sensitive headphones of 4,000 ohms resistance. BROADCASTINC WIRELESS RECEIVINC SET One Mullard " Ora " detecting valve. Set ofcoils from 300 metres to 25,000 metres wavelength. Descriptivepamphlet and prices on application to A REFINEMENT.-If desired with a coil holder and a setofbroadcasting coils asillustration, SIEMENS BROTHERS &. CO., LTD. These allow a much finer tuning. 25/- extra. General Offices and Works : Send at once for Our Illustrated Catalogue LONDON, S.E. 18 WIRELESS INSTALLATIONSLTD. WOOLWICH, 15, Aldersgate Street, London, E. C.1 Telegrams-Siemens, Woolwich. Telephone-City 6400 TRADE ENQUIRIES INVITED. And at Belfast, Birmingham, Bristol, Cardiff, Glasgow, Leeds, Manchester, Newcastle, Sheffield, Southampton.

till11111111111111111111111111111111111111111111111111111111111111111111111111111111111111M1111111;kiI xiv THE WIRELESS WORLD AND RADIO REVIEW N,,vENTHER 25, 192:2 !MINI ZODEL

MAHOGANITE CONDENSERS

This is the latest product of our Factories- a superior insulating material for high grade sets, which -ingrain and colour closely resembles mahogany. Its high insulating and non -warpingproperties,combined with a beautiful finish, make it an ideal material for Panels. The Trade are warned against imitations- ordinary mottled Eboniteis NO T RADION - MAHOGANITE. All genuine Sheets are stamped " RA D I 0 N ". THE LAST WORD IN PRECISION. enquiries frombona -fide Manufacturers and The Zodel Condenser embodies new ideas.Specially Wireless 'Dealers solicited. designedplates, mounted eccentrically.Gives an open scale at lower readings. Low body capacity-no rubbing contacts-therefore silent. Made to engineers' fine limits.Machine engraved ebonite dial.Supplied AMERICAN HARD RUBBER in all capacities-skeleton type-or boxed to order. COMPANY (Britain) LIMITED, V008 - 17/6 ;V002 - 15/- ;Vernier - 10/6 13a, Fore Street, London, E.C.2 YOU,CAN RELY ON ZODEL GOODS. Full Price List post free, TELEPHONE -12754 CENTRAL. WALLACE HEATON, Ltd., EAERI.,.2 84,HIGHSTREET, SHEFFIELD. NENNENNI J THE BIRMINGHAM TWO NEW INVENTIONS RADIO COMPANY Carlton.] House, BIRMINGHAM offer high-class.Valve and Crystal Receiving Sets at the following FilamentResistance prices :- in one unit, for individual control Single -ValveSet,'' fittedwithTuningCondenser,Blocking Condenser,VFilament Resistance, Grid Leak and Condenser, of a number of valves.Dispenses engraved Panel and Mahogany sloping Cabinet,ready for with separately mounted filament use .. .. . Price £5 5s. Two -Valve Set, ready for use ..Price £7 10s. resistance for each valve. CrystalReceivingSets, consisting Ebonite Panel mounted in Oak Cabinet with lid, Tuning Inductance and Condenser, high-grade Crystal Detector, 4,000 ohms 'Phones (conforms to the P.O. regulations).Price £5 complete.Carriage paid. VariableCondenser All our apparatus is produced under the personal supervision of giving by simple operation of one our Technical Director, Mr. E. D. Gledall, B.Sc., F.R.G.S., late Technical Assistant to Marconi's Wireless Telegraphs and control knob, combined vernier and Chief Inspector to the Colonial Po3t Office Telegraphs. ordinaryadjustment. Also the following component parts - Dispenses

Filament Resistances 3 - and 4/- each with separately mounted vernier De Forrest Pattern Coil Plugs.. .. 1/- each condenser. Twin Ebonite Coil Stands, fitted plugs, etc... 8/6 each Three-way Ebonite Coil Stands, fitted plugs, etc . each (Patentsappliedfor.) Variable Condensers, Air Dielectric,fitted with knob and pointer- .001 ..12/8 each. 0005 10/- each. MANUFACTURED AND SOLD DIRECT BY .0003 7/6each. -00005 ..4,6each. Grid Leak Condensers, sealed pattern, fitted with H. SAVILLE, Terminals .. .. - .. 2/- each Delamere Works, STRETFORD, Blocking do. do. do. 1/9 each Component parts are of the best material and workmanship. near Manchester. Cash with order. Postage extra. Your Enquiries Solicited. NOVEMBER 25, 1922 THE \VIRELESS WORLD .AND RADIO REVIEW NV Crystal of To- THE GREAT66 Price 2/6 post free WithBalland day and Future HERTZITE" Socket Detector 5/6 VALVES :-" C.V.C.,"" ORA,"" XTRAUDION,""R.M.R." 15/- each. RUSSELL & SHAW, 38, Great James Street, Bedford Row, W.C. 1 THE WIRELESS WORLD AND RADIO REVIEW THE OFFICIAL ORGAN OF THE WIRELESS SOCIETY OF LONDON A MAGAZINE DEVOTED TO WIRELESS TELEGRAPHY AND TELEPHONY CONTENTS Critical Tuning Devices :Some Methods for Obtaining Fine Adjustment- 253 History of the Wireless Society of London - - - - - 257 Electrons, Electric Waves and Wireless Telephony.By Dr. J. A. Fleming, F.R.S.- 264 Of Interest to Inventors :" Licences of Right " Patents- 269 Contents continued on next page,

RADIO INSULATION AS SPECIFIED AND USED BY THE BRITISH ADMIRALTY

BRITISH MADE PAXOLIN BRITISH MADE

TUBES DISCS PLATES, 8(43. MANUFACTURED IN ALL FORMS, SIZES AND THICKNESSES BY THE MICANITE &INSULATORS CO. LTD. EMPIRE WORKS WALTHAMSTOW LONDON, E.17 TELMORAMS :- MYTI LITE. PHONE. LONDON." TELEPHONES r-WALTHAMSTOW 738. 799 xvi THE WIRELESS WORLD AND RADIO REVIEW NovEmucit 25, 1922'

MEN IN THE WIRELESSSERVICES DESIRING RAPID ADVANCEMENT should train in_aere time with the College which ensures this. "U.E.C." (Regent's Park, London, N. has in Twelve Years secured hundreds of succ sssss by Individual Postal Training for Engineering Examinations and Professional Work. State YOUR ambition in confidence, to-SECRETARY'S DEPT. (Desk W.), UNIVERSITY ENGINEERING COLLEGE, WESTGATE-ON-SEA, KENT, and expert advice with the New prospectus. No. 8, will be sentyou without obligittion

aimr

CONTENTS(Continued) Experimental Station Design.By F. H. H. 271 Further Notes on Four -Valve Receivers - 274 Notes - - - 277 Correspondence 278 Calendar of Current Events 279 Wireless Club Reports 280 Questions and Answers - - 285 Share Market Report - - - 288

THE WIRELESS WORLD AND RADIO REVIEW is published weekly on Saturdays. Allcorrespondence relatingtocontributions should be addressedto THE EDITOR, THE WIRELESS WORLD AND RADIO REVIEW, 12-13, Henrietta Street, Strand, London, W.C.2. No responsibility can be taken for MSS. or photographs sent without stamps to defray cost of return postage. Editorial and Publishing Offices 12-13, Henrietta Street, Strand, London, W.C.2. Telegraphic Address :" Radionic, Rand, London." Telephone No.:Gerrard2807. Advertisement Managers, Bertram Day & Co., Ltd., 9 and to, Charing Cross, S.W.t. Telephone No.: Gerrard 8063 and 8064 SUBSCRIPTION RATES. 28s. per annum, post free.Single Copies 6d., or post free, 7d. Registered at the G.P.O. for transmission by Magazine Post to Canada and Newfoundland.

We are almost ready to supply receiving sets conforming in every way with the latest instructions of the Postmaster -General as related to Broadcasting. Write us now concerning your particular requirements ; no obligation will be incurred by your so doing. There are no regulations to prevent the sale of our component parts, of which we supply a very large number.Advice and assistance freely given.Write or call and see us.Demonstrations daily. Offices and Shoterooms : 88o6 Gerrard.110, STRAND, LONDON, W.C.25806 Gerrard NOVEMBER 25, 1922 THE WIRELESS WORLD AND RADIO REVIEW xvii VALVES DELIVERY FROM STOCK.

Filament Anode Type. Voltage. Voltage. PRICE.. RLI- 6o R4.B 5o 1 10 0 V2 5 ' 2 36 1 4 0

5.2Q 5o 1 40 so as amplifier) QX 5.2 5o 1 4 0 SPECIAL LOW TEMPERATURE VALVES. Wei FilamentFilament Anode Type. Voltage.Current. Voltage. PRICE. L.T.i 1.8 .4 36-5o £2 10 0 L.T.3 1.8 .11 )) TRANSMITTING. Rd Filament Anode Voltage. Voltage. PRICE. PP Type L.T. 1. A .T.2 5 5.5 t: P ToI )00 0 21 10 0

A.T.4.ox ,, 1,000 2 15 0 44m THE MARCONI SCIENTIFIC INSTRUMENTco., LTD. TELEGRAMS: THEMASINCO, WESTCENT 40 DEAN STREET, SOHO, W.1 TELEPHONE : GERRARD 7746 viii THE \VI IIELESS \MI1Lp AND 11.\ WIT EEV f: ...\-.-Eum.:1; Ir.. I 2 1!

Call andseethis Receiving Set Demonstrated.

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Sliders, with springs and studs 9d.ea. Ebonite Panels, cut to order 3,6lb. Illustrated Catalogue Single Valve Panels including List ofStationsat fitted with variable Condenser, Filament 6d. post free. Resistance. Grid Leak and fixed Conden- ser,EngravedPanelandRosewood finished Box. ready for use - - EONSWIRELESS VulcanisedFibre and Ebonite SUPPLY CO. Sheets, Rods & Tubes from stock. 115, FLEET STREET, E.C.4. THE WIRELESS WORLD AND RADIO REVIEW THE OFFICIAL ORGAN OF THE WIRELESS SOCIETY OF LONDON

No. 171 [VONL:-8XI.] NOVEMBER25TH, 1922. WEEKLY Critical Tuning Devices. SOME METHODS FOR OBTAINING FINE ADJUSTMENT. NDOUBTEDLY many experimenters, adjustment is not required, the worm spindle when tuning to weak telephony, havehas to be swung out of use.Another arrange- Usometimes been annoyed to discover,ment is shown in Fig. 2, where by means of reduction gear, the small knob below the dial gives critical adjustment, whilst the large knob on the dial can be turned when it is desired to widely change the wavelength of reception. Another scheme for providing critical condenser adjustmentistoarrangeseparate control for a few of the moving plates.Fig. 3 shows a condenser so designed, where by withdrawing the knob the main plates of the condenser are disconnected from the moving spindle when the approximate adjustment has been obtained, whilst a few moving plates are still carried, and can be critically set by turning Fig.1. An American device. the knob. upon removing the hand from thetuning instrument, that signals decreased in strength or vanished entirely. Many variable condensers and coil holders in use are of such a design as to permit of onlycoarseadjustment,whileothersare provided with separate vernier control.Those of the latter design are a step in the right direction, but they become somewhat tiresome in operation when rapid tuning is desired over a wide range.Without vernier adjustment it often happens that signals are entirely missed, owing to the rapid rate of change that is produced when operating the tuning instrument. With regard to critical condenser adjustment, it is now becoming common practice to Fig. 2. Condenser with gearing. fit a worm or geared drive to the dial, or to a separate pinion.Fig. r shows a device which To be of real use, the vernier device must is now on the market, though when criticalpermit of instant change from coarse to vernier --.^=11.- -

254 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922 control, and if possible, the design should permit of the change being made without resort to the operation of a third control.The fitments shown in Figs. 4 and 5 are assembled in such a way that the wheel D is only in friction contact with the spindle of the condenser, thoughthisfriction,whilstinsufficientto prevent the condenser being adjusted when the wheel is held, has sufficient grip to revolve the plates when the worm wheel is revolved. The parts shown have been specially designed for use with the type of condenser which is usually fined in the Mark III. tuners.The collar E, fitson the square spindle, whilst the wheel D, resting on this collar, has a clearance hole. A and C are washers, which

Fig. 4.Friction driven critical control designed by Mr. A. J. Bull.(Condenser dial removed.) hold between them .thespring washer B. The screw in the head of the condenser clamps these parts down on the spindle, slightly com- ENLARGED VIEW OF pressingthespringwasher.Thiscauses DIVIDED SPINDLE. sufficient grip between the wheel D and the spindle, so that when the worm wheel revolves, the spindle of the condenser turns also. For rapidly changing the setting, however, the friction is not so great as to impede the turning of the condenser spindle, whilst the wheel D remains in mesh with the stationary worm -wheel.Fig. 5 is another view of the same mechanism. The assembling of the parts beneath the dial of the condenserwill of courseraise it away from the top of the instrument, and consequently it is necessary to fit a screw, the slot in the head ofwhich Fig. 3.kcondenser in which provision i8 made serves as an indicator for thecalibrations on for moving only a few of the plates. the dial. NOVEMBER25, 1922 THE WIRELESS WORLD AND RADIO REVIEW 255

This principle can with equal convenience be applied for the critical adjustment of tuning

diferiff,Rft- 111111111111111111111111111113 11141111

13) Fig. 7. Filanzent rheostat with separate critical control for three valves. coils, mounted in the usual form of swing -about holder.Fig. 6 shows in detail the method of assembling the components on the spindles, and requires no further explanation. The coils can easily be pushed through a wide -range, whilst when fine adjustment is required, the extension handles give a useful degree of critical control. Using this method of vernier adjustment,itissurprising howwell Fig. 5. Details for assembling a friction critical control.

3M r i. 1110.0, IItiLlill.In1111 I "..I co 8 BRASS WASHER SOLDERED TO SPINDLE , ..-. , ;1111111111111111111fim i.1,11 ilMILTAI MEIIIIIMLIIIIIIMINI 3BA BRASS SCREW Fig. 6.Critical control for inductances with friction clip for wide movement. B 2 256 THE WIRELESS WORLD ANDRADIO REVIEW NOVEMBER 25, 1922 manystationscan be brought in, which without this device are so difficult to tune to, that their signals are quite unreadable. Vernier adjustment has also been applied to filament currentcontrol-not perhaps so much in this country, where hard valves are available, but in America, where valves are less hard and critical rheostat control is necessary.Fig. 7 shows a novel form of rheostat intended for controlling the filaments of three valves.The main adjustment is obtained by turning the knob in the centre, whilst the extension handles each operate levers working on resistances which are connected separately in the valve filament circuits.This device is particularly useful when three similar valves are employed to function in different ways, such as high frequency amplifier,detector, Fig. 8.The ebonite stem seen in the clips on and note magnifier. the right can be put in mesh with teeth on the rim of the condenser. TheWireless Society of London. PRIZE COMPETITION. AT the last meeting of the Wireless less Society of London or members of an Society of London, held on October affiliated Society. 25th, the Chairman announced that The closingdateof thecompetition it was proposed to offer prizes for the most to be January i5th next.All apparatus efficient Armstrong super -regenerative circuit to be sent to the Hon. Secretary of the produced by a member of the Society or of Wireless Society of London. an affiliated Society, and that conditions with (5) Each competitor may demonstrate his regard to the competition would be issued own set if he so desires, or may depute later. someone to do this for him, failing which Two prizes are offered as follows :- the Committee will make their own tests A first prize of £15, and a second prize according to the written instructions which of Do. The amount of theseprizesis accompany the set submitted. contributed by three members of the Society In the tests to be conducted some constant who prefer to remain anonymous. source of transmissionwill be employed. The conditionsforthe competition areThe winner of the prize will be expected as follows :- either to lecture, or prepare a lecture on the (1) In the award of the prizes the rulinginstrument, to be read before the Wireless of a sub -committee of the Wireless Society Society of London, on which occasion the prize- of London will be final. winning instrument will be demonstrated. (2) The instrument made up must not In awarding the prizes the following points employ more than three valves, and the setwill be taken into consideration :- must work on a loop aerial which should (A) General design. accompany the instrument when sent in (B) Adjustment to maximum efficiency forjudging. A diagram of connections for four or five different ranges of wave- and a written report as to what the set length from 200 to 600 metres in minimum claimstoaccomplish should accompany time. the instrument. The names of those who desire to enter for (3) The actual assembly of the apparatusthis competition should be sent without delay, to be carried out by the competitor. and in any case within a fortnight of the date (4) Thecompetitiontobeopento of this announcement, to the Hon. Secretary, members or associate members of the Wire-32, Quex Road, West Hampstead, N.W.6. NOVEMBER25, 1922 THE WIRELESS WORLD AND RADIO REVIEW 257 History of The Wireless Society of London. " Lookpia the seeds of time, And say wh, grain will grow awl wh;, not." --M VrBETH. THE Wireless Society of London now changesHon. Secretaryship. These three have held the offices its name to the " Radio Society of Greatever since, save that Mr. Klein became a Vice - Britain," and comes under Royal Patronage.President in 1919, and Mr, McMichael took his We have represented to its founders that itis place as Hon. Secretary ;so ifit is ever possible on occasions like this that one may legitimatelyto speak of individuals as Founders of a great look backward as well as forward, and we haveInstitution created by the loyal and disinterested asked them to revive their memories of the earlyservices of many influential men, to them must days to indulge in retrospect for the benefit of ourthe honour be accorded. readers. The following announcement appeared inthe Thefirstmeeting washeldon July5th,English Merhani- of July 11th, 1913. 1913, at the house of Mr. Rene H. Klein, on his initiative, in West Hampstead.Mr. Klein was then a well-known wireless amateur who foresaw the difficulties which no doubt would arise through THE LONDON WIRELESS CLUB the lack of co-operation between amateurs, and At a meeting of wireless -telegraphy amateurs more especially as to their position with regard hold on Saturday, the 5411inst.; an association was formed, under thetitleofthe London to the Government regulations. Wireless Club, having for its object the bringing together of all amateurs interested in wireless telegraphy and telephonyThe need of such a club has been apparent for sometime, and. judging from the support promised and given, will no doubt prove a success. This meeting being of an informal nature, it was decided to elect a temporaryhonorarysecretaryand treasure:, leaving the proper electionof the committee to the general meeting, which. will be held early in September nextThe honorary secretarywill be glad to hear from amateurs intending to join club as sons as possible, andwillforwardformsofapplicationfoi membership His address is.Mr.11.Klein, HonSec. (pro tem.), 18, Crediton-road. West Hampstead. N W

A similarnoticeappearedintheWireless 1--.. World for August 1913, and to these invitations there -was considerable response, for among those thatattendedthe next meeting or who sent in their names as would-be members were the following, who constituted the first Committee :- Mr. H. F. Brand, M.A., B.Sc. ;Mr. E. W. Kitchen, A.M.Inst., C.E. ;Mr. W. J. Fry ;Mr. W. J. Shaw ; and Mr. V. W. Delves Broughton and Mr. A. G. Hansard.Enterprising and ambitiousforthe success of the Society as these gentlemen were, it is doubtful whether in these first few months the great possibilities were quite realised ; even the title then selected, " The London Wireless Club," indicated a domestic rather than a national policy. It was at the third meeting, held at Mr. Klein's house on September 13th, 1913, that Mr F. Hope - Jones,M.I.E.E.,firstappeared on the scene. He, in common with every first accession to the ranks, was impressed with the ability and enthusiasm of the group, and advocated a Society Mr. A. A. Campbell Swinton, F.R.S., founded on a more ambitious scale than that of the First President. Wireless Clubs then springing up all over the Among the five other gentlemen who were present country, a Society which would secure the con- were Mr. Leslie McMichael and Mr. L. F. Fogarty,fidence of the authorities at St. Martin's le Grand, A.M.I.E.E., who became Vice -Chairman and Hon. and capable of wresting from them a charterof Treasurer respectively, whilst Mr. Klein assumed thefreedom for the wireless amateur. 258 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922

FIG. 1.2.=THE SIPHON PEN, ON THE RIGHT, TRACING OCT IN MORSE ALPHABET, THE FIRST WORD-" LE*-OF COMMANDANT FERRIeS MESSAGE The signals are photographically reproduced from the original tape record, which is slightly enlarged

jYTe.

FIG IX -THE THIRD WORD-" FERRIE ' -OF THE MESSAGE Photographically reproduced from the original tape record, whichis slightly reduced in size Reproduction of a reprint of the first Presidential Address illustrating General Ferries.Message. n With this object in view he suggested the ap-at the service of the Society for its Committee pointment of men of eminence in the science meetings.He created many valuable precedents, ofwirelesstelegraphy as Vice -Presidents, from whom a President should he selected, and advocated a change of name.These views proving acceptable, he was asked to become its Chairman and carry them intoeffect.His inventions in" electric clocks " had brought him in touch with a large circle of friends in the world of science, and he was then launching a campaign against the Post Office on his own account to secure freedom for the watch and clock maker to take the Paris time signals.Within -a few weeks Vice -Presidencies were accepted by Dr. Silvanus Phillips Thompson, F.R.S., Sir John Macpherson Grant, Bart., Mr. Wm. Duddell, F.R.S. and Mr. Russell Clark, all now unhappily deceased during the War, but gratefully remembered for their prompt support. The Hon. Stuart P. Bouverie, Dr. W. H. Eccles, F.R.S., Dr. Erskine Murray, Col. Hippesley and Sir Charles Bright followed closely on their heels, as alsodidProf. Fleming, F.R.S.,Prof. Osborne Howe, Prof. Ernest Wilson, Prof. E. W. Marchant and Mr. S. G. Brown, F.R.S.The late Sir William Crookes F.R.S., became an honorary member and also Sir Oliver Lodge, F.R.S., while more recently theSocietyhasbeenfurtherhonoured by Senatore Marconi accepting a similar position. The Presidency was first offered to Dr. Silvanus P. Thompson, but he declined in view of the heavy burden of his other similar responsibilities.It was however,accepted by Mr. A. A. Campbell Swinton, F.R.S., and no better choice could have been made. He held the office for seven years, during four of which the Society was in a state of suspended animation owing to the War. When finally his resignation was accepted in January, 1921, he was presented with an illuminated address and by special resolution was made a member of General Ferrid, a VicePresid,ent. the Committee forlife.His handsome officesnot the least important of which was that he was n Victoria Street are still most generously placeda working President, attending Committees as NOVEMBER 25, 1922 THE WIRELESS WORLDAND RADIO REVIEW 259 well as presiding at the monthly general meetings,ratus, as we know it, had not begun, club -rooms and his successors have always done the same. equipped with a first-class receiving set were con- His first Presidential Address, given in the lecturesidered essential.After some hesitation, due to hallof the Institutionof Electrical Engineersthe fear of apparent alliance with a business firm, on January 21st, 1914, will long be remembered,a generous offer from Mr. A. W. Gamage of rooms with its special wireless message of greeting trans-at 107, Hatton Garden, was accepted.An " In- mitted from the Eiffel Tower by Commandantstrument Fund " was opened, and £100 quickly Ferri6 (already a Vice -President of the Society), raised.The premises were furnished, equipped received on a syphon recorder, projected on to theand opened before the close of the year 1913. screen by an epidioscope, and duly interruptedMorse classes were held and expert advice on all by Admiralty transmissions from Whitehall! Thetechnical matters was generally available, but the Rt. Hon. Sir Henry Norman, Bart., M.P., alsoaerial was of course dismantled on the outbreak addressed the large and distinguished company,of war, and the instruments officially sealed up. and the Society may then be said to have been The Society may be justly proud of its war ser- fairly launched upon its prosperous career. vices.Itsyoungermembers,readytrained,

Group of Officers of the Society taken October 1919.Back row (left to right), Mr. L. F. Fogarty, A.M.I.E.E., Mr. R. H. Klein, L.S.C., Mr. H. L. McMichael, Mr. M. Child, Mr. E. W. Kitchen, A.M.I.C.E.Front row. Dr. J. Erskine -Murray, M.I.E.E., Mr. A. A. Campbell Swinton, F.R.S., Admiral Sir Henry B.Jackson, G.C.B., K.C. V.O., F.R.S., Mr. F. Hope -Jones, M.I.E.E. In the meantime, the beat type of wireless amateurflocked to the wireless units of the Navy, Army had been attracted. Among the earliest membersand Air Forces, which they served with distinction were Dr. F. C. Knight, G. G. Blake, H. H. Harrison, those who stayed at home set a good example Tingey pere etfile,PhilipCoursey,Mauriceby shutting down their own installations and offer- Child, W. H. Shortt, Leslie Miller, Basil Binyon,ing their services in the detection of illicitin- G. P. Mair, A. W. Sharman, A. E. Dean, Rickardstallations.Assistanceinthelatterdirection Taylor, H. W. Scott, and H. R. Rivers -Moore, manywas not required, but practical help waggiven of whom have since served on the Committee or into several innocent victims of spy mania ! Offices, and have contributed to the Proceedings. When it was desired to resume activities after In those days when instruments were not sothe war, the authorities seemed reluctant to allow easily made and the manufacture of -wireless appa-us to use our ears again, and it was not untilJuly, 280 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922 1919, that the Committee came together to formu- late their plans for re -opening.They found that thevalvehad arrived, and the stay-at-homes envied the service men their knowledge of it. One of the first matters taken in hand was the Affiliation of the Provincial and Suburban Societies. The direct advantages of affiliation from the point of view of the individual Provincial Society were not self-evident, and it was recognised that the success of the scheme depended upon public spirit and their recognition of the fact that union is strength.Fortunately this was not lacking. The immediate response was sufficient to justify calling the first Conference in February, 1920, when fifteen Societies were represented.Next year there were fifty affiliated, at the last Conference-the third- there were 78, and at the time of going to press there are upward of 120. It has been and still is the one Parliament of the Wireless Amateur in this country, and it has

Dr. J. A. Fleming, a Vies -President. F. A. Loring, R.N., one of the Vice -Presidents of the Society.It was assumed by some that the Conference woulddegenerateintoindignation

Senators C. Marconi, G.C.V.O., LL.D., D.Sc., M.I.E.E., Honorary Member. enabled the President to speak to the authorities in no uncertain voice in the demand for freedom, subject, of course, to reasonable control.They on their part have welcomed the representative voice, for it must be remembered, though the public do not see it, that the constant desire of the civil servant engaged in executive duties is to give all the freedom that can safely be granted, and in administrating such an indefinite law as the Tele- graph Acts, to find out what is wanted and what can be given without detriment to important interests and services.Hence, a representative of the Postmaster General has always attended the Conferences, happily in the person of Captain Sir Oliver Lodge, F.R.S., an Honorary Member NOVEMBER 25, 1922 THE WIRELESS WORLD AND RADIO REVIEW 261 meetings, but such fears have always evaporatedbroadcasting. The lay press and public ought to be in an atmosphere of sweet reasonableness. told that broadcasting has been in operation for three years in the form of transmissions by some dozens of amateurs, members of the Society, in all parts of the country.In the London district there have been few evenings in the week since 1920 without entertainment of some kind, so much so that the Society had to call together the holders of transmitting licencesin the London District in July, 1921 in order to regulate their programmes to avoid interference.But all this was on low power, and in so far as it was broadcasting it was technically against the law.In March, 1921, the second Conference, held under the Presidency of Dr. J. Erskine Murray, asked that permission should be granted to the Marconi Company (who

H.R.H. The Prince of Wales, Patron of the Society. The results have been achieved instead by peaceful penetration or by the iron hand in the velvet glove.Take for instance the originof

Major J. Erskine Murray, D.Sc.,PastPresident,1921. were ready and willing to do it) to transmit a weekly concert.A certain mental backwardness or lack of vision which we are accustomed to in Bureau- cracies took six months to make up its mind about this request, and then refused the music.They were invited to face music of another kind, and did so with a good grace when the Secretary presented at St. Martin's le Grand on December 29th, 1921, the Broadcasting Petition signed by the Presidents of 63 Societies representing most of the amateurs inthecountry, and the Postmaster -General's representatives were told by the Chairman that " the Society's only constitutional means of access Admiral of the Fleet Sir Henry B. Jackson, G.C.B., to Authority was through the Postmaster General, K.C. V.O., F.R.S., President. and it was their intention to urge their plea with all J= -,4.1

262 THE WIRELESS WORLD AND RADIO REVIEWNOVEMBER 25, 1922 the force of which they were capable consistentdone. A reasonable demand, properly formulated with the constitutional methods." and backed by a thoroughly representative body, strengthens the hands of the administrators against conservative influences; perhaps in this case the overcautiousrepresentationsofthedefensive services of the Realm. The interviews at St. Martin's le Grand have always been of a most cordial nature, and the Com- mittee have invariably been made to feel that the Society was valued by the Department as a means of control and as a channel for the expression ofcollectiveviews.The Committee hasfelt it to be a great privilege to assist the Department in determining who were fit and proper Orsons to be granted licences.Membership of the Wireless Society of London or of an Affiliated Society has been accepted as prima facie evidence of fitness for a receiving licence, whilst the more difficult

Mr. F. Hope -Jones, Chairman 1913 to date. Within a fortnight permission was granted for Writtle to begin its Tuesday evening concerts, and three months later Mr. Kellaway made his broadcast announcement in the Rouse of Commons.

Mr. R. H. Klein, Vice President, and Founder of the Society. matter of transmitting licences has been dealt with by an Advisory Committee on technical qualifications consisting of Mr. Campbell Swinton, Dr. Eccles, Professor Howe and Professor Ernest Wilson. But perhaps the greatest service that the Society has yet been able to render to the Government is in connection with the revision of the terms of transmitting licences.This question originated at the last Conference when wavelengths, working hours, and free communication were discussed, and Captain Loring stated that recommendations would be welcomed, indicating that they should be accompanied by an assurance that they repre- Mr. L. F. Fogarty, Honorary Treasurer. sented also the views of the Provincial Societies. Yes, there is no doubt that the authorities haveA Control Committee, consisting of Mr. Maurice been " gingered up." There is equally no doubtChild, Mr. Klein, Mr. G. P. Mair, Mr. Frank Phillips that they like it.It is all a matter of how it isand the Secretary, happened to be sitting at the NOVEMBER 25, 1922 THE WIRELESS WORLD AND RADIO REVIEW 263 time, and it fell to them to draft the recommenda- It only remains to add that the Wireless Society tions.After consideration by the Main Committee of London has been welcomed in a very friendly they were submittedto wayby theoldestab- theCommitteeofeach lishedSocieties and Insti- one of the affiliated Societies tutions. The Institute and unanimously approved. ofCivilEngineersand These recommendations the Royal Society of Arts may be cited as a typical havegrantedtheuse example of the value of oftheirlecture halls on collective bargaining. They many occasions, while took a complete gripof the Institute of Electrical the position of the amateur Engineers has never lost throughoutthecountry, an opportunity of showing and basing their considera- itsgoodwill. When the tions on a broad view of Wirelesssectionofthat the present condition and Institution was bein'g future congestionof the established, its first Presi- ether, the authors unfolded dent,Dr. W. Eccles, the anomolies and incon- F.R.S., attended the Com- venienceofthe existing mitteeMeetingsofthe licences whilst making Wireless Society ofLon- practical suggestions which doninordertoensure were shown to be to the thatthere should be benefit of the authorities nooverlappingnorap- as well as the individuals. pearance of rivalry.The So complete and forceful monthlymeetingshave was this documentthat always been held in their its recommendations were lecturehallsince the accepted en bloc, and it was building wasrecovered the subjectofunofficial, after the occupation of the but none the less sincere Government. commendation from indi- A historycannever vidualmembersofthe be up todate,sono Wireless Board.Nothing attemptwillbemade short of a Conference of the todealwiththe AffiliatedSocietiescould current events under have given a mandate for Mr. L. McMichael, Honorary Secretary. the Presidencyofthe such drastic recommenda- Admiral of the Fleet Sir tions and none but those accustomed to deal with Henry Jackson, G.C.B., F.R.S.His distinguished such matters from a National point of view could services to the Society would require another have formulated them. chapter. Tuned Anode Coils. NOW that the use of the tuned anode system wavelengths.The number of turns in use need of high frequency amplification is gainingonly be approximate, of course, as the inductance favour,the following two devices are ofis bridged with a variable condenser having a special interest. maximum value of about 0.0001 mfds. Fig.I shows a spooldesigned by Mr. V. R. Mills, turned in ebonite, wth grooves for carrying the inductive winding.Threaded holes are made

PROTECTIVE sunsTO WRAPPING TAME WIRE

PLATE PIN

31,, ,

IN Fig. 1. Fig. 2. in the ends to carry 3 BA screws, and lock nuts hold them secure.The ends of the windings are Fig. 2 shows a simple arrangement for substi- soldered to the screws, and a little spare soldertuting tuned anode in the place ofintervalve is allowed to flow round the nuts. Spring connectors transformers. Two tappings are taken out on the may be made from bronze spring or hard brass. winding as it is put on, and the fitting of a three- Very little experimental work isrequired toway switch on the receiving instrument panel find a suitable number of turnsfor the variousprovides a tuned anode coil having a wide range. 264 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922

Electrons, Electric Waves,and Wireless Telephony-VIII. By DR. J. A. FLEMING, F.R.S.

The articles appearing under the above titleare a reproduction, with some additions, of the Christmas Lectures on Electric Waves and Wireless Telephony givenby Dr. .7. A. Fleming, F.R.S., at the Royal Institution, London, in December and January,1921-1922.The Wireless Press, Ltd., has been able to secure the serial rights of publication, andany subsequent re -publication. The artides are therefore copyright, and rights of publication andreproduction are strictly reserved.

4.-THE PERIODIC LAW OF ATOMIC PROPERTIES. We can also attach to each element a number It was long ago pointed out by the Englishcalled its Atomic Number, given in italics in chemist Newlands, and the Russian chemistbrackets in the table, which representsits Mendelejeff, and by Lothar Meyer, that ifnumerical order of the elements in the series. the names of the elements are written dowitThe atomic number of hydrogen is 1 and that in the order of their atomic weights, thesameof uranium 92. kindof propertiesrepeatthemselvesat It is seen that at the beginning of the series regular intervals in the series. the atomic weight is about double the atomic It is now usual to arrange the elements innumber, or at least differs only by zero or a a table called the Periodic Series, which bringssmall number.At the end of the series there out these points clearly. is, however, a great difference between the If we rule up a sheet of paper into nineatomic weight and double the atomic number. columns and twelve rows, we can write in each Mr. Stephen Miall, in his little bookon of these spaces, or in nearly all of them, the" The Structure of the Atom " (Benn Bros., names of the elements in order of their atomicLondon), has pointed out that the atomic weights, proceeding from left to right in eachweight w is related to the atomic number n row and downwards in eachcolumn.* Weinthe manner expressed by the formula then find that when arranged as shown inw = 2n + h, where b may be called the the table on p. 265, all the elements of similardead weight or ballast. character fall into the same column or group. Van der Broek made the suggestion adopted The atomic weight of hydrogen is 1.008,now very generally, that the atomic number when that of oxygen is taken as equal to 16.represents the resultant number of positive The columns are numbered 0 to 8.Inelectrons in the nucleus, or what is the same column 0 we find all the elements like helium,thing,the number ofplanetaryelectrons argon, neon, etc., which are non-valent andcirculating round it in a neutral atom. do not form any chemical compounds.In Thus the nucleus of the helium atom column 1 we have the mono-valent highly consistsof fourpositiveelectronsbound electro-positive alkaline metals like lithium,together by twonegativeelectrons.The sodium,potassium,etc. Incolumn 7 resultingpositive charge is then2units. the haloid elements,like fluorine, chlorine,The atomic number of helium is two, and its bromine, iodine, and in column 8certair atomic weight is 3.99 or nearly 4.It has groups of three metals. two negative electrons which circulate round At the end of the series we come to thethe nucleus.Inthiscase the" ballast " radio -active elements, radium, thoriumandweightiszero.In thecase of uranium, uranium, this last being the heaviest atom,however, the atomic number is 92, the atomic with an atomic weight of 238.2. weight is 238.2.Hence the " ballast " is 54.2. One important thing discovered is that the * The Table on next page has been taken from an chemical properties of the atom are more article by Dr. Saul Dushman on " The Structure of closely related to the atomic number than to the Atom" published in The General Electric Review.the atomic weight. In short, it is possible to NOVEMBER 25, 1922 THE WIRELESS WORLD AND RADIO REVIEW 265 MENDELEJEFF 'S PERIODIC SYSTEM OF THE ELEMENTS Containing Atomic Weights, Atomic Numbers and Isotopic Radioactive Elements

Group 0 Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7 Group 8 E,0 EO E203 E02 E20, E03 E 2 0- EC:04 EH 4 EH, EH, EH H1.008 He (1) Be* B C N 0 F 3.99 Li 9.1 11.00 12.00 14.01 16.00 19.0 (3) 6.94 (4) (5) (6) (7) (8) (9) (3) I Nei Na Mg Al SL P S CI 20.2 (10) 23.00 24.32 27.1 28.3 31.04 32.07 35.48 Neil (11) (12) (13) (14) (15) (16) ( 1; ) 22 Ar K Ca Sc Ti V Cr Mn Fe CoNi 39.88 39.10 40.07 44.1 48.1 51.0 52.0 54.93 55.84 58.97 58.68 (18) (19) (20) (22) (23) (24) (25) (26) (27) (28) Cu Z n G a Ge As Se Br 63.57 65.37 99.9 72.5 74.96 79.2 79.92 (29)Sr 32) (33) (34) (36) Kr Rb Zr CI31- Mo 1Ru Rh Pd 82.92 85.45 87.63 83.0 90.6 93.5 96.0 101.7 102.9 106.7 (36) (37) (38) (05) (40) (41) (42) (43) (44) (46) (46) A g Cd In Sn Sb Te I 107.88 IL? 10 114.8 119.0 120.2 127.5 128.92 (47) %,`, (11)) (.50) (51) (.5) (53) Xe Cs Ba La CE 130.2 132.81 137.37 139.0 140.25 (54) 55) (56) (5'i) (,.-,) Pr Nd Sa Eu 140.6 144.3 150.4 152.0 (59) (60) (61) (62) (63) Gd Tb Ho Ds Er 157.3 159.2 163.5 162.5 167.4 (64) (65) (66) (67) (68) Tmi Tm11 YbtLu Ta Os IrPt 168.5 172.0174.0 181.5 184.0 190.9 193.1 195.2 (69) (70) (71) (72) (73) (74) (76) (76) (77) (78) AuJ Hg Ti , Pb Bi 197.2 200.6 204.0 207.15 (79) (80) R2a10.D2 R21108E20 R21a0.2F Ac C, 1 211.2 (81) Ac D Ac B 1(83)Ac C Ac AI

207.2 , 211.2 211.2 215.2 Th D ' ) Th B Th Ci, (84) Th C2 208.2 212.2 212.2 212.2 (c%) Th D2 Th A 208.2 216.2 R a C , R a B R a C Ra Ci, 210.2 214.2 214.2 214.2 Ra D, Ra A' 210.2 %. 218.2 AcEm9 AcX 219.2 223.2 ThEm80 Th X 220.2 (87) 224.2 (88) RaEm Ra Ac Rd 222.2 228.2 227.2 8,0) 227.2 Mes Th11 Mes The Rd Th

228.2 1 228.2 228.2 I o 230.2 (90 Th 232.2 Ux1 Ux. U11 234.2 234.2 234.2 (J, (91) U ") 238.2J Be Atomic Weights listed in Bold figures. t Cb = Nb Atomic Numbers listed in Italics in parentheses. Neoytterbium = 173.5 266 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922 have atoms of identical chemical propertiesweight 6 and 7, boron 10 and 11, neon 20 but different atomic weights.These atomsand 22, chlorine 35 and 37, argon 36 and 40, have been named by Professor Soddy isotopes.potassium 39 and 41, bromine 79 and 81. Thusthere appear to be several differentWhilst krypton,tin, xenon, mercury, mag- kinds of atoms of the metal lead of slightlynesium and lead, have many more than two different atomic weights, but all having the isotopes. atomic number 82 and all the same chemical It appears quite clear therefore that the properties. atomic number which givesus thetotal It was long ago suggested by Prout that allnumber of negative electrons circulating round atoms were built up of multiples of a certainthe nucleus in the neutral atom is the deter- primordial element, and hence that atomicmining factor in the chemical behaviour of weights should all be integer multiples of some the atom.It is now considered that these unit.As, however, analytical chemistry pro-planetary electrons are arranged in rings or gressed it was found that this was not theshells, one outside the other. case.Enormous skill and knowledge have Thus in the carbon atom of atomic number been brought to bear of late years upon the6, there are six resultant positive units of determination of the atomic weights and itcharge in the nucleus and two shells or rings has been found that Prout's hypothesis is notof planetary negativeelectrons,the inner supported by facts. containing two and theouterlayerfour Take, for instance, the atomic weight ofnegative electrons, making six electrons in all. chlorine, which is 35.46, when that of oxygenIn the oxygen atom there are eight electrons is 16.The weight of the atom chiefly residesin all, viz., 4, 2, and 2 in three shells, and in as we have seen in the positive electron, andthe sulphur atom there are 16 in all, arranged there must be an integer number of thesein four shells of 8, 4, 2 and 2, reckoning positive electrons in the nucletis.The sug-from within outwards. gestion has therefore been made that there The electrons in these shells or zones are are two kinds of chlorine atom or two isotopes, in rapid rotation round the nucleus, but the one with atomic weight of 35, and the other different groups do not necessarily all revolve with an atomic weight of 37.They bothin the same direction nor in the same plane. have the same chemical properties and ordinary The outer shell or layer of negative electrons chlorinegasisamixtureof thesetwo in the atom is that which chiefly determines kinds of chlorine atoms in such proportionsthe type of chemical compound formed with that the average atomic weight is 3546. other atoms and these are termed the valency The explanation of this may lie in the fact electrons.Some of these valency electrons that small variations in the ballast weight ofare easily detached in the case of the metallic the atom may take place without variation in atoms.In a mass of metal, say,copper, theatomicproperties.Thustheatomic there are, therefore, free electrons which are number of chlorineis17.One kind ofjumping about from atom to atom and moving chlorineatomhasanatomicweightofin the inter -atomic spaces with a velocity of 35 = 2 x 17 + 1 and the other isotopeis approximately 50 miles per second. 37 = 2 x 17 + 3, and 1,300 atoms of ordinary chlorinegascomprise about1,000 atoms 5.-ELECTRIC CONDUCTIVITY AND ELECTRIC weighing 35 and 300 weighing 37units, CURRENTS. equivalentto 1,300 in all, weighing 35.46 These free electrons bestow upon the metal on an average. itselectricconductivity because when an It is a singular fact that taking the oxygen atom electromotive force, due say to a Voltaic cell, to weigh 16, the following atoms have nearlyis applied to the metal, these free negative exact interger atomic weights, helium = 4,electrons are caused to drift or move as a carbon = 12,nitrogen = 14,fluorine = 19, whole towards the positive end of the conductor. sodium = 23, phosphorus = 31, sulphur = 32, The electronshave superimposedupon: arsenic = 75, iodine=127, and caesium = 133. their irregular motion a drift in one direction, On the other hand, Dr. Aston, of Cambridge,just as a swarm of gnats, in which each insect working with improved methods originated byis flying hither and thither in an irregular Sir Joseph Thomson, has determined withmanner, might be blown as a whole down a great exactness that the following elementsstreet by a gentle wind.This drift of electrons comprise two isotopes :lithium of atomicconstitutes what we call an electric current. NOVEMBER 25, 1922 THE WIRELESS WORLD AND RADIO REVIEW 267 Hence our usual convention as to the directionimmense velocity approximately tothat of of the electric current in a conductor is wrong.light waves, viz., 300,000 kilometres per second. We commonly say that the direction of theIn addition to this the impact of a /3 -particle current in a wire is the direction of movementagainst other molecules gives rise to the proof positive electricity in the wire.But, induction of certain very short electromagnetic fact,thereisno movementofpositivewaves called y -rays, which are like the X-rays electricity, only a drift of negative electrons inin properties. one direction in the wire.Hence all our The atoms of which the nuclei can break usual mnemonic rules involving the directionup in this way are called radio -active elements. of the current and that of the embracingProminent amongst them are radium itself, magnetic fieldrequire to be restated andthorium and uranium, all of which are atoms reversed. of large atomic weight and relatively bulky A negative electron revolving in an orbit isor heavy nuclei. - therefore equivalent to an electric current and We all know that when a heavy flywheel is produces a magnetic field.Hence atoms inin rapid rotation it contains a store of energy which the negative electrons revolve in themeasured by half the product of its so-called same direction and nearly in the same plane,moment of inertia and the square of its angular will exhibit magnetic polarity, and this may velocity. account for the magnetic properties of the If the flywheel bursts, the fragments are oxygen and iron and nickel atoms. flung away far and wide,generallywith 6.-RAoto ACTIVITY. disastrous results.Ir the same manner when A brief reference must then be made to thethe nucleus of a radio -active atombreaks up special qualities of the so-called radio -activeitsa and /3 -particles are hurled away with elements, of which the most remarkable issuch enormous velocity that they break up or the element radium. ionise other atoms in their neighbourhood. It is found that certain of the atoms of highThe nucleus may therefore be inextremely atomic number break up spontaneously andrapid rotation. gradually are transformed into atoms of lower The break up of a radio -active nucleus, atomic number and weight.In the case ofhowever, is not exactly like the bursting of a an atom like uranium, of atomic weight 238.2,flywheel.It proceeds by many stages and the nucleus is a very bulky thing relatively tothe variousintermediate atoms which are that of the hydrogen atom, which, accordingsuccessfully formed have " lives " of very to a prevalent view, consists simply of a singledifferent duration, varying from a few minutes positiveelectron,withasinglenegative to many thousands of years. electronrevolving round it.The uranium Thus for instance, beginning with the atom atom, on the other hand, has 92 planetaryof uranium, with atomic weight 238.5,its electrons,and 92effectiveandprobablyaverage life is 5,000 million years.It throws about 240 actual positive electrons packedoff an a -particle,thusreducingitsatom into its nucleus, and perhaps about 148 negativeweight by four units, to 234.5, and isthen electrons as well. transformed into a substance called uranium As the planetary electrons revolve roundX1.This, however, only lasts a few days the nucleus they may set up strains in it or(about25)andisthen transformedinto tidal actions, which may increase to such auranium X2.The latter gives off a /3 -particle, point that the nucleus breaks up. When thiswhich does notsensiblyalterthe atomic is the case, we have thrown off from it eitherweight, and is thus transformed into a far one or morenegativeelectronscalled/3 - more permanent atom called uraniumII, particles or else one or more helium nucleiwhich has a life of about two million years. called a -particles.The helium nucleus con-This,by the loss of two successive a -particles sists of a group of four positive electrons andthus becomes ionium and finally radium, with two negative electrons, having thus two effectivean atomic weight of 226.5.This in turn positive charges.These six electrons mustgives off a gaseous " emanation," which has be bound together very tightly because thean atomic weight of 222.5, and is often called helium nucleus appears to be a remarkablyniton.Finally, by further losses of a and permanent and indestructible article. /3 -particles, this last substance is transformed When the nucleus is ruptured or brokeninto metallic lead, with an atomic weight of up these a and /3 -particles are shot off with206-5. 268 THEWIRELESSWORLD AND RADIO REVIEW NOVEMBER 25, 1922 There is another chain or series of atomicmass of a helium nucleus ora -particleis transformationsstartingfrom uraniumIIabout four times that of a hydrogen atom, or, which, in the end, also yields lead, but withsay, nearly 6 x 10-21 of a gram, the energy of an atomic weight of 210.Finally, from thethe a -particle is about thorium atom, there are a series of descendants 6 -1 4 x 1018 = 12 x 10-3 ending also in lead, with an atomic weight of 21021 208.Hence the lead atom exists in several isotopic forms, and there are atoms, all ofergs, or, say, 12 microergs. which, chemically speaking, are lead, but have On the other hand, the/3 -particlesare different atomic weights.Accordingly, somethrown off from radio -active atoms with a part at least of the atomic weight of lead,velocity of about 0.9 of that of light, or, say, viz., that over and above twice its atomic270,000 kilometres per second.Since, how- number, which is 82, has t o influence on theever, the mass of an electron is only 9 x 10-28 chemical properties, for all these varieties ofgram, we have the kinetic energy of a lead atom have the same atomic number. particle given by 2 1 Thus, in a certain sense, the dreams of the 1 9( -9x 3 x1010)= - x 10-8 nearly old alchemists have been realised.Although 1T-28 10 3 we have not been able to transform lead into or nearly one-third of a microerg.Therefore gold, as they hoped, we now know that thethe single a -particle has 30 to 40 times the element uranium is slowly and spontaneouslykinetic energy of the single fl -particle. changed into radium and finally into lead. In consequence of their very small size and It appears therefore as if the nuclei 'of allof the very porous or open structure of atoms atoms are built up in part of the extremelygenerally, the chances of a fl -particlebeing permanent helium nuclei, held together in some stopped when fired through a volume of air, way by negative electrons, into a very compactis much smaller than that of the larger mass.Possibly also free positive electrons or a -particles. Thefl -particlesscarcelylose hydrogen nuclei may be present as well. half their velocity in passing through a thickness From certain experiments made by bom-of air of one metre, whereas the a -particles barding nitrogen and oxygengas with a - are stopped completely by a few centimetres. particles, Sir Ernest Rutherford has shown Owing to the very open or skeleton structure that nuclei or atoms of an atomic weight ofof atoms, which has already been mentioned, three carrying two, or it may be one, positive it is possible for the a -particles to pass through electric charges, are liberated.It seems asthin sheets of metal, but the fl -particles can if these nuclei were composed of three positive pass through plates of several millimetres, or electrons,heldtogether by onenegativeeven inches, in thickness. electron or perhaps two. In the passage of the particle it will come It has been long known that the atomicinto close proximity with other atoms of the weights of many elements which are integersmetal plate and be deflected from itspath. can be represented by the ger eral formulaThus an a -particle may come close to some w= 4nor w = 4n + 3, where nis someother atomic nucleus and will then whirl integer.This seems to support the view thatround it and be flung off in a hyperbolic path the atomic nuclei in these cases are built upjust as a comet is affected when passing round of helium nuclei of mass four and of thethesun.Similarlyafl -particlewillbe unnamed nuclei of mass three, the atomic num- deflected by atomic electrons. ber being then given by a = 2n or 2n + 1. When an a -particle strikes a screen covered Harkins has suggested that all atomic nucleiwith fluorescent material, such as zinc blende, are built up of hydrogen nuclei, helium nuclei,its impact gives rise to a tiny flash of light and the above unnamed nucleus of mass three,which can be observed through a lens or but having one positive charge and not two. microscope.This fact was utilised by Sir When the helium nuclei or a -particles areWilliam Crookes in the construction of an expelled from the disrupted nucleus of ainstrument he called a spin! hariseope, in which radio -active atom, they are flung off witha minute fragment of a radium salt on the velocities which may be of the order of 20,000 head of a pin was held near a small fluorescent kilometres per second, or, say, 12,000 milesscreen and the little flashes due to the bom- per second, a velocity which would take thembardment ofthis target by the a -particles round the earth in two seconds.Since thewas observed through a lens. NOVEMBER 25, 1922 THE WIRELESS WORLD AND, RADIO REVIEW 269 Sir Ernest Rutherford and manyother electron.Moreover, since we know the mass investigators have made use of this methodof the hydrogen nucleus, which is 1.66 x 10-21 in a highly ingenious manner to determine gram,weseethatthedensityofthe a maximum limit to the size of the nucleushydrogen nucleus or positive electron must of atoms by calculations made from observa-be of the order of 7 x 1013, an enormous tionsof the deflection of an a -particle bynumber when comparedwiththemean a thin plate of metal. density of atoms themselves,or masses of matter. By bombarding molecules of hydrogen gas Hence we arriveatthe conclusion that i n this manner with a -particles, it has beenatoms are very open or porous structures, but found that the centres of the hydrogen andthe particles, viz., the positive and negative helium nuclei must approach within a distanceelectrons of which they are made, have a of 1.7 x 10-13 centimetre. Hence the sum ofstupendous density. the radii of these nuclei must be if anything From experiments made by the deflection less than the above number. of a -particles in passing through sheets of We canconclude,therefore,thatthe variousmetals,Sir Ernest Rutherford has diameter of a single positive electron such asconcluded that the diameters of the nuclei forms probably the nucleus of a hydrogenof atoms are of the order of 10-12 centimetre, or atom,islessthan 0"; x 10-13centimetre. one billionth part of a centimetre. Now this is less than the diameter of a negative (To be continued.)

Of Interest to Inventors-" Licences of Right "Patents. By a BARRISTER -AT -LAW. T has always been a matter of difficultyprobably stipuldted for some return on each Ifor what may be termed the non -pro -article made or sold, but unless he has been fessional inventor, once he has succeeded verywaryhewillfindhimself without in passing his specification safely through the any remedy should the purchaser actually Patent Office, to find a suitable channel throughdecline to manufacture. which he can either dispose of his patent rights There are many instances of such " block- or in some way or other get his inventioning " methods in which patents are main- manufactured and marketed. tained by one firm simply and solely to prevent In practice there are many reasons which some other firm from putting the article upon may operate to prevent the proper exploitation,the market. The holder of such a patent adopts even of a really meritorious invention.The a dog -in -the -manger policy. He will not make fact that it will supply a long -felt want, or himself, because it pays him better not to do that it will enable a given article to be produced so, and he abuses the monopoly grant he holds more efficiently or economically, is by no means by forbidding others to manufacture. a sure passport to commercial success. The consumingpublicingeneralare, For example, a manufacturer who, say, has perhaps, the greatest sufferers in such circum- recently laid down expensive plant to produce stances.They have the right to expect that an article of a given design is approached bythe system of protecting invention by Letters an inventor with plans for the production ofPatent shall result in a meritorious invention a better article at a less cost.If the patenteebeing at once utilised and marketed.The is u poor man, or one who does not know theinventor is an asset to the community only ropes, he may sell his patent rights for someso far as he succeeds in producing something quiteinadequatesum. Thepurchaser that fulfils a want, either in the form of a new promptly " pigeonholes "thepatent. He or improved commodity, or by the more will not make the improved article himself, foreconomical production of an article already it involves the scrapping and replacement ofin use. his new machines, and he is now in a position to prevent anyone else from making it under This form of abuse therefore strikes at the the penalty of infringement. very roots of the Patent System. The State does This is a great injustice to the inventor,not give a monopoly grant in order that it shall who naturally wants to see his idea upon the be bottled up to suit certain vested interests. market where it will earn him royalties. He has The Patents Act of 1919 is very clear on this 270 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922 point.It says very distinctly and specifically,consistent with the largest possible manufacture " Patents for new inventions are granted notwithin the United Kingdom. only to encourage invention but to secure that There may, of course, be more than one new inventions shall so far as possible be workedlicensee, but since there is always the Comp- on a commercial scale in the United Kingdomtroller of the Patent Office as referee, the grant without delay." of subsequent licences must be made on such In an attempt to prevent such abuses theterms as are equitable and fair to the interests Patents Act in question has created what is inof existing licensees, and at the same time must effect a new kind ofLetters Patent, whichnot endanger an adequate return in the shape possesses certain advantages over the ordinaryof royalties to the inventor. grant.Itis intended more particularly to When a thoroughly sound invention is thus, serve those non-professional inventors whoas it were, advertised in the open market, it neither possess the necessary capital to market isfairlycertain toattract the scrutiny of their own ideas nor have direct access tointerested manufacturers.Each knows that interested manufacturers. he may get a licence to work, simply by agreeing to pay a reasonable royalty, and will hesitate to The new form of patent is distinguished fromlose an opportunity that may be seized by a the ordinary grant by being labelled or endorsed competingfirm.Naturallythefirst -comer " Licences of Right." The procedure, so farwill get the better terms. as obtaining the grant is concerned, is presisely Obviously itis impossible for anyone to the same as before, and the initial stamp fees" bottle up " such a patent so as to prevent are identical, i.e., £5 up to and including theit from getting on the market. sealing fee. When the grant has been sealed, Once a patent has been labelled " Licences it may be endorsed " Licences of Right " on of Right " it is only liable to pay half the normal the payment of a single further fee of Li. renewal fees, which means a saving of more This endorsement is a formal notificationthan £60 spread over the full term of 16 years. to all concerned that the invention so protectedThis represents a considerable sum to the may be manufactured under licence, whichinventor of small means. can be obtained from the patentee as a matter Finallyitis by no means an uncommon of right.The terms of the licence involve,thing for a" poor " inventor tofind his of course, the payment of a reasonable royaltypatent rights filched from him simply because tothe inventor.In thecase of disputehe has not the necessary means to fight an between the patentee and a would-be licensee,action for infringement in the High Courts. the points at issue are referred to the arbitra-In the case, however, of a Licence of Right tion of the Comptroller of the Patent Office, Patent,theinterestsof thelicenseesare who is directed by the Act to decide them ininvolved just as much as those of the patentee, accordance with the guiding principles that theand all parties will join forces in resisting any inventor isto secure the maximum rewardsuch attempts upon their common property. The Transatlantic Tests. INVITATION TO CONTRIBUTE T.0 THE PRIZE FUND. N the last occasion of the Transatlanticprize fund which is being started. Tests, when Britishamateurswere Manufacturers are specially asked to interest 0successful in the reception of Americanthemselves in these tests, whether in the matter amateur transmissions, prizes were offered byof offering prizes or by giving their support a number of manufacturers of wireless appa-in other directions. ratus in this country. The names of those At the present time most interestsare firmscontributingtotheseawards werenaturally concentrated on the question of the published in various issues of this journal,development of the industry springing up as and the conditions under which the prizesa direct result of broadcasting.The work of were offered werestipulated by the firmsthe scientific amateur should not suffer eclipse indiv. dually. on this account, but rathera keener public Now that further tests are shortly to beinterest should be felt in any such enterprise conducted, manufacturers are again invited to asthatcontemplated intheforthcoming contribute, should they desire to do so, to thetransatlantic tests. NOVEMBER 25, 1922 THE WIRELESS WORLD AND RADIO REVIEW 271 Experimental Station Design (Continued from page 13o, October 28, 1922.) XVI.-A SINGLE VALVE BROADCAST RECEIVER. THE regulations of the Post Office permitdepends, entirely upon the constants of the of the use of reaction for broadcastaerial to which the instrument is connected. reception,providingthattheplate Of course, the tuning range of the instrument circuit inductance is only loosely coupled tois limited, and the reaction coupling that is the aerial circuit, so that the oscillations whichprovided must be suitable for the band of are set up are of so small an amplitude thatwavelengths on which reception isdesired. interferenceisconsidered to be negligible. Itis found in practicehowever, that the In order that the inexperienced user, who isextent of reaction coupling needs to be altered unacquainted with the interferenceeffects as the value of the capacity in the aerial produced by tight reaction coupling, may not tuning circuit is changed.If the full advantage operate his receiving apparatus in a way thatof the use of reaction is to be obtained, an

01. ommunin

iimnm 100 90 1111E 1 , III: :II

I ut ORO CONDENSER

GRO LEAK AERULlertuci-ssicE TAPPINGS

re. ANENT RESISTANCE

ri I 11

U Del Da J 11 iI oa

FLAT INDUCTANCC EXTENSOR FOR CASTLE PINION AND RACK Suggested Design for a Single Valve Broadcast Receiver. The condenser spindle may be extended .to carry a pinion to engage on rackwork to increase reaction. coupling as the capacity of the tuning condenser advances. is likely to spoil reception at near -by stations, arrangement by which the extent of reaction the Post Office state that reaction couplingcoupling is automatically altered as the value to the aerial circuit, when provided, must beof the aerial tuning condenser increases, may fixed, and arranged in such a manner that itpartly serve as a solution of these difficulties. cannot be varied by the user without dis-In practice such an arrangement presents mantling hisreceiver.To fulfilthesere- many difficulties.The desired increase in quirements in a receiver that may be connectedreaction coupling does not vary proportionately to an aerial having a wide range capacity value,as the value of the condenser is increased to and for use on aerialsof alldimensions,vary through a given range of wavelengths. presents many difficulties, as the extent ofThe only way to accomplish this is to so shape reaction coupling that can safely be usedthe condenser plates that the capacity variation 272 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922 for a given turning of the condenser spindleebonite,onwhich may be wound, non - gives a suitable amount of movement forinductively, about 40o turns of No. 38 single increasing the reaction coupling.The stem silk -covered" Eureka "wire.Thisnon - of the condenser is then of course extended, andinductiveresistanceisshunted acrossthe a portion of the aerial inductance is moved inaerial circuit, and tends to make the point of the field of the reaction coil.Referring to the oscillationlesscritical.To providefor diagram, this arrangement can be provided bydifferences in aerial length, the loading aerial extending the spindle to a plate carrying theinductance, which is wound on a tube which flat inductance.This inductance would beforms a cover for the variable condenser, is moved over the reaction inductance by racktapped out, so that connection can be made work as the condenser spindle is turned. Ato the most suitable point on the inductance suitable setting depending upon the capacityat the time of installing the instrument, to give of the aerial circuit would be obtained whenthe broadcasting wavelength by a mid -position installing the instrument by disengaging thesetting of the condenser scale.The value of rack work and sliding the inductances to thethe aerial tuning condenser should not exceed required position, or alternatively the stationary o.00025mfds.The circuittowhich the inductance might be slipped along to theinstrument is wired is that usually employed desired extent. for single -valve reacting receivers, excepting, Here it might be pointed out that the degreeof course, that the aerial circuit is shunted of reaction coupling of course depends upon with the resistance as stated above. the amplitude of the currents produced in the So many difficultiesare encountered in plate circuit, which in turn varies with the designinganefficientsingle - valvenon - type of valve employed, filament birghtness,radiating receiver which is not provided with and the value of the high tension battery.Itvariable reaction coupling, that it is probably is presumed that with receiving instrumentswise to entirely abandon the use of reaction in of this sort, the type of valve to be used willa single -valve receiving set.The usual . type be specified, and also the variety of highof British valve, when used as a detector tension battery of definite voltage.In instru-without reaction, is usually very little better ments of this sortit becomes essential, ofthan a crystal, and hence it is probable that course, that the filament current cannot bethe only application of a single valve is that varied by the user, and consequently fixedof anoteamplifierfollowing acrystal filament resistance must be provided for usedetector. on a particular voltage.The filament re- It is with satisfaction that we learn that re- sistanceisshown wound on anebonite,action may be used in single -valve broadcast fibre or china tube held on one of the rodsreceiving apparatus ;but until the problem which support the platform carrying the flat as to a method of using fixed reaction has been inductances.This rod may alsoserveas solved, the privilege is of little value.The a stem for the aerial terminal, and for bringingPost Office, whilst giving authority for the use the aerial connection through to the baseof reaction, should lay down some standard of the instrument, for connecting to one of theor specified test which could be applied, so flatinductances.Anothersimilarterminal thatthemanufacturer may know whether arranged symmetrically on the other side ofthe apparatus that he is designing is likely to the instrument should also carry a piece ofmeet with official approval. XVII.-AN IMPROVEMENT IN THE USE OF A TUNED ANODE CIRCUIT. THE use of the tuned anode system of It is the general practice, when using this highfrequencyamplificationbringssystem of high frequency amplification,to with it the difficulty of adjusting a useasecondary inductance intheaerial number of circuitssimultaneously. This circuit.Now, if this inductance is of identical difficulty_is a serious one, and unless eachvalue to the inductance inserted in the plate circuit is carefully tuned with a wavemeter,circuit of the first valve, it follows that the the efficiency of the receiver is considerablycondenser which bridges its ends must be of impaired.The difficulty increases with thethe same value as that used for bridging the number of tuned anode circuits in use, though anode coil, and consequently the two condensers even with only one such circuit, rapid tuningmust be adjusted together. The accompanying is by no means simple. diagram represents a condenser built with its NOVEMBER 25, 1922 THE WIRELESS WORLD AND RADIOREVIEW 273 moving plates divided on to p two sides of a common spindle, whilst the two sets of fixed plates are insulated from one another as indicatedin the r view of the under side. This condenser consists of two sections, each of which gives precisely similar values. The spindle is connected in thecircuittothe H.T. +, whilst oneset of platesis j joined to the grid end of the ill closed circuitcoil,and the . other set of fixedplatesto the plate of the firstvalve. This method of connecting up necessitates the use of a suitablegrid condenser and leak in the grid lead.Great care must be taken in building up a condenser of this sort to ensure that all of the moving platesarecentrallyspiced between thefixedones,as evenoneplate a little out of place will considerably 111 increase the capacity.With careitispossibleto build up apair of condenser units 91tri similar to the one described, Variable Condenser for Tuning Two Circuits simultaneously andto couple the spindles together for the purpose of tuning a number of high fre- quencytunedanodecoils. Alternatively one double condenser can be used for tuning two anode inductances, whilst aseparatesinglecondenser may be used for tuning the aerialclosedcircuit. This single condenser should have an ebonite coupling with the spindle ofthe double condenser,if itis not desired to use a grid condenser and leak with the first valve. , It isessential that the inductances with whichthese condensers are connected should have equivalent values, and with short wave working this is quite a simple matter if the inductances are wound as single layers on an ebonite former. ' End View, showing Connections to Spindle and separate Fixed Plates. 274 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922 For critically adjusting the condenser, it isany excessive friction that may occur on the helpful to adopt some such arrangement asbearings when two condensersare coupled

BO 90 MO 10 A / /Pe //12

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Geared Condenser Control to revoke coupled Condensers.

shownabove. As wellas providing thetogether, andperhapsveryslightlyout critical tuning usually necessary in high fre-of alignment. F.H.H. quency circuits, this arrangement also overcomes Further Notes on a Four -Valve Station HOW TO COMPLY WITH THE LATEST P.M.G. REGULATIONS. By PERCY W. HARRIS. IN some recent articles contributed to thisrapid change from stand-by to tune isstill magazine (beginning July 15th last) thepossible, tuning is facilitated, and C.W. can present writer described in detail the construction of a four -valve receiving set embodying a tuning unit, a H.F. amplifying and detecting unit, and a two -valve note -magnifying unit.Provision was made for single -circuit tuning with reaction coupling to the aerial, and for two -circuit tuning with similar reaction. At the time when this set was designed the PostmasterGeneral'sregulationsregarding reactionwerescarcelydefined.Many of these four -valve sets have been constructed by readers and no doubt are being used with the reaction coil acting on a loosely coupled secondary. This method, however, is liable Pivoted coil holder in position. tocauseinterferenceintheimmediate vicinity of the station.The present articlebe received by the autodyne method, with describesa simple method by which theeither direct or inductive coupling tothe reaction coil can be made to act on the anode aerial.In short, the set retains its efficiency, coil behind the first valve, thus limiting thewhile complying with the latest regulations

extent of radiation.At the same time theof the Postmaster -General. NOVEMBER 25, 1922 THEWIRELESS WORLD AND. RADIO REVIEW 275 Very little constructional work is necessary,handle can be fitted tofacilitate moving the and thereis no interference with existingcoil, but in practice it does not seem neces- connectings or fittings.Briefly, the method sary. consists in fixing a support to the front of the The writer strongly recommends this form H.F. and amplifying unit, the support carryingof reaction to all who have made up the four - a hinged piece which in turn carries a standard coil plug.Into this plug a suitable plug-in coil is fitted and can be swung nearer to or farther away from the anode coil on which it reacts.No new coilsare needed, as one simply transfers the reaction coil form the tuner to the new fitting.The materials needed are one standard coil plug, two terminals, REVERSE THESE CONNECTIONS one hinge, and some odd strips of ebonite TO REVERSE REACTiov 17/s- from thescrap -box.Wood can be used F. 1413' fv\ instead of ebonite for the main support, if preferred.Ebonite, however, looks well, and is recommended to those who like their set to have a well -finished appearance. First cut a strip of 4 -inch ebonite to the dimensions shown in the diagram.Then Cut rLEXIBLE a further strip of the same width, but ins. LEADS long.Obtain from the ironmonger one brass TERMINALS hinge (as used for bureau flaps), one inch wide andin. across when folded.It should be of the type with parallel sides. Drill the support and the swinging arm each With threeclearanceholes for 6 BA metal screws, 17g in.long.Fitthehingewith these screws and secure them at the back BOX LEVEL withsuitablenuts,asshown. The plug should next be secured to the swinging arm by two 6 BA metal screws about f in. long, clearance holes being drilled in the arm and tapped holes in the ebonite of the plug.Drill holes also in the support for the two terminals and fit them with nuts. In the lower portion of the upright support drill two countersunk holes to take a pair of wood screws.These will secure the upright to the wood of the box. The uprightshould not be screwedto theboxuntiltherestof the device is finished, as then it can be placed easily by plugging in any suitable coil and moving it about until the correct point is foundIf the swinging coil extends too far forward, a slip of wood should be inserted between the upright and the box.It will stand up about Details of construction of bracket and arm. three and a half inches above the top of the box.Stiff wire can be used from reactionvalve set.It is easy to manipulate, is efficient terminals to support terminals, and flexibleand is also simple to construct.As it now leads from the latter to the coil plug. stands, the set is proof that one can comply The smaller diagram shows the top of thewith all the P.M.G. regulations, in letter and H.F. amplifying and detecting unit, with thein spirit, without losing that efficiency we all new device in place.If desired, an extensionaim to attain. D 2 276 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922 The Transatlantic Communications FURTHER INFORMATION. By PHILIP R. COURSEY, B.Sc., F.Inst.P., A.M.I.E.E. FROM the latest information received fromRadio Relay League and will be sent by Sainte America inconnection with these , tests, it AssiseRadioStationatapproximately0710 appearsthateven greater enthusiasmis G.M.T. on a wavelength of 15,000 metres.They being shown there on this occasion than last year. will be repeated fiveminuteslater by Marion As has already been announced, in these columns,station, in the United States. the American Radio Relay League has imposed During the transmission tests to America from stiffer conditions this year for their transmitters. this country and from France, similar daily reports They have stipulated that in order to qualify for will be made by the A.R.R.L. from New Brunswick an individual transmission periodin the final Station, WII, on a wavelength of 13,600 metres, tests, transmitting stations must have signalledat 2000 G.M.T.(8.0 pm.).These reports will over a range of at least 1,200 miles.These pre- be addressed to " Coursey, London," and will be liminary tests were held at the end of last month repeated by Carnarvon MUU on a wavelength of and a few British amateurs have reported reception 14,200 metres five minutes after reception there. of signals from some of the American stations All wireless amateurs in the country will there- during these tests.This result gives hope for thefore be able to follow the progress of the tests success of the main tests next month. from day to day by listening in to these transmis- RECEPTION FROM AMERICA. sions from Carnarvon at 0700, and from Sainte The main transmission tests from the UnitedAssize at 0710 G.M.T., during the reception tests States will continue for 10 nights and will last fromhere, and to the Carnarvon reports at 2000 G.M.T. midnight, G.M.T., to 6 a.m., on each occasion. during the transmission tests from this side. This 6 -hour period will be divided up into a " free- SPECIAL. TESTING SIGNALS for-all " period lasting for 21 hours commencing In order to help listeners here to adjust their at midnight, followed by individual transmission sets to the maximum sensitivity arrangements periods for the remaining 3i hours.The " free- have been made for the transmission each evening for-all " period will be divided up into shorter of special testing signals from a station near periods which will be allocated to the variousLondon on a low power and using wavelengths districts of the United States and Canada, much asapproximately covering the band to be used by the was done last year.Before the commencement of Americans. the tests, details will be published of these time These signals will be sent on wavelengths of allocations, as a guide to listeners in this country. 200, 230, 275 and 325 metres, commencing at 2000 The wavelengths to be used during each of the (8 p.m.) on Thursday, November 23rd.The signals individual transmission periods will also be pub-will be in the following form lished as soon as they are received from the TEST TEST TEST de 2 VK 2 VK 2 VK. American Radio Relay League ;but should they XXXXXX XX. WAVE- reach this country too late for publication in this LENGTH METRES." way, they will be circulated by post to all amateurs who have registered their names with the writer The transmission on each wavelength will last as desirous of listening -in for the signals. for 10 minutes, and the 'change over from one DAILY REPORTS. wavelength to the next in the above order will Through the kindness ofMarconi's Wireless be made as quickly as possible, so that the trans- TelegraphCo., and the Radio Corporationof missions will be as follows :- America, arrangements have been made for the From 8 p.m to 8.10 p.m. on 200 metres. transmission at 0700 G.M.T. each morning during From 8.15 p.m. to 8.25 p.m. on 230 metres. the tests of a report addressed to the " American From 8.30 p.m. to 8.40 p.m. on 275 metres. Radio Relay League," giving details of any recep- From 8.45 p.m. to 8.55 p.m. on 325 metres. tions that are reported here.In order to enable A low power will be used for transmission in order these reports to be prepared by the Sub -Committee to make the signals a real test of the receiving of the Wireless Society, which is making the nec- apparatus.Reportsofthereceptionofthese essary arrangements, every amateur hearing signals signals are invited, particularly in order to compare is requested to report their reception immediately the relative transmission qualities of the various by. telegraph or telephone to the writer.Such wavelengths.These transmissions will not take reports will be verified by comparison with theplace on Saturday and Sunday unless otherwise special code letters which will be sent over by theannounced on Friday, November, 24th These American Radio Relay League, before inclusion intest signals will continue untilthe evening of the daily reports. December 11th. These daily reports will be sent by Carnarvon TRANSMISSIONS FROM EUROPE. MUU at 0700 G.M.T. on a wavelength of 14,200 These transmissions from Europe will be made metres, at approximately 12 words per minute, from this country and from France.They will andwillberepeatedfiveminutes laterby extend from December 22nd to December 31st inclus- New Brunswick WIL sive and will last from midnight to6.00 a.m.in Similar arrangements have been made by the each case.Three hours each night have been French Transatlantic Signals Committee for theallocated to the British transmitters, and three to daily transmission of reports of the reception ofthe French, the periods alternating on successive Americansignalsby French amateurs.These nights,commencing withBritishtransmissions reports will also be addressed to the American from midnight to 0300'on December322nd, followed NOVEMBER 25, 1922 THE WIRELESS WORLD AND RADIO REVIEW 277 by French transmissions from 0300 to 0600 oncolumns, and have registered their names with the the same night.The next night the French will writer,specialindividualtransmittingperiods have the first three hours, and the British the second will be allocated, with special code letters to be period ;and so on alternately.This arrangement used.Details of what is to be transmitted by these should give a very fair distribution of the trans- stations will be forwarded by post shortly before mitting periods to the two countries. the commencement of the transmission tests. In order to meet the desires of many of the AVOIDANCE OF INTERFERENCE. ordinary low powered transmitters here,it has It is hoped that every amateur in the country will been decided toreserve thefirsthalf-hour of co-operate to make these tests a success by avoidance both British transmission periods for a " free forof interference during the periods of listening for all "transmission,during which anylicensed American signals between December 12th and 21st. transmitting station in Great Britain may trans- Not only should transmitters be kept quiet after mit on their licensed power and wavelength without midnight between these dates, but receiving sets registrationinanyway. Thesecallsshould also should not be used so as to avoid jamming simply be in the form of " TEST TEST TEST the other listeners in the vicinity.In particular also call letters, 3 lines." repeated as often as desired.all those who intend to listen for the signals are These transmissions should preferably all be made urged to take every possible precaution against on the shorter licensed wavelengths in the 150 to radiation from their signals by using a separate 200 metres band. heterodyne far removed from the aerial circuit, To those transmitting stations which comply in the manner that has already been outlined in with the conditions recently_ announced in these recent issues of the Wireless World and Radio Review. Notes. London University Union. 1005 G.M.T. on 2600 m. spark.3. Additional On November 7th, Lord Haldane opened the reports(synoptic)from European and North University Union. A wireless concert was partAfrican stations, and from ships in the Atlantic, of the programme. are now sent out at 0400, 1600, 2100 G.M.T., wave- Broadcasting in Argentina. length 7,300 m. C.W. 4. "Agricultural meteors " are Transmissions from the Coliseo Theatre, Buenosnow sent daily at 0640, 1115, 1710, 2210 G.M.T. by Aires, have been greatly increase -1 in power.Antelephony on 2,600 m. Italian Company recently rendered " The Geisha," Nantes (UA).-A meteorological report giving which was an excellent transmission and highlythe general situation in North America, the Atlantic appreciated by the wireless enthusiasts and othersand Western Europe, with probable changes, is who listened in.The number of amateur trans- now sent at 1230 G.M.T. on 2,800 m. spark. missions in the Buenos Aires district has increased Mediouna (CNM). - Observations fromfive and now some commercial firmsgiveregularstations in Morocco. sentat 0845, 1430, 1945 G.M.T., transmissions.A suggestion has been made that on 5000 m. C.W. British apparatus might find 'a market in Argentina. 550 Pairs of 'Phones Used at one Reception. Oran (FUK).-MessagesTat 0300,0900,1445, When the Finchley and District Wireless Society 2000 G.M.T.Now sent on a wave of 3,500 m. c.w. listened in to the Lord Mayor of Bristol's broadcastinstead of 3300 m. C.W. speech, two halls were used and 550 pairs of 'phones Bizerte. (FUA).-Messages at 0315, 0920, 1520, were used.The reception was effected on an indoor2020 on 5,150 m. C.W. aerial.A demonstration and lecture was part ofTransmissions of Telephony by theEiffel the programme, and loud speakers were used. Tower. A Boys' Club Station. The following transmissionsof telephony by A small receiving station has been establishedthe Eiffel Tower Station now take place on a at St. Michael's Schools, Buckingham Palace Road, wavelength of 2,600 metres :- for the benefit of St. Michael's Boys' Club. G.M.T. Local Demonstration at Gt. Crosby. 0640Weather forecasts, by districts, for France. Mr. S. Frith, founder of the Liverpool Wireless 1115Reports of General Meteorological situation, Association,assisted by Messrs.J.A.Barton GeneralForecasts,andforecastsfor and C. Pellak, conducted a demonstration at a Winds on French Coasts. Bazaar atSt.Luke's Church, Gt.Crosby. A 1710General Forecast by Districts. temporary aerial had been erected.Mr. J. Jardine, 2210General Meteorological Report; Hall Road, transmitted excellent telephony and General Forecasts, telegraphy. Forecast of Winds for the French Coasts. French andNorth African Meteorological 1720After the forecast message (1710) a Radio Services. Concert is transmitted. The following changes and additions have been Commencing on November 25th the 1710 trans- made in the French and North African Meteoro-mission and the Concert at 1720 will be changed logical Services, with effect from October 15th as regards times to 1820 and 1830 hours respectively. last :- The duration of the Radio Concert is half an hour Eiffel Tower (FL) daily transmissions. -1. Themaximum. French collective (synoptic report) messages atChange of Address. 0220, 0820, 1420 and 1920 G.M.T. are now sent on a Messrs.Burndept,Ltd., have removed their 7,300 m. wave (C.W.). 2. The International collective Leeds Offices to larger premises at London Assurance report (including American stations) is now sent atHouse, Bond Place, Leeds. 278 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922 Correspondence To the Editor of THE WIRELESS WORLD intimation that he would communicate with Com- Agn RAmo REVIEW. mandant Jullien, Chief of the Eiffel Tower Wire- SIR,-Recently I suspected that the dual ampli- less Service. fication (two -valve and crystal) circuit I was using On the 10th inst., I received a letter from Com- was not as efficient as it ought to be.The circuitmandant Jullien in which he intimated that he in use is described by me in The Wireless World would be happy to organise the transmission which and Radio Review of May 27th, 1922. would commence at21.30, but unfortunately, the As a test for sensitiveness I tried on October 15th intimation came too late for announcement in the to receive PCGG on my 4 -ft. frame with 17 turns, Wireless World and Radio Review. in order to compare the strength with the strength I presume that many of your readers were, I used to get a year ago. PCGG was so loud thatlike myself, privileged to join in the fine wireless it was just audible all over the room with theservice which was transmitted, and trust that I telephones hooked on to the trumpet.This wasecho the wishes and sentiments of them all when so encouraging that I changed over to the singleI express the wish that the service, which one valve dual and crystal circuit (described in the issuemight characterise as of international character of The Wireless World and Radio Review previously and significance, will be only the first of a series. referred to), and succeeded in receiving PCGG VERNON I. N. WILLIAMS. with only a single valve. To the Editor of THE WIRELESS WORLD AND To make sure that the reception on October 15th RADIO REVIEW.

was not a freak, I repeated the experiment to -day, SIR,-I see in the last issue of the Wireless World and again received PCGG on the frame quiteand Radio Review that Mr. Deloy has heard several easily with a single valve, so loud that even theBritish amateurs-using an aerial wireof160 voice of the speaker could be recognised. metres. On the 100 -ft.aerial, using the two valve dual As I wrote it to the owner, Mr. Burbury of Wake- and crystal circuit plus one valve note magnifier,field, I hear the station 2 AW very easily with and hanging the loud speaker out of the window, the following apparatus :aerial 20 metres long, PCGG's music was audible 100 yards from thesteel wire (0.6 m.m. diameter) well under the level loud speaker. of the surrounding roofs. It would be interesting to know if the above My set is home-made and consists of a Reinartz results are records or not. Tuner(modified)or an ordinaryregenerative London, S.E.23. receiver (tuned plate circuit), and only one detecting P. G. A. H. VOIGT. valve (French " Metal "). To the Editor of THE WIRELESS WORLD Mr. Burbury told me his output is only 0.9 in AND RADIO REVIEW. the aerial. SIR,-I notice in your current issue some details I very often hear British amateurs on telegraphy oftransmission from English amateurs beingand telephony but they are hardly readable, due heard at Nice.If it is of any interest, we haveto very marked fading.(My station is located in been working regularly for some weeks, to a manthe centre of Paris and a big railway station is at Geneva, who reports signals very strong, audiblebetween England and my aerial-fading due to all over the room.Current in aerial from 0.75 to smoke 1). 0.9 ampere.Receiver, three valves (detector and So, you see that the reception in France of two note magnifiers).Also received very strongBritish amateurs transmissions is not such a diffi- in Paris on a single valve, the aerial there beingcult job. very short and badly screened by high buildings Paris. all round. J. PERROUX, ENO. E.S.E. H. H. T. BURBURY (2 AW). To the Editor of THE WIRELESS WoRLD AND To the Editor of THE WIRELESS WORLD AND RADIO REVIEW. RADIO REVIEW. SIR,-I am very happy to give you the following SIR,-As a Wireless amateur who has been veryreport of reception of British amateurs. much interested in and derived considerable pleasure My receiving set consists of : and mental profit from the telephonic transmis- Aerial loop 2.50 metres x 2 metres consisting of sions of FL, and in pursuance of an idea which hadone turn of 12/10 copper wire, variable condenser been in my mind for several months, I wrote to 0.0005mfds., Detector valve with reaction coil

General Ferric on the 25th October, suggesting that and note magnifying valve. it would be a fine thing if he could see his way to 40 volts high tension battery was used and no grant permission for a wireless Commemorationfilament rheostat or grid potentiometer. Service to be transmitted from the famous station The telephonesare" Ducietet "make.On on the evening of Armistice Day, November 11th, November 1st, between 8 p.m. and 9 p.m. I could so that the wireless amateurs of the Allies, withhear 2 KF, who came in very loud and clear, and their circles of friends-ex-Service and civilian-2 NM, 2 AF, 2 AW (telegraphy). could join in simultaneous homage to the great On November 5th, 2 DO (not very constant.) ones who gave their lives for freedom in 1914-1918. I would be very much obliged to you if you With the suggestion, I send a proposed pro-would congratulate the British amateurs I heard gramme. so well.I am situated in the centre of Paris, ' I was delighted to receive a kind letter froni thebetween a great number of very high buildings and General, under date of 31st October, expressingwithout any external aerial, on the first floor of his warm approval of the idea and conveying thethe house. NOVEMBER 25, 1922THE WIRELESS WORLD AND RADIO REVIEW 279 I hope to answer the British amateurs in a few DERBY WIRELESS CLUB. weeks, and I look forward to the opportunity of At7.30p.m.At" TheCourt,"Alvaston. speaking to them by telegraphy and telephony. Informal Meeting. be- P. BurEy. ILFORD AND DISTRICT RADIO SOCIETY. ". Paris, Lecture on " Reaction and how to keep within November 7th, 1922. the P.M.G.'s Restrictions," by Mr. J. F. Payne. Friday, December 1st. Wireless Society of London Accounts. BRADFORD WIRELESS SOCIETY. At5,RandallwellStreet.Lecture by Mr. The Treasurer of the Wireless Society of London Liardet. states that the account and receipt books are MANCHESTER WIRELESS SOCIETY. closed for annual audit until December 1st. He is, At 7.30 p.m.At Houldsworth Hall.Lecture therefore, unable to answer queries relating thereto on " Radio Measurements and Measuring Instru- until after that date. ments," by Mr. Bertram Hoyle, M.Sc. LEEDS AND DISTRICT AMATEUR WIRELESS SOCIETY. At 7 p.m.Lecture on " Construction of Con- Calendar of Current Events densers-FixedandVariable,"byMr.S. Friday, November 24th. Kniveton. LEEDS AND DISTRICT AMATEUR WIRELESS SOCIETY. NEWCASTLE AND DISTRICT AMATEUR WIRELESS At8 p.m. Demonstration of" Burndept ASSOCIATION. Apparatus," by Messrs. Townend and Phillips. At 7.15 p.m.At Engineering Theatre, Arm- WIRELESS SOCIETY OF HULL AND DISTRICT. strong College.Lecture on " Some Observations At 7.30 p.m. Sale of Surplus Apparatus at on Distortion in Wireless Telephony," by Mr. the Signal Corps H.Q., Park Street. W. Owen. BELVEDERE AND DISTRICT RADIO AND SCIENTIFIC BELVEDERE AND DISTRICT RADIO AND SCIENTIFIC SOCIETY. SOCIETY. Lecture on " The Armstrong Super -Regenerative Lecture on" Common FaultsinReceiving Receiver," by Mr. C. E. Morris. Circuits," by Mr. A. H. Norman. SMETHWICK WIRELESS SOCIETY. Saturday, December 2nd. Lecture on " Alternating Current Applied to CROYDON WIRELESS AND PHYSICAL SOCIETY. Generating Stations," by Mr. R. H. Parker. At 7.30 p.m.Annual General Meeting and lecture Saturday, November' 25th. on " Small Rectifiers for Charging from A.C." THE RADIO SOCIETY OF HIGHGATE. At 7.30 to 11.30 p.m. At the Gate House, Highgate, N.G. Radio Dance. Fancy dress optional. Prizes. Tickets7s.6d.(double Books Received 12s. 6d.). Sunday, November 26th. DIRECTION AND POSITION FINDING BY WIRELESS. Daily Mail Concert from the Hague, 3 to 5 p.m. By R. Keen, B.Eng.(Hons.).(London :The Monday, November 27th. Wireless Preys, Ltd.,12/13, Henrietta Street, IPSWICH AND DISTRICT WIRELESS SOCIETY. W.C.2. Illustrated. Price 9s.net.) At 8 p.m.At 55, Fonnereau Road.Lecture WIRELESS : POPULAR ANDCONCISE.By Lt. - by Mr. Mellor. Col. C. G. Chetwode Crawley, R.M.A. (London : Tuesday, November 28th. Hutchinson & Co.,Paternoster Row, E.C. Transmission of Telephony at 8 p.m. on 400 Illustrated. 92pp. Price Is. 6d.net. metres, by 2 MT Writtle. 71" x 5".) PLYMOUTH WIRELESS AND SCIENTIFIC SOCIETY. WIRELESS TELEPHONY SIMPLY EXPLAINED. By Lecture on " Elements of Alternating Current R. W. Hallows.(London :C. Arthur Pearson, Theory," by Mr. E. W. Pinney. Ltd.,HenriettaStreet,W.C.2.Illustrated. Wednesday, November 29th. 125 pp.Price 2s. 6d. nett.7f" x 4r.) MALVERN WIRELESS SOCIETY. Lecture on " Electrostatics and Condensers." EDINBURGH AND DISTRICT RADIO SOCIETY. Official List of Radio Stations of Canada. At8p.m. At R.S.S.A.Hall.Lectureon We have just received from the Radio Telegraph " Some Notable Inventions," by Mr. J. S. Smith. Service, DepartmentofMarine and Fisheries, PLYMOUTH WIRELESS AND SCIENTIFIC SOCIETY. Ottawa, a copy of the official list of radio stations Demonstration of Reception at Y.M.C.A., Union of Canada. Street. Thislistincludes not onlythecommercial Thursday, November 30th. stations, but also all amateur experimental stations HACKNEY ANDDISTRICT RADIO SOCIETY. and broadcasting stations, and,in addition,it At Y.M.C.A., Mare Street.Lecture on " Elec-contains particulars of the procedure of working trical Units and Ohms Law," by Mr. F. G. of direction -finding stations, together with a list of Francis. International Morse Code abbreviations. OLDHAM LYCEUM WIRELESSSOCIETY. Supploments to this list can be obtained by filling Lecture on " Amplifier Characteristics," by Mr. in a postcard with accompanies each book.Being A. T. Howes, of Manchester. of the loose-leaf pattern, these supplements can LUTON WIRELESS SOCIETY. easily be added from- time to time as they are At 8 p.m.At Hitchin Road Boy's School. issued. Lecture on " Valves," by Mr. R. Cox. The price of the list is 5s., and copies are obtain- Daily Mail Concert from the Hague 8 to 9 p.m. able from the publishers of this journal. 280 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922 Wireless Club Reports NOTE.-Under this heading the Editor will be pleased to give publication to reports of the meetings of Wireless Clubs and Societies.Such reports should be submitted without covering letter and worded as concisely as possible, the Editor reserving the right to edit and curtail the reports if necessary.The Editor will be pleased to consider for publication papers read beforeSocieties. An Asterisk denotes affiliation with the Wireless Society of London. Correspondence with Clubs should be addressed to the Secretaries direct in every case unless otherwise stated. Walthamstow Amateur Radio Club.* The 'second monthly lecture was given by Mr. Hon. Secretary, Mr. R. H. Cook, 30, UlverstoneC. S. Dunham, of the Wireless Society of London, Road, Walthamstow, E.17. on " H.F. Transformers and Couplings."This On October 15th, Mr. Nickless, 2 KT, gave alecture was one of the most technical and instructive very successful demonstration of telephony receptionthe Society has had the pleasure to hear.Very on his five -valve set with loud speaker. excellentresults were heard on a three -valve 2 LO came through splendidly, as did also 2 ON,receiver. who kindly transmitted music and speech for this Morse practice under the direction of Mr. R. H. occasion.At the end of the demonstration Mr.Cox, precedes all meetings from 7.30 to 8 p.m. Nickless replied to many questions. By an amendment to the rules, membership is Mr. A. J. Smith gave a lecture the week previousforfeited when the annual subscription of 5s.is on" Alternating Current and the Thermionicone month overdue.Membership increases steadily, Valve " ably assisted by Mr. Allen, he cleared upnew apparatus has been added to the club set, and many debateable points. a loud speaker is now available for members' The Club is now affiliated to the Wireless Societyprivate use. of London and membership is steadily increasing. The Club was originally formed on October 1st, 1920. Radio Experimental Association. Hackney and District Radio Society.* (Nottingham and District).* Hon. Secretary, Mr. E. R. Walker, 48, Dagmar Hon. Secretary, Mr. D. F. Robinson, 99, Musters Road, Hackney, E.9. Road, West Bridgford, Nottingham. An informal meeting was held at the new head- At the new headquarters, Bennett's Garage, on quarters (theY.M.C.A., Mare Street, Hackney, November 2nd, Mr. Thornton occupied the chair, E.8), on November 2nd.The first unit of theand Mr. Carpenter lectured on " The Valve as a Society's wireless set, made entirely by amateursDetector," assisted by Mr. Ford, who demonstrated. of the Club, was installed.It permits of the use Mr. Carpenter dealt with spark transmission, of valve or crystal detection.Further units arespark rectification, and the valve as a detector. in the course of preparation.With the aid of aExperiments were made with potentials applied to three -valve Mark III L.F. amplifier, kindly lent by athe grid, also various values of grid leaks and con- member, telephony was very well received.Thedensers,usingMarconi-Osram " R "type and Society's set is as far as possible being built byMullard " Ora " valves. means of contributions in the form of money or Meetings are held every Thursday. apparatus. Borough of Tynemouth Y.M.C.A. Radio and On November 9th, a special General Meeting Scientific Society.* was held. Hon. Secretary, Mr. Geo. J. S. Littlefield, 37, On November 16th a debate on valves andBorough Road, North Shields. crystals tookplacebetween Mr.Valinsand The third session opened on October 2nd, when Mr. Bell. the Hon. Secretary gave a short talk on " Aerial Mr. F. G. Francis will lecture on " ElectricalConstruction." He described the different kinds Unitsand Ohms Law " on November30th. of aerials in use and explained why certain types Visitors are cordially invited. were to be preferred for given. conditions.He Luton Wireless Society.* showed specimens of various kinds of insulators Hon. Secretary, Mr. W. F. Neal, Hitchin Roadand wires, and gave a great deal of valuable in. Boys' School, Luton. formation to beginners. A number of questions The third winter session was opened on October were asked and answered. 5thby a public lecture and demonstration by On October 9th, Mr. W. G. Dixon, of the New- Mr. W. B. Cole, of Marconi Company, on " Modern castle and District Amateur Wireless Association Wireless Telegraphy and Telephony," and a large was to have lectured, but owing to unforeseen public hall was filled.The Mayor of Luton wascircumstances was unable to do so.Mr. Littlefield Chairman.Lantern slides were used.During thestepped into the breach and gave a very interesting evening telephony and music were received andtalk on the " Sterling No. 1 Aircraft Transmitter." highly appreciated. The instrument was described in detail. A Practical Class for instruction and experiment The lecture was followed by an interesting is held fortnightly under the direction of Messrs.practical demonstration. A. E. King, F. W. Pellant, and the Hon. Secretary, Mr. Scott demonstrated the " Ducon " appliance. a workshop being available on the premises through On October 16th, Mr. E. C. Lythgoe gave an the courtesy of the local Education Authority.exceedingly interesting talk on Trench Com- A single valve receiver is being constructed andmunication." He described and illustrated with experiments on different circuits, etc., are conducted. blackboard sketches, the various means employed On October 19th Messrs. B. & A. Wireless Com-during the war for maintaining communication pany, of St. Albans, exhibited and demonstratedbetween the front line trenches and headquarters. with a Burndept Ultra 4. A hearty vote of thanks was accorded Mr. Lythgoe. NOVEMBER 25, 1922 THE WIRELESS WORLDAND RADIO REVIEW 281 Belvedere and District Radio and Scientificto 7 a.m., G.M.T., the actual transmission being Society.* for a duration of the first 15 minutes in each hour. Hon. Secretary, Mr. S. G. Meadows, 1, Kentish Call letter, 5 MS. Road, Belvedere, Kent. Extraordinary results are being obtained with The tenth general meeting was held at the Erith the Society's 10 -watt set, and the benefit thus Technical Institute, on November 3rd. gained will be used in conjunction with American Recommendations of the Committee meeting tests. held on October 31stwere confirmed, viz.:- A special section of the Society is being devoted That ladies should be admitted as members of the to " Broadcasters," for whom lectures are being Society on the same terms as gentlemen members, arranged at a special fee, with a view to training and that " Broadcast " members should be in them to become real experimenters. eluded at a reduced subscription. East London Radio Society.* It was decided to purchase a loud speaker. The Hon. Secretary, Mr. W G Simmonds, 60, East equipment engineer was asked to proceed with theFerry Road, E.14. construction of a wavemeter. On October 17th Mr. Keens was unable to give Mr. S. G. Meadows delivered his paper on " Thethe second half of his lecture on " Coils," being Electron Theory as Applied to the Thermionic unavoidably absent, and October 24th was fixed Valve."The lecturer dealt with the structurefor this event.Members listened in to 2 MT and of the molecule, and of the atom according to theother transmitters.2 FQ was received very well. now generally accepted electron theory, demon- Mr. W. C. Wells explained the Society's apparatus strating his points as he went along on suitable in detail to new members and visitors.Visitors apparatus. are welcomedon Tuesdays and Fridays, from At the conclusion of the lecture, the Chairman7.30 p.m. to 10 p.m. (Mr. T. E. Morriss) added a few appropriate remarks and accorded a vote of thanks for such anFulham and Chelsea Amateur Radio and Social interesting and instructive paper. Society.* Coventry and District Wireless Association.* Hon. Secretary, Mr. W. Wood, 48, Hamble At the Club Rooms, 128, Much Park Street, on Street, Fulham, S.W. 6. November 1st, Mr. Sidley, the President, gave a A satisfactory and instructive meeting was held short address on general subjects connected with on October 31st. wireless telegraphy, which was followed by dis- The Secretary gave a lecture on " Elementary cussion. Inductance," and Mr. Whitts,assisted by the Mr. Sidley appealed to all members using re-Secretary, gave an explanation of the cause of actance to revise their circuits. The only permissible " dead spots " found in different countries.A arrangement was, he said, to couple the reactance hearty vote of thanks was passed to the Secretary. coil with a secondary coil of a closed circuit in- A reception set for the use of the Society is in ductively coupled to the aerial coil.He offered course of construction, and the necessary licence to dealwith any difficulties which might present applied for. themselves to members in converting their apparatus Bradford Wireless Society.* to the standard permissible form. Hon. Secretary, Mr. J. Bever, 85, Emm Lane, Mr. Sidley referred to his experiments in " wiredHeaton, Bradford. wireless." An informal meeting was held on November 3rd. These remarks led to some interesting discussions. A discussion took place on the " Evils of the Oscilla- Considerable interest was shown in the President's ting Valve." The principal speakers were Mr. A. remarks upon apparatus embodying the Armstrong Liardet and Mr. J. Bever, who both dealt very regenerative principle, and it was hoped to giveably with the subject and explained the various. fuller particulars of this apparatus at a subsequentmethods by which " howling 'could be avoided. meeting.Discussion on the use of frame aerials Questions were invited and ably dealt with. followed. Arrangements are now in progress for the Society's Manchester Wireless Society.* Exhibition, which is to be held in January. Any Hon. Secretary, Mr. Y. W. P. Evans, 2, Parkside firms desirous of exhibiting should communicate Road, Princess Road, Manchester. as early as possible with the Organising Secretary, A very interesting lecture was given by Mr. Mr. N. Whiteley, 8, Warrels Terrace, Bromley, P. C. Stephens on " Electricity, Past and Future," Leeds.All applications for space will be promptly in which he dealt with electrical progress from its dealt with. earliest inception.An interesting discussion fol- Sutton and District Wireless Society.* lowed. Hon. Secretary, Mr. E. A. Pywell, Stanley Lodge, On November 1st, Mr. Y. W. P. Evans gave the Rosebery Road, Cheam, Surrey. first of his series of elementary lectures and dealt The Society is now affiliated with the Wireless thoroughly with simple crystal circuits and also Society of London, and the membership is steadily combinations of crystal and valve. increasing. All technical matter was entirely eliminated and At the meeting held on November 1st, the Presi- the various actions explained in everyday language, dent, the Rev. F. C. Lees, gave an interesting suitable for those just taking up wireless experi-account of his experiences with a Mark III* tuner menting. in conjunction with a high frequency amplifier and The high power transmitting valves for thetuned anode coupling, with which he obtained transatlantic tests have been received and are beingsome very remarkable results. tested preparatory to erection.Four special tests An attractive programme is being arranged for with a 1 -kW. spark set are being carried out onthe winter months, and it is hoped that a good each Sunday morning in November from 1 a.m. attendance will result. 282 THE WIRELESS WORLDAND RADIO REVIEW NOVEMBER 23, 1922 Bishop'sStortfordandDistrict Amateur Mr.R. Brockbank gave a very interesting Wireless Association. * discourse on " Valves and their Characteristics Hon.Secretary,Mr.J.Cooper,Halfacres, at the meeting held on October 27th.The lecturer Bishop's Stortford. showed how the characteristics were obtained, The monthly meeting was held at the Institute,and explained their use. Bishop's Stortford, on November 3rd, the Vice - Ilford and District Radio Society.* President, Councilor E. F. Cooper, occupying the Hon. Secretary, Mr. A. E. Gregory, 77, Khedive chair.The President, Mr. W. A.Field, gave Road, Forest Gate, E.7. an address on " Aerials."Various types of aerials Under the auspices of the above Society, demon- were described and shown in diagram, and theirstrations of wireless telephony were given in aid erection, construction, capacity, directional pro-of Church Funds at the Seven King's Baptist perties,etc.,dealtwith.. Thematerialsbest Church, on November 2nd, 3rd, and 4th.Tele- suited fix: the purpose were indicated, and methods phony was successfully received from Marconi of jointing demonstrated.Specimens of the best House, 2 ON and 2 JX.The loud speaker was types of insulators were passed round for inspection, loaned by Messrs. Radio Instruments, and the and a special form of lead-in tubing shown. necessary -batteries by Messrs. Fullers. The Chairman announced that the Society had Bedford Physical and Radio Society.* become affiliated with the Wireless Society of Lon- Hon. Secretary, Mr. Q. W. Clarabut, 194, Castle don. A vote of thanks was accorded Mr. Field. Road, Bedford. General meetings are held on the last Friday in Meetings were held as follows :- every month. May 27th.Mr. R. W. L. Phillips was Chairman. Radio Society of Highgate.* The name of the Society was decided upon.It was Hon. Secretary, Mr. J.F.Stanley, A.C.G.I., then proposed by Mr. Craddock and seconded by B.Sc., 49, Cholmeley Park, Highgate, N.6. Mr. Tearle, that Mr. R. S. Allen be asked to be Mr. L. Grinstead, on October 20th, lectured onPresident. " Valve Characteristics and Design," illustrating The followingofficerswere thenelected by means of characteristic curves. Vice -Presidents : Messrs.L.Bolton,Willmer On October 27th a paper was read by Mr. S. Phillips, C. W. Hansel, R. W. L. Phillips.Hon. Croneen on " The Magnavox Equipment."The general features and internal construction of the Secretary, Mr. C. W. Clarabut ;Hon. Treasurer, Mr. C. E. Craddock Committee :Messrs. B. F. loud speaker and amplifier were described. Skinner, R. T. Rolfe, 'P. S. Hudswell, W. S. Pyrah, A lecture on " A Simple Wavelength Calculator " L. G. Noble, W. S. Tearle, A. H. Mackley, P. H. S. was given by Mr. F. Stanley on November 3rd. This Kempton. calculator is in the form of a chart which shows The subscription was fixed at 10s. per annum. at a glance the solution of the expression It was resolved :That the Society should meet X = 1,885 CL fortnightly on such day or days as may be fixed There are still a few tickets left for the Radioat a later meeting ;That the Society be devoted Dance (see Calendar). entirely to radio work for the present ;That the FinchleyandDistrictWirelessSociety.* Society be affiliated to the Wireless Society of Hon. Secretary, Mr. A. E. Field, 28, Holmwood London ;That Mr. R. W. L. Phillips be deputed Gardens, Finchley, N.3. to approach Messrs. Wilton & Co., with a view On November 3rd the broadcast speech of theto their abandoning the project of a new club, Lord Mayor of Bristol was received.Two halls and the intending members joining this existing were used, one holding 300 people and the other Society. 250.The Marconi Telegraph Company sent a A vote of thanks was passed to Mr. Phillips. representative with apparatus, and the Stirling June 24th, 1922.The Rev. H. W. Evans took TelephoneCompanysuppliedtwoMagnavox the chair. loudspeakers.Mr.Turner,ofRegentStreet The minutes of the meeting held May 27th Polytechnic, conducted the demonstration, giving were confirmed and signed.The rules were taken two lectures, one before and one after.Every as read, and unanimously approved. An amend- person present had a pair of 'phones, the wiring ment that S.1., Rule 3, be altered to include ladies being entirely done by members. A Marconiphone as members, was lost. IJ.2. and a Marconi amplifier were used in con- It was resolved that a lecture and demonstration junction with an indoor aerial for the reception. be arranged for July 11th, admittance to be by The Society met on November 6th, when Mr. invitation tickets. Grinstead, of the Mullard Radio Company, lectured A lecture and demonstration by Captain H. on " The Valve and its Applications." Anthony Hankey, of Marconi's Wireless Telegraph Southend and District Wireless Club.* Company, Ltd., took place on July 11th in the Hon. Secretary, Mr. C. G. Jackson, Lynncroft,Bedford Modern School.Over 400 were present. Leigh Hall Road, Leigh -on -Sea. A special concert was received from 2 LO, also Meetings are held every Friday at 8 p.m. atmusic from 2 MT. The lecturer used his own 51, Princes Street.On October 6th, Mr. Mayerapparatus.ThePresident,Mr.R.S.Allen, (2 LZ) lectured on the " Elimination of Reradia-proposed a vote of thanks to the lecturer, which tion."He pointed out the trouble caused by the was seconded by Sir George Royle, O.B.E. careless use of reaction, and explained that the There were 48 members present on July 25th. three -circuit tuner may reduce interference con- Mr. R. W. Phillips took the chair.Mr. W. S. Pyrah siderably provided the reaction coilis coupledand Mr. W. S. Tearle lectured on tuning and ele- to the secondary. mentary valvepractice.Mr.C.W. Clarabut At a subsequent meeting Mr. Mayer gave a lecturetransmitted musical items from his experimental on " The Reinartz Tuner." - station 2 WD. NOVEMBER 25, 1922 THE WIRELESS WORLD AND RADIO REVIEW 283 Hoylake, West Kirby and District Wirelessheld .on Tuesday, November 21st, at 8 p.m., at Association. 36,Hamilton Square (topfloor),Birkenhead. Hon. Secretary, Mr. Roper Brattan, 14, KirbyA demonstration of telephony was given, and Park, West Kirby. various parts ofradio apparatus belonging to A general meeting was held on October 23rd, members were exhibited and demonstrated. at the Green Lodge Hotel,Hoylake.In the Application forms for membership were handed unavoidable absence of Mr. Welding, the chairround duringthemeeting.Affiliationtothe was taken by Mr. S. Evans, Technical Adviser to Wireless Societyof Londonisbeingapplied the Association, who announced in the course of for.Subscriptions are :10s.for members over his opening address that a stage of H.F. amplifica- 18, 5s. for members under 18, and 2s. 6d. for lady tion, designed by Mr. Brattan, was being added members.All subscriptions should be sent direct by the Committee to the three -valve set then in to the Hon. Treasurer, Mr. G. A. King, 17, Kingsland use, and it was hoped that this would be in actionRoad, Birkenhead. by the next meeting. Mr. Roper Brattan, with the aid of blackboardHartlepools and District WirelessSociety. diagrams, then gave a very helpful list of various Hon. Secretary, Mr. Robert L. Howey, 33, Grange symbols used in wireless work, together with aRoad, West Hartlepool. particularly clear explanation of the variometer On October 10th a very interesting lecture was type of tuning and of crystal and single valve sets. given on " Wireless Control," by Mr. G. Wenn. Specimens of the latest Marconi valves were veryA model ship contructed by Mr. Wenn was used to kindly loaned by a member for inspection. demonstrate.This ship was built and worked A vote of thanks was accorded the lecturer.nearly fourteen years ago. Individualdifficulties were then dealt with,a The lecturer also mentioned the wireless control member's inductance coil being discussed and valu- of airships. able improvements suggested by Mr. Brattan. Mr. Patterson, President of the Society, proposed a hearty vote of thanks to Mr. Wenn, and con- Newton-in-MakerfieldandDistrictRadio gratulated him upon building his model ship. Society. The proposal was carried with applause. Hon.Secretary and Treasurer,Mr.R.W. An interesting syllabus of lectures and. events Mayhew, 220, Earle Street, Earlestown. has been prepared for the coming winter. A meeting took place in the All Saints' Mission The Society asks for lecturers. Room, CrowLane,Newton - le - Willows,on October 25th, Mr. Goff being in the chair. Manchester Radio ScientificSociety. The Chairman reported successin obtaining Hon.Secretary,Mr.H. D. Whitehouse,16, the use of a room in the Newton -le -Willows CricketTodd Street, Manchester. Pavilion for the winter months, and that the weekly The Annual General Meeting was held on October meetings would commence there on Wednesday, 13th, Mr. G. G. Boullen being in the chair.After November 8th, at 7.30 p.m. A discussion followedthe minutes of the last annual general meeting, as to the programme, and Mr. Norman, the Vice - October 19th,1921, had been read and passed, President of the Society, kindly consented to give the Secretary gave his report of the year's work, a short address on " The General Principles of theand also read some correspondence of the Wireless Theory of Wireless Telegraphy and Telephony," SocietyofLondon.Questions on thesubject and Mr. Goff a short address on " The Variousmatter were then invited and duly answered. Types of Circuits Suitable for Beginners' Use." The meeting proceeded with the revision of rules, Mr.Smith gave an informativespeech onand also discussed the question of how to meet " Wireless Licences," and pointed out that there the coming wireless boom.The election of officers were two kinds, the Experimental and the Broad- for the forthcoming session was taken in hand, casting, and dwelt on the fact that in the case ofand the following gentlemen were re-elected :- the latter no changing of the circuit could beChairman, Mr. G. G. Boullen ;Hon. Secretary, contemplated, and a ready -built set must be pur-Mr. H. D. Whitehouse ;Hon.Treasurer, Mr. chased made by a firm associated with the Broad-J. R. Halliwell ;Press Secretary, Mr. J. W. Hand. casting Company. He strongly advised all mem- An ordinary meeting was held on October 25th. bers to apply for experimental licences, by the pos- The minutes of the annual general and the last session of which they would be able to make theirordinary meeting were read and passed, the new own sets and experiment with different circuits. rules formulated coming into force.Four new Mr. Newell gave his personal experience in themembers were dulyelected.Suggestions were natter of experimental licences and correspondence received by the Committee for the holding of he had had with the Postmaster -General on the meetings weekly instead of fortnightly as hitherto, subject of aerials. every alternate Wednesday being left open for Mr. Goff gave a brief idea of the capabilities ofnew members, especiallythose justbeginning, one or two types of circuits, and said the Broad- to receive help and advice from older experimenters. casting Station would be open at ManchesterThe Society is laying itself out to assist the new- very shortly, and should be received quite well oncomers, and hopes that interested people will not a good crystal set. fail to communicate with the Secretary.Mr. J. R. New members were enrolled. Halliwell then gave " His Impressions of the All - BritishWireless Exhibition," which proved of Radio Society of Birkenhead. greatinterest.The lecturer concluded with a Hon. Secretary, Mr. R. Watson, 35, Fairview frame aerial demonstration, using a three -valve Road, Oxton, Birkenhead. set.The MetropolitanVickersStation,Man- The opening night of the above Society was chester (2 ZY) came through very well. 284 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922 Bromley Radio and Experimental Society. At the Central Polytechnic, Croydon, on November Hon.Secretary,Mr.J.Furgusson-Croome, 4th, Mr. S. H. Naylor lectured on " Hints to' the Gowrie, Wendover Road, Bromley, Kent. Student and Teacher of Wireless Telegraphy." A meeting was held on November 1st at the Mr. Naylor explained the easiest ways to study the Club -room, Ex -Service Men's Club, London Road subject, and emphasised his points with several (permanent headquarters).Meetings will be held analogies and demonstrations with simple models. on Mondays,.at 7.30 p.m.An interestingledure or A keen discussion then followed, and the meeting demonstration has been arranged for every meetingterminated with a hearty voteofthanks to this year. Mr. Naylor. The Secretary introduced Mr. L. Stopes (Chairman The next meeting, which will take place on Satur- of the Society), who gave an instructive and interest. day, December 2nd, at 7.30 p.m., being the annual ing lecture on " Primary Cells and Accumulators." general meeting, it is requested that all members A representative collection of cells kindly loanedwill endeavour to be present.There will be a by Messrs. Siemens Bros.,of Woolwich, showedlecture on " Small Rectifiers for Charging from the practical application o the lecturer's remarks. A.C." Plymouth Wireless and Scientific Society. Wembley Wireless Society. Hon. Secretary, Mr. G. H. Lock, 9, Ryder Road, Hon. Secretary, Mr. W. R. Mickelwright,10, Stoke, Devonport. Westbury Avenue, Alperton, Wembley, Middlesex. A joint meeting of the Society and of the Junior On November 2nd, Mr. H. E. Comben gave a Institute of Engineers was held on October 31st. most interestinglectureon" Inductance and A lecture was given by Mr. G. H. Lock on " Wireless Capacity,"anddemonstratedwithanalogous Reception."The lecturer referred to the pioneer mechanical apparatus. On November 9th, Mr. H. E. work of Carl Hertz, Branley and others.The Wallis lectured on " Tuning and Tuners," and principles of tuning were explained, and the magnetic on November 16th members queries and difficulties and crystal detectors dealt with.The Edison were dealt with in a general discussion.The Society effect,theFleming two -electrodevalve,and, now has over 80 members, and a Junior Section ultimately,thethree -electrodevalvefollowed. has just been formed for the education and assis- A typical characteristic curve was shown, and the tance of boys starting wireless.The age limit rectifying and amplifyingpoints explained. Magnetic is 12 to 16 years. reaction and the reception of continuous waves A social evening is being arranged for Dec. 8th. completed the lecture. A demonstration followed, Plymouth Wireless and Scientific Society. during which, by means of a seven -valve set, the Hon. Secretary, Mr. G. H. Lock, 9, Ryder Road, lecturer was able to illustrate the principles of Stoke, Devonport. " beat " reception. At a meeting of the above, held on November 7th Ealing and District Radio Society. atPlymouth Chambers,a lectureon " High Hon. Secretary, Mr. W. F. Clark, 52, Uxbridge FrequencyAmplification "was givenby Mr. Road, Ealing, W.S. L. J. Voss.Starting with a lucid explanation The new series of lectures has proved to be aof the amplifying regionof the characteristic valuable asset in attracting new members. Oncurve of a normal valve, the lecturer proceeded October 27th, the Society unanimously decided to describe the various methods of communicating to forward a protest to the responsible apthori- the amplified impulses to the grid of the succeeding tiesagainstthe inadequate representation that valve. the wireless experimenter hasreceived at the Seven new members were elected, bringing the meetings of the British Broadcasting Company heldpresent total membership up to forty-two. recently.They asked that the position of the bonaThames Valley Radio and Physical Association fidewirelessexperimenterbe moreexplicitly Hon. Secretary, Mr. Eric A. Rogers, 17, Leinster defined. Avenue, East Sheen, S.W.14. Sale, Altrincham, and District Radio Society. Meetings now take place every fortnight at the Hon. Secretary, Mr. H. Fowler, Alston, OldHut, Wigan Institute (one minute from Mortlake Hall Road, Sale. Station, L.S.W.R.) and interesting lectures are A Society has now been formed with headquartersgiven each evening.Morse code is taught and at the Reform Club, Sale.It is proposed to form through the kindness of several members, a four - a ladies' section and also a junior section. valve set will shortly be installed. Portsmouth and District Amateur Wireless Major -General Shaw and Dr. Mackintosh have Society. just consented to become Vice -Presidents. Hon. Secretary, Mr. R. G. H. Cole, 34, Bradford Broadcasting is specially catered for and every Road, Southsea. help given to beginners. The fortnightly business meeting was held on Trafalgar Wireless Society. November1st.There was afairattendance. Hon. Secretary, Mr. F. H. Stanlake, Trafalgar Discussions took up considerable time, and the Hotel, Greenwich, S.E.10. lecture by Mr. Harrold on " Wireless Telegraphy, The eighth weekly meeting took place on October Telephony Broadcasting," had tobe, curtailed. 30th, at the above address.It was decided to Mr. Harrold is a master of his subject.He con-proceed with the erection of an aerial and receiving veyed to the members the system of the earliestapparatus for demonstration purposes. Mr. R. J. forms of transmitters. A hearty vote of thanksStanley, the Society's instructor, gave a lecture was accorded the lecturer. entitled" Valve Reception and Amplification," Croydon Wireless and Physical Society. which proved exceptionally interesting and in- Hon. Secretary, Mr. B.Clapp, " Meadmoor,"structive to beginners.Amateurs are welcomed Brighton Road, Purley. every Tuesday evening at 8 p.m. NOVEMBER 25, 1922 THE WIRELESS WORLD AND RADIO REVIEW xi x MAGNAVOX THE WORLD'S FINEST

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vow NovEneEn 25, 1922 THE WIRELESS WORLD AND RADIO REVIEW 285 Questions and Answers NOTE.-This section of the magazine is placed at the disposal of all readers who wish to receive advice and information on matters pertaining to both the technical and non -technical aides of wireless work.Readers should comply with the following rules :-(1) Each questions should be numbered and written on a separate sheet on one side of the paper, and addressed " Questions and Answers," Editor, THE WIRELESS WORLD AND RADIO REVIEW, 12/13, Henrietta Street, London, W .C.2. Queries should be clear and concise.(2) Before sending in their questions readers are advised to search recent numbers to see whether the same queries have not been dealt with before.(3) Each communication sent in to be accompanied by the " Questions and Answers " coupon to be found in the advertisement columns of the issue current at the time of forwarding the questions.(4) The name and address of the queried, which is for reference and not for publication, to appear at the top of every sheet or sheets, and unless typewritten, this should be in block capitals.Queries will be answered under the initials and town of the correspondent, or, if so desired, under a " nom de plume."(5) In view of the fact that a large proportion of the circuits and apparatus described in these answers are covered by patents, readers are advised before making use of them, to satisfy themselves that they would not be infringing patents.(6) Where a reply through the post is required every question sent in must be accompanied by a postal order for the amount of ls., or 38. 6d. for a maximum of four questions.(7) Four questions is the maximum which may be sent in at one time. " E.S.W." (Manor Park) asks(1)For anot think you will be able to pass a current of over circuit employing 1 H. F. valve, crystal detector, and 2 amperes through the rectifier, and the safe voltage 1 note magnifier.(2) Which coils are the best to across each is about 40 volts.We suggest you use in a circuit of this type. connect four 200 volt 50 candle -power carbon (1) See Fig.1. The tuned anode method offilament lamps in parallel, and join the rectifier H.F. amplifyingisemployed, and the crystaloutput in series with the lamps. detector and L.F. transformer is connected across " B.H.R.S." (London) asks (1) For a criticism the anode and reaction coil,in order that the of a set.(2) If it will respond to telephony. (3) maximum amount of potential is available for theThe capacity of the variable condenser.(4) The input circuit of the note magnifier.(2) You will wavelength of 2 LO under various conditions. find it very convenient to use a three -coil holder (1) The circuit is all right, except that 50 megohms for the tuning and reaction coils, and for the is much too high for an anode resistance.It should anode coils we suggest plug-in honeycomb coils.be of the order of 50,000 ohms.Also, the leak

DETECTOR 14

o+Lx HE LF

Fig. 1. " A.W." (Harrogate)-We areafraidyou resistance of the second valve should be takenLto cannot wind the transformer core to deal with the filament of the valve instead of back to the 1 kW. if the frequency of supply is 50 cycles and the plate of the first valve as shown.The choke voltageis200 volts.To ensure a reasonably coil in the anode of the second valve is not really small no load current you will require 600 turns necessary.(2) Yes, but as we have repeatedly of No. 18 D.C.C. wire, and this winding would pointed out,itis undesirable to use a parallel more thanfillup the window area available. condenser on such short wavelengths.(3) The We suggest you use a transformer core with ancondenser should be about 0.0005 mfds.(4) The area of cross section about 4 square inches, and if wavelength used by this station is always 360 you would send us further particulars, we shall be metres.It is not changed at different hours of pleased to calculate a suitable winding. We do the day, as you appear to suppose. 286 THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922 " SEEKER " (Holloway) asks for criticism of " A.R.T." (Derby) asks (1) Correct values of circuit submitted, and whether it is covered by patents. condenser; described on page 714 of our issue of The circuit submittedis quite correct, and of September 2nd.(2) Whether inductance coil having course is covered by patents. 600 turns of S.W.O. wire round 31" tube, and " J.F.E." (Cape Verde Isles) asks (1) Forreactance having 145 turns of 30 S.W.G. will give criticismoftransmittingcircuitsubmitted.(2) good results. (3) Criticism of arrangement. (4) Range.(3) If set could easily be altered to transmit Whether his circuit is likely to receive sanction from telegraphy. the Post Office. (1) We do not care for the arrangement. (See (1) The correct value for the condenser is 0.0005 Fig. 2. (2) The range would be about 25 miles mfds.(2) The values proposed for L and L2 will underthebestconditions.(3)Unfortunatelydo very nicely.(3) The proposed arrangement you have not much apparatus at your disposal,will not give any results.The loop should consist andwe suggest you couple the microphone and aof 12 or 14 turns, spaced f" on a 3' former. few turns of wire to the aerial inductance, or you (4) The loop is small, and although there may be could tap the microphone across a portion of theoscillating energy in it, the energy radiated will be A.T.I. small.Considerable skill and experience is necessary before you can hope to successfully make satisfactory use of the Armstrong super -regenerative circuit.(4) We cannot say whether the Post Office will grant you permission to use this circuit. " G.N.W.B.' (Wisbech) asks questions about a transmitter.(1) Capacity of condensers.(2) Re: sistance of grid leak.(3) Size of frame aerial' for 400 metres. (1) Gridcondenser, A=0.002 mfds.Tuning condenser B=maximum value 0.001 mfd.By-pass condenserC=0.001mfd.(2) Thegridleak resistance should be about 30,000 w.(3) A suitable frame aerial for your purpose would consist of 12 turns of No. 16 wire, spaced + in., wound on a frame 4 feet square. " J.B.B."(Wolverhampton)asks(1) For criticism of his circuit.(2) The best ratio of L.F. Fig. 2. transformerwindings.(3) Bestvaluesof H.T. voltage. (1) The diagram submitted iscorrect, except " FRAME AERIAL sug.that the reaction terminals should be between the gest you employ the first aerial arrangement.Itanode and L.F.transformer primary.(2) The would be better if you could use an outdoor aerial, best ratio for L.F. intervalve transformers is 1 to 2 but you should receive signals with the proposedor 1 to 3.A high ratio transformer is useless if arrangement, although another H.F. valve will bethe primary impedance is low.(3) We suggest requiredto make thesignalsofsatisfactory you use 60 volts, but you can alter this value if a strength. We thinkathree -valveset,using littleexperimenting shows anothervoltageis 1 H.F. 1 detector and 1L.F. valves,willbe suitable. required, and a suitable diagram is Fig. 4,page 147, " MACK " (Brixton).-To connect up the October 28th issue. amplifier to your single valve set, take out the " SPARKS " (Swansea) is about to build a telephones, connect the input transformer in the five valve amplifier set, and asks for an efficient wiring plate circuit of the single valve.If you have any diagram. difficulty, consult the diagrams which have recently You will be able to obtain back numbers of this appeared showing low frequency valves connected journal from the Mail Order Department, The together. Wireless Press, Ltd., 13, Henrietta Street, London, P.D."(Blackheath).-(1) The suggested and we think you will experience no difficulty in values are quite correct.(2) The disadvantage of choosing a circuit using five valves. asemi-aperiodiccoilistuningisbroadened. " A.B." (Bloomsbury) asks whether it is possible (3) Thefirstarrangementisbetter, and you to obtain five -electrode valves such as described inshould adjust the distance yourself, finding by Mr. Prangnell's article in our issue of June 24thexperiment the most suitable position.(4) No last, and, if so, where they can be bought. condenserisrequired across the reactioncoil, We believe it is possible to get these valves, and but a few tappings will be useful.We suggest you we suggest you write to the valve manufacturers.wind 60 turns of No. 38 D.S.C. wire. " H.R.B. '(Holloway) asks(1) For correct " E.T-B." (Malta ).-(1 ) The number of turns values of condensers C2 and C3 described on page 714 of wire in the H.F. transformer is too low, and we of our September 2nd issue.(2) Whether a low suggest you make the transformers described in the temperature valve would be suitable for the super - issuesof September 2nd,16th and 23rd.For regenerative circuit. wavelengths above about 2,000 metres it is more (1) See reply to " A.R.T." (Derby) below. (2) convenient to use the resistance -capacity method. Low temperature valves are useless for this purpose. (2) The manufacturers do not publish the amplifi- It is always better to use the valves for which the cation factor of the valves to which you refer. set is designed.Full constructional articles have (3) A full constructional article appeared in the appeared in the issues of October 21st and 28th. issues of October 21st anc1,28th. NOVEMBER 2.1, 1922 THE WIRELESS WORLD AND RADIO REVIEW xxi

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" Ebonitical, Han, London." HOLESALE ONLY. TELEGRAMSPHONE:Ealing 1889. NOVEMBER 25, 1922 THE WIRELESS WORLDAND RADIO REVIEW 2S7 " A.S." (Southport)askscertainquestions of the sun's rays.At night this disturbance about a crystal set. no longer exists, and the upper layers settle down (1) Aboutlb. will be sufficient for the purpose. into more or less level strata, which have thepro- (2) The coil described will easily tune the circuitperty of reflecting back to the earth a great part up to 4,000 metres with the value given belowof the signals which are dissipated and lost in the for the parallel condenser.(3) No. 1, 0.001 mfds. ; upper regions of the air during the day. A fuller No. 2, 0.0005 infds. ;No. 3, 0.002 mfds.(4) The treatment of this point will be found in most good circuit shown is quite good for a simple set.Some- text -books, and in particular the new bookon what better results would of com.se be obtained directional wireless by Keen, recently published with a loose coupler, but thisis by no means by the 'Wireless Press, Ltd. essential. " J.M.P." (Euston).-(1) The type ofset " P.G." (Ireland).-(l) You should haveas sketched is not at all efficient.Apart from various good a chance of getting this station with the set details, the arrangement of the crystal is almostyou mention as with anything on the market, useless.If used, it should be connected into thebut we doubt whether the reception is possible circuit as shown in Fig. 1, page 670, August 19th, at the distance.(2) You might get Paris, and pro- and many other cases.Any ordinary receiving bably the broadcasting stations in the West of valve will be all right for this circuit.(2) There England when these come into operation. is no definite formula to determine the relation between the tuning coil and the reaction coil.The " L.C.J.B." (Ealing) asks (1) For a criticism size of the latter depends chiefly on the electrical of two sets.(2) Approximate current consumption constants of the aerial, particularly its resistance, of an Ora " valve.(3) What the range of the sets and those of the valve. mentioned above will be. (4) If either of the circuits (3) For a closed circuit are capable of receiving 2 MT and the Dutch concerts. wavelength in metres = 1885L mhys C mfds. For an aerial circuit, in which the capacity of the (1) The single valve set is all right except. for aerial itself has to be reckoned with, the formula;the facts which we have to call attention to in nearly 50 per cent. of the criticisms whichwe give, are not so simple.Formulae applicable to a variety viz., use of a parallel condenser of cases will be found in various text -books, notably on short waves is inefficient, and reaction back on to theaerial Nottage's " Calculation of Inductance and Capacity. leads to serious radiation. (4) Apply to the Wireless Press, Ltd., for a full The crystal arrangement list of their publications. in the other set is useless (see Fig. '3,page 537, July 22nd issue).(2) Aboutampere.(3) They " J.G." (Edinburgh),-(1) A circuit of thewill not be allowed in the form shown.With typesketched shouldwork quitesatisfactorily reaction suitably modified they will give telephonic on all wavelengths, and those that you should ranges of approximately 30 and 50 miles.Tele- be able to obtain are therefore only limited by thegraphic ranges depend entirely on the power of the set of slabcoils which you possess.(2) This transmitting station. behaviour is not very unusual.Coupling up the aerial adds damping to the circuits, which may quite possibly be sufficient to extinguish oscillations. All the evidence points to your aerial having rather a high resistance, and you should endeavour to improvethis.(3)The wavelengthswiththe smaller condenser will be in each case approximately 4f5ths of the values with the larger condenser. MAXIMUM (4) The only alteration necessary to improve rp000,r results on wavelengths as short as are projected 0 for broadcastingisthe substitution of a series condenser for that shown in parallel with the A.T.I. " C.M.L." (Deal) asks (1) If successful results could be obtciinedin. London with a loud speaker attached to a two -valve set.(2) What is the cost of a transmitting licence. 19 (1) Such a combination should give quite useful results on 2 LO, and possibly on amateur stations Id in the immediate neighbourhood, but it should not be expected to give loud speech from a large Fig. 3. number of stations.The valves should preferably " ARUNDEL " (Liversedge) asks (1) Whether be used as detector followed by a stage of L.F. circuit submitted will be approved by the Post Office. amplification.(2) £1 per annum. (2)Criticismof circuits.(3) Circuit for 440 m. wave spark transmitterusing motor sparkcoil. " ENQUIRER " (London) asks (1) Why it is (4) For circuit. that wireless signals have a greater range at night (1) We do not think the Post Office will approve than they have in the daytime.(2) Where he can this circuit.The values suggested are correct. find an explanation. of the .pbanomenon. (2) The circuit (a) is better than circuit (b), because (1) The generally accepted explanation is that interference can be reduced.(3) We, cannot give during the day the upper layers of the atmosphere you detailsforasparktransmitterwithout are in a state of disturbance owing to the action further particulars.(4) See Fig. 1. s2 AND RADIO REVIEW NOVEMBER 25, 1922 268 THE WIRELESS WORLD " J.S.F." (S.E.24).-The variometer which thewill have capacities of 0.0005 mfd., 0.0003 mfd., author of the articles describing a super regenerative and 9.0000s mfd. receiver used was a simple variometer of American " BUZZ " (Bexhill -on -Sea) asks (1) How to pattern. We suggest you write to manufacturersadd a valve to the circuit given to " W .V ." (Fulham), who advertise American pattern wireless compo- September 19th issue.(2) What are suitable con- nents in the columns of this journal, stating yourdenser values.(3) Whethertheabovecircuitix requirements. capable of energising the aerial circuit. COUE " (Peebles) asks(1) For criticism (I) We suggest you add one H.F. valve, using of his aerial and receiving set. the tuned anode method of coupling.See Figs. 4 (1) The aerial is quite suitable, and is in a veryand 5, page 147, October 28th issue.(2) Suitable favourable position.The sketch of your receivingvalves for the condensers are marked in the above set submitted shows several wrongconnections, figures.(3) The circuit referred to is capable of and we suggest you rewire the set, usingFig. 4.energising the aerial, and you will notice in Fig. 4, The V.24 valves are clearly marked, and you shouldpage 147, October 28th issue, thereaction coil is be sure to fit them to the valve holders correctly. not coupled to the closed circuit, but to thetuned anode coil. Energy cannot he radiated to any serious extent from the aerial circuit when this arrangement is used. " MAGNUS SPES " (Hornsey) asks for a criticism of his circuit submitted. The proposed arrangement is quite suitable, and the connections are correct.The reaction coil may consist df 100 turns of No. 40 S.S.C. wire.Should you wish to receive long wavelengthsignals, you may find it necessary to add a smallcoil in series with the reaction coil. " H.C.P ." (Kent).-We suggest you abandon the scheme and use a normal method of switching. It is very bad practice to include jacks in H.F. circuits, unless the jacks are specially constructed to possess low capacity. Why not use themethod of connecting shown on page 883, September30th issue. Fig. 4. " W.G.P." (E.11) asks us to criticise the diagram of connections submitted. The general arrangement of the apparatus is " INTERFERENCE (Sheffield).- (1),(2) satisfactory, but we do not care for the method of and (3). See recent issues. A good methodis to use anode coil, orusing reaction.The reaction coil should couple the reaction coil coupled with the with the anode coil of the first valve.You would secondary coil of the H.F. transformer.Several also find it better to use a closed circuit.The diagrams have been given, and you shouldchoose circuit is easier to operate when the grid leak is one which suits yourrequirements. joined to the L.T. " S.F.W." (Berwickshire).-(1)We suggest " REGULAR READER " (Birmingham)asks you use a four -valve set, 2H.F., 1 detector, and 3, page 111, (1)For criticismof circuitsubmitted.(2) The 1 L.F. valve, as shown in Fig. capacity of a variable condenser.(3) Whether the October 21st issue.(2) You will be able to make and estimate the costcondenser will give fine tuning.(4) Whether the up a list of parts required, electric light will affect reception. yourself.(3) Your suggestion is correct, and we think if you make up the set as shown in page111 (1) The circuit connections are correct, but we (4) We suggest you couple the reaction coil to thesecondary you will be satisfied withthe results. (2) and (3) Unfortunately cannot say, but you should protectyourself by of the H.F. transformer. firms ofyou do not give us sufficientparticulars to enable purchasing guaranteed apparatus from us to calculate the capacity,but the condenser standing.See our advertisement pages, and makeprobably has a capacity of 0.0003 mfds.,and a careful selection. (4) The isbetter thereforeissuitableforfinetuning. " A.C.R." (Twickenham).-(1) It supply, if direct current, will not affectreception, to wire up your set with tinned copperwire, and hum which not use the lighting flex.(2) When receivingbut if A.C., you may hear a disagreeable short waves you should cut out a gooddeal of the will be difficult to remove. reaction coil.Your reactioncoilisapparently made for use on long waves, and youwill not, therefore, require such a large reactioncoil when SHARE MARKET REPORT receiving short wavelengths. Prices se we go to press on November17th, are :- " J.A.P." (Yorkshire) asks (1) Thenumber of of capacity Marconi Ordinary £263 plates required for a variable condenser .. 203 mfds.The Preference 0.001 mfd., 0.0005 mfd. and 0.0003 Inter. Marine.. 170 moving plates are 24" diameter, 0.028"thick, and .. 90 Canadian spacingwashers 0-125".(2) Thecapacitiesof condensers he has constructed. Radio Corporation of America :- (1) You will require 93 plates for the0.001 mfd. 180 29 for the Ordinary condenser, 47 for the 0.0005 mfd. and Preference .. 133 0.0003 mfd.(2) The condensers you have made NOVENIBER 25, 1922 THE WIRELESS WORLD AND RADIO REVIEW

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HIGH TENSION BATTERIES THE UNIT DRY CEIL Any size or voltage with any tappings or sockets at 3 or 6 volt " Build up your batteries as you build up yor Intervalsforuse with Wander Plugs can be suppliedtoorder Marconi Sets." With 23 sockets as illustrated. Unlimited flexibility In size, voltage and intermediate tappings.Each cell is fitted with brass No. Wag, 36 volts, 24 cells, 8/6 each. Size61i x X31. Weight z screw terminal and looped wire, and they are lb. 8 on. efficiently Insulated to prevent current leak. Wander Plugs1/-perpair. With 2 SpringContacts. volts. No. Wax, x5volts,11cells, 3/6 each. Size 91 x x 21. No. UW. x, 7/6 per dozen.E.M.F. xi. Weight xlb. 2 oss. Weight] 31 or Dimensions zi x x 5/x6 diam.

Art Catalogue of Standard Sizes and Voltages and list of Amur ulster, for Valve Filament Supply sent on request.Dept. D.L. THE EVER - READY WORKS, HerculesPlace,Holloway,N. 7.

The MARCONIPHONE PHCE £25 00 RECEIVING MODELS FOR BRITISH BROADCASTING Incorporate unique features which ensure perfect reception Fullcompliancewith Government Regulations. THE MARCONIPHONE DEPARTMENT' MARCONI'S WIRELESS TELEGRAPHCO.,LTD. MARCONI HOUSE, STRAND, LONDON,W.C. 2 xxvi THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 2T,. 1922 Absolutely IT. -D A Y_- THE TURNEYAUTOMATIC MORSE BUZZER (Prov. Patent 22768.) Is the easiest and most fascinating means of mastering the code. NOT NEXT WEEK! By simply turning a small handle a travelling tape connects two 4i volt dry batteries with a loud buzzer.This tape is set We hold large stocks ofall to transmit the sounds in Morse for the alphabet, figures, signs, calls, etc., at a slow rate of speed and each letter or character parts, sundries and materials is indicated in type while being rendered.The tape, however, fortheAmateur, and can be re -set in a few minutes by the operator to his own message at any speed, thus making same invaluable for practice at all CAN DELIVER PROMPTLY stages of tuition. This apparatus quickly trains the ear to instinctively read the Every letter has attention within code as heard in the telephones. 2-1 hours. YOU MUST LEARN MORSE. Don't waste your time with distracting and useless tapping. ELECTRICAL SUPPLY STORES, Price complete 30f-Post free 5, Albert Terrace, King Cross, Halifax. W PRESTON TURNBULL, 28, Cowper Street Leeds.

WITH GOOD APPARATUS YOU CAN GET GOOD RESULTS THE " W.P. " TO THE TRADE

Nearly all the principal dealers are stocking Morse Practice Key OUR Variable Condensers, while most of the Well Made. First-class Finish. Thoroughly Reliable. big manufacturers are incorporating them is their Sets.There's a reason I Price7/6Post Free WRITE FALLON CONDENSER COMPANY THE WIRELESS PRESS,LTD. 230a, HERMITAGE ROAD, LONDON, N.4 12-13, HenriettaStreet, London, W.C.2

1-NORTH- EASTERN SCHOOLSOF-1 FRELEss WIRELESS TELEGRAPHY Established 1P11. 18, Eldon Square, Newcastle -on -Tyne RECEIVERS 6, Blenheim Terrace, Leeds CAN BE 33, High Street, Southampton Young men between the ages of 16 and 25 are trained at REWOUND these Schools in the profession of Wireless Telegraphy and Telephony.All Four Systems are taught, Marconi, Tele- TO funken, Poulsen and Valve. Specialterms topartly 4000 ohms trained students. Splendid Openings for Trained Wireless Men. PER1 2, SET- Write or call for Illustrated Prospectus. G. TURNOCK,41 High St. Aston, Bham. IN SPEARS and COMPANY im FOR W.A. C. SMITHTERMINALS 236, Argyle Street, SCREWS, NUTS, WA SEERS, PLUGS and SOCKETS, CONTACT STUDS, BUSHES, VALVE LEGS, CONDENSER VANES and TURNED and PRESSED PARTS OF EVERY DESCRIPTION. GLASGOW Actual Manufacturers to TRADE ONLY are Sole Scottish Agents for the We regret we cannot supply small lotsto Amateurs. Write for Illustrated List. Famous Burndept Receivers CAPSTAN RKPITITION WORKS, PARK ROAD, HOCKLEY, BIRMINGHAM Telephone: 3265 Central. Telegrams: " Firettes,' Birmingham IIII III 11 II N4rt I922TILE WIRELESS WORLD AND RADIO REVIEW XXVII WIRELESS TRAINING WHALE WARNINGS Most thorough trainingin Wireless Telegraphy orTelephonygivenunderidealconditions. Do not let your chance of obtaining" R Special Postal Course for Amateurs. Valve11/-. 15ft.Portable Mast 10 - 'Prospectus Free. complete. BrownPhones H.R. £2, L.R.II :10s. Best Transmitters 6 -. WIRELESS APPARATUS Rewound Coils for Army Intervalve Trans- Complete stocks of all Wireless Instruments and formers from Accessories. Prompt Deliveries. List I id. stamp. A. WHALE & CO. WIRELESS COLLEGE 201,POWIS STREET, WOOLWICH,S.E. COLWYN BAY 'Phone:Woolwich 548

SKINDERVIKEN BUTTON. TO THE TRADE A Supersensitive Microphone. Known all over the world and patented in every civilised country. Over 80,000 sold.ENGLISH Manufacture. EBONITE - SHEETS - RODS Make up your own Loud Speaker. Transmit your GRAMOPHONE music to any room in your house. COPPER WIRE - S Td4,ZUDGAEr The only practical Microphone for use in Detectiphone Seta. Price 51- each AERIALS -SLEEVING, &c. Special Low Resistance Receivers (for use with Skinderviken Buttons) ..10/. each Special Gramophone Attachments Write for 18 page BOOKLET fully illustrated and containing CABLES & ELECTRICAL SUPPLIES. much usefulinformationforallinterestedinElectrical Sound Transmission.Bd. Post free. MICA HOUSE, OFFORD STREET, Telephone: Sole Proprietors : CALEDONIAN ROAD. LONDON, N.I. North 805. MIKRO LTD., 274/6, PentonvilleRd.,London, N.1 (Opp. King's Grose (Met.) Rly. Station). " EIFFEL TOWER TYPE." F. WIGGINS & SONS Telephone MASTSLIGHT. STRONG. Avenue 2248 WOOD LATTICE. EASY TO ERECT. Largest Stock ROT AND WATER PROOF. MICAin the World. 20 to50 feet - - - 1/3 per foot 55 100 - - - 1/9 FOR CONDENSERS FROM STOCK. CASH WITH ORDER. AND ALL PURPOSES. WILKINSON, Lonsdale Road, Kilburn, N.W.6 102,103 &104, Minorles, London, E.1 Same Address since 1900. Trade Supplied. Bankers-Lc:Knox CITY AID limasaiii, Ksustnus, TUBE, SHEET, Ebonite Panels WIRE, STRIP, O Cut accurately to size, with clean square edges, or bevelled. ROD& CASTINGS EnqUi/iC5 Solicited for Quantitie,. IN PROMPT DELIVERY. RELIABLEQUALITIES ONLY. PHOSPHOR BRONZE, Mouldings, Sheets, Tubes, Rods. oniv. COPPER, BRASS,&c.,&c. RADIO EBONITE SUPPLIES, 4 LITTLE COLLEGE STREET. LONDON. E.C.4 CHARLES CLIFFORD & SON, LTD, 'Phone-Central 4839. (2 min. Cannon Street Station). 0 0 0 0 0 0 0 0 0 0 0 BIRMINGHAM. xxviii THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922 "Clarivox99 LOUD SPEAKING TELEPHONE. (BRITISH MANUFACTURE.) Patent Pending.

inexpensive adjustable amplifier, suitable for Home use, adjust- ANment being made by turning milled screw at side of case after connecting to high resistance terminals on your Wireless Set.No special accessories or battery power required.Results obtained are sufficient to enable Broadcast Music, Speech, Telegraphy, etc., to be heard in comfort all over any ordinary size room, and are equivalent to those obtained on many considerably higher priced instrumentson the market. Specification. Heavy brassnickelled case and terminals.Strong braided twin cord, 50 -ins. overall, substantial wall hook.Patent milled nut adjustment.Laminated magnets guaranteed to retain their strength. Circular coils wound to 2,000 ohm resistance on insulated bobbins, " Stalloy " diaphragm sizespecialdesignedfor maximum efficiency forall conditions. Extra heavy spun aluminium horn,highly polishedandofpleasingappearance, diameter91 -ins. by111 -ins.inlength. Overall lengthof" Clarivox 14 -ins.

SPriUBJEce LIBERAL £ 3 0 0 TRADECT DISCOUNTS.TO

To be obtained from all WirelessStores or Sole Distributors and Patentees E. SHIPTON & CO., TELEPHONE and WIRELFSS ENGINEERS, 40, King Street, Covent Garden, W.C. Telephone: GERRARD 374. E.P.S. I. NOVEMBER 25, 1922THE WIRELESS WORLD AND RADIO REVIEW xxix

The Holborn Radio Company, Ltd. THE"DESKOPHONE"SET This handsome single -valve set, in a beautifully finished Price Complete andpolishedmahogany cabinet, is suitable for any room and will not detract 7:15:0 from the beauty of your (Less Valve) home.Provision is made Royalties payable to Marconi Co., and for- adding other units to Broadcast ( z 2. 6 extra. amplify. Ma. VALVE 17/6 EXTRA

These instruments are passed byH.M.Postmaster -General and bear the B.B.C. stamp and Regd. No. 1019. Quite simpletoconnectup. Full instructions aregiventoallpurchasers. 8, High Holborn, London, W.C. 1. 5 Doors from Gray's Inn Road. Phone :Chancery 7278. TRADE SUPPLIED. CATALOGUE OFALL WIRELESS GOODS POSTFREE. XXX THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922

Makers of over Half the World's Telephones. Western Electric WIRELESS RECEIVERS combine maximum efficiency with low cost of production, and are proving deservedly popular everywhere.

The DOUBLE HEAD RECEIVERS are surprisingly light in weight and mostefficientin service. The regular characteristics o f the windings have been fittedto the dimensions of the Receivers to ensure a uniform efficiency over the whole audiblerangeof frequencies. LOUD SPEAKING RECEIVERS can be used when speech or music is received in sufficient volume to be really loud on head receivers. They make head receivers over the ears unnecessary. They can be used with the valve detector alone or in conjunction with either the one stage or two stage low frequency amplifier. Western Electric Company Limited. 62, Finsbury Pavement, London, E.C.2 Telephone-London Wall 7608 WORKS :- North Woolwich, Lcndon, E.16 Telephone-East 3540 (ro lines) Also at BEXLEYHEATH, KENT, and NEW SOUTHGATE, N.11 Birmingham-Grenville Buildings, /2, Cherry St. Manchester-NorthenrAssurance Buildings. Leeds-Standard Buildings, City Square. Newcastle -20 Saville Row. Cardiff-Motor House Chambers, r, Wood St. Glasgow -49. West Campbell Street. NOVEMBER 25,1922 THE WIRELESS WORLD AND RADIO REVIEW xxxi

Laboratories and Factories : J'11communications to Reg. Offices : King's Rd., St. Pancras, 265, STRAND, W.C.2 LONDON. ANODE Tele. Nos.: City 4887,!Cen. 3722 WIRELESS AND SCIENTIFIC INSTRUMENTS LTD. Members ofthepritish Droadcasting Company

ANODE POPULAR SETS. Variometer "C" (simplified model) These Sets Receive Two Bands of Wavelengths - 150-600 metres... 1 50 350 -600 metres (for British Broadcasting) Fitted with coupling coil 2,0004,600 metres (for Paris Time Signals and ... 1 176 Concerts, also NAUEN. POPULAR CRYSTAL SET £4 116 ANODE PATENT VARIOMETERS (n" x51" x 2f" with Renewable Crystals). (New Type) Patent Condenser Tuning. Improved pattern employing Two Lattice Wound Coils POPULAR SINGLE VALVE SET... 7 10 0 only, so keeping both Resistance and Self -capacity low (9" x 8" x 3" with Fixed Reaction). Patent Condenser Tuning Model 'A" 350-3,600 metres ...£3 186

ANODE VARIOMETER SETS. "B" 2,500-25,000 metres... 3 186 Employing out New Type of Patent Variometer 350- "A" or "B" fitted with Vari- 3800 metres continuous. CRYSTAL SET 6 7 6 able Reaction Coil ...... 4 150 (71." x fir x 5f" with Renewable Crystals). The above Variometers are complete in Cases. SINGLE VALVE ... 8 19 6 (9" x 6" x54" with Fixed Reaction). Also supplied for Panel Mounting.Same price The above ReceivingSets allconform to the Manufacturers to Post Office design of Receiving Sets now in Postmaster -General's latest Regulations. operation at " Leaffeld " " Cairo " " Northolt " etc. NOW is the Time to Order. YourFinal Choice.Why Not Your First? Trade EnquiriesInvited.

NOTE. " 00JAH " The Condensers we list heremustNOTbe confused with some of the cheapand inferiorinstruments BASKET INDUCTANCES that are on the marketto -day. The FINEST WORKMANSHIPandthe BEST QUALITY material isembodiedinthem, and ALL customers can restassuredthatthese two points will be MAINTAINEDin allour goods. FILAMENT REITASTAT. Finest on themarket. Guaranteed - Fitted with Knob and Pointer-4/. , Bevelled Ebonite Dial5/9 CRYSTAL SEA.First -Class Instrument for BROADCASTING WAVELENGTH 13 15 0

PanelPanelCabinetCabinet Mount -isPol- We have pleasure in announcing that owing to the reduction Value Mount- Mount- Mount-Mount- ing As- mahog_hed in the price of wire and greatly increased output we are able Kr.in ing ining As-ing ining As-sembled to lower the priceof 00JAH BASKET INDUCTANCES to PartssembledPartssembled in CabinetCabinet PER 5/. SET 0015.. 23/- 25/6 24/- 26/6 88/- 6/8 Postage 4d. '001 .. 16/9 19/8 17/9 21/- 28/- 5,18 '00075 .. 18/8 18/8 14/8 18/8 22/- 5/8 LIBERAL DISCOUNT TO FACTORS. .0005.. 10/11 18/- U/9 18/9 18/- 4/8 All " OMR " Inductances are wrapped ina transparent .0004.. 101- 12/8 11/- 18/8 17/8 4/8 coveringandsealedwiththeRegisteredTrade Mark 0008.. 9/- U/8 10/- 12/- 16/- 4/- "BAH .0002.. 7/- 9/- 8/- 9/8 13/6 4/- The Seal is a guarantee of quality. .0001.. 81- 8/- 7/- 8/8 12/8 4/ - None are genuine without. Vanier .. - 4/8 - IV- 9/- I 8/8 " 00JAH " Basket and Slab Inductances are being extensively Fitted with Bevelled Ebonite Dial 1/9 extra. copied, as most good things are, and purchasers are advised Special Sines Made to Order. Price list on request. to not only specify " 00JAH " Brand in their order, but to ALL SUNDRIES AND COMPONENTS IN STOCK. see that the seal is intact. ORDERS OVER 20/- CARRIAGE PAID. TRADE ENQUIRIES SOLICITED. GREENSLADE & BROWN The "Broadway" Radio Works LANSDOWNE ROAD, CLAPHAM, S.W.9 DEVONSHIRE ROAD, BEXLEYBEATH, KENT. Telephone-BRIXTON (39 & 3251. ssaii THE WIRELESS WORLD. ND RADIO REVIEW NOVEMBER 25, 1922 Intervalve Transformers AND Telephone Transformers.

WIRELESS DIRECTORY

An absolutely up-to-dateandcomplete list of all land, ship and amateur call signs. It is as much a necessity to the real experimenter as a telephone directory is to a telephone subscriber. PRICE 2/6 NET. ( BLUE COVER)(Post free z/g). Order yourcopy at(MCCthrough the trade or direct from RADIO PRESS LTD. Devereux Court. Temple, W.C.2 Regiitered1)040 NV. 693,493. (0,0poszte the Lava Courts, )

PRICES : 30/- each for Intervalve Transformer GENTS' MAKE 22/6 each for Telephone Transformer Tested to LOCO volts between the windings and specially suitable for use in connection with the Armstrong Super Regenerative FITMENTS Circuit. Dimensions-Height 31' ;Width 21". Dimensions SEND FOR OUR over feet, 2". SUNDRIES PAMPHLET DUBILIER CONDENSERS AND SPECIALITIES Appointed agents for Manchester and District, deliveries can be given ex stock Manchester. MAKE USE TRADE TERMS forallour specialities canbehadon application. OF OUR STOCKS

ASK US TO QUOTE FOR YOUR The Manchester Radio Co., Ltd. WHOLESALE REQUIREMENTS RADIO ENGINEERS, F. H. McCREA, Managing., Director. W. R. BURNE, Directing Expenutental Department. 155, OXFORD RD., MANCHESTER GENT & Co. Ltd. FARADAY W,0 R K S LEICESTER (Entrance Boundary Street East) LONDON: 25, Victoria Street, S.W.1. - NEWCASTLE-ON-TME) Tangent Hoiie, 52, Blacked Street. Telephone : Central 4935 NOVEMBER 25, 1922 THE WIRELEss\Mit 1,I)AN I)li.\1)10 REVIEW GREAT BARGAIN OFFER Dry Batteries for Wireless Sets To Readers of the " WirelessWorld" No. 1 W. Standard Pocket -lamp size, 4 volts (as illustration), with patent spiral wire terminals for connecting in For a short time only series. Insert straight terminal in spiral of next battery and bend -while the stock same, no soldering required. lasts. PRICE 7/- Per doz. NOTE.-(r doz.-54 volts). 2,000 Pairsonly No. 2 W. Slab. No. 4 W. 4,090 ohm x5 volts(ii Rectangular. PHONES cells),3 screw 36 volts, I screw terminal terminals, (NEW) size and 8 plug holes at o" x r with wander high. p!ug. Size 62" 15/ 211" x 2.1". PRICE PRICE PER PAIR. 3/ - Postage 9d. 7/ - extra. EACH EACH Fitted headbands and cords, beautifully finished, thoroughly efficient.Each pair carefully packed in box.Satisfaction No. 1 W. guaranteed. Connect as illustration. A wonderful bargain, never before offered and cannot (Patent applied for). be repeated.Readers of the " Wireless World " are urged to take advantage of this astonishing offer im- BRITISH MADE-CARRIAGEPAID. mediately. All orders will be executed in strict rotation. Manufactured by- GreatSaleof our enormous stock of THE BRITISH BATTERY Co., Ltd. Clarendon Rd., WATFORD, HERTS. (Telephone :Watford 617.)

4 BA. Double Solid Brass or Plated, 2/'per doz. (post. extra)

2 B.A. Single 9d. 11,0 SpecialOffer at Reduced Prices of our NEW W. J. HENDERSON, Inter valve 351, Fulham Rd., S.W.10 Transformer Owing to the unex- 'Nearest Stations, Earl's Court or South Kensington. pectedlylargesale t Bus Routes Nos. 14 and 96 pass the door.) of these instruments, we areenabled to reduce theprice to " WirelessWorld " readers to - CONDENSERS of QUALITY Postage 9d. 14/ extra. Fittedwithpanel Reduction in Prices fixingplate and earthing wire for iron Skeleton Type for Panel Mounting core.Fully te.ted. Ratio 5 : (asillustrated) To obtain goods .at: these special bargain prices, please mention the "Wireless World" '00143 Vanes, 20/- We have ENORMOUS STOCKS OF EX-W.D. WIRELESS GEAR, too numerous to mention, at absurdly low prices. '0006 29 Vanes, 15, - Write for particulars of your requirements or, better still, call and see our enormous stocks. '0003 15 Vanes, 12/ - THE JOYPHONE (Reg. No. ow) 2 -Valve Broadcasting and Receiving Sets. Vernier 3Vanes, 5/ - PRICES ON APPLICATION. J. LIPOWSKY- '& CO. (Postage6d.'extra). 614, Old Ford Rd., Bow, Lontion, E,3 Telephone-East 3345. LISTS :ON REQUEST. Neat Old Ford Station, N.L.Ry. Nos. 8 or 39 'Bus xxxiv THE WIRELESS WORLD AND RADIOREVIEW NOVEMBER 25, 1922

'PO " No Equal Between the Poles." CONTRASTS. THE COMMON MULTI- THE " POLAR" CON - VANE CONDENSER. DENSER. Per Mare, Per Terram. SIZE. Is necessarily bulky - some 29 plates being re-Condenses the zo plate quired to obtain acondenser intoa space capacity ofootmid.3' x 3r x x" deep. ADJUSTMENTS. Has an openly divided Requires a Vernier forscale of 33o° each divisioi fine adjustment. of which affects the same amount of change in C.W. signal note. DESIGN. Isonlyearth -screenedIs completely cart h - inthe more expensivescreened by its brass co instruments. tainer. DIELECTRIC. Commonly air or ebonite.Finest grade ruby mica. CONNECTIONS. Employs neither flexible Involves the use of noisyleads nor rubbing con - connections, either itacts, noises being thus flexible leads or rubbingtotallyeliminated even Photograph contrasting the space cccupied by a plate typecontacts. inthemostsensitive condenser and a " Polar" condenser cf th same Rangz and circuits. Capacity. TESTS. Every" Polar "Con- denser is tested to with- Unspecified. stand a P.D. of Loco "P 0 L A R" volts across the plates. GUARANTEE. the 12months VARIABLE Is not guaranteed. guarantee of the Radio Communication Co., Ltd. DELIVERY. Available onceagain CONDENSERS from stock and will con As may be. tinue to be unless orders exceedoptimistic ex- ... 14/- pectations. Panel TypeUnit, RA. 36 RANGE In PolishedWood Case, RA,36a 20/- Special sizes are required-000r mid. to cior mid. fordifferentcapacityOne standard size thus ranges. coversallnormalre- POST FREE. quirements. PR CE. IsveryexpensiveinItscheapness is an outstanding feature.Set " MAGNAVOX " LOUD SPEAKERS. large caPacitles. below. We hold large stocks of this world -famed loud speaker, the product of the original " Magnavox " factories. Undoubtedly the most successful loud speaker, differing in principle from the horned microphone, the " MAGNAVOX " is designed to eliminate distortion. If your set is delivering clear speech or music the " MAGNAVOX " may be relied on to make this delightfully audible to your friends. For large gatherings or for the family party there is nothing to equal the results obtainable with the " MAGNAVOX." " MAGNAVOX " JUNIOR MODEL, complete, with step-down transformer, black enamelled spun copper horn, 14." diameter. £10 10s. each, carriage paid in Gt. Britain. RADIO COMMUNICATION C ° Lrn manufacturers of :-" POLAR" RADIOPHONES FOR BROADCASTING. " POLAR " SHIPS SETS FOR MARINE AND -COMMERCIAL PURPOSES. suppliers of the G.P.O. Transmitting Stations at N. Foreland (G.N.F.) and Seaforth (G.L.V.), and of installation> for various colonial Governments, and for most of the great shipping companies. Head Office -34/35, NORFOLK STREET, STRAND, LONDON, W.C.2. Telephones :Central ton and 3005. I,elegrams :Radiocomco, Estrand, London. DEPOTi :-NEWCASTLE 17, Sandhill. LIVERPOOL : 67,DaleStreet.CARDIFF :AtlasChambers, James Street. SOUTHAMPTON :19. Queens Terrace. GLASGOW :to, Blythswood Square. NOVEMBER 25, 1922 THE WIRELESS WORLD AND RADIO REVIEW %XXV BROWN'S

HEADPHONES British and Best

The Finest Headphones Procurable for 30/- This priceisforone pair of either TYPE F." Featherweight." 120 or 4000 ohm 'phones,including Actual weight, including cords, cords of good quality. is doze. only. Catalogue Post Free. Head Office and London Works : Showrooms : Victoria Road, 19 MortimerSt., North Acton, W.3S. G. BROWN, Ltd London, W.1

CRYSTAL BROADCAST "RADIO -WAVE RECEIVER. This Broadcast Receiver conforms to the Post Office Regulations for Broadcast Receiving apparatus.There are many receivers being offered to the public which do not conform to these requirements and broadcast licence holders may later experience the annoyance of having them condemned by the Post Office Inspectors.Apart from this thereare other reasons why you should not hesitate to fix your choice on the " Radio Wave " Crystal Broadcast Receiver. (1) You will not be confined to the reception of Broadcast. Amateur telephony and morse code messages from ships may be tuned in. (2) The short wave switch gives ULTRA EFFICIENCY on amateur wavelengths. (3) The twelve -point inductance switch gives 100 per cent. tuning accuracy.The instrument is therefore extremely SENSITIVE to the WEAKEST OF SIGNALS. (4) Only selected Hertzite crystals are used in the detector. (5) The detector is robust, comfortable to handle, and easy to adjust, giving every possible point of contact. (6) The detector cup may be easily removed-facilitating rapid replacements. (7) Owing to the special care taken in the construction to avoid electrical leakage this instrument should give a slightly larger signal range than the average crystal receiver. (8) It is a well made handsome apparatus, metal parts being highly polished and lacquered, and the cabinet work French polished mahogany. (9) It is sent out with full instructions, under guarantee. Price, including cost of aerial wire, insulators, 4,000 ohms resistanoe headphones, with two earpieces,/10 10. MADE BY THE MEDICAL SUPPLY ASSOCIATION, Ltd. 167/185 Gray's Inn Road, London, W.C.1.Works: London & Sheffield. Tel-ohnees :MUSEI'M 7210. '211. THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922

The I GENUINE 1{-11 Precision HELLESEN CONDENSER. DRY BATTERIES A HIGH-CLASS INSTRUMENT, designed and WIRELESS constructed on Scientific Principles, mechanically Et.1 510 N and electrically perfect. SPECIFICATION. VANES of hard rolled aluminium, dead flat. BEARINGS of special design and adjustable. OPERATING tension device. SPACING WASHERS gauged to plus or minus '001". MOUNTED on high-grade Ebonite. CABINET MOUNTED. Complete in Polished Solid Mahogany Case, with Ebonite Top, and fitted with graduated rotating Dial and Knob. PANEL MOUNTING. Complete with graduated rotating Dial and SPECIAL TRADE AND WHOLESALE TERMS Knob, also necessary fixing screws. Code word. Volts. Details. Price. Each Instrument is carefully tested for accurate " WIRON " 15 Screw terminals 4'- each " WIRTO " 15 Strip , 4/- capacity and electrical efficiency, before despatch. " WIRIT " 36 2 insulated wander plugs 8 6

Mounted '001 mfd.--CI It 0 " WIRIN " 60 2 1, 14'- PricesCabinetPanelMounting '001 mfd.-- Cl 7, Wander Plugs and Terminals are included in the Delivery from Stock. Trade Enquiries Invited. price of the Battery and are NOT AN EXTRA. SoleManufacturers: KNOWN THE WORLD OVER AS THE BEST. THE KINE-RADIO CO., Scientific and Wireless Instrument Makers, ALL LISTS FREE ON APPLICATION. 146 Sunbridge Road, BRADFORD. A. H. HUNT, LTD. Vele. :[Bradford,5966. H.A.H. Works, Tunstall Rd., Croydon, Surrey For theyarejolly good Fellows': INTERVALVE -11"" TRANSFORMERS

Use Fellows Intervalve Transformers, and secure maximum amplification with freedom from distortion and extraneous noises. (British made throughout and guaranteed. PRICE 22/6(POSTAGE 6d.) FELLOWS MAGNETO CO., LTD. LONDON, N.W.10. Telephone : Telegrams : Willesden 156o -I. Quiarnag, Phone, L mdon NOVEMBER 25, 1922 THE WIRELESS WORLD AND RADIO REVIEW

Es/ablishe,190o.

I 6 Pages. handsome coverinthreecolours, gives you full information \ OUR NEW BIG - and prices on Wireless ILLUSTRATED CATALOGUE / Receiving Sets complete from E3 10s. to X12 10s. Hearallthe concerts. speeches.ser- mons. news, cropand s:-SUPPLIEST CanIhelp you ? weatherreports. sow being broacicasted daily. I WILL GIVEYOU £50 Costs you nothingafter if I tail to produce over 7.000 testimonials from others I have first cost.Easy to install and operate. helreltoA. SUCCESSFUL CA 12FE12. And hundreds of other Wireless articles. Write to -day. FREE. Yours to success, PERMANENT ONLY CRYSTAL 7/6 leerymonis the Architect of his own Fortune DETECTORPostpaid ARE YOU QUALIFIED Ready to attach to your set. FOR THE JOB YOU SEEK Greatest boon ever known to Wireless Experimenters. Alwaysready. no WE TEACHADVICE FREE. LEARN A TRADE fiddlingorsearching for point. BY POST Most moderatecharges. OR Crystal always active. Largest mail- PAYABLE MONTHLY. PROFESSION. order firm in Europe. (E. Important Notice.-All our apparatus isguaranteed "yourmoney back in full"if Write for one of our FREE BOOKLETS on any of the sotsatisfied. Write to -day. followingsubjects: Architectural Drawingi Matriculation Construction Metallurgy Clerk of Works' Duties Mining Aviation MineSurveying BRITISH RADIO -4 Boiler Engineering Motor Engineering SALES CO. LTD Boiler Making STEPINAS 1110.111.CS, G%%%% Vt. Naval Architecture RAT0101111 rt Kt, LONDMII Chemistry Pattern Making Civil Engineering Salesmanship ConcreteandSteel Sanitation Draughtsmanship Shipbuilding Electricity Structural Engineering Engineering Surveying and Levelling Foundry Work Telegraphy & Telephony New Audio Frequency Internal Comb. Engines Wireless Telegraphy Marine Engineering Special Course for Mathematics Apprentices Intervalve Transformer beiproof do 3 ou rare) t Your word to an employer is not proofthat you are efficient, but a College Qualifying Diploma or Certificate, signed by the Professional Staff, is a proof of efficiency, arid a valuable meet in seeking a remunerative position. Specially designed for long life and maximum epeetellse In all exams.connected wish techni- amplification. cal subjects. If you are preparing for any exam. ask our advice.All Thorough insulation between Particulars FREE OF CHARGE. Parents should seek our advice for windings. Correct impedance of windings. their sons. If you are interested in any of the subjects mentioned above write, naming the subject, and we will send you our FREE BOOKLET No distortion.Correct design of core, made Please from specially stamped laminations. state your see. Courses specially Com- binedto meet all mimes - r

PRICE High Tension Batteries. 17'6 15 VOLT. Postage 9d. 216 Each. (Post 9d.) POST FREE on 2 or more. J. BRIDGE & SONS, Nelson St. Works, Southend - on - Sea or CONSOLIDATED TRADING & MANUFACTURING Co., Ltd.,FulwoodHouse, Fulwood Place, BOWER ELECTRIC, LTD. High Holborn, W.C.1 15, Grape St., Shaftesbury Av., London, W.C.2 F 2 xxxviii THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922

AnExceptionalOffer! TointroduceourFirstQualityWirelessHeadphones to the GeneralPublic,weare makingthisexceptional offer on thefirst200(only)Phonessold. DOUBLEHEADPHONES 140 ohms.231- 4,000ohms.251_ POSTAGE1/- PER PAIR. Take advantageofthisofferRIGHTNOW.Youwillbe more thansatisfied. ,NoteourAddress. These phonesarefullyguaranteed,andcashWillbe refundedif notabsolutelysatisfactory.

MECHANICAL&ELECTRICALENGINEERINGCO. ROBUSTWORKS,BRADFORDSTREET,WALSALL. Velephone . 512 Walsall Velegram - Robust,"Walsall.

32Iper Pair I t- no 4000 ohms.

All Resist CQ Std bi

antes in stock. for ERICSSON PHONES WHEN you install your wireless set-crystal or

valve-you'll get maximum results if you fit I Ericsson Phones-clarity, sensitivity, strength of signals and absence of " click."Specially suited to telephony. Ericsson Phones embody the accumulated experience of telephone manufacture for a generation. Easy to the head, light and comfortable.The magnets I neveriosetheir strength and "shorts" are non-existent. I Write for Particulare I The:BRITISH L. M. ERICSSON I I MANUFACTURING Co., Ltd. Head Office : 67/73, International I Buildings, Kingsway W.C.

I TELEPHONES

Mil NOVEMBER 25, 1922 THE WIRELESS WORLD AND RADIO REVIEW xxxix Radio in the Ideal Home HoW Manufacturers can makethe most of theBroadcasting Boom

At the Seventh Daily Ideal Home Exhibition, whichwilltake place atOlympia from March1stto INTRODUCING THE 24th next year, alimited amount ofspaces will be devotedtoa WIRELESS SECTION, for the AX -AM purpose of enabling approved ML.F. Transformer manufacturers tobringtheir products before a particularly receptive (,'tCade throughout by Pet. Scott Co.) and well to-do public. Building your own Set costs time and money, and you won't want to take unnecessary risks Spaces in this section-of which by puttinginan untriedand unproved this isthefirstpress announce- L.F. Transformer. ment-are already in great THE MAX -AMP comes to you with splendid demand, and immediateappli- credentials-it has passed the most cr.tical tests with cation should be made for plans flying colours. These are a few of its special points : and particulars, to the Organising The primary and secondary windings are heavily insulated Secretary :- from each other and tested for breakdown between windings on 500 volts.A protective core winding effectively preventsthefinesecondary windingfromaccidental damage. Heavy brass brackets permit easy fisting to any Daily Mail panel.The ratio of turns is 4:to 1, a figure which research has proved to be the most suitable.You will find that everything has teen done to make the MAX -AMP the finest L.F. Transformer on the market.Of courseitis Heal Rome tested and fully guaranteed-the name PETO SCOTT ensures satisfaction. Exhibition Send Si. for RADIO BOOKLET showing HOW to build up your own Receiving Set with Standard- March 1stto 24th, 1922 ised Radio Parts. Full Description 21/. 130, FLEET STREET, ofprinciples involved in plain language. LONDON, E.C.4 32 PAGE CATALOGUE FREE. Post Free.

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Offices and Showrooms : 64 HIGH HOLBORN,pis W.C.1 lhe THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922 CLLOPHONE 2 -VALVE RECEIVING CABINET A high grade instrumentata very low price.This set has been especially designedforreceivingbroadcasting, and complies with all the Postmaster- General's regulations.It can be used eitherforlisteninginwithhead- phonesorwith a loudspeaker. Additional interest anduse is secured becauseitwillreceiveallamateur transmitting stations withinarange of zo miles. The " Fellowphone " is mounted in a handsomeoak cabinetandissentoutcomplete with H.T. battery, 6 volt Accumu- lator, wo foot aerial,2 shell insulators and one pair of Fellows4000 ohms double headphones, but without valves. British Made Throughout. PRICE COMPLETE £9 : 0: 0 (Without Valves) (Carriage 2/-) EXTRA FOR 2 MULLARD " ORA VALVES, 80/- EXTRA FOR ADDITIONAL FELLOWS DOUBLE HEADPHONES, 80/- (postage I O.

FELLOWS MAGNETO Co.,Ltd. LONDON, N.W.10 Telephone,: Willesden 1560-1. Telegrams Quamag, Fhone, London NOVEMBER 25, 1922 THE WIRELESS WORLD AND RADIO REVIEW xli

relating to wireless telegraphy and telephony published by Radio PressLtd. Anything emanating from Radio Press carries with it a guarantee as to its accuracy andusefulness. I f any purchaser were to make any complaint we would immediately offer torefund him the purchase price. Only by acquiring the goodwill and confidence of the wireless public is it possible to carry on a business of our kind.A poor book, badly written, badly edited or badly produced would react on all our productions. A discontented reader woulddo us equal harm. As it is, our readers recommend our books to their friends without hesitation.The new broadcast man is advised to buy " WIRELESS FORALL " and then " SIMPLIFIED WIRELESS." The great usefulness of our Directory-the first of its kind-is talked of in all wirelesscircles.We bring out a book of valve circuits and thousands are sold at once.Why ?Because the fact that a new publication has been produced by Radio Press is a guarantee in itself. Aix din -Vrez z,cad. PUBLISHERS OF AUTHORITATIVE WIRELESSLITERATURE DEVEREUX COURT, STRANDW.C. 2. OPPO.S/TE THE [-AV" COURTS TEL.. CENT. 4393 slii THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922 THE WIRELESS WORLD EXCHANGEAND MART

TARIFF. Advertisements are accepted for FOR SALE. this Section at the rate of twopence per word, with a minimum charge of two shillings. The advertiser's name and address will be charged for, and single letters and single figures will be counted Gamage Mediwaver, Longewaver and Short - Electradix Radios as words.Compound wordswillbe countedwaver, 400/30,000 metres.Gamage three -Valve Telephones in stock as two words. L.F.Amplifier, two Brown dowle telephones, SterlingMarconi, one Sterling telephone 3 -valve L.F. Amplifier, 2,000 ohms, 49/-; DEPOSITS. All advertisements must be6 -valve French Amplifier, 3 -Crystal receiving sets, prepaidintheform 4,000 ohms, 50/-; ofPostalOrders,theone Brown loud speaker, two Government variable 8,000 ohms, 57/ - remittance being forwarded to Messrs. Bertramcondensers,threeditto,two buzzersets.A Day & Co., Ltd., 9 & to Charing Cross, per pair, complete bargain, £25 the lot.-A. M. HALL, 20, Albert with cord and tag. Road, Middlesbrough. Sullivan's L. R. Grid Leaks.Constant reliable articles, straight Head 'Phones with GECOPHONE RECEIVING SETS APPROVED from manufacturer,is.gd.postfree.Trade cord, 14/6 per pair. BY THE POSTMASTER -GENERAL FOR THE enquiries inviteds--ZoLA, Crescent Avenue, Stoke, RECEPTIONOF ALL BROADCASTER .i. Coventry. New L.R.Head No. 1 Crystal Set.Range 25 miles, £5 10s. Sets, 12/- per pair Brown Loud Speaker, 1,000 ohms, as new, gos. with cords. New No. 2 Crystal Set.Range 3o miles, £9 15s. Three Sullivan H.F. transformers,15s.each. complete with buzzer combined fortin, 1,5oo ohm Head Bumdepttwo -notemagnifier,7os.Complete Setswithcords, adjustment ofcrystal.The abovesets valve receiver, 400-4,000 metres, £2.Variable complete with aerial and all accessories. condenser, .003 mfds., ebonite dielectric, 25s.- 20/- per pair, Two -Valve Set Complete in mahogany cabinet SingleReceivers SALISBURY ARMS, Bush Hill Park, Enfield. and Cord, 4/6 each. with mahogany case for 'phones, and teak Five Wireless Sets Given Away 1Particulars case with straps for accumulator.Range 3d.-Hisgs, Wireless Dept., Hardington, Yeovil. Large stocks of too miles, £25. Ammeters and I Brown Loud Speaker, 120 ohm, with amplifying Allthe above sets are manufactured and relay perfect, price, kg.Also three -valve amplifier Voltmeters, Milli -ammeters and Hot Wire guaranteed by The General ElectricCo., with lever switch controls, £t5.Can be seen. Ammeters, 10/- to 60/-.Morse Inkers, 45/-, Ltd.Write for Illustrated Lists. EQUIPMENT ENGINEERING CO., 2, Norfolk Street, ReceivingSets.MarkIIB. 2 -valve,in Strand, W.C. polished mahogany case, new and guaranteed, WIRELESS SUPPLY, £75s. CrystalSets,variable condenser 21, GEORGE ST AEET, HULL. Low FrequencyAmplifier,singlestage,by detector, and fixed inductance, mahogany Gamages, new,3os.-E.SoAmirs, Cyprus Street, E.2. 34, case, 45/, 5o D.C. Sets for Crystal and Two Four -ValveSet.ReactanceH.F. Valves, £75s.,in sloping desk pattern, Detector, polished mahogany cabinet,calibratedfor 2L.F. panels,3coiltuner,coils, condensers, broadcast telephones, £16.-WILLiAmsorr, Dunedin, London wavelength.SwitchArms, Lane, Bromley, Kent. and 1/9 each.5 Buzzers.2/6, 8/6 and 9/- each.Terminals, Fifty -Watt Marconi Portable Spark Transmitter 2/6 and 3/- per dozen. NOTE THESE PRICES !! Crystal Valve Receiver, Six guineas or offer.- Valve legs, ld. each. 32, Whitehall Lane, Grays, Essex. Studs, 1/6 per dozen. Wavelength 150to4,500Mebres. Condensers, zM.F., 1/8 each. Three -Valve" Britwire "Receiver,receives 4M.F., 5/- Hague and Eiffel Tower Telephony, £5 los.- each.VariableforPanel,6/6, umand HUTCHINSON, Jeweller, Kirkby Stephen. 13/9.oor Cabinet, 32/6. Murdoch Rheostats Mark III* Tuners, brand new, complete, £8 cos. for panel, 7/3, with vernier extra lever 8/-. Brown's A Type 8,000 telephones, 425. R.A.F. Our make, 3/9. Connecting up wire, 23'5/40's, 7 -Valve amplifier, £20.C. Mk. 3 valve amplifiers, ld. per yard.Insulated Sleeving,fid. per yard 155.-TAYLOR, 41, Newlyn Road, Tottenham. in four colours. Mark 16 Balance Crystal Set, Marconi make, Aerial Wire. -7/22 enamelled copper, 5/6 per too' ; hard -drawncopper,5/6pertoo'. in perfect condition, for sale, £8, also one -valve Aerial Down Leads, 12 yd. lengths, 1/- each. set for sale, most compact in walnut, polished EarthClips, cabinetsize,12. x X to"Completewith ed.each.Earth Mats, 10/ - telephones, H.T. battery and valve, 12 guineas. each. Reason for selling, making room for three -valve Transformers.Intervalve Transformers, 20/ - set. -4, Northampton Road, Wellingborough. each.Telephone, 15/-,all brand new and New BritwireMark IV Receiver, guaranteed.Lightning Arresterparts,6d. 4 -Valve, Switches.AerialtoEarth,2/9.Dewar EXCELLENT FOR TELEPHONY. also Britwire Tuner in rosewood cases, ebonite Flush type, three-way lever switches, 8/6 each. Per set of 7, 5/-.Post 3d. panels.Cost£24.What offers P-CARR,Hill Crest, Dronfield. Eight -way A.T.I. Switches, 8/-. 3o amp. D.P., 16/-.R.A.F. Light Weight Insulators, CONDENSERS. Three -Valve Receiver-one H.F. (tapped trans- Ebonite, 4d. each. COMPLETE SETS OF PARTS former, 200-30,000 with switch to cut out), one H.T.BatteryUnits. 4.* volts, 6d. Approx. No. detector, one L.F. mounted 3/8" ebonite, mahogany each ; cabinet, t6" x II-, without valves, £15 or nearest. i5 volts, 8/2 each. capacity of Price All Wireless Components can be Supplied from Microf'ds. Plates. -F. W. GARNETT Clare College, Cambridge. Two -Valve Complete, polishedteak cabinet, Stock.Write for Catalogue, 4d.Call and too amp. acc. spare condenser, £45. inspect our Huge Stocks. .00I 58 7/6 Three -valve, -00075 43 6/9 £2o.-Particulars H. W. WILKINSON, 89, Kingsway, TheHandiestDepotforCityBuyers. 0005 3o 5/6 ' Cleethorpes. Near Aldgate Station, Metropolitan Railway. .0003 4/6 Diddy-da-da-Diddy.-TheMorsophone gives First on the left in Minories. '0002 13 3/8 correct Morse at any speed.Learning the Morse 000I code made apleasure,25s.carriage paid.- 7 3/ - BOULTON, Oxley Bank, Wolverhampton. LESLIE DIXON & CO., Postage1/- per set extra. BrandNew FullersBlockAccumulators, 9, COLONIAL AVENUE, MINORIES, E.1. ill make up as illustrated Type B.L., 12 volt 4o amps actual capacity, in teak brass bound case, with handle contained in FILAMENT RESISTANCES..each 41- heavy oak universal accessory box to contain and A.E.G. VALVES, TESTED .. 7/6 mount wireless set.Value /r2los., our price MARCONI " D " TYPE 10/ - 5s.-ELus, Palace Chambers, Bridge Street, Postage Extra. Westminster. ALL AMATEUR WIRELESS SUNDRIES Wireless Gear.Amateur disposing of, offers or IN STOCK. exchanges-F., 14, High5eld View, Stoneycroft, ILLUSTRATED CATALOGUE IN COURSE Liverpool. WIRELESS CABINETS OF PREPARATION. One Valve Set Complete, 6 volt 20 amp. accumu- PROMPT DELIVERIES lator, 6o volt battery, double head receivers, etc., Grafton Electric Company IS ios. Inspectioninvited.-J. HAGGART, COMPETITIVE PRICES Showrooms -5 4 ,G RAFTON STREET. Douglas, Lanarkshire. TOTTENHAM COURT ROAD. Wireless Masts.-Improved girder type, light LONDON, W.I.Telephone-Museum 24 r. and strong.Up to so ft. at is. 3d. per ft.Over PICKETT BROS., Works-Slough. 5o ft., Is. gd. per ft.Cash with order.Carriage forward.-F. ARMSTRONG, Weybridge. Albion Rd., BEXLEYHEATH, S.E. NOVEMBER 25, 1922 THE WIRELESS WORLD AND RADIO REVIEW THE WIRELESS WORLD EXCHANGE AND MART FOR SALE -continued, B.A. Screws, Nuts and Washers, assorted gross 2S.,lists 2d.-J. H. BENNETT, Station Road, Willesden Junction. Reliable Valves,Superior French R.3 and R.5, with certificate of characteristique by Radio Telegraph, France, guaranteed.Post Free, xis. 6d.Quota- tions to the trade. --GEORGE & GEORGE, 434, Radio Supplies Market Place, Broughton, Manchester. L.F.IntervalveTransformers,15/-,17/6. R. Valves 10/- each, £5 per dozen.B. Valves H.F. Pin Type Transformers, 3/6, 4/6, 5/6. 12/-each, £6 per dozen.All new and tested. LIVERPOOL MARINE Post free. Ebonite Variometer Rotor 5/- each. 4,000 ohm Headphones,19/6,25/-. B. CALVER, 52, Linver Road, London, S. ,V.6. Enclosed Crystal Detectors, 4/9. AND GENERAL Three -Coil Holders, standard type, 10/6. WANTED. INSURANCE CO.,LTD. TownsendWavemeter (calibratedmustbe Honeycomb Coils, 1/3, 1/9, 2/-, 2/6. perfect.Approval.-FITZPATRICK,liuntly, Filament Resistances, 31, London Office: 7,Angel Court, Aberdeenshire. Terminals, L 6, 2/-, 2/6 doz. Throgmorton St., E.C.2. Second-hand Machine or other D.C. Generator giving 3o milliamperes at 1,50o volts.State price, SETS OF PARTS. DIAGRAMS FREE. FIRE. ACCIDENT. MARINE.particulars and delivery.--Cameamox & PAULI New List being prepared. INSTRUMENT CO., LTD., Cambridge. Write for particulars of our SPECIAL AMATEUR SUPPLIES, WIRELESS POLICY (Annual SITUATIONS VACANT. Premium 7 6) which covers fire and Wanted Experienced Teacher, to take charge of 134, Coteford St., Tooting, S.W.17 other damage 'o the complete N ireless wireless college.Salary, £200 and commission.- Set and also indemnifies the Owner Reply 7, Exeter Street, Saltbum-on-Sea. against claims arising from damage to SITUATIONS WANTED. property or persons through the break- Ex -Naval Wireless Petty Officer, twelve years down of outside aerial and its supports. soundpracticalexperience,seekssituation, assembling, testing, demonstrating, or any other ENGRAVING capacity.-JAMES BACON, Aveley, Purfleet, Essex. Wireless Operator desires position .First-class for every style of instru- Certificate, good experience with firm in the trade. ment on anymaterial. -" H," 37, Dudley Road, Ilford. EX -GOVERNMENT SURPLUS STOCK. MUST BE SOLD. APARTMENTS. F. OSBORNE & CO., LTD. Apartments.-Large, lofty well -furnished bed - 27, Eastcastle St., Oxford St., London, W.1 Mark III Tuners, brand new.Make excellent sitting room, with wireless experimenter.Quiet, But. 1874. Museum 2264 broadcastreceivers, no children.Convenient City and West. Clapham, ortuners. Limited good neighbourhood.Overlooks tennis.Terms number only .. 18 100 B. Mark H two -valve receivers, new, with with breakfast 25s., or as arranged.-Box Z3,1 Aerial Tuning Condensers BERTRAM DAY'S ADVERTISING OFFICES, g and to, ..£3 150 Charing Cross, S.W.I. 50 TrenchSets,new,butcontacts )9 missing .. £2100 APPRENTICES. Telephone Plug and Jack, pair.. £0 1 9 Vacancy Occurs fortwo youths asarticled " NATIONAL Rubber Flex, 60', with two new ebonite aerial pupils with premium (returnable in pocket money). insulators .. £020 Manufacture of wireless.Splendid opportunities. P.O. Standard Microphone .. 0 -NATIONAL WIRELESS & ELECTRIC CO.,7A, CONDENSERS. P.O. Double Current Keys, soiled only, in Church Road, Acton, London, W.3. All Guaranteed and yetour PRICE CON.

carrying case . .. £150 TRADE ENQUIRIES. STITUTES LOW RECORD SATISFACTION P.O. Relay Sounders .. 17/6 and 21/ - OR MONEY BACK. SiemensField TelephoneSets, Agency Wanted, to sell foolproof receiving sets, withhand Buying demonstration set, selected firm.-W., 26. Complete with knob pointer,etc., ready for Microphone Transmitter,extra Telephone Alexandra Parade, Weston -super -Mare. Receiver, D3 Buzzer, etc. .. £126 panel mounting, a fine variable condenser, Two only,C.W. Mark DI Receivers, two Working Drawings supplied for wireless ap- .001, 10'6 .0005, 9/-.Mounted in polished paratus.Motors,generators,etc.,designed. case with ebonitetop, terminals and scale valves, complete . £60 Informationandadvice.-PUGKLE,Buckhurst Silvertown Relays, new..each£30 extra 3/6.Polished and engraved dial and Hill, Essex. knob,extra1/9.Postageextra11-each Uprighting Relays .. . -each£1 10 P.O. Resistance Box to 4,000 ohms, new Wireless Dealers throughout Great Britain are strongly advised to stock parts for making up ACCUMULATORS. £1 5 wireless sets.Buy your parts direct from the P.O. 71 mfd. Condenser Variable fixed £17 factory at wholesale prices.-NEwTotaia WIRELESS THESE ARE SPECIALLY MADE FOR US Two only, differential glavos, new .. £10 FACTORY, 53 and 55, Whitcomb Street, W.C.2. BY HARTS, AND ARE GUARANTEED, One only, Morse hiker, new ..£60 ABSOLUTELY - B.A.O. Terminals.. .. doz.£02 KEY SWITCHES (Dewar) 4v. 40a. .. 18)- 6v. 40a. 26/- B.A.2 Terminals (post 9d.)doz. £02 Or instrumentscontainingsame.Quote 4v. 60a. 21/- 6v. 60a. .. 31/ - B.A.2 Double Terminals (post 1!-) quantities and terms for cash.-Box M.7, Packing and Carriage, 2/6. doz.£02 BERTRAM DAY'S ADVERTISING OFFICES, Carriage forward. We regret owing to cut g and to, Charing Cross, S.W.I. BATTERIES. prices of above goods, we cannot allow trade AGENTS WANTED HELLESENS ARE THE BEST AND ARE discount. Old -established London Firm, making one to GUARANTEED FOR STOCK SIX MONTHS - BRITISH WIRELESS SUPPLY CO., LTD., five -valve broadcast receivers, desires provincial 15v. with Terminals .. each4/- 6, BLENHEIM TERRACE, LEEDS. agents.Every assistance and good terms offered. 36v. with 2 Wander Plugs..each 8/6 Telephone -26826. -Box 76,c/oF. ALDRIDGE, 26,Paternoster 60v. with 2 Wander Plugs . each 14/ - Row, E.C.4. Postage 6d. eLoh. BOOKS. HAVX; YOU BEEN WATCHING OUR RadioMagazines,allthelatest," Radio ADVERTISEMENTS ?IT WILL PAY YOU. World,"mid.; " PopularRadio," ic+1. ; WE MAKE AND STOCK EVERYTHING FOR HOW TO MAKE YOUR OWN WIRELESS " Radio Broadcast,"us.6d. ;" Radio News," WIRELESS AND OUR BROADCAST SETS RECEIVING SET. us.6d. ;" Science andInvention,"Is.gd. ; ARE BEST. COME AND SEE OUR WORKS. Amplifiers and Detectors.No marking out. " ScientificAmerican,"as.6d.Post Full-sizeDiagrams andallwiringdetails free.- BEST TERMS TO THE TRADE. accuratelygiven ;successguaranteed.In INTERNATIONAL NEWS COMPANY, LTD., 15, two Series, 2/6 each.Publisher, T. Appleby, Bream's Buildings, London, E.C.4. 109, High Street, Boston, Lincs. ;or London MISCELLANEOUS. National Wireless & Electric Co., Agents :Messrs. W. & G. Foyle, Ltd., 121, East Ham, Wanstead, Ilford, Manor Park and CharingCrossRoad, London, W.C.2. and Forest Gate. Amateurs should not failto come 7a, Church Road, ACTON, LONDON,W.3 Economic Electric, Ltd., 10, Fitzroy Square, to the RADIORENDEZVOUS, 709, Manor Park London, W.1. Broadway (over Lipton.). Club open till to p.m. Tel. Chiswick 2266. nightly. x iv THE WIRELESS WORLD AND RADIO REVIEW NOVEMBER 25, 1922 THE WIRELESS WORLD EXCHANGE AND MART

Cheapest house in the Trade for The ROWCELL Reg. No. 22533. tai HIGH TENSION " WIRELESS " C Wireless BATTERY CABINET 1. No Internal Wir- (24 ing, Soldering or Supplies other connections A AND necessary. 1.4 2.3.Capacity 7 Tappings. zoCI) Equipment FlasklampBat- teries or less may be used. 4. Volts obtainable :20, 30, 40. 50, 6), 70, 70, So, 5, Spent (Wholesale only) Cells can be instantly replaced, singly or otherwise. METHOD OF CHARGING. Open cabinet, slip in flashlamp batteries,close cabinet and an 33 D'Arblay Street automatic and perfect connection is made. Latest improved model, with ebonite panels, postage free, 21/-. SOHO,W.1 ASK FOR A few left of original model 12/6. Trade enquiries invited. OUR LIST Messrs. ROWCELL & Co., 28, Rendezvous Street, Folkestone.

HIGH TENSION ACCUMULATORS As cheap as dry cells. Described in the November " Broadcaster," HEATH & Co., Ltd. Page 225 to 227. Instrument Works, New Eltham, S.E.9 Reputable House PASTED PLATES.-In groups of 30 volts, are prepared to undertake in their fully actual amp hour. in PRICE 10/- per 30 volts group. equipped works-Wireless Apparatus Buenos Aires "'theCheapestontheMarket."Write and Parts for the trade. Quotations given is interested in Radio Telephones and enclosing stamped envelope, " High Tension Accumulators," toBlue Prints.Immediate attention. Accessories-particularly apparatus 121, HONOR OAK PARK, S.E.23. Phone-Lee Green30r. Lendno.. for amateurs.Letters and Cata- logues should be addressed to Your Case Work IBuy Wireless Gear R. & L., c/oC. W. HARTRODT Let us quote you for your wireless casework. We are specialists in this of every description. & CO., LTD., class of work and feel sure our work- Send your particulars to : 9/10, ST. MARY -AT -HILL, manship and prices will interest you. LONDON,E.C.3. Phone-L.W. 2720. WILKINSON, Lonsdale Rd., Kilburn, N.W.6 Trade references will be submitted CARRINGTON & NEWBERY LTD., with first order. 111120, Normans Buildings,Old Street, E.C. SAME ADDRESS SINCE 1900. CONQUEST The Magazine of Popular Science Price ONE SHILLING Monthly CONTENTS OF DECEMBER, 1922 ISSUE.-London's Motor 'Bus Hospital ; What is Asbestos ?; Stagecraft Secrets of Drury Lane-How Decameron Nights is Produced ;A Scientists Diary ;The Oldest Pictures in the World ;Wireless Notes of the Month ;Make Your Own Wireless Apparatus-Practical Hints for the Home Constructor ;Simple Inventions ;Novel Devices of Interest and Utility ; Photographic Notes ;Photographing Coins without a Camera ;Torch that Burns under Water ; The Cunning Stoat ;The Heavens in December ;Result of Home Hints, Prize Competition. 12/13 HENRIETTA STREET, The Wireless Press Ltd. STRAND, LONDON, W.C.2. NOVEMBER 25, 1922 THE WILELESS WORLD AND RADIO REVIEW xlv

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(I. The self -tightening bull -dog grip Eiffel fittedtotheElwell plugenables BULL DOG GRIP Tower telephones or loud speaker connections to be changed in a moment. CONNECTORS Elwell patented self -tightening grip L ons (2) By the terminal adaptor, the bull -dog grip connector can be added to any fittingsareabigconvenience. PA existing terminals. Withoutsoldering,tighteningof Nantes nuts or screws or the use of any tools whatever, electrical connections s.--40-(3) For fitting to the face of a panel this pattern is recommended.It combines can be made, broken or changed a standard terminal forfixed con- in a moment. nections with a bull -dog fitting for connectionswhich yourequireto change. Moreover, the connections when (4) A series connector with a bull -dog made are electricallyperfect and grip at each end.Invaluable for con- self -tightening.The more you 6' others necting telephones in series. pull them the tighter they grip. But they canbereleasedina moment when desired. (5) The series connector in use. Tetephones can be connectedinseriesin an instant.No amount of pulling can Ask tosee themat your wireless break the connection.It thus avoids those annoyinginterruptions caused dealer or write for descriptive leaflet. by involuntary movements. C. F. ELWELL,LTD., Radio Engineers, CRAVEN HOUSE, KINGSWAY, LONDON, W.C.2 Telephone :REGENT 421. xlvi THE WIRELESS WORLD AND RADIO REVIEW NovEmeku 25, 1922 CUMMOMMCUMMMUNIUMMUIMMMMUUMMCMMMUMMUDICHIMMIUMMCUM 9 8 8An Auction of Interest to Amuteurs8 8 8 I NCLUDED in this important sale of EX -GOVERNMENT N El Note the Date 8 WIRELESS APPARATUS there will be a large number 8 WEDN E S DAY of SMALL LOTS eminently suited for purchase by Wireless 8 8 6th DEC., 1922 Experimenters. 8 8 at 12.30 o'clock El THE TRADE will also have an excellent opportunity of8 98 ::precisely:: 8 8 securing :- 8 8 V NEW MARK III TUNERS, MARK III C.W. TRANSMITTERS 8 and RECEIVERS, B. MARK II 2 -VALVE DETECTOR AMPLI- B 8 On view all FIERS, so WATT SPARK TRENCH SETS for Receiving and 88 Tuesday 8 and Transmitting. C. MARK III 3 -VALVE AMPLIFIERS (low frequency) E4 8 on morning of in new condition. BROWN'S HEAD TELEPHONES Reed Type, 8 8 Sale from 9.30 120 and 8,000 ohms in new condition.Valve Boxes, Teak Instrument El El till12 o'clock Cases, a quantity of 13 ft. masts and a large quantity of Miscellaneous 8 8 WIRELESS GEAR. 8 8 El

STEVEN'SAUCTION ROOMS, LTD. QEl (Established 176o) 8 8 will Sell the above by Auction at their Great Rooms, (El 8El 38, KING STREET,COVENT GARDEN, W.C.2 El 8 Telephone -1824 GERRARD. Catalogues free on application. Telegrams-" Auks, Rand, London." MIUMMMMMM=MMMMULMHHOLMMHMMHMMMHMHMMUMMUMMHMEDMM ACCUMULATORS 4 volt 40 amp. ..18/6 6 volt40 amp. ..26/3 Compare Our Prices

4 60 21/6 6 32/9

4 80 28/2 6 80 37/3 FILAMENT RESISTANCE, Latest Pattern ..each 3/8 4 100 30/- 6 100 42/6 IN CELLULOID CASES. Switch Arms (Best Quality) .. .. each 2/ - Engraved Ebonite Condenser Dials,bevelled,highly ALL GUARANTEED NEW STOCK. polished, scale 0 to 180...... each 1/9 SPECIAL OFFER :- Best French Headphones, 4,000 ohms.. ..each 25/ - 4 Volt, 30 Amp., in Celluloid, 13,/- each. Porcelain Reel Insulators, 2- x r, 3d.; 2/6 doz. Leading -in Tubes, 9'. 1/4 ; GOOD DISCOUNT TO THE TRADE. 12', 1/8 each.

Aerial Wire, 7/22 enamelled, per 100' . 5/ - KNIFE SWITCHES. COIL Saxon Coil Holder, 2 _Coil, 8/6; 3 Coil, 12/- each. , DOUBLE POLE DOUBLE PLUGS. VARIABLE CONDENSERS for Panel Mounting.With THROW ON EBONITE. engraved ebonitv dial and scale- 2/9 each. 2/- each .11/8 .0005 -001

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E111111111111111111111011111111111111111IIIIIIIIIIIIIIH111111111111111111111111111111MIIIIIIIIIIIIIIIIIIIIIIIIII 11111 111111111111111111IIIIIIIIIIIIIIIIIIIIIIIIII111111111111111111111111111110111111111111111111111111111MMIMill ADVERTISINGPAYS Ifyouusetherightpaper The following extracts are typical of letters beingconstantly received testifyingto the wonderful advertising valueof the "WIRELESS WORLD" "52, Linver Road, London, S.W.6 3rd .Nov., 1922. " iflthough I have only had two small advertisements inthe Wireless World,' they have more than proved the wonderful results of which your paper is capable.In my case it has been thousands of orders from 4/6 for ildvertising. " You are quite at liberty to make use of this,should you so desire. B. G. CALVER.

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lllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllilllllllllllllllllllllllllllllllllllllllllllllllllllllltlllllllllIOU 1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111:11116 NovEmiEn 1922 THE WIRELESS W01:1,1) ANI) RADIO REVIEW - NOW READY Designof BINDING CASESModernRadio VOL. X. The ReceivingSets Vol.I (The.Brown Book) Wireless World Vol.II(The Blue Book) & Radio Review ByM. B. SLEEPER (INCLUDING INDEX) Price2 /6each

Price (Price 3d) 216 nett (Post free 2, 11.) Showing the construction of instruments so simplethattheycanbe assembled in the " kitchen table work- INDEX(IF PURCHASED SEPARATELY) shop," yet so designed that they give Price 8d. Post free. the appearance and resultsof commercial equipment. The unique feature of these books Alimited number only of isthat every instrument describedis COMPLETE BOUND VOL. X first built and tested in the laboratories (April-September, 1922) oftheSleeperRadioCorporarion.

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