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TWO PIECES OF METAL NEW PRICES Effective January 15, 1916. TONED All previous prices void. ALIKE Switch Contact Points \Ve are in a position to furnish prompt shipment of the follow- will both vibrate when one of ing sizes of switch points: them is struck. This same to take 6 -32 screw. principle has been applied to Tapped Brandes \Vireless Receivers. No. Diam. Height Doz. 50 100 inch $ 30 $1.00 $1.75 By perfectly 626.. t4 inch matching the inch .30 .90 1.50 tone of the two receivers, the 628..34 inch t4 threaded 6 -32 weak you With 34 inch shank sounds that would inch $.36 $1.25 $2.00 otherwise lose, are brought 627.. t4 inch t4 "Superior" Set. Price $5.00 com- Nickel points 50 per cent. advance. out so as to be easily inter- Postage extra. preted. plete, including headband Brandes \Vireless Receivers they're as easy on your head are made expressly for wire- as your hat. The "Albany "Combination Detector less service; they are not tel- Our Catalog E contains ephone receivers adapted to some very valuable informa- serve the purpose. tion about radio receivers, as They are very light and well as a full explanation easily adjustable. No pinch- 'of several types of Brandes ing or slipping. You set them head sets. Send 4c. in stamps to fit exactly; after that for your copy to-day. Lacquered brass $2.50 C. BRANDES, Inc. Polished nickel 3.00 Postage extra-Weight .1 lb. Wireless Receiver Specialists - Room 814, 32 Union Square, New York MAGUIRE & SHOTTON Brandes Wireless Head Sets 814 LANCASTER ST ALBANY. N. Y.

te advertiser You benefit by mentioning www.americanradiohistory.com"The Electrical Gxpe enter" when urúima March, I916 THE ELECTRICAL EXPERIMENTER Goi

NEW 320 -PAGE ELECTRICAL DUCK'S N7.9 and WIRELESS CATALOG MORE THAN EVER JUSTIFIES YOUR VERDICT _ 9 THAT IT IS THE ONE CATALOG WORTH WHILE Co. The William B. Duck

150 pp. Wireless In- struments. 170 pp. Electrical Sup- plies. Over 40 pp. of Wireless Instruments. 15,000 of our catalogs ready for delivery to Only 8c. in stamps will bring this unri- eager electrical and valled catalog to your wireless enthusiasts home. The great cost of catalog and the ex- in all parts of the ceptionally low prices world. One of ten (oftentimes fully 25% below usual retail price) consecutive ship- prohibits its distribu- ments of catalogs to tion otherwise. You may deduct the 8c. on our patrons during first $1.00 purchase. last November. WHAT OUR BIG CATALOG CONTAINS 150 pp. Wireless Instruments, magnet wire of all kinds, raw material, storage batteries, telegraph instruments, battery motors, commercial motors and generators, sewing machine motors, telephones, step -down transformers, massage vibrators. bells, push buttons, auto accessories, flash lights, hand lanterns, auto and miniature lamps. Xmas tree outfits, voltmeters, ammeters, lighting plants, Victrolas, air rifles, electric aeroplanes, model builders, electric railways.electrical and mechanical books and general electrical supplies. 230 -232 SUPERIOR ST. The William B. Duck Co., TOLEDO, OHIO -NEW VARIOMETER A De Luxe Wireless Receiving Station Wave Length 3,000 Meters On An Average Length Antenna DE LUXE improved variometer a complete Station to receive N. A. A. Arlington, Va., N. A. R. Key West, Fla., W. S. T. Miami, Florida, capable of receiving all government or commercial Stations along the coast, and has a wave length of 3,000 meters on an average antenna. The Station consists of variometer tuner working on entirely new principles, different from any heretofore offered. It consists of a primary and secondary loading inductance placed in non -inductive relation to each other. The Tapped Loading Inductance does the tuning by means of units and tens switches, which produce the most efficient tuning. A Short wave variable condenser is placed in across with the antenna so as to enable you to work the amateurs at leisure, another variable is placed across the secondary by means of which the capacity of the secondary circuit is raised to a higher wave length. In this set is placed a new Instant Radiograph in place of a detector which will enable you to receive signals instantly at all times without loss of time or messages. This Station is set into a mahogany finished cabinet and hard rubber top, complete with 2,000 Ohm Brandes Superior Head -set, at our lowest possible price, $20.00 for March. This outfit is well worth $50.00 to you. Send 6c. Stamps for 156 Page Wireless Catalog 'You need this new book, "Radio Stations of the World." A complete authentic list of call signalsof!every public wireless station. Price, only 50c. N I C H O L S ELECTRIC CO. 1 -3 West Broadway, New York

You bencfrt by mentioning "The Electrical Experimenter" rohen writing to advertisers. www.americanradiohistory.com 602 THE ELECTRICAL EXPERIMENTER March, 1916

SATISFACTION OR 1VI O N E B E F U N D E-D "QUALITY" is our Wireless Watchword OUR MOTTO

r_,:;}_z Mesco Universal Detector Stand Iles a heavy brass cup, with four binding screws; will hold crystals up to 34 M. diameter. A hollow standard encloses a brass ball. Through an opening a brass arm with hard rubber haudle is secured fast C g, to the ball, making a ball and socket joint, allowing 1 it to he adjusted at any angle or used in any position. ]lard rubber bas.- 2%x41ax44 in. All metal parts Gar= nickel -plated. Remains permanently in adjustment under jai -a and vibrations of every description List No. Price. 248 Mesco Universal Detector Stand $3,00

: Mesco Wireless Spark Coils Have low current consumptiou. Best to op- Mesco Rotary Spark Gap erate on dry batteries. Contact points of heavy platinum iridium. Has primary condenser in Emits a high musical note. Can he heard at greater distances than the note from the stationary type. Cannot ease, Made for wireless work. Permits of close be mistaken for static or other atmospheric disturbances. tuning. Spark at interrupter reduced to a mini- Produces pure wave of low damping decrement. Increases mum; spark is heavy; made in %4-inch to fl- transmitting efficiency 20 to 30 per cent. The rotating member has twelve sparking points mount- inch sizes. Our Manual gives all the technical ed ou a hard rubber disk and is carried on the motor points. Can be used ou our or up shaft. spark coils transformers List No. Price. to 1 K. W. Ilas two stationary electrodes with special ...Busting devices. 462 Spark Coil, 1 Inch; can be operated A C. or Blur Globe Motor is need. Win operate on 110 on G Red Seal dry batteries $5.40 U. C. eirenils; speed of 4,500 R.P.M. Also made with our Globe Battery Motor, which can be operated on a six -volt circuit. List No. Prie,'. 222 Masco Rotary Spark Gap, 6 volt $12.00 Mesco Codegraph 223 Masco Rotary Spark Gap, 110 v., A. C. or M. C 13,00 Send 1Oc. for Copy of 216 Rotary Unit Only, with two Stationary Elec- A dandy practice trades for 3/16 in. shaft 5.00 Our Wireless Manual set for the beginner. Just the right kind for the apt No. 9 boy. Manhattan Wireless Receiving Set YOU GET YOUR MONEY BACH T h e Codegraph ON AN ORDER OF $1.00 Plate is of metal It contains 120 pages and tells hew to erect with insulated and maintain wireless telegraph stations. Shows dots and dashes. a number of diagrams. Ilas the Morse and The Pen is con- IIIiIllltifllilli@di1i119111i1 continental Telegraph Codes. Illustrates the nected with the best instruments to use; tells what they are Red Seal Dry Bat IIIRl,liñ'Ì'rGil"eG$A for and how to use them. Ilas many new dia- tory and the grams and other valuable information not con - Wireless Practice tatued in ally other hook. Do not wait. Send Set. When the pen your request new. is drawn across Get the Best 10e. Value You Will Ever Buy the dots and SEND FOR OUR POCKET CATALOG, W 26 dashes it closes the circuit, and the buzzer sounds. It is possible to attach a sounder to the outfit and It contains 24S pages, 1,100 illustrations and get the telegraph click also. A practical and efficient Consists of a I. coupler, fixed a Mouser detector. and costs you nothing. troy of learning wireless and telegraph signals. an SO ohm receiver with curd. Will tune up to 1,600 me- IT MEANS MONEY SAVED TO YOU List No. Price. ter wave length on a 60 -foot aerial. Can be tuned to to have our Manual and our Catalog when you 303 Masco Codegraph Set $2.50 waves over 4,000 meters with larger aerial and properly want to buy. 304 Codegraph Plate, Pen and Book 1.00 connected to loading inductance and variable condenser shunted across the secondary of the receiving transformer. List No. Price. 210 Manhattan Wireless Receiving Set $10.00 MANHATTAN ELECTRICAL SUPPLY CO. New York, 17 Park Place. Chicago, 114 S. 5th Ave. St. Louis, 1106 Pine St. Mesco Intensifying Transformer San Francisco Office, 604 Mission St.

Mesco Flexible Mesco Wireless Receivers Have powerful field magnets and WIRELESS thin diaphragms, No. TRANSFORMERS 480 Double?fve`eOur Head sets complete Will make wireless ap- used in paratus 200 per rent. have been more efficient. When receiving commer- short circuited or when cial wireless mes- charging condensers sages over dis- does not consume tanee s of 2,000 any miles. Il receiv- more power tban the ers are wound Used for intensifying signals received from any crystal magnetic shunt is set with silk covered detector by connecting an audiou detector on the other for. Can be connected copper wire. two au- direct to alternating cir- side of the transform.. winding. Used between cuit, Best steel obtainable used in construction dio.. detectors. signals will be intensified 10 to 25 times. of the permanent magnets. Users bave had As many as three of these transformers can be con - List Ca secondary head sets for live years and over without any eeted between auction detectors in cascade, forming an No. paciU-. Voltage. Pr. deterioration in sensitiveness. This Cannot be intensifier, making it possible to rend signals not heard said of any light- weight receivers. with any single known detector. Diagram of connections 330 % kw. 5,000 v. 515 List No. Price. with full directions with each instrument. 363 ys kw. 10,000 v. 201 480 Double Head Band, with six -foot No. Price, receivers, List 331 1 kw. 20,000 v. 25 green silk cord and two 224 Intensifying Transformer $12.00 moo gins curie $6.00 Mesco Wireless Practice Set Mesco High Efficiency Spark Gap comprises a regular telegraph key, without circuit breaker. a special high pitch Adapted for stations up to ja K.W. buzzer, one cell Red Seal dry battery, rapacity. Base is of polished hard and four feet of green silk -covered flexi- rubber. Standards are of hard rub- ble cord. The main object of the set is ber composition of the highest in- to enable the beginner to master the sulating properties. Hard rubber ends wireless code, and the buzzer reproduces on the brass rods permit the length the sound of the signals of the most of the gap to be varied, while send- modern wireless stations perfectly, ing. Spark terminals are of zinc, and List No, Price. are renewable. 342 Wireless Practice Set, with bat- List No. Price. tery and cord $1.88 465 High Efficiency Spark Gap. .82.80

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Vol. III Whole No. 35 CONTENTS FOR MARCH, 1916 No. 11

FRONT COVER-"THE TESLA DESTROYER" ...... \r. \RVELs OF MODERN PHYSICS By Roger: U. Re:k, 623 From a painting by Thomas N. Wrenn. I:ARON \I('N('IIII. \l'SEN'S NEW SCIENTIFIC .\I)VEN'l'11RES. TIIE UTILIZATION Ob"THE SUN'S ENERGY ; -0110 lly Ilugo Gernsback. r: Lí;43 TIIE CIIOR.\LCELO, A WONDERFUL ELECTRIC PIANO 007 NEW 500 W. \TT MILIT. \RY RADIO PACK SFT 625 NA' \\' UUSES FOR( ELECTRICITY IN 'í'1ííi \ \'. \IL u') L4 E'LECTR000TING SUPERFLUOUS C'Al'S AND DOGS 009 'I'll E EVOLUTION OF \\ IItELI:SS TELEGRAPHY uan -rat FILLING THE SMOKE NUISANCE ELECTRICALLY THE RECEPTION OF LONG DAMPED ;\XI) UNDAMPED WAVES i By Samuel Cohen 6111 By Thomas Appleby. 631-63:: TIIE TESLA IIIGH FREQUENCY OSCILLATOR 1.íSí' OF NEWLY LICENSED . \\T.\TEUR RADIO STATIONS... 634 By II. Winfield Secor, E.E. 614.615 'r111ì USE AND l't)NS'l'Rl'(l'ION OF A DECREMETER ELECTRICITY WONDERFUL AID TO MODERN SI'RGEIRY 616 By Milton II. Sleeper. 635 -037 ELECTRICITY, THE BENEFICENT Ily Benjamin CONSTRUCTION OF AN EI.ECTIRO -M IC SKULL G. Lamine, Chief Engineer, Westinghouse Eke. & Mfg. Co. 0IO By /Joiner \'andur1111 63.1'

-! .i'--+l.'+(_'+l. á. l. +\.J'rA.-wïA+ïA. J'r-r.*. MTWAAM The Future of Wireless

I the present state of the art, Wireless can be 11h)' he probably would not be the president ofthe huge sub -divided into three classes: corporation to -day. A 1st. \Vireless Telegraphy or Radiotelegraphy. This brings us to Radiotelephony. To us there does 2nd. Wireless Telephony or Radiotelephony. not seem one field in the entire electrical industry that 3rd. \Vireless transmission of Power. The is destined to a greater and speedier development than latter we may term as Radioki),ctics. this one. %Ve venture to say that within the next As is well known, the first two are already in every- fifteen years, Radiotelephony will become one of the day use, all over the world. The third is as yet unde- greatest electrical industries, for it supplies one of the veloped, but already it looms large above the horizon. predominating wants of the times. Like all great things, \Vireless has had its share of The radiotelephone can be used by anyone, just as trials and tribulations. It takes time to develop an en- easily as the wire phone To operate the instrument tirely new art. Moreover, \Vireless received a black it is only necessary to take down the receiver and talk. eye in its earliest infancy in this country. As will be But three months ago it was demonstrated that it is recalled, a number of unscrupulous individuals unloaded eminently practical to catch the wireless voice -on the millions of dollars of worthless stock on a credulous wing as it were -and connect it with an existing wire public, before the art had sufficiently advanced to make telephone line. Vice versa, President Vail talked into possible a successful commercial exploitation. a wire telephone at New York, where his voice was Practical commercial \Vireless Yelegraphy is not much transmitted to Arlington; here it "took wings" and was older than ten years to -day. Commercial Radiotelephony wafted without wires to Honolulu, some 4!100 miles dis- has but made its appearance during the past one or two tant. This accomplishment more than anything else has years, while Radiokinetics dots not exist at all as yet. opened the public's eyes. But let us consider how the three classes of Wireless We Prophesy that in less than 15 years every automo- line up as far as their ultimate usefulness and commer- bile, whether pleasure or commercial, will carry its cial practicability are concerned.. Let us look the prob- small radiophone outfit. Its occupants will thus be in lem square in the face and let us see what we shall find. constant touch with their homes or offices and vice It is our opinion that a purely \Vireless Telegraph versa, a convenience much needed to -day. Imagine the Company can never reach such immense proportions as immense usefulness of such a device. Nor is this an our wire telegraph companies. The reason is obvious. idle dream. There is at least one company in existence The wire telegraph companies are too well intrenched to -day capable of filling an order to equip autos with to be driven out of the field; it is quite certain that radiophones having a 20 mile range. Nor will there be wireless telegraphy can no more hope to supersede wire much confusion of voices becoming mixed up in tran- telegraphy. than the telephone superseded the wire tele- sit; our tuning apparatus is becoming more accurate graph. Aside from this it seems hopeless for any one each day and it will he an easy matter to tune out un- large central wireless plant to send out and receive with- wanted voices. It will take considerable capital and a in a single hour, 8,366 separate messages, as is the case host of trained men to turn out enough radiophones for instance with one of the New 'York offices of the to equip several million automobiles, aeroplanes, motor- Western Union Telegraph Company. \Vireless will boats, yachts, and large vessels, but it will be done probably never lend itself to such exploitation. Its nevertheless and soon at that. Every farmer will have greatest use will always be long distance transmission his Wireless Telephone to talk with his neighbors. of intelligence, either over land or water or both, and Every train will have its radiophone enabling passen- between land and ship or vice versa. or between ships. gers to talk to their homes or offices. The radiophone This is its true field and here the wire companies cannot will link moving humanity with the stationary one. the compete. This naturally limits its possibilities. Thus. while same as the wire telephone linked humanity together the future -of \Vireless telegraphy does not seem too rosy, before. To us there is nowhere a brighter future than we need not feel discouraged. The young man who in the vast possibilities of the Radiophone. embarks in radiotelegraphy to -day, will use it only as a As to Radiokinetics, this will surely follow the Radio- stepping stone towards something infinitely greater. telephone in due time. Its future is probably even This was the exact case of E. N. Vail, the present head brighter than the latter. Already Tesla speaks of trans- of the American Telephone and Telegraph Co., popu- mitting energy by the thousands of horsepower wire - larly known as the Telephone Trust. Vail was origi- lessly. Who dares predict what this branch of wireless nally a telegraph man when he was called in by Bell will bring during the next twenty years? and his associates ; had he not known all about telegra- H. GERNSB.\CK.

LUEUEMEE IBEBED cuicaLL cvvFlvoca'vóo>iV'äVF,d'V6s)6 E TEE ELECTRICAL EXPERIMENTER is published on the 15th addressed to: Editor. THE ELECTRICAL EXPERIMENTER, 233 of each month at 233 Fulton Street, New York. There are 12 num- Fulton Street, New York. Unaccepted contributions cannot be re- bers per year. The subscription price is $1.00 a year in U. S. turned unless full return postage has been included. ALL accepted and possessions. Canada and foreign countries, $1.50 a year. contributions are paid for on publication. A special rate is paid U. S. Coin as well as U. S. stamps accepted (no foreign coins or for novel experiments; good photographs accompanying them are stamps). Single copies, 10 cents each. A sample copy will be sent highly desirable. gratis on request. Checks and money orders should be drawn to THE ELECTRICAL EXPERIMENTER. Monthly, Entered as second -class matter at the New York Post Office, March 1, 1916. order of THE EXPERIMENTER PUBLISHING CO., INC. If you under Act of change your address notify us promptly, in order that copies are Congress of March 3. 1879. Title registered 17. 8. not Patent Office. Copyright, 1915, by E. P. Co., Inc., New York. The miscarried or lost. A green wrapper indicates expiration. contents of this magazine are copyrighted and must not be repro- All communications and contributions to this journal should be duced without giving full credit to the publication. 603 www.americanradiohistory.com (,u4 THE ELECTRICAL EXPERIMENTER March, 1916 CY 44)4Wit3t, M4ffi4, let,

We will save you time and money. Our new catalog "W" is Blitzen 43 plate Rotary Vari- filled with "up to the minute" wireless apparatus. Our new able Condenser. Glass case, Model II, Hot Wire Meter, 0.8 112 page "Book of Electrical Apparatus" contains motors, aluminum plates and base. amps, or 0.5 amps. Nickel case, liard rubber composition top rubber composition back. A dynamos, parts and materials, meters, lighting plants, storage and binding posts. The best small, quality instrument. batteries, phonographs, motion picture cameras, etc., at prices small condenser money can that will positively save you dollars. Both books sent for 6 buy. Price $3.75 cents stamps to cover mailing. Price $4.00 Manufacturers and Dis fr+hu- CLAPP -EASTHAM CO tors of Everything 141 Main Street - - - CAMBRIDGE, MASS. Electrical

The Blitzen Tesla Coil. Works with any transformer and con. denser. % K.W. gives 9.inch spark, price $10.00; 1 K.W. gives 18- The Cambridge Long Wave Tuner receives up to 15,000 meters inch spark. with good antenna. A masterpiece of design and workmanship. Total length 38 inches. This tuner will enable you to receive the Price $16.00 very long waves used by Turkerton, Sayville, Nasen, Germany and others. Price $40.00 .1

IIIIIIIVIIIIIIII il IIIIIIIIIIIIIIIIIIIIIIIVIIVI IIIIIIIIIIIIIIIIIIIIII III!gl l!11IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIllll111!IIII!1N!IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIllll11111111!IlllllllL=

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Hew De Foa-ezt Auellon -Detector THE BEST AUDION DETECTOR EVER OFFERED FOR PRIVATE USE

4] The Audion Detector is the most sensitive detector in existence. (Bulletin C. S. Bureau of Standards, Vol. 6, No. 4, Page 540.) The new and improved forms are more sensitive, more reliable and more adaptable than ever before. The new Type RJS Audion Detector represents the greatest value for the money ever offered. 41 It is equipped with potentiometer control for the high voltage circuit, giving extremely close regulation which is so essential to obtaining utmost efficiency with the Audion. It is a panel type instrument of the very best construction. It is thoroughly reliable and constant in operation, is not affected by mechanical vibration or by the transmitting spark, and is always to be de- pended upon for reception of signals over the greatest possible ranges. Q It is worth a stamp for you to be informed on this and the other new DeForest instruments. "There is wally ONE AUDIIOH -t1 e DI FOREST" Send stamp for M 16 Bulletin on the New Audions

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H. GERN 5 B ACK EDITOR H. W. 5ECDR ASSOCIATE EDITOR Vol. III. Whole No. 35 MARCH, 1916 The Utilization of the Sun's Energy Years Ago Man Endeavored to Make Practical Use of the Energy Contained in the Sun's Rays -Even Tesla, the Electrical Wizard, Has Patented a Sur. Motor, While the Shuman -Boy's Engine and Sun Boiler Has Developed 100 II. P. There Is Great Promise Ileld Forth to Future Engineers Who May Work on This Problem.

IT has been given to astrophysicists to were lacking, our planet, with all its thou- the untaught son of nature brightens his measure the heat generated by the sun sandfold life, its thick forests and fruitful hut, the twigs with which he stokcs his and calculate the force emanating from plains, would turn into a dead, rigid hall fire, what are they but pieces of trees it. We know that the surface of our lumi- of rock, for the average annual tempera- that grew in the sunlight? The gas of thc nary gives out a heat estimated to be about ture, which is now one of 13° centinradé city dweller, the coals with which he heats 6,000° centigrade, and that its light equals of warmth for Europe, would, without thc his house and from which the gas has been that of 27,000,000,000 candlepower a quar- heat of the sun, sink to 73° centigrade of sucked, what are they but transformed ter of a mile away. The heat which the frost, it is calculated. sunbeams? The coal in the grate is the

A Successful loo H.P. Sun Power Plant Located at Meadi, on the Nile, Egypt. earth receives from the sun in the course Every sort of light with which we il- petrified wood of perished forests that of a year would suffice to melt a belt of luminate our home when the greater light covered the earth's surface millions of ice about .55 yards in thickness extending has sunk beneath the horizon, every fire years ago, and flourished in the rays of the dear around the earth. Only the 2.735 - that warms us when the solar rays can no same sun tl : °t ripens our corn to -day. millionth part of the total energy given off longer do so, is a product originating in Petroleum, that l.: ^sterious earth -oil, comes by the sun reaches our earth and, if this the sun. The chip of wood with which from the bodies of ,. illions of dead and

www.americanradiohistory.com 6436 THE ELECTRICAL EXPERIMENTER March, 1916

gone animals, chiefly natives of the ,ea. the atmosphere to the land surface proper val, during which the rays are allowed to which lived in the gray ages and fed on of the earth, at noon on a clear day. act in the manner aforementioned may things growing in the sun. Alcohol is also Lesser amounts, of course, are received in manifest itself in a powerful discharge, a plant product. and the candle our an- the early morning and late afternoon, which may be utilized for the operation or cestors took to be an ideal light, is won owing to the greater thickness through control of a mechanical or electrical de- which the energy must pass. vice consisting of an instrument R, to be Relative to the basis upon which solar operated and a circuit -controlling device energy is calculated for the earth's sur- d (Fig. 2-A). face, this is generally made, it may be said, Tesla bases his theory on the fact that on the "solar constant," as it is termed, as- the earth is negatively charged with elec- certained from 696 tests conducted by the tricity and he considers same to act as a Smithsonian Institute of Washington, in vast reservoir of such a current. By the various parts of the world, which resulted action of the sun's rays on the plate P in accepting 1.93 calories per square centi- there is an accumulation of electrical meter per minute, equal to 7.12 British energy in the condenser C. A feeble cur- thermal units per square foot per minute. rent is supposed to flow continuously into This is an average value, all things con- the condenser and in a short time it is ex- sidered. pected to become charged to a relatively Only about three -fifths of the solar radi- high potential, even to the point of ruptur- ation produce any impression on the ing the dielectric. This accumulated charge earth, and it is only the radiant energy can then, of course, be used to actuate any which falls on some material body that is device desired. converted into heat. The best body for this An illustration of a proposed form of conversion having been ascertained to be apparatus which may be used in carrying a dead black one. out his discovery is referred to in Fie. 2 -B. Many scientists and philosophers in the In this figure, which in general arrange- past century have tried various methods bye ment of the elements is identical to Fig. which to concentrate the sun's rays, such 2 -A, the device d is shown as composed as schemes utilizing an immense number of of two very thin çonducting plates, t Fig. 1. Common Form of Sun Motor Adopted by Experimenters, Utilizing a Large Num- lenses built in the form of a huge cone, as placed in close proximity and very mobile, ber of Mirrors and a Central Boiler. previously described and illustrated at Fig. either by reason of extreme flexibility or 1. A European experimenter in the year owing to the character of their support. from the animal and plant kingdom. The 1820 constructed one similar to this, but on To improve their action they may be en- smoking fish oil lamps of the Eskimo are a small scale. This model concentrated closed in a receptacle from which the air indirectly dependent on the sun for their the rays sufficiently to melt tin at a dis- may be exhausted. The plates t t' are fuel. And what of our own electric light? tance 68 and connected in series with a working circuit, is of yards from the apparatus, The dynamo developing the electricity also it was possible to cook food and melt including a suitable receiver, which in this driven by steam, and the steam engine has silver instantaneously. case is shown as consisting of an electro- to be fed with coal or with other materials In the year 1882 a Frenchman by the magnet M, a movable armature a, a retrac- gained from the animal and plant king- naine of M. Pifres devised a solar engine tile spring b and a ratchet-wheel w, pro- doms. Ilow about the waterfall? It which was built on the roof of a building vided with a spring pawl r, which is pivoted would not exist if the sun did not suck up in Paris to drive a printing -press, and the to armature a, as illustrated. When the water from the earth's surface, and which paper so published was callzd the "Soleil radiations of the sun or other radiant is again deposited on the earth in the form Journal." .Capt. John Ericson experi- energy source fall upon plate P a current of rain. mented with solar engines from 1868 to flows into the condenser, as before ex- If it were rendered possible to use the 1886 with more or less success, but nothing plained, until the potential therein rises sun's heat itself for the firing of furnaces remarkable or practical was developed. sufficiently to attract and bring into con- an ideal state of affairs would be at- Another early worker was A. G. Eneas. tained. There was a sun motor used for Fig. 1) His solar engines are described in United some time on an ostrich farm (see States patents issued in 1901, bearing the in South Pasadena, Cal. This consisted of numbers 670,916 and 670,917. a concave mirror made of single glass planes set together, and measured about 12 Getting down to basic and simplified ap- yards in diameter. The sun's rays were paratus for utilizing such radiant energy as collected and focussed on to a water tank, that possessed by the sun's rays, both let into the mirror in the shape of a visible and invisible, we may consider the cylinder, 2% yards long, which acted as its apparatus of this nature devised by Dr. axis. When the water tank remained empty Nikola Tesla, the well -known electrical on a sunny day its walls grew red hot in scientist. His United States patents on less than an hour. The 400 quarts of water "Apparatus for the Utilization of Radiant it contained was brought to the boiling Energy" bear the numbers 685,957 and 685,- point in 15 minutes and the steam de- 958. This apparatus, intended to absorb veloped drove a motor of 10 horsepower, and transform such radiant energy as that which in turn worked a pulley raising 5,600 given forth by the sun, is shown in the quarts of water per hour; a decidedly note- illustration at Fig. 2. worthy performance. Tesla says of this matter that his own The temperature of the sun, as afore- experiments and observations have led him mentioned. has been calculated to be about to the conclusion that such sources of 6,000 degrees centigrade. Several authori- radiant energy as the sun throws off with ties point out that this terrific heat there- great velocity, minute particles of matter fore precludes any possibility of the sun which are strongly electrified, and are,, being a molten mass in the process of com- therefore, capable of charging an electrical bustion. It has been thought recently by conductor, or, if not so, may at any rate many to be a great mass of matter pos- discharge an electrified conductor either by sessing to a remarkable degree radio -ac- carrying off bodily its charge or otherwise. tivity akin to radium. Helmholtz proposed His patents in this direction are based on that the sun could keep on producing alleged discovery by him that when such energy at its present rate by accounting for rays or radiations are permitted to fall saine on the basis of a slight annual shrink- upon or impinge against an insulated con- age in its size. From observations and ducting body P connected to one terminal measurements of this heavenly body made of a condenser, such as C in Fig. 2, while from year to year it has been computed the other terminal of the condenser is that the age of the sun would, on the made by independent means to receive or F.g. Tesla's Scheme of Utilizing the Sun's shrinkage basis, be 17,000,000 years. carry away electricity, a current flows into Energy. The radiant energy received from the the condenser so long as the insulated tact the two plates t t. thereby closing the sun at the outer surface of the earth's body P is exposed to such rays; so that circuit connected to the two condenser atmosphere is equivalent to 7,300 horse- an indefinite, yet measurable, accumulation terminals. This permits a flow of current power per acre. Of this about 70 per of electrical energy in the condenser takes which energizes the magnet M, causing it cent. or, roughly speaking, 5,000 horse- place. to draw down the armature a and impart power per acre, is transmitted through This energy, after a suitable time inter- (Continued ou page 662.)

www.americanradiohistory.com March, 19t(, THE ELECTRICAL EXPERIMENTER 607 The Choralcelo, a Wonderful Electric Piano This Marvelous Electrically Operated and Controlled Musical instrument is More Than a Piano -ft Produces Sustained Notes of the Lowest and Highest Register Over a Range Heretofore Unattainable, and, Moreover, Is Played Like a Regular Piano

IN India, far away, as the popular song violin. are just so many outrages on the upon the revolving discs. Tt will thus be goes, the natives are content to regale purity of the tone. seen that in order to produce the funda- themselves musically with the plaintive The Choralcelo, by the very means which mental periodicity of any given "string" it notes given forth by a goat skin stretched it employs in producing the tones, is freed is only necessary to rotate a disc containing over the end of a hollow log, upon which from all obstructions. Vibration without a certain number of segments at the cor- the musician beats a tune with the flat of contact, involving perfect freedom of vibra- rect speed. his hand. tion, and thus the Choralcelo gives all the A large variety of combinations are pos- The music of the cavemen was the wind natural overtones and harmonics; rich - sible through the manipulation of a few sighing through the trees, accompanied by full -pure and per fect, thus opening to the keys, which correspond to the stops of an the rustle of the leaves. Even they wanted musician wonderful possibilities of expres- organ, and such a keyboard is clearly to express themselves in a harmonious mansion and emotional power of which he pos- shown at Fig. 1. This resembles a piano, ner, hence the drum, the horn and other sibly never dreamed. and it really is one, with additional keys crude instruments of musical expression. The manner in which this result is ac- and pedals. The pedals are used to vary Then we may possibly expect some complished is one of wonder It is the the strength of the current sent through marked advances in our musical culture and subtle pull of the electro- magnet which now the electromagnets. education since the advent of he "Choral- achieves pure tone production. These elec- A tremolo effect is given by means of a celo," despite the prophecies of those who tro- magnets are caused to act directly upon slow speed interrupter giving a pulsating take a pessimistic view of life in general. the strings of the instrument. current at a few revolutions per second. The piano becomes a tongue -tied infant The most delicate graduation of tone The instrument which produces this effect beside this latest masterpiece of the Fig. 1. Appearance of Chor- musician's a r t . At alcelo, Showing keyboard times its notes thun- der forth and seem to shake the very earth itself, and then again they may be subdued to an elusive softness like unto the faint notes of a distant church choir. But what is it? How is it accomplished? What is the result of many years of untiring labor on the part of several Fig. 3. Various "Chime' and of the cleverest men "Flute" .1ttachments. of the world? \Vhat is it on which a for- tune that would ran- som a king has been spent? The Choral- celo! The Choralcelo, the most wonderful musical instrument ever thought out by the human mind, is like nothing else the world of music has ever known. This masterpiece reproduces any piece of music in any form of instrument, from a string to a flute; not only does tg. 2, Instrument or Pra Fig. 4. "Flute" Auxiliary Ap. it reproduce them, ducing Special Music. paratus having great range. but the notes emitted by it are sustained, pure and sweet, which is entirely different power can be produced by the mere varia- is depicted on the right of Fig. 2, while the from the ones produced by the instruments tion of the strength of an electric current, one toward the left reproduces tones repre- that are in present use. and not by smothering devices which the senting a flute. The regulation piano tone Practically all the musical instruments, present form of instrument employs. The is produced with the usual percussion ham- previous to the invention of the Choral- tone, therefore, retains all its original mers, which may be thrown into or out of celo, carry into the tone which they pro- purity through all vibrations and intensity, action by the pressure of a key. The stac- duce certain impurities which arise from something which has been impossible here- cato notes of the piano may be struck upon the manner in which they are caused to tofore. strings already vibrating with the pulsating vibrate. The violin interrupts the free vi- We will next inspect the mechanism em- current. Thus sustained notes of a higher bration of the string by the grating rub of ployed to perform these wonders. It may pitch are produced upon the string. A the bow. The piano adds the noise that be stated that the vibrating elements are piano which employs both the electro -mae results from the blow of the hammer on caused to oscillate by means of a pulsating nets and hammers is clearly shown on the the string -while the organ mingles the electric current sent through an electro- left of Fig. 3. Note the large number of breathiness of its air current with the pure magnet acting on the vibrating membrane. wires which are employed for connecting vibration of the column of air within the The machine which breaks up continually the various magnet coils. It is an engineer- pipe. In like manner all instruments em- the electric current into a series of waves ing feat in itself to even make and wire the ploying extraneous contacts to start the vi- is really the "heart" of the Choralcelo. The various circuits. bration destroy the purity of the note pro- operating device consists essentially of a Marvelously sweet tones are produced by duced. And as they seek to amplify the series of metal discs having a certain num- vibrating pieces of brass, wood and alumi- tone that they have produced they increase ber of insulating segments inserted in their num. In fact, any resonant body susceptible the intrusion of extraneous and false peripheries. These discs are arranged to to vibration may be made to emit tones. In sounds. The soft pedal of the piano, the revolve at a fixed speed. Silver -tipped order to cause these bodies to vibrate it is swell -box of the organ, the mute of the brushes are so placed that they will bear (Continncd oit rage 661.)

www.americanradiohistory.com Gci8 THE ELECTRICAL EXPERIMENTER March, 1916 New Uses for Electricity in the War MICROPHONE NOW DETECTS building will be located about a half mile AGING WINE BY ELECTRICITY. MINE SAPPERS. back from the shore on the site of the city A method of "aging" raw wines and Electricity has been utilized to an unim- water works. spirits by electricity has been perfected by aginable extent in the present titanic strug- The City Commissioners have leased the Professor Charles Henry of the University gle across the ocean. In the interesting property to the Marconi company for 10 of Paris (the Sorbonne), and it is already being successfully used in some of the Burgundy wine districts. The process is said to impart to liquors the same properties which they acquire by being kept for a number of years in cellars. The spirit or wine is placed in a special receptacle fitted with two tubes called "purgers," and the tubes are charged with high tension electricity at from 60,000 to 120,000 volts. The result is that all the bacteria, ferments and impurities collect in the tubes and are removed and all further ferment tion is stopped. The process is very rapid, and the cost is less than two cents per hundred gallons. Similar experiments are now being made with beer and essential oils. with in modern warfare is the tremendous nervous strain under which -'the men labor during or even before the actual fighting, owing to the heavy cannon and gun fire, as well as that of the machine guns, etc., which results in nervous exhaustion, and indeed in some cases in complete collapse. In this event the roldiers so affected are invariably sent to the rear or to the nearest field hospital, if properly equipped for treatment of this kind. In the illustration herewith a number of convalescent German soldiers are observed taking treatment from a specially designed electro-therapeu- tic machine, supplying current of a certain frequency and strength. The current pro- How French Mine Sappers Utilize the Microphone to Hear the Germans Counter -Mining by Sound Conduction Through the Earth. duced by this particular machine may be so regulated, when desired by the operator illustration shown herewith we see one of years, and the operation of erecting a tower in charge, that it will have the characteris- the latest adaptations of this wonderful 140 feet high will be started immediately. tics of the well-known Faradic current, used agent of man and involving the micro- extensively in the treatment of rheumatism phone. The microphone, the electrical in- HOW ELECTRICTY AIDS GERMAN and like complaints. Again the current strument which will pick up a delicate SOLDIERS TO GET WELL. may be specially controlled and regulated sound and transmit it in the form of undu- The rigors of a hard winter in the to the proper frequency and wave form lating electric currents over a circuit, has trenches, besides the stiffness and other adapted especially for the treatment of solved many an important problem in the muscular complications resulting from bul- nervous exhaustion previously mentioned, past. and especially during the present war. The two men at the right of the illustration are seen in the act of listening for German mine "sappers," and the men here shown are French. They, as you will note, are wearing shrapnel -proof metal helmets. A small box contains the batteries, etc., and the soldier leaning forward and listening so intently has in his hand a small but delicate watch case telephone receiver which is connected with the wires running along the wall to a supersensitive microphone placed in contact with the earth wall of this underground passageway. The French sappers are running a counter -mine out of the entrance of which one of the men is looking, as perceived at the right of the illustration. It is indeed remarkable to what distances such sounds as those produced by pickaxes and shovels can be propagated through the soil. The sound conduction is also en- hanced wherever rock or mineral forma- tions are present to any extent in the earth. While the opposing sappers may explode their mine and blow up the French soldiers here observed resting so contentedly in the act of writing letters home, there is some consolation in knowing that they have a fair chance to climb out of the underground passage before the German mine has been driven far enough to do any damage, thanks to electricity. TO BUILD NEW MARCONI TOWER Medem Photo Service AT CAPE MAY, N. J. German Soldiers Undergoing Electrical Treatment for Stiffened Muscles Nervousness and Sherman Sharp, a contractor of Cape Other Ailments. May, N. J.. has been awarded the contract let and shell wounds, are bound to show which ailment, by the way, has beer more to build the new building for the Marconi up in the sturdiest Wireless soldier sooner or later. noticeable in the present war than in any Telegraph Co. at Cape May. The Another important factor to he reckoned previous conflict.

www.americanradiohistory.com March, 1916 THE ELECTRICAL EXPERIMENTER Electrocuting Superfluous Cats and Dogs

WHEN your favorite Tabby or 1.1(10 the animal in the cha tuber. :\ metal pan i ited to the feline, but to its inherent vital- strays away or is turned out for placed in the electrically insulated inner ity, to its higher organic resistance to the good you would like, doubtlessly, to cabinet, while above it is fastened at either electric current and also to variations in the see it killed as humanely as possible, if that side; there is mounted a metal bar from contact made, depending on the dryness of is to be its end; and killed all such animals which is suspended a strong spiral spring the skin. invariably must be, especially in large cities, fitted with snap hooks at the free end. The A most interesting fact in connection where the total number of unclaimed pets lower electrode or pan is joined to one pole with the electrocution of these animals is gathered up by the authorities is truly of a high- tension transformer, and the that the current when first switched on astonishing. metal rod carrying the spiral spring elec- rapidly reaches a maximum and then falls Electrocution, now widely adopted in trode to the other high -tension pole. When off to about one -half of this value. The various State prisons, has been happily in- the door of the cabinet is open the trans- voltage employed for this work varies from corporated in the latest apparatus employed former primary is automatically opened d!Nto to .ions. It is believed that a much by the Animal Rescue League of Boston, also, to protect the electrocutiuncr; but lower potential will do the work in a sat- Mass. The illustrations here shown and when the door is closed the primary circuit isfactory manner. but so far such tests have reproduced through the courtesy of Hunt- of the transformer is completed. A flexible not been made, duc mainly to humanitarian ington Smith, director of the above asso- metal collar fitted with suitable electrode reasons. One kilowatt -hour of electrical ciation, depict the electrical apparatus used points is placed around the dog's neck and energy will suffice to kill from 800 to 1!000 for rapidly and painlessly killing such un- the spiral connection is hooked up to the animals, it is said. An altercating current lucky quadrupeds. Besides the apparatus collar. This stage of the electrocution is has also been found to be the best for this installed in Boston for this purpose, there seen in the center illustration, with the an- work. I

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Electrocuting Cats and Dogs at the Animal Rescue League, Boston, Mass. The Most humane Way in which to Kill Superfluous Pets.

have been similar outfits adopted by over imal alive, standing in the metal pan. In ELECTRIC LAMP THE BEST READ- twenty other cities, which in the past five a second's time the door is closed and the ING LIGHT. years have helped to destroy an unbeliev- dog receives the full strength of the elec- Recent scientific investigation has shown able number of such animals. tric current. which is believed from careful that the reading lamp which is equipped In the year prior to 1915 there were de- observations to kill him instantly,-so that no with the proper electric incandescent light stroyed no less than 480.848 small animals pain whatever or torture is experienced. and shade is superior to any other form of by 252 humane societies and their agents. The illustration at the left of the group de- lamp for reading purposes. The essential In the past and, of course. to a very large picts the dog after electrocution. features of this lamp are that the incan- extent at the present time there are sev- In the illustration at the right the elec- descent bulb is all frosted and that the eral different methods employed for dis- trocutioner is seen 'holding the remains of shade is so arranged as to protect the eye posing of superfluous animals of different an extinct feline. The apparatus for doing from the direct light of the bulb. kinds, but mostly cats and dogs which are away with cats electrically is fitted up with One occasionally hears a preference ex- turned out of homes when people move metal electrodes hung at either end of a pressed for the kerosene lamp for reading away, etc. Among these methods are those slate tray. The top of the cabinet auto- purposes. the statement usually being made involving the use of poison, chloroform, matically operates the transformer circuits, that it is easier on the eyes. This is doubt- carbon monoxide, illuminating gas and as in the case of the machine previously less due partly to force of habit and partly shooting. None of these methods is in any described. The cover is rigged up with a to experience with unsuitable electric way as humane as the new electrical method foot treadle so that by the pressure of the lamps. for exterminating such animals. The elec- foot the top may be opened or closed, thus The brilliancy of the incandescent lamp trocuting outfit was first installed in the leaving both hands free with which to man- can be reduced to approximate that of the Animal Rescue League of Boston in 1911. age the animal, for, as most of us know. it oil lamp by using an all -frosted bulb. By It possesses all the best features recom- requires some skill and agility to put a cat using a suitable shade the eyes will be still mended by those in charge of this kind of in a box or bag. The cat is grasped firmly further protected and the light directed work, besides being highly recommended with both hands and is then placed in the onto the book or paper which is to be read and advocated by many members of the box or cabinet so that its fore feet rest on and a pleasing color tone may be obtained. medical profession who have looked into one electrode, while the hind feet rest on The light from the oil lamp is made up the subject deeply and who believe that life the other. The instant the cover is closed principally of yellow, orange and red light, is cut off before any pain can be felt. the high voltage is passed through the body while the incandescent lamp gives much In the illustrations herewith we perceive of the cat and it is rendered unconscious more nearly white light from which by (the center photo) how a dog is placed in or dead instantaneously. Peculiarly enough, means of proper shades any color can be one of the electrocution chambers. This it has been ascertained that cats require obtained. cabinet measures about 2 feet G inches wide about twice the length of time necessary to Proper lighting for reading purposes is a by G feet long and stands 4 feet G inches electrocute dogs. Contrary to the reader's big factor in the general health of persons. high. It is so mounted that it is at all probable intpression, this is not believed to since eye -strain reacts on the body, causing times convenient for the operator to place he duc to the proverbial nine lives accred- headaches, nervousness and indigestion.

www.americanradiohistory.com 610 THE ELECTRICAL EXPERIMENTER March, 1916 Killing the Smoke Nuisance Electrically By Samuel Cohen WE watch the smoke floating upwards smoke, dust and mist is to charge all the virtually consists of a rotating arm of four from the chimneys of our manu- particles in the stack with electricity. In poles connected as perceived in diagram. facturing plants with thoughts this way they will be collected on the side This arm is revolved at constant speed by that differ with the individual. The house- of the conductor, and as soon as a large a synchronous a.c. motor. One of the wife thinks only of the damage done to quantity of the soot is accumulated, it falls stationary terminals is connected to a wire her freshly washed clothes. The engineer down to the bottom of the stack. A suspended in the stack and properly in- thinks of the inefficiency of the plant, while schematic diagram showing the connection sulated from it by a high tension insulator. the good citizen thinks of the effect such of the various apparatus used is depicted The opposite terminal from the stack is smoke will have on the health connected to the ground, which of the community. We will not consists of a large number of as enter into a discussion here Note the Dense pipes placed in the base of the to which one takes the proper Smoke Columns chimney, while the other two or best view, for it is well Pouring Out of the terminals are interlocked with clear at- Stacks at Fig. 2. known that a pure and No Current On. the secondary of the transform- r-osphere is necessary for the er. This rectifier is used to health and welfare of a com- At Fig. 3, the Re- change the high tension alter- duction of Smoke is munity. Noticeable. Current nating current to direct current. The smoke nuisance has been Has Just Been which is of extreme importance, made the subject of laws in Switched On. as the whole secret of this type manufac- of many cities, but the In Fig, 4, the apparatus lies in charging the turer was at a disadvantage. NO Smoke Has Entire- particles with one kind of practical or reliable smoke pre- ly Disappeared a charge, so that they may adhere Few Seconds After vention method was within his Applying Current. to one of the terminals and are reach until recently, so that he thus prevented from escaping had to rely on special grates, the out of the stack. If an alter- use of hard coal or else on ex- nating current supply is not pert firing to prevent the levy- available. a motor-generator set ing of fines. is employed and the rectifier re- Leading engineers and scien- volving disk is then placed on tists of this country and abroad its shaft. have been constantly laboring Several interesting illustra- on this problem, and although tions are herewith given show- some of them have invented ing stacks fitted with this appa- schemes for preventing the un- ratus for eliminating smoke necessary smoke from entering electrically. rig. 2 illustrates the atmosphere from the stack. such a stack when the current vet these were not of commercial was turned off; note the density value on account of being too of the smoke cloud rising from complicated. The electrical pre- it. As soon as the current was cipitating method, however, has switched on, the smoke was re- proved far superior to any other duced (see Fig. 3), and a few in its operation. The operation seconds later it had entirely dis- of this scheme is described here- appeared, as shown by Fig. 4. with. Two other striking illustrations The electrical precipitation ap- which show the marvelous effi- paratus was originally devised ciency of this apparatus are por- by Sir Oliver Lodge, but it was trayed in Figs. 5 and G; the for- finally developed and perfected mer depicts the dense smoke by The Research Corporation, ut der the in Fig. 1. It will be observed that a trans- issuing from the chimney, while the latter direction of Dr. F. G. Cottrell, the in- former is employed for supplying the high illustrates the appearance of the flue when ventor of the present form of this ap- tension current. The voltage required de- the current was turned on. paratus. Since smoke is nothing more or pends upon the size and condition of the Although the above mentioned apparatus plant in which the apparatus is to be in-

The Smoke Nuisance Eliminated. Compare Fig. Fig. 7. A Laboratory Demonstration of Smoke s (no current on) with Fig. 6, Where High Fig. 8. The Vapor Cloud Has Vanished a Fey or Vapor Elimination Electrically. Com- Tension Electric Current Has Been Seconds After Applying the Electric pare with Fig. 8 at Right. Applied to Interior of Stack. Current. Compare with Fig. 7 at Lett. less than minute particles of carbon and stalled, so they vary from 50,000 to 100,000 is being extensively employed in the pre- other solids suspended in the air the basic volts. The secondary of the transformer cipitation of smoke, it has also been used principle of his scheme for precipitating is connected to a special rectifier which (Continued on page 669.)

www.americanradiohistory.com I March, 1916 THE ELECTRICAL EXPERIMENTER t.II

ELECTRICITY ON OCEAN LINERS. The amount and variety of electrical ap- What All the Electric Plants in America paratus carried by any large ocean liner is quite astounding. From the wireless Could Do aerial suspended high above the upper deck IT was after Watt's wonderful discovery one hundred feet apart. The power re- to the cargo lamps in the lowest hold elec- of the power of steam, resultant from quired to light this gigantic line would also tricity is in constant use. observing a tea kettle, it is said, and represent the electrical energy produced by The usual electric installation on a large later terminated in the invention of his these ever -humming dynamos. liner consists of four engines and dynamos, steam engine, that people realized its great \n interesting comparison showing still each dynamo having a capacity of 40o kw. energy producing possibilities. They then another effect of this tremendous electrical at 400 volts. There are also auxiliary gen- began to build Watt steam engines and energy is noted herewith. A fleet thirteen erating sets, consisting of two 30 -kw. en- used them advantageously for driving their times larger than Uncle Sam's navy could gines and dynamos situated on a platform machines. Although this source of power be hauled through the water by means of a m the turbine engine room 20 feet above has rapidly increased in use the introduction massive electric motor stationed at some the water line. These auxiliary emergency of the generation of electricity, the internal fixed point. The power would have to be sets are connected to the boilers by means combustion engine and modern water power supplied from the generators through ex- of a separate steam pipe, so that should the developments have revolutionized power tremely large conductors, of course, in or- main sets be temporarily out of action they plant design and made practical the small, der to withstand the enormous electric cur- can provide current for such lights and isolated plant. To -clay electricity is invari- rent. The motor would also be of a spe- power appliances as would be required in ably used in manufacturing plants for light cial design. and of truly gigantic size in the event of emergency. Working in con- and power, which, in those requiring a large order to develop 27,614,766 horsepower. The junction with these emergency sets is a amount of energy, is usually generated by only difficulties that would probably inter- 1 battery with a capacity of 3,:500 ampere - steam driven generators. while gas is used fere with such an enterprise would be in hours, situated on the promenade deck, for- in some of the larger plants. obtaining or building transmission line, the ward of the first -class smokeroom. One cannot conceive of the vast amount motor and a proper foundation. This latter The electric light- I,I ing on such a steamer is equal to that of a good -sized town, the total number of incandescent lights being about 11,000, ranging from 8 to 16 candlepower. There are special dimming lamps in the first - class rooms, and the electric bell system includes 1,700 b e l l pushes and 29 indicator boards distributed all over the vessel, with fire alarm pushes distributed throughout the great liner and an alarm bell and indicator in the chart room. There are electric beating, power and mechanical ventilation apparatus in service, altogether 188 motors and 600 electric heat- ers being installed throughout. The system of ventilation consists of electrically- driven fans -some suction, others pressure, and in many The Total Electric Power Developed by United States Electric Plants Could Haul a Fleet Thirteen Times Larger cases provided with Than Uncle Sam's Navy. steam coils for warming the air. Loud -speaking telephones of of electrical energy that is daily being gen- would have to be very strongly built to navy pattern are fitted for communication erated throughout the United States. The withstand the torsion when the motor between the wheel house on the bridge and following comparisons will serve to make started to haul the vessels. forecastle and after docking -bridge, engine somewhat clearer the great magnitude of Again, if 20.350,000 1, Yn) -watt lamps room and wireless room, and also in the the energy developed by all the plants in were connected to a common circuit and chief engineer's cabin. this country, including those driven by grouped in such a manner as to cause The telephones are operated both from water, wind, etc. If these were connected their total light to fall upon a concave re- the ship's lighting circuit, through a motor in a single, continuous circuit with its flector the total candle power of the light generator, and alternatively by a stand -by terminals linked to some device, as a motor produced by this lamp bank would be about storage battery, which is introduced in the or electric lamps, we could then readily 18,408,150,000, which is enormous, of course, circuit, should the main supply fail, by observe the effect of this tremendous Dower. in comparison with the largest lighting dis- means of an automatic switch. There is One of the simplest electrical devices plays with which we are ordinarily familiar. also a separate telephone system for inter- known to the average person is the. incan- A simpler lighting arrangement than the communication between a number of the descent electric lamp. If we could obtain one before mentioned might be obtained by chief officials and service rooms, through a sufficient number of these lamps of the using two proper sized carbon electrodes, a 50 -line exchange switchboard. A num- 20 -watt size, and string them along a wire connected to some source of current and ber of the pantries and galleys are also in line from the earth to the moon, the lamps operating them as an ordinary arc lamp. direct telephonic communication. being 15 inches apart, the amount of cur- The light evolved would be of such magni- The apparatus for wireless telegraphy rent necessary to light them would then tude that it would be detected for several consists of a 5 -kw. motor -generator. The represent the amount of power generated hundred miles, of course, but the curvature house for the instruments is situated on by all the dynamos in the United States, of the earth is not taken into account in the boat deck. There are four parallel which in their entirety have an output of stating this distance. The heat produced aerial wires extending between the masts about 20,350,000.000 watts per hour. by such a scheme would be so terrific that fastened to light booms; from the aerials For another illustration we might stretch anything known to man would be boiled. connecting wires are led to the instruments a line of two conductors 15 times around This vast sum of energy is nearly in- (Continued on page 655.) the earth and place on this 1,000 -watt lamps conceivable.

www.americanradiohistory.com 612 THE ELECTRICAL EXPERIMENTER March, 1916 WINDMILL GENERATES ELEC- The "Nokolyd" Motor Car Rear Signal TRICITY FOR HOUSE AND Our readers will find it worth while look- "left" signal shows white letters on a green BARN. ing into the merits of this automobile rear background. Both the "right" and the By H. E. Zimmerman. signal, as it is one of the most ingenious of "left" signals are supplemented by arrows It looks as though the farmer, who has all the automobile devices tested by the showing the direction. By day the signal learned to appreciate the cheap power pro- Safety First Society. is plainly visible for a long distance and duced by the windmill, is going to extend by night it is automatically il- its utility by inducing it to make electricity luminated. A tiny bell rings as well as to pump water. A Wisconsin when the signal is given, farmer-J. F. Forrest, of Poynette, that which informs the operator State-has adopted a very unpretentious that the instrument has regis- and practical method of carrying out this tered correctly. idea. To a 12 -foot windmill on his farm he has harnessed a dynamo. This, in con- FIREMEN AND ELEC- nection with a storage battery, converts and TRIC POWER LINES. stores the energy of the wind into that of The slight danger that fire- electricity. The amount thus rendered men run through the elec- available is sufficient to light a system of 25 tric current passing fro m lamps distributed through the house anu heavily charged wires along barn and to operate an electric flatiron and the stream c F water they are vacuum cleaner. Feed is also ground for squirting ís r, 'ovcd by an ex- the stock and conveyed to bins through a periment cone tete.l by Ugo canvas conveyor. Tartaglini an.. reported in The lighting system is a low- pressure, 30- La Scienzu per ï utti. volt affair, while the flatiron and vacuum A trolley car wire c'iarged cleaner are supplied from a separate 110 - with a direct current of 525 volt generator. The - storage battery and volts had one end. grounded: generators are located in a shed, or wing on the other end lie directed of the barn, over which the windmill is a stream from a hose with erected. Specially designed generators and a nozzle 15 millimeters in governor pulleys serve to stabilize the usual for Auto Signal. diameter. At 220 meters dis- Fig. t. Control Handle Operating "Rear" tance a voltmeter attached to The device is electrical. It is operated the nozzle registered 20 volts. At 65 cen- from the storage battery, which forms part timeters distance it registered 70 volts of the equipment of every automobile, or aul at 20 centimeters 210 volts. The it may be operated by ordinary dry cells. ave.-age man can stand a current of 50 As each signal is set the current is auto- volts without serious shock, so a fireman matically cut off, from which it becomes who holds his nozzle apparent that the current cinsumption is : nr 6 feet from a live very low. wire runs no great The controlling mechanism (Fig. 1) is danger. fastened to the steering wheel, and within Mr. Tartaglini made is an automatic stop mechanism which op- the same experiment erates in a similar manner to a Postal on two lines of alter- Telegraph call box. The dust -proof box at nating current, o n e Above: Storage Battery. the rear has a square member inside with Left: Windmill. Below: Dy with 2,300, the other namo Drive Arrangement for four faces marked "stop," "right." "left" with 4,600 volts, and Wind -Electric Power Plant. and the fourth space is plain white and the voltmeter did not shows when the controller is in a neutral register any current position. in the stream of When the controlling lever is turned to water, although a the letters "S," "R," "L," or "O." the slight shock was per- square member in the rear is turned by an ceptible when he put electric magnetic device until the face his hand into it. With a chemical extin- "stop." "right." "left." or blank, corre- guisher he got a current of 1,350 - sponds to the letters on the controller. The 235 volts at millimeters from a wire carrying a controller can be turned one complete revo- current of 2,050 volts. lution without stopping at the interme- diate letters, and the square member will CALIFORNIA YOUTH EXPLAINS also turn one complete revolution (Fig. 2). NEW WIRELESS PHONE. Earl C. Hanson, a Los An- geles youth, states that he has erratic speed of the windmill. An automatic evolved a wireless telephone cut -out in circuit between the generator and apparatus capable of operating storage battery keeps the current in the between the shore and boats at latter from flowing back into the generator sea. Young Hanson believes and reversing its polarity. With the e: c- his system will render life tricity costing practically nothing after the saving in the future far easier equipment is fully installed, the owner's titan it has been heretofore. plan is to use it lavishly while the w..4 blows, and save it during the calm. Sonic Hanson has been working day the windmill -electric plant may be so on his idea for years. He has common that we no longer will look upon applied for a patent, and those it as a curiosity. who have inspected his workshop pronounce his scheme AS OF OLD. feasible. For the benefit of Fond Mother -"Bobbie, come here. I the skeptics, the ir.ventor re- have something awfully nice to tell you." cently gave a. demonstration at Bobbie (age six)-"Aw. I don't care. I the Venice pier. when he ex- know what it is. Big brother's home from plained how his apparatus college." works. Fond Mother -"Why, Bobbie, how could Hanson, who began his work you guess ?" on the instrument when he Bobbie -"'Cause my wireless won't work was 12 years old, declares that no more!" the apparatus is inexpensive z. How New Auto "Rear" Signal Appears. A case two feet square will The carelessness of some people is as- The "stop" signal shows White letters on hold it. It can be operated like an ordin- tounding. A recent report has it that a a red background; the "right" signal shows ary telephone. The world has been a long baker stepped on a cinnamon bun and the black letters on an orange background; the time waiting for such a device. "currant" ran up his spine! www.americanradiohistory.com March, 1916 THE ELECTRICAL EXPERIMENTER 613

AN IMPROVED POLICE TELE- SUBSTITUTES FOR COPPER IN AN ELECTRIC SIGN THAT GRAPH BOX. GERMANY. DANCES. By Warren E. Fastnacht. So scarce lias copper become in Ger- One of the latest electric signs which Police telegraph boxes are very often many, owing to the trying conditions of interests thousands of persons nightly is located in such a position that it is impos- the war, that substitutes have been found seen herewith. We illustrate night view of sible for the officer to see the index dial to replace the copper wherever possible, the sign. The operation of this mag- at night, and unless he uses his electric especially in electrical pocket -light or a match he very often sends plants, where, of course, in the wrong report. In this improved box such large amounts of there is a light over the index dial, which this valuable metal are is operated by the button in the end of the used. The new regulations index lever ; the officer pressing this button of the German Association in the act of setting the lever to the proper of Electrical Engineers code index, see Fig. 1. In other boxes cover this saving of cop- use is made of illuminated dials of opalite per by the substitution of glass, lighted from the rear. This opalite other metals, notably zinc plate with black letters makes an efficient and iron. dial, both day and night. Zinc busbars are advo- In the smaller cities very often the boxes cated, and tables llave are placed far apart and, as the officers' been worked out for the beats overlap, a number of them report carrying capacity of same, from the same box. The greatest number as well as for zinc bolts of signals which can be sent in from the and zinc and iron wire. boxes on the market at the present time Where zinc is used its is seven, and this does not meet the de- low mechanical strength, mand in many cities. Twelve different sig- low elasticity, low melt- nals can be sent in from this new box and, ing point and its sensitive- as the code is made up of a number of ness to high and low tem- round head screws properly spaced in holes peratures must be taken on a revolving cylinder or drum (see Fig. into account, of course. 2), the code or the number of the box Wherever iron and steel can be readily changed without removing are used for contacts they the mechanism. In police reports each of- must be protected proper- ficer has a particular number or report at ly by means of zinc plat- each box, and this number or report is ing, lead plating, or else always followed by the number of the by greasing, etc. box, so that the desk man knows exactly With regard to iron where the report cones from. busbars, the rule in the This set is non- interfering, as the mo- case of direct current for ment the drum starts to revolve the index the permissible current is lever is locked and rem tins locked until to have the relation of 1 it completes its function. to 2.8 to the permissible To protect the boxes ant' mechanism and current in copper bars of also the officers from burn -outs or shocks, the same dimensions. If the inner boxes are wholly constructed of the war continues copper asbestos wood. The office's are further will be nearly unknown in protected, aside from grounding the out- Germany.-Elec. World. In this Latest New York Electric Sign the Highlander Dances Briskly, side shells, by enclosing the entire receiver Attracting Great Crowds Nightly. cord in _a flexible rubber tube. WIRELESS SERVICE DIRECT TO nificent sign is indeed interesting as Very often there are repairs to be made ARGENTINA. the mammoth figure, representing a Scotch - after dark and it is not very satisfactory Chauncey Eldridge, president of the Fed- man. continuously performs numerous steps or handy for one man to use a flash -light eral Holding Co.. of New York City, which of the "Highland Fling." This huge figure or a lantern. In this box there is a small controls the Poulsen wireless telegraph is 47 feet high and is mounted on a frame spot -light placed in an upper right corner patents in this country and has for three 50 x 50 feet. Upon the same frame the of the inside chamber and mounted on a years operated a wireless system between, words "Haig and Haig" with the other ball socket joint, which permits its being San Francisco and Honolulu. announced words of the sign are mounted. The large directed toward any part of the mechanism recently that the company had obtained a letters are 12 feet high. while the others (see Fig. 3). This light as well as the one concession from the Argentine Govern- vary in size. ment for the erection of a This sign employs about 2,000 incan- high -power wireless station at descent electric lamps, which are controlled Buenos Aires. automatically by an ingenious flasher Mr. Eldridge said that it was switch. This is another addition to the intended to begin the building spectacular array of signs studding Broad- of stations with wireless tow- way at 46th street, New York Citv, aptly ers 1,000 feet high near New called the "Great White Way.' This York City and near Buenos unique display was built by O. J. Gude Aires within a short time, and & Co. that probably within a year NAVAL RADIO SERVICE. there would be for the first OUR Our naval radio service now includes 47 time direct communicatidn be- land stations scattered all over the world. tween this country and South Two of these are high -power stations hav- America by wireless. ing a generating apparatus of 100 kilowatts The proposed wireless tow- or more. They are located at Darien on ers of 1,000 feet in height will the Canal Zone and at Arlington, Va. A be higher than any now in use, third station of the high -power type will and the distance of 4,600 naut- be completed at San Diego within t e next ical miles between New York six months, while contracts have been let New Police Telegraph and Buenos Aires is a greater in Hawaiian Box Fitted with Elec. for two others-one the tric Light Over Dial. distance that any now spanned Islands and one in the Philippines. These It Is Non -interfering. -,, -..;, by ordinary radio stations. new stations are being constructed along The longest wireless span at the most modern lines. It is believed that present in commercial opera- they will have a much wider range of com- above the index dial are supplied from the tion is from Tuckerton, N. J., to Eilvese, munication than any others in the world, local talking battery. Germany. The Tuckerton station uses the and their completion will put the United By the removal of only three screws, the Poulsen wireless apparatus of less than States distinctly ahead of any other nation whole of the signaling mechanism, includ- 100 -kilowatt capacity. The proposed plants in radio equipment. ing the index lever and starting lever, can will have a 300 -kilowatt capacity. be removed from the cabinet and taken in Why not improve your electrical educa- somewhere to be repaired. In removing levers pass through openings in the door of tion? Read The Electrical Experimenter this mechanism the index and starting the inner chamber. every month.

www.americanradiohistory.com 614 THE ELECTRICAL EXPERIMENTER March, 1916 The Tesla High Frequency Oscillator By H. Winfield Secor, E.E. TESLA, probably the highest authori- a foundation. The location of the oscil ar vessels could be applied to similar con ty to high frequency electrical en- lator tower, from which the electrical en- tainers of high explosives on land, such as gineering to -day, has not been ergy is transmitted, and also the position those carried by the heavy artillery corps dreaming these past few years, although of the war vessels being blown up are not of an invading artny. we have not heard much from him, ex- to be considered literally in the way they Further, it may be said that Tesla, all in cept through the daily newspapers, which are here shown. As a matter of fact, the all, does not believe in the modern Hertzian now and then publish some world- startling enemy could soon shell the tower down. wave theory of wireless transmission at interview describing a all. Several other en- "marvelous" Tesla gineers of note have wave with which it is also gone on record possible to commulti- as stating their belief cate with Mars and to be in accordance several hundred oth- with Dr. Tesla's. er astounding stunts More wonderful still that the winner of the is the fact that this Noble physics prize scientist promulgated probably never even his basic theory of thought of, much less earth current trans - attempted to accom- mission a great many plish. years ago in some Most of our read- of his patents ers have, no doubt, and other publica- tions. Briefly ex- famous Tesla wireless t, S r plained, the Tesla tower located at tiY .,, ti theory is that a wire - Shoreham, Long Isl- Ñ; ,f ;' less tower, such as and, and which struc- that here illustrated ture has involved the and specially con - expenditure of a vast strutted to have a sum of money. From high capacity, acts as this lofty structure, a huge electric con - which was designed denser. This is charg- in the neighborhood ed by a suitable high of 20 years ago by frequency, high volt - Dr. Tesla and his as- age apoaratus and a sociateg, there was current is discharged to be propagated an into the earth periodi- electric wave of such tally and in the form intensity that it could I 1 of a high frequency charge the earth to alternating wave. The such an extent that electric wave is then the effect of the wave to travel or charge could be +t thróusfig t h e earth felt in the utmost along its surface shell confines of the globe. and in turn to mani- ell. ell. 4!: .+. M+ es. . fest its presence at Our front cover il- QC PP. 88 !1 ßR' lustration shows the Ill 811 üt: xg g r;,. any point where there ICR 1l,t Of NP might be Tesla tower in (the l' erected a Aara similar high capacity oretical) operation - tower to that above and, in line with described. some of the latest statements from this A simple analogy marvelous man, there to this action is the may be perceived sev- following: Take a eral dreadnoughts be- hollow spherical ing blown to atoms, chamber filled with a which is due to the liquid, such as water; high tension electric and then, at two dia- wave sent out from metrically opposite this center of vast points, let us place, electrical activity. respectively, a small Tesla, for obvious it piston pump, such as patent reasons, does a bicycle pump, and not go into details- Fig. s. Probable Appearance of the Wonderful Tesla Oscillator Tower at Night-It Is Located at an indicator, such as just how whole Shoreham, L. I.. and Is Intended for Radiating Electrical Energy in the Form of Nigh a pressure gauge. Frequency Propagated the Earth -Tower Stands IBS Feet High. fleets of a hostile Waves Thru Itself Now, if we suck some navy can be destroyed in this way by and hence it becomes evident that if this of the water into the pump and force it means of powerful electric waves. but quite system is ever perfected and applied prac- back into the ball by pushing on the piston possibly he has in mind the fact that the tically, the elevated radio energy transmit- handle, this change in pressure will be in- latter can be tuned, undoubtedly. to a par- ting station will have to be placed at a dicated on the gauge secured to the opposite titular wave of certain frequency and considerable distance inland. Again, as side of the sphere. In this way the Tesla power to accomplish this result when lib- this wireless energy can be transmitted earth currents are supposed to act. crated from such a mighty station or os- hundreds and even thousands of miles The patents of Dr. Tesla are basically cillator as that located on Long Island. without any appreciable loss, according to quite different from those of Marconi and Such ships as the great steel shell dread- Tesla's beliefs and statements, no disad- others in the wireless telegraphic field. In noughts of to -day would, of course, have vantage or inefficiency would be incurred the nature of things this would be expected a large electrical capacity and this would by so locating the tower away from the to be the case, 'as Testa believes and has help out the Tesla theory which covers the coast: but conjointly, on this theory, the designed apparatus intended for the trans - transmission and reception of an electric invading fleet of war vessels could be de- mission of larrr amounts of electrical en- wave of sufficient intensity to do great stroyed when they were still several hurt- ergy, while the energy received in the good or damage, as the case might be. dred miles off shore. Hence, it would be transmission of intelligence wirelessly The illustration on the front cover of impossible for them to hurl projectiles this amounts to but a few millionths of an am- this issue shows future possibilities which distance. Also presumably this method of pere in most cases by the time the current may be developed on the Tesla theory as detonating the powder magazines of the so transmitted has been picked up a thou-

www.americanradiohistory.com March, 1916 THE ELECTRICAL. EXPERIMENTER 615

sand miles away. In the f- lertzian wave million volts pressure. The external ap- metrical distribution of the current. Other- system, as it has been explained and be- pearance of the Tesla generating plant and wise, when the frequency is very high and lieved in, the energy is transmitted with a antenna support (18.' feet high) are shown' the flow of large volume, the performance very large loss to the receptor by eleetro of the apparatus might be impaired. The magnetic waves which pass out laterally primary C is excited in any desired man- front the transmitting wire into space. In lier, from a suitable source of current G, Tesla's system the energy radiated is not ,40k,7ï::! !(13..ii;44),, which may be an alternator or condenser, used, but the current is led to earth and to the important requirement being that the an elevated terminal, while the energy is 11p9T 111,, resonant condition is established; that is to transmitted by a process of conduction. say, that the terminal 1) is charged to the That is, the earth receives a large number maximum pressure developed in the cir- of powerful high frequency electric shocks cuit. every second, and these act the saute as The adjustments should be made with the pump piston in the analogy just citcd. particular care when the transmitter is one These electrical impulses or shocks given of great power, not only on account of to the earth are to be picked up at receiv- economy, but also in order to avoid dan- ing stat' . us by . recting a suitable capacity ger. It has been shown that it is practica- in the form of a metallic tower, as will be ble to produce in a resonating circuit as described more in detail hereafter. E A B B D immense electrical activities, Quoting from one of Tesla's early pat- measured by tens and even hundreds of Ii ents on this point: "It is to be noted that thousands of horsepower, and in such a the phenomenon here involved in the trans- case, if the points of maximum pressure mission of electrical energy is one of true should be shifted below the terminal D, conduction and is not to be confounded along coil B,a ball of fire might break out with the phenomena of electrical radiation and destroy the support F or anything else which have heretofore been observed. and in the way. An induced earth current out which, from the very nature and mode of of phase with a "tower capacity" current propagation, would render practically im- meeting at any point along the coil, ete., possible the transmission of any appreci- would buck each other and so balls of fire able amount of energy to such distances as could be produced; the instantaneous value are of practical importance." of the energy so involved being truly as- He states further: "Front my experi- tonishing. For the better appreciation of ments and observations I conclude that the nature of this danger it should be stated with electromotive impulses not greatly ex- that the destructive action may take place eeeding 15,000,000 20,000,000 Fig. z. Structure of the Tesla High Frequency with inconceivable violence. This will or volts, the Tower and Exciting Coils. cease energy of many thousands of horse -power to be surprising when it is borne in mind may be transmitted over vast distances, at Fig. I. Tue huge high frequency step - that the entire energy accumulated in the measured by many hundreds and even up transformer is shown diagrammatically excited circuit (instead of requiring, as thousands of miles, with terminals not at Fig. 2. under normal working conditions, one - more than 30,000 to 35,000 feet above the Referring to this great structure which quarter of the period or more for its trans- level of the sea; and even this compara- involves several peculiar design features, formation from static to kinetic form) tively small elevation will be required we see at the upper extremity a large ca- may spend itself in an incomparably small- chiefly for reasons of economy, and if de- pacity, D. This is made up of a metal er interval of time, at a rate of umiiy mill- sired it may be considerably reduced; since, framework upon which there is mounted a ions of horsepower. The accident is likely by such means as have been described. vast number of hemi -spherical metal elec- to occur when, the transmitting circuit be- practically any potential that is desired trodes. These are advocated for the rea- ing strongly excited. the impressed oscilla-. may be obtained and the currents through son that the minimum electrical leakage tions upon it are caused, in any manner the air strata may be rendered very sisal!, will then ensue. As points, of course, dis- more or less sudden, to be more rapid than whereby the loss in the transmission may charge any high tension current as rapidly the free oscillations. be reduced. It will be understood that the as possible, they are done away with, as It may seem quite impossible for many transmitting as well as the receiving coils. this is exactly what Tesla does not desire of our readers to comprehend the large fig- transformers, or other apparatus may be in to have take place in this instance. The ures cited by Tesla with regard to the volt- some cases movable -as, for example, complete electrode comprises a suitably age and horsepower liberated or propa- when they are carried by vessels floating shaped metallic ring and the half -spherical gated from such a structure as he has de- in the air, or by ships at sea." electrodes appear at P P. Hence, within signed. However, by referring to Fig. 3, Tesla is not an idle dreamer. as many a reasonably small space an extremely this matter can be more readily understood. men are inclined to believe, but back in the large electrical eapacity is formed. This This diagram shows how a graphic curve, year 1898 be succeeded, in some very elab- capacity rests upon insulating supports, C, would appear for. say. 100 horsepower orate tests carried out in Colorado, in pro- which in turn are well insulated from the liberated or passing through a circuit for ducing high frequency electrical discharges, earth. the time period of one second. Now con-. the like of which had never before been The high frequency exciting circuit com- sider that instead of this 100 horsepower I witnessed by man, nor have they been du- prises a massive coil, A, which is in close of energy being allowed to pass along in plicated since, to our best knowledge. Some inductive relation with the primary winding normal fashion for a period of one second, of these sparks measured 100 feet in length C, one end of which is connected to a that it is heaped up or liberated in about and produced a roar like the Niagara Falls. ground plate. E. The other end of the coil one -fifth of a second as at B. The horse- The multitude of mighty sparks and flashes is led through a separate self -induction power or watts, let us say in this case, produced a discharge so terrific that no hu- and auto -transformer coil, B, and the me- would be dissipated at a much higher in- man being could stay in the building in tallic cylinder B' to the terminal D. At tensity rate than was the case at C. In which they took place. Some of the sparks other words. the rate of dissipation in this were as thick as a malt's arm and others instance would he 500 horsepower for one - manifested even greater intensity. They fifth of a second instead of 100 horsepower were produced by a gigantic Tesla high for one second. frequency coil with which experimenters of Now consider that a Tesla current as to -day are more or less familiar in a small produced by an oscillatory discharge from way. About 300 kilowatts were utilized in condensers and the like take place in very producing these discharges, which resem- small fraction of time, then Tesla's state- bled actual lightning bolts and not imita- ments in his patent and aforementioned tion ones. The amperage measured 800 with regard to the production of hundreds and the voltage was up in the millions. of thousands of horsepower is not so fal- The illustration of these sparks, as well as lacious at it may seem. In an interview Tesla's early work along this line, have with one of our editorial staff he has been covered in previous issues of The vouchsafed the information that the oscil- Electrical Experimenter. lator here pictured is supposed to be ex- Regarding the Tesla tower on Long Isl- Fig. 3. Diagram Showing How the Rate at Which cited with an input of 300 kilowatts. The and and the general Energy Is Dissipated Increases as the gasp air. engineering features Time Element Decreases. average person then begins to for of same, we may refer to his patent which An input of only 300 kilowatts ! How, then. covers the design of the high frequency the apex of the mast the connection with could this tower be caused to oscillate and apparatus of mastodonic design and capa- D is to be made at or near the center, liberate energy at the rate of hundreds of ble of charging the structure at several Tcsla specifies, in order to secure a sym- (Continued on page 663.1

1 www.americanradiohistory.com 616 THE ELECTRICAL EXPERIMENTER March, 1916 Electricity Wonderful Aid to Modern Surgery

THERE have been various improve- The current to the motor is run through which gauze or cotton was placed. The ments made in surgical instruments the foot switch previously mentioned and, liquid was poured on and the vapor, of in the past few years, and the ap- as the name indicates, the latter is oper- course, inhaled with resulting unconscious- paratus described here is the final result ated by the pressure of the foot. With ness. of extensive experiments and painstaking this type of switch the surgeon had at all There were drawbacks even to this labor on the part of specialists to evolve a times perfect control over the speed of the method, and physicians started experiment- device that would ing with apparatus simplify operations that would simplify on bones. this part of t h e Heretofore an op- operation. Several eration which neces- schemes were sitated the sawing worked out, but or cutting of bones none possessed the was more or less great efficiency or clumsily done, due ease of manipula- to the fact that the tion of the appli- instruments entirely ance illustrated in suitable for t h i s Fig. 3. This ap- purpose were not to paratus consists of be had and the sur- four units : 1. A. geon did the best he motor blower and could with those at rheostat. 2. Ether hand. or chloroform con- The surgeon of tainer. 3. Mercurial to -day, however, is manometer regis- equipped with a tering from 5 to 50 unique instrument mms. and capable for this work in the Fig. f. Complete Electric Bone Set for Surgeons' of being easily set way of an electric- for any operation ally operated bone set. which is shown in motor, which is very important when the and acting thereafter automatically. 4. Figs. band 2. The ou fit comprises a source different attachments are being used. Hot water for adding both heat and of power, in this case taking the form of an With this bone cutting instrument bone moisture to the vapor. Another form of electric motor made of very light material. grafts and their recipient beds can be an etherizing machine is depicted in Fig. 4. a foot switch for controlling the motor and speedily and accurately made with a mini- The apparatus shown at the right is used various attachments as shown in the illus- mum expenditure of time and work, with for administering the gas to the patient. tration. They consist of a selection of vari- the consequent lessening of the danger The mask is adjusted over the lace, and ous small drills, saws and cutters, and are from infection which contributes to the the amount of ether to be given is placed ultimate s u c- cess of the operation. Of the utmost importance to modern surgery is the method of administering the anaesthetic. In days gone by, when the surgeon w a s compared more 3. Elaborate Electric Device for Administering Ethrr or less to a to Patients. "butcher," the Fig. 4. Another Form of Eke Bally Operated Etherizer. usual manner all interchangeable. They are held in place of anaeathe izing the patient was to place in the vaporizing chamber. As soon as the by an automatic catch built in the motor a piece of cotton over his nose and mouth heat is applied the ether is quickly vapor- shaft. A specially made angular twin saw and then pour the anaesthetic, chloroform ized and forced into the patient's lungs by is provided with this outfit and is used for or ether, over the cotton. The vapor means of the blower. very deep wounds. therefrom was, of course, inhaled by the The fact that these attachments GREAT FUTURE FOR X -RAY. can be so rapidly changed is of great The results already achieved by value to the surgeon, as he can the X -ray in combating ills are only change from one to another almost a hint of ultimate successes ex- as quickly as he could select an in- pected, specialists recently told the strument from the table. Time is an annual convention of the American important factor in any operation, as Roentgen Ray Association. Dr. W. the faster the work is done the less D. Coolidge, of Schenectady, N. Y., danger there is of fatal results. Be- said that the investigators were deal- sides being very light and comfort- ing with the future and not so much able to handle, the motor used is with present attainments, because very powerful. The apparatus as a they saw tremendous discoveries whole is easily sterilized and thus re- clearly ahead within striking dis- duces the liability of infection to a tance. minimum. He spoke of the need of standard- The motor being specially designed ization and checks upon manufac- i for this work has several refinements turers of the apparatus used, and not found in other small motors of asserted the belief that it will be as a similar type. The most noticeable simple a matter to standardize the of these improvements is the way in equipment of X-ray specialists as it which the flexible cable is connected Closer View of Electric Motor and Special Tool was the incandescent lamp. Experi- to the apparatus. Formerly this flex- Chuck Used for Bone Operations. ments had shown, he said, that it ible cable has been of more or less was possible to get one -third more trouble, due to the fact that it often be- patient with the desired results. radiating energy with the direct current came heated and stalled the motor. In This method was improved upon by the than from the alternating current and to this design such trouble is done away with use of a mask which was placed over the vastly increase the intensity of the ray entirely. face. It had a receptable at the top in with the aid of revolving targets.

www.americanradiohistory.com 1 r 111arch, 1916 THE ELECTRICAL EXPERIMENTER 617 NEW HIGH -CANDLEPOWER f Edison Perfects Storage Battery Miners' Lamp FLASHLIGHT. A novel and useful flashlight has been The latest device brought out by the The battery container holds two cells of perfected by George K. Burleigh, known Edison laboratory is a highly perfected the nickel- iron -alkaline type, and thus pro- as the Fire Fly Light. It has many new 1 storage battery miners' lamp. This is de- duces two and one -Half volts. The ele- features as well as being very attractive. veloped to the finest detail, and it has been ments, nickel hydroxide and iron oxide in The case (Fig 1), which contains an ordi- considered so meritorious that it was a potash solution, arc encompassed by a nary dry battery, is enameled red, the fiber awarded the Rathenau Medal of the Amer- strong, nickel -plated steel container, her- disc which covers the battery white, the handle blue. The two tungsten lamps are operated from one switch, and by mirror reflection triple the illumination given by a n y single battery light is obtained. it gives a dif- fused and not a concentrated light, so that by placing it in one corner of a small room you c a n read in any part of the room. Other new features are that if anything happens to one of Ilse lamps you always have t h e other in use, and the U clip shown in the cut, which slides up between battery Fig. I. New Double and battery case, Bulb Electric Lantern. can be screwed to the floor of New Edison Battery Miners' Lamp in Use. The Angle of Illumination Is Well automobile or carriage, in any safe place, In Excess of the 130 Degrees Required by the Government. and the light can tc pulled off the clip instantly to measure gasoline, read sign- boards, make repairs around motor, et cetera. ican Museum of Safety. This medal is metically sealed except at one small out- placed at the disposal of the above let for the escape of harmless The second illustration shows the strap -men- the and odor- furnished with each light' for hanging it tioned museum by the Allgemeine Elek- less gases when being charged. The cell around in- trizitäts Gesellschaft, of Berlin, to be may be turned upside down without in any the neck, with battery buttoned the best device or process in way proving disastrous to the side the coat. This gives at all times the awarded for miner or to free hands. In it is the electrical industry for the action the is use of both this way safeguarding in- of battery. This ar- especially useful in looking after the fur- dustrial life and health. The Edison mine ranged for by the unique design of the nace, for the farmer pitching down hay lamp was the first to receive this marked ventilating tube, which prevents the escape or milking cows, firemen rushing from one honor. of any of the solution, even though the cell room to another and carrying occupants The illustration herewith shows respec- be violently shaken. The cell fits snugly overcome by smoke. etc. The whole out- tively the perfected Edison mine lamp in into a light outer casing, which is rust- fit weighs about four pounds. proof and made of monel metal. The battery is held on the miner's back or, rather, at his waist line by means of a leather strap passed around the body. An extra heavy flexible conductor leads up to the lamp, which is fastened on to the cap. The lamp is usually lighted when handed to the miner and they are generally charged in groups every night at a central charging room or station located at the mouth or the entrance to the mine. The battery case is secured by a padlock so that it cannot be tampered with. The whole outfit proves practically f ool- proof and as safe as any lamp available for the purpose. The automatic battery Interchangeable Cover Removed from Case and Batteries Being Watered by Automatic Filler. filler and "watering" gauge shown in the second illustration makes it Fig. 2. Triple Bulb Battery Lamp Strapped actual use down in a coal mine and the possible for unskilled attendants to readily Around Neck. Excellent for thumb actuated refilling device which is not care for the batteries. It assures absolutely Firemen and Others. only a great time and labor saver, but is proper filling in every case when employed. also very cleanly in its action, preventing as it not only indicates when the normal the spilling of the solution over the out- level of the battery has been reached, but water at that point. It can likewise be side of the battery casing, etc. it also automatically cuts off the flow of used for renewing the alkaline solution.

www.americanradiohistory.com 618 THE ELECTRICAL EXPERIMENTER March, 1916

UNIQUE DIVING BELL TO HELP are definitely charted. on the hydrographie where there is but one telegraph wire. RAISE SUNKEN SHIPS. maps of the Government. To reclaim such Such offices, as a rule, have a telephone, A California inventor has perfected a wrecks and the buried treasure thus lost and this circuit could be used to forward submerging or diving bell formed of a sin- has been the dream of untold numbers of their messages without having to wait their gle hollow steel casting, which is capable inventors, and this device bids fair to ac- turn on the telegraph circuit. of accommodating an operator, and it is complish some valuable work in this di- Quite a number of these instruments are rection. in successful operation in the South and West, and reports indicate that they now TELEGRAPHING OVER TELE- form a part of the permanent equipment PHONE LINES WITH SIMPLE of those lines. DEVICE NOW POSSIBLE. There can be no induction on parallel A patent has just been allowed to Paul lines, as no additional battery is required P. Banholzer, of Philadelphia, Pa., on a to operate the instrument. What has been mechanical telegraph instrument for tele- said in regard to the wire telephone system graphing by wireless telephone and over also applies to the wireless telephone sys- telephone circuits. It is claimed that this tem. instrument will further introduce the dot and dash system of telegraphy, which can be CARNEGIE SENT FIRST TECH. understood by any wire operator. Further- WIRELESS MESSAGE. more, the sound it produces is unmistakable Andrew Carnegie sent the first message and carries much farther than the voice. from the new wireless station at the Car- For telegraphing over telephone lines the negie Institute of Tezhnology, Pittsburgh, modified key here illustrated is clamped Pa., the most powerful in the State, and to the post of a desk telephone and when one of the largest in the country, when he the key is manipulated the Morse code attended Carnegie Day celebration, Nov. characters are received at the distant end 23. The outfit is nearly twice as strong as of the circuit clearly and distinctly. The the average outfit on United States battle- dots and dashes on the key are transmitted ships, and will send messages as far as Colon, Panama. The Radio Club of 30 members installed the apparatus. The club is composed of Tech. students and wireless men of Pitts- burgh. It has applied for membership in the American Institute of Radio Engineers. ELECTRIC IRON MAKES INTER- ESTING PARADE FLOAT. In line with the widely extended advertising campaign during "Electrical Prosperi- ty Week" there were many parades and electrical demonstrations conceived and car - vied out to further the aims of this busi- A large Diving Bell Designed to Aid in Raising ness- getting propaganda. Sunken Vessels. Among the very interesting floats and provided with powerful securing or retain- beautifully decorated autos that appeared ing magnets, as well as electric searchlights in the various parades there was one that and large glass windows. through which seemed to appeal to the public more than the submerged wreck may be inspected the rest. This resembled a gigantic sad- This salvage machine. if so it may be iron mounted on an automobile. The illus- termed. is suspended on a steel cable from tration herewith gives some idea of the ap- a tender ship on the surface, as our illus- pearance of this unique float. In one of tration shows. When the steel shell attains these recent events held at Liberty, N. Y., the proper position with respect to the the sad-iron float was selected as one of sunken vessel, the electric current flowing the best decorated of all the entries made. through an insulated cable from the tender Such decorated autos or wagons do not on the surface is thrown into the powerful cost an exorbitant amount, and the one just electromagnets and the entire ball is held referred to entailed an outlay of about $31. rigidly at that particular point against the This is very low when the size of the float hull of the vessel. A specially devised and is considered, the over -all dimensions of controlled drill then bores a hole in the the outfit having been 16% feet long, 7 feet steel shell of the sunken ship and by an in- wide, and 9u/s feet high. Muslin was used genious arrangement of screws on the out- to make a smooth outline of the base of side of the salvage machine, the body prop- the sad -iron, being stretched over an under er of same can be moved several feet laterally or vertically, with respect to the holding magnets. After a hole is drilled, this Simple Key Attachment Enables You to permits the operator within the bell to ma- Telegraph Over Any Telephone Line nipulate a magnetized arm, which picks up one of the pontoon cables, as may be noted in the illustration. The end of this cable mechanically to the diaphragm of the is fitted with an automatically locking tog- microphone through the metal stand parts gle hook which is secured in the hole pre- and are transmitted over the line, as are viously drilled. Thus the operation is re- voice currents, and reconverted into sound peated until all the pontoon cables are fas- waves in the receiver at the Other end. A tened to the hull of the boat. desk telephone, with this device attached, These pontoons are fitted individually can be "jacked" into any telephone circuit with electric motor- driven pumps, so that and used as an extension telephone. In this the water can be pumped out of same sep- way the hinged fastener can be used any- arately or all together simultaneously; in where without having to change the fast- this way the vessel is supposed to be read- ener or use bushings. ily raised to the surface, when it can be This instrument is stated to be an espe- towed to the nearest harbor or to shoal cially useful device in connection with tele- water for overhauling and repairs. phone train dispatching, since the telegraph A Flatiron Float that Can be Built for S31 or Such work as this is extremely interest- system could be used when telephone con- Less. ing to a large class of people, as many of versation is not understood or is otherwise framework or skeleton made up of some the stories of sunken vessels carrying vast difficult owing to bad weather effects on light wooden strips. Storage batteries and amounts of gold are not mythological, but the line. etc. low -voltage tungsten lamps enable some actual facts, and a great number of these It is claimed that this key could be used wonderful, and spectacular effects of this wrecks, worth many 'millions of dollars,. with advantage in branch telegraph offices nature to be attained at a nominal cost.

www.americanradiohistory.com V March, in[6 THE ELECTRICAL EXPERIMENTER :19, Electricity the Beneficent By Benjamin G. Lamme Met Engineer Westinghouse Electric & Mfg. Company, and Member Civilian Naval Advisory Boards THE benefits of electricity to mankind service. No other means can faintly com- the electric motor? Take the use of electric are so various and so far -reaching pare with the electric car systems in motors in general throughout such establish- that it is difficult for any one per- bringing the people of city and country to- ments. How would the necessary power son to fully appreciate them. These ben- gether. Steam service, with its infrequent be distributed over the vast areas of mod- efits are both direct and indirect, the latter trains, did little in this direction. The ern manufacturing plants if electricity were sometimes far overshadowing the former. ligures giving the great growth of passen- eliminated? Possibly a way could be Many of the present generation are so ger traffic between country and city dis- found. but in most cases it would require accustomed to electrical appliances and tricts following electric car operation, tell a complete reorganization of many of our methods that they do not fully perceive the a most interesting story. present industrial methods, and efficiency large part such take in our daily life. It Electric haulage in coal mines is now would take a long step backv ards. has been said that one cannot fully ap- standard practice. Decrease in fire risks In the smaller shops and power appli- preciate a thing until he has to do with- and increased capacity are two prime rea- cations, the electric motor fills a fully as. out it. This points to a important place. Small very effective way of steam plants are utterly calling attention to the IMA(IINE, if you can, that when you awake to- morrow morning, the impracticable in some far -r.a lung influences places. Gas or gasoline of electricity in the life whole world will be suddenly without electricity in any of its present engines are often very of the world. forms. Have you Even a faint idea how it would affect your every- objectionable. but still Let us assume by that possible. But how about . some means, all electri- day life? What would happen if such a cataclysm should take place over the electric spark for cal apparatus, methods night? How would it affect humanity? This is the theme of the present ignition, if electricity is and usages are suddenly to be eliminated? It withdrawn from t h e article selected by its distinguished author. It makes good reading and must also be kept in world. By considering brings home to us the fact that the world in its present state is vitally mind that many estab- the consequences of this lishments using power we can possibly get a dependent upon the mysterious fluid. have been so designed fair idea of the scope of that the replacement the electrical field. of the electric motor Let us consider first the general subject sons which have led to electric operation. by any form of steam or gas engine is of transportation. Possibly no other activ- Eliminate the electric current and coal not practicable for many reasons outside ity has had as great a bearing on the pres- mining can doubtless be carried on with the mere question of ability of the latter ent high development more or of mankind as our less success, but with decreased to develop the required power. Available - modern methods of transportation. Tak- production and increased cost, which must space, high temperatures, fire risks, dis- ing steam operation, wherein does electric- be borne by the public. We can always posal of burnt gases, noise, and many ity play an important or controlling part? go back to the old ways of doing things, other conditions enter into this matter. Or, by a more specific question, supposing but we will have to pay the price. Outside of shops and industrial plants. the electric telegraph were suddenly eli- in water transportation electricity. per- the electric motor also has a very wide minated, how would general railway trans- haps, has not played such a conspicuous field of application, and many kinds of portation conditions be affected? They part as on land. Yet if the electric in- service have developed simply through the would be completely disorganized tem- stallations on ocean vessels were elimin- availability of the electric motor as a porarily, and would be very greatly handi- ated, there would have to be quite a re- soulce of power. This part of the sub- capped permanently. Rarely is it appre- organization. Electric propulsion of large ject is too large to allow consideration in ciated to what an extent our great railway and high- powered vessels promises to be detail in any article of limited scope. systems are conditioned upon means for one of the most important steps in naval Coming now to one of the oldest and almost instantaneous communication be- engineering in the near future. Wireless best known fields of electric activity. tween distant points. Without such means telegraphy has become a necessity in mod- namely, electric lighting, we find a class of a busy railroad could only operate upon ern sea service. service the abolishment of which would be an exact time schedule. Once that sched- Taking up next our business and indus- felt by all classes in civic life. If electric ule is broken, disorganization and disaster trial life. let us imagine a few of the things street lighting were abandoned, we could would follow. Incidentally, someone will which would happen if electricity were en- doubtless manage with some other form suggest that if the electric telegraph were tirely eliminated. Without the telegraph, of illumination. but the results probably eliminated, the railroads would turn to the business would he very badly handicapped, could never approach the present stand- telephone. But this again is an electrical although it might limp along after a ard. In the case of interior lighting, the apparatus. fashion. But the telephone -here would result of a replacement of the incandescent A second great item in railroad trans- be the rub, if we had to give it up. lamp by other forms of illumination would portation at the present time is electric Whole systems of conducting business are create still more dissatisfaction than in the signaling for the dispatch and control of dependent upon the telephone. Disorganiza- case of street lighting. It may he said that trains. If eliminated, this would certainly tion would be certain to follow in many the vast majority of electric light users mean a great step backward, especially in lines if it were eliminated. Even home - would pay a greatly increased price rather sections of very .heavy and frequent rail- life would be greatly affected. than be obliged to give it up in favor of way service. Let us next consider the elevator. What any other known method of illumination. What would be the effect of complete has been its influences on life and busi- Another class of electric service of a cessation of electrical operation of city, ness in the cities? How about the large comparatively recent period is represented suburban and interurban cars? In the many- storied department stores? Can any- by household utilities. such as electric cities we might go back to horse cars for one conceive of a practicable 30 or 30- irons, toasters, coffee percolators, and the surface lines. The service would be story skyscraper without elevators? And other electric heating appliances. Motors almost unbearable, but might be possible. one must remember that most of these for general household purposes, for run- Elevated trains in large cities could go elevators are electrically operated. True, ning sewing machines, washing machines. hack to steam, however, with great ob- there are other very good methods of etc., are becoming rather common. These jections from adjoining business firms operating them, but nevertheless. the eli- are luxuries which are fast becoming and residents. But subways -here would mination of the electric elevator would necessities. If these were eliminated a big be a real nut to crack. make a large gap in our methods of ver- gap would be created. even though they In suburban service, the elimination of tical transportation. represent a comparatively new field of ap- the electric car service would spell dis- This leads us to a very common piece plication. aster, except to those relatively few in- of apparatus, namely, the electric motor. The above is only a very incomplete dividuals who could have their own equip- This has come into use so gradually, and presentation of the direct possibilities ages. IHow few appreciate that the rapid with so little ostentation. that we almost which would occur in case there was a growth of suburban districts has been feel that it has always been with us. Yet. complete cessation of all electrical activi- consequent upon electric railways. Auto - in less than one generation. it has revolu- ties. Many of the special applications of busses and "jitneys," or some other form tionized all kinds of manufacturing estab- electricity such as electro- chemical, electro- of gasoline engine equipment, might fur- lishments and industries. Take the elec- metallurgy, electro- fusion. etc.. have not nish a solution eventually, but then. how tric crane for instance, shat would the even been touched upon. and yet great in- about the electric spark for ignition? great industrial works of the present time dustries have been built upon them. The Again, let us consider interurban car do without this particular application of (Continued on page ,056.) Prepared exclusively for The Electrical Experimenter.

www.americanradiohistory.com 62o THE ELECTRICAL EXPERIMENTER March, 1916

GEORGE SIMON OHM. MARCH, 1916, MARKS HIS 128TH Electricity Renders Safe Impregnable. BIRTHDAY. By George C. Denny. (Born 1787 -Died 1854.) Electricity. the adroit crook's most for- has made a complete turn. These devices In 1827 Dr. George Simon Ohm, a Ger- midable enemy. is forever beating him at become necessary when the safe is placed man physicist, rendered a great service to his own game. It moves silently and quick- in a niche in the wall or surrounded by a electric science by his pamphlet containing ly, strikes when least expected and, land- lattice work, as shown in the illustration. his theories that the flow of electricity was ing him behind the bars. prevents him from This manner of placing the safe effectively governed by certain fixed laws. It ex- obtaining his much- desired haul. In a re- prevents its motions from being followed plained what is accepted and known to -day volving safe, the sub- as "Ohm's Law," and the "Ohm" is now ject of a recent patent, universally employed as the unit of resist- which appears to be ance in an electrical circuit. This law the latest invention states that 7 he current varies directly as for foiling the ex- the elcetro- motive -force, and inversely as pert cracksman, the the resistance of the circuit. Like all great unknown medium inventors. Ohm was ahead of his time, so plays the leading role. his ideas were ridiculed by great and small. By continuously turn - He was the son of a thrifty locksmith, nmg the safe. which of keen intelligence, and was born March may be made still 16, 1787. George Simon Ohm started his m o r e impenetrable career in the village of Erlangen, Bavaria, and secure by placing as a helper in his father's shop. He inher- it in an enveloping ited a love of mathematics from his father, sheath, electricity will a man of studious disposition. The parents render his drills and early recognizing the latent talent in their other tools of this son, accumulated enough money to send class ineffective George to college. Owing to lack of funds, against it and. more- he was compelled to forego his schooling over, prevent the use a few years later. He then reluctantly of an explosive as turned to teaching in a primary school. by pouring it in the cracks in the safe or in a hole bored for that purpose, as is usually done. T h e motion of the safe and sheath, too. will attach to it so many An Electrically Protected Safe That Constantly Rotates, and if uncertainties that the Tampered with Gives a Code Signal on the Sign ambitious yeggman Outside the Building. who might smilingly tackle the job. were and the safe or sheath from being worked the safe at a standstill, would soon turn upon. The lattice work is also wired, so away for an easier one with less risk. that any tampering with this structure That the motion of the safe may not be would cause the sounding of an alarm. slowed down or stopped. over -load and A street sign with a number of lights, under -load cut -outs are provided which are secretly wired to the safe and placed out- acted upon by the motor which turns the side, would, by the alternate lighting of the safe and which runs at a regular and pre- lamps, caused by a commutator on the mo- determined speed. When one of these cut- tor shaft, inform a watchman that the safe outs is placed in action by an over- or un- was intact at the completion of each revo- der -load on the motor, a signal is promptly lution. Another novel method of protec- given that the safe is being tampered with. tion would be to place the safe in a win- To indicate the position of the safe door dow. and the revolving thereof, besides a bell mounted in a certain place on the attracting attention and acting as an adver- sheath is struck, or a light placed in the tisement, would insure the safety of its proper position energized when the door contents. George Simon Ohm, After Whom the "Ohm," Unit of Resistance, is Named. CLASSIFIED! chine. This motor, which sells at a nomi- The applicant for the post of second nal price, does not have to be attached or This sudden financial stress did not daunt wireless operator seemed somewhat dense, screwed fast to the cabinet of the talking the Young locksmith student one bit. He but otherwise appeared to be a clean -cut machine in any way, but simply rests on the filled in most of his spare moments study- shelf of same. On the lower end of the ing. but it must not he that he chap. thought gave I a single asked motor shaft is secured a friction pulley, up Ampère, suppose you are man ?" all outdoor pleasures. Unlike the port operator during the conversation. which by frictional contact with the disk he was popular among the students and no, sir," he stammered; "I'm platen of the phonograph drives it at the professors and joined in all the social life "Er -er, and athletic games. twins." In 1817 George Simon Ohm was appointed professor of mathematics in the A MOTOR THAT OPERATES ANY Jesuit Gymnasium at Cologne. The fol- DISK PHONOGRAPH. lowing year he published his famous "Ele- One of the latest electrical motor produc- ments of Geometry." He resigned a few tions brought out by a New York concern years later and went to Berlin, where he appears to solve a very important problem became interested in electrical experiments. which has long confronted the owners of Ohm then pushed his researches in the foot- a Victrola or other disk -type talking ma- steps of Galvani and Volta. the results of which were embodied in a pamphlet called to be one known to all electricians in every "The Galvanic Circuit." part of the globe. Wherever you find the About 14 years after publishing his volt chasing the ampere around the cir- theories, when he was in the midst of his cuit, there also will you encounter the wonderful career, Ohm was awarded the "ohm." who bucks their onward rush with Copley medal by the British Royal Society all the strength he possesses. Ohm's law in 1841. For a time thereafter profes- written algebraically, C = E over R, sional jealousy reduced Ohm to a condi- This Unique Electric Motor Drives Any Disk E Style Talking Machine. Does Not Mar tion of comparative poverty, but regard- (C - -), has been adopted as the emblem the Cabinet. less of this he continued the course of his R investigations. The International Congress of the National Electric Light Association, proper speed. The regulator on the talking of 1881 gave Ohm's name to the unit of one of the most powerful scientific organi- machine can be employed in the usual way electrical resistance, and so his name came zations extant to -day. for varying the speed of the record.

www.americanradiohistory.com March, 1916 THE ELECTRICAL EXPERIMENTER 621 RADIO AMATEURS TO RELAY MESSAGE OVER U. S. ON FEB. 21. President Wilson 'Phones Message to Boys' Club M. S. G. (message) will Another radio The Boys' Club, located in New York the youth of America. I hope this may be be relayed from Rock Island Arsenal, Illi- City at Avenue A Tenth had on Feb. 21. This radiogram will and street, only the first of the signs of friendship nois, what might be called, without a doubt, a that all ought to feel for ti e boys who to 9 X.E. by the U. S. Army be delivered "large size" evening on Jan. 17 last, when bring us our papers. My sympathy has officer in charge of the arsenal station. Owing to the fact that Feb. 22 is Wash- ington's Birthday the message will be partly military in nature and also in keeping with the spirit of the day, which is dear to the heart of every loyal American. It will be sent out on a Q. S. T. by many stations- special and amateur. It will be up to the many stations listening in to pick up the M. S. G., as the list of sending stations, their time and wave length will be given in the final instructions. Each Governor and Mayor of every State throughout the United States will receive this message. Arrangements have been completed with the Boy Scouts of America to assist in delivering it wherever possible, and suitable ceremonies will be held at Bunker Hill and Mt. Vernon by these coming citizens of the U. S. A. Valuable assistance has already been given by the various local and national radio clubs. The A. R. R. L. have promised their assistance. Every wireless amateur in the country is requested to "talk" this over with his favorite relay station. Telegram blanks will be furnished each receiving station later by 9 X.E. A. A. (Arlington) has promised to N. Photo Cop,rlgbt In? IoterNnonl Film Service. assist in this great undertaking, the same At the Boys' Club, New York City, When President Wilson Talked to Them Over the 'Phone as it did during the Rotary relay message from Washington. sent broadcast on Dec. 31 last, by sending out a warning to all amateurs to "keep over 200 newsboys who were campaigning always been with the newsboys. Please out," after the N. A. A. routine report of for a half -million -dollar fund for the erec- give them all my very best wishes." Feb. 21, 1916. tion of clubhouses listened to a talk by Behind the boys who held the receivers We all owe our thanks to Capt. Bullard, President Woodrow Wilson in the White were several hundred other members of who has given us every assistance. All House at Washington through the medium the club. The smallest lads were given the are requested who may be assigned the de- of a long- distance telephone and a number preference at the receivers, but while the livery of this message in their respective of multiple receivers. President spoke many receivers were States or cities to deliver it, no matter The boys were so delighted by the Presi- passed back into the crowd to give others where your man may be. Yours is a per- dent's words of encouragement that they an opportunity to hear. The doors of the fectly legitimate mission and you have no cheered him to an echo over the 'phone, clubhouse were closed and locked at 8 cause to fear anyone-just land your man and he was highly pleased by this ovation. o'clock. Outside the street was black with and give him the telegram. The lads who heard the President had been youngsters who could not gain entrance. Yours for a great success, 9 X.E. invited by the club from the streets of the They took the cheering up after the Presi- [The Rotary M. S. G. of Dec. 31, 1915, East Side of New York; many of them dent had talked and for several minutes ï was received in Texas and Utah. All were newsboys with hands blue from the Avenue A was filled with lusty shouts, the States between these received the radio- cold, with torn clothing and heavy, ill - like of which had not been heard in that ;- Also Niagara Falls to Washington, fitting shoes. They were gathered behind locality in many a day. desks arranged in large square in their Long live the telephone, the annihilator iI Dagram.. and all cities between received it.] a C., gymnasium, their begrimed faces glow- of distance and the gift of science to man- UNIQUE ELECTRICALLY ing with the enthusiasm of the moment, kind which has made it possible for gath- LIGHTED TRAFFIC SIGNS. their hearts beating furiously as they lis- erings such as this to hear and enjoy a' The accompanying illustration depicts tened for the first words of the President's speech by such men as President Wilson, talk. All of these boys are to be bene- although they may be located hundreds or ficiaries of the campaign carried on to even thousands of miles away. It is now raise the sum of $500,000 for new club- a common occurrence for club diners in houses in Greater New York. New York to listen to speeches made in This was the President's address: "I San Francisco, and vice versa. For these am very glad to have this opportunity to occasions special equipment is installed by address a few words to the boys. I hope the local telephone company, including a with all my heart that you will have suc- sufficient number of multiple receivers, so cess in raising this fund to be devoted to that each guest can hear the speech.

public square of M. Vernon, Ohio. As policemen on duty at the center of the in- noted from the illustration, these signs tersections in order to prevent collisions. read, "Keep to Right." These words are visible to traffic in either direction, both NEW WIRELESS TO ALASKA. night and day. At night there are two 25- For years the only telegraphic communi- watt tungsten lamps suspended from cation with Alaska has been by way of the brackets above the sign on either side of Sitka -Seattle and Valdez -Sitka cables. The same, so that it can be read at a consider- growing commerce between Alaska and the able distance. States has resulted, as stated by H. Brown, The upright standards supporting the sign commercial superintendent of the Western and tungsten lamps are constructed from Union Co., in the establishment of an alter - 1 -inch conduit. .Above the lamps there nate wireless route by way of Astoria, Ore., extends a 10 -foot piece of % -inch conduit, which furnishes a telegraphic connection through which the feed wires for the lamps with a number of important points in Mt. Vernon, O., Makes Use of Portable, Electric Alaska. Lighted Traffic Signs. are run. These wires are connected with the over -head 110 -volt circuit. the unique and also inexpensive form of Prior to the erection of these signs, Why not become a regular reader of The electrically lighted traffic signs which have which, by the way, may be moved about, Electrical Experimenter? Subscribe to -day! been erected at the four entrances to the it was necessary to keep two or three It will cost you but $1. Do it now

www.americanradiohistory.com THE ELECTRICAL EXPERIMENTER March, 1916 Electricity Fills Important Rôle in Modern Automobile THE automobile of to -day is rapidly armature is connected to the driving shaft. to about I0 per cent. This slippage is coming to the point where every- The motor field is stationary and its ar- sufficient to generate enough current to thing in the operation of same will mature, like that of the generator, is transmit 40 or 50 horsepower through the be controlled by a series of push buttons. rigidly connected to the driving shaft as apparatus with high efficiency. We light the headlights, start the motor, illustrated in Fig. 2. Thus it is evident This may not seem possible, but it must or blow the horn by merely pushing the that the generator field is revolved at en- be remembered that the slippage between proper button, and now by means of the gine speed, and both generator and motor the generator's field and armature has been device illustrated at Fig. 1 we even shift armatures revolve at wheel shaft speed. decreasing as the car is accelerated, so that the transmission gears. Instead of the The motor and generator are direct cur- the relative speed of field to armature is usual wrist strain and noisy grating of the rent machines; the motor being series small when this connection is made. With gear teeth that used to accompany any wound, while the generator is shunt wound. this small relative speed the armature re- change of speed we merely select our This arrangement necessitates the revolu- action is not great enough to break down speed, push the button and a touch of the tion of the generator brushes at the same the torque. In this condition a point of clutch pedal does the rest. speed as the field. In order to deliver cur- equilibrium is reached where the slip is This system is operated entirely by elec- rent to the brushes of the motor they are just sufficient to generate enough current tricity and all the gear shifting done in connected to slip rings, this same device to maintain the magnetic grip. The oper- the gear case by means of magnetic sol- being used for making connections with the ation is analogous to that of the induction enoids energized from a storage battery. field. motor, in that an increase in load is bal- Each of the solenoids is connected to its The complete system operates as follows: anced by an increase in slippage. If a respective control button, mounted on the For cranking the generator is energized by grade is encountered the slip increases and steering column, and a master switch is current obtained from storage batteries, because of this a greater torque is exerted controlled by the clutch foot pedal. The causing it to act as a motor, thus starting on the driving shaft, due to the additional switch here illustrated has three speeds the engine in the same manner as the corn- current generated. - ._ All these operations are controlled by an extra lever situated on the steering wheel, thus eliminating the clutch pedal and gear levers. There is no flywheel, as the generator field acts as such. A mechanical brake is also provided, but this is not used except when it is necessary to bring the car to a sudden or dead stop. If the controlling lever is thrown to the neutral position when the car is running at high speed a resistance is thrown in series with the motor, which develops a torque that tends to stop the car. This brake will not bring the car to a dead stop as its braking power depends on the car's motion, but it is very useful in keeping down the speed. The storage batteries are charged from the motor, which contains an auxiliary field that furnishes current to the batteries Some Late Electric Developments in Au- when it is on high speed. These batteries tomobile Gear Shifting and Driving. Stars are used for lighting purposes: in Fig. i Indicate Electric Push Button With these rapid advances in the elec- Controller, Also Foot Pedal Control. trical equipment of automobiles we may safely predict that the car of the near future will not only be started, lighted and its speed controlled by electricity, but it will be steered by this willing servant of man. It will require no more effort to drive a powerful racing car than it does to call a waiter. The control of these machines. will be so simple that a five -year- old child can handle one with ease. forward and one reverse, which is suffi- merciai motor starter now extensively em- cient for most ordinary work. ployed. For starting the car a resistance NEW ELECTRICAL MANICURE. The operation of this apparatus is as is connected across the field of the gen- Los Angeles ladies are having their nails It's the latest follows : When the proper button is pushed erator, and as the magnetic flux builds up manicured by electricity. it closes the circuit to the solenoid, which the field exerts a torque on the armature method of beautifying the hands. Pink will throw the gears into the required posi- and turns the driving shaft and conse- powders and polishers are unnecessary on tion. The clutch pedal is depressed and quently starts the car. The resistance in milady's toilet table, for the same electricity when released closes the master switch, the field is then cut out and short circuited, which has been harnessed for great indus- which throws an enormous current into thus more current flows in the fields iii - tries does its little turn in milady's boudoir the solenoid for a mere fraction of a sec- creasing the flux and exerting a greater and polishes dainty fingers. ond. The change of gears is accomplished torque on the armature which accelerates Mrs. F. A. Scott, of Los Angeles, who so quickly that they mesh cleanly without the car. The generator is constantly pro- conceived this latest device for manicuring a clash or any damage. This saves both ducing current due to the difference in and beautifying, declares it trims, files, the driver's temper and the cost of stripped speed of its field and armature. This cur- cleans, smooths and polishes the nails in a gears. rent is led into the motor, which exerts a most sanitary, businesslike way. It will be thought that nothing more torque on the driving shaft and helps the B- r -r -r! and one's nails are filed and could be devised in connection with the generator to drive the car. To further cleaned by a little whirring machine. A gear transmission, but in Figs. ° and 3 increase the speed resistance is switched faster revolution and the nails are polished_ we show a transmission mechanism which into the motor circuit, thus throwing more with a shine that won't come off-a shade does away entirely with the necessity of a current through the field of the generator, pinker than seashells. A third pressure of gear shift and yet gives a finer regulation which thus tightens its grip on its ar- the button, a louder b -r -r-r and a splash of of speed. R. M. Owen & Co., to whom mature and decreases the slippage between toilet water, and the work is done. Why we are indebted for the illustrations, call the armature and the field. Successive re- don't someone invent a machine to give their car when equipped with this device sistances are cut in until practically there the male of the species a shave, a massage "The Car of a Thousand Speeds." is no current drawn from the generator. and a hot towel automatically, and finally This system of electrical transmission is The motor is then cut out of circuit and to release the "hat" without the everlasting as unique as it is flexible and consists of the generator armature feeds the fields "tip!" a generator, motor, storage batteries, re- only. The generator now acts as a mag- sistance coils and controlling switches. The netic clutch, the current necessary to en- Do you enjoy this magazine? If so, tell is a be- others. If not, tell us. Remember we generator field is rigidly connected to the . ergize produced by slight slippage crank shaft as shown in Fig. 3, and the tween ite armature and field which amounts publish it to please our readers.

www.americanradiohistory.com II C>23 11 March, 1916 THE ELECTRICAL EXPERIMENTER Marvels of Modern Physics By Rogers D. Rusk Ñ Physics, Ohio Wesleyan University Assistant Instructor in f SOME MISSING LINKS. force must have been recognized as a com- Cavendish's apparatus, in order to double' r T is just as important that the scientific mon fact long before his time. What the effect, two large spheres were used, and 1 man should know about the stumbling Newton really did was to discover the uni- likewise two small ones. These are repre- blocks of science, as that he should versal law by which the force acted, and sented in Fig. 2, and the small ones as have a well ordered knowledge of the facts not the force itself. shown were connected by a light bar and and laws already determined. This law -the universal law of gravita- Man has perplexed his mind with many tion- states that : "Every body in the uni- difficult questions. In the physical field verse attracts every other body, with a alone he has asked himself : Is space in- force that varies directly as the product finite? What constitutes matter? How of the masses and inversely as the squares does gravity act? What is electricity? of the distances." Etc., etc., ad lib., ad infinitum. This, of course, was a startling state- Ages of weary labor have been expended ment of the fact that the force we com- on these problems with the result that we monly term gravity is in reality a universal )fit are hardly nearer the direct answers than force acting between all bodies, and that it we were before. Some of the blanks seem is only because the carth is so very large is likely never to be completely filled, but at that it does not fall to the apple instead. least we know more extensively and ac- For a long time it was the pet dream of curately concerning them and the phenom- the more fantastic minded to discover a ena to which they are related. force of "negative- gravity" which would Most of the puzzle questions of the counteract or neutralize gravity itself, but Fig. 4. Mechanical Analogy of Electric Strain scientists have not been practical and the discovery of such a force seems quite Existing in a Charged Leyden Jar. far away indeed. l!I 'worth while, however. It has hardly been ;uspendcd by a thin silver wire. The 500 years since scientists were loudly Newton's' law of gravitation brought out many interesting experiments. The sun, amount of twist of the wire was then a wrangling over such frivolous and absurd measure of attraction between the spheres. questions as, "How many angels can stand Many theories as to the nature of the on the point of a needle ?" force of gravitation have been presented, It was in the midst of these absurdities but the only theories which seem at all that Roger Bacon made his remarkable reasonable or possible imply the existence prophecy in the thirteenth century, in of some invisible and intangible medium which he predicted the coining of the which exists throughout all space. and per- steamboat, railroad and aeroplane. His meates all matter ; which exists between the prophecy is the more remarkable coming heavenly bodies, beyond the limits even of from such an age, but unfortunately he any atmosphere. added that the fountain of youth would In following this line of thought we are be and baser metals changed discovered the treading exactly in the footsteps of the 11i into gold. Like perpetual motion they have older scientists, beginning with Newton. always proved to be the phantom at the end Fig. x. The Famous Cavendish Experiment Little of a definite nature was done with of the rainbow. for Determining Relative Gravity Values. referencc to the establishment of such a To -day, excepting, of course, the absurd theory until 1678, when Huyghens, perceiv- and impossible, there are still many miss- moon and earth have each been weighed ing that light traverses a vacuum unim- ing links in our chain of knowledge. (a seecmingly difficult task) by an applica- peded, decided that it must have some me- Some years ago Physics was defined as tion of this law. If in the diagram, Fig. dium to travel in or on. Also. as light "the science of matter, ether and motion." (1) "A" represents the sun, "M" the moon comes from the sun, and even from the These terms at once suggest to our mind and "B" the earth, while "a" and "b" rep- most distant stars. this medium must in- three of our big Unknowns. deed be infinite in extent. Earlier theories The last two of these will be treated of of light liad miserably failed, but Huyghens in this article, while the subject of matter formulated his theory that light is nothing and its constitution will be taken up sep- material, but that it is a wave motion in arately later. some invisible medium, which medium we With reference to motion, the different call the ether. kinds are pretty well known and under- Wonderful to relate, this theory, with stood. Of course many perplexing ques- the exception of a slight modification along tions can be asked such as: "How can electro- magnetic lines by Clerk Maxwell the top of a cart wheel move faster than and others, is the accepted theory of to- the bottom ?" and, "Can Achilles ever over- day. take the tortoise ?" but these are more The development of our theory of the mathematical Fig. 3. Illustrating Mechanically a Sphere than physical problems. Containing Opposite Electric Charges. ether has been the biggest unifying factor Two of the forces which cause motion, in the history of modern physics. It has however, are much less well understood. resent their respective distances of 93,000; brought the different branches of physics They are gravitation and magnetism. 000 miles and 240.000 miles, then the ratio in close touch, and paved the way for Isaac Newton is popularly accredited between the relative pulls of the earth and wonderful future progress. sun upon the moon works out to be about There is little more to say concerning 120 gravitation until we have considered the -. This makes the sun approximately ether further. 54 Is the ether material or not? Matter is 300.000 times the mass of the earth. that which occupies space, but the ether o Now to find the absolute weight of any does not occupy space in the ordinary sense of the bodies, the weight of one must be of filling space. It is intangible and im- found before the proportion can be formed. ponderable. therefore we say it is not mat- This was done by Cavendish in 1798 in ter; but on the other hand if matter is that his experiment which has since become which exists. and has certain physical char- fig.l famous. He definitely measured the attrac- acteristics, then ether may well be classed tion between a lead sphere 12 inches in as matter. The horns of the dilemma are diameter, weighing 350 pounds, and a obvious. Fig. I. Diagram Showing the Relative Pull o smaller sphere two inches in diameter, Some years ago the ether was character- the Earth "B" and Sun "A" Upon the weighing one pound and ten ounces, and ized as continuous (not composed of unit Moon "M.» also the attraction of the earth for same. particles), infinite in extent, infinitely elas- The previous problem was really repeated tic, frictionless and without weight. with the discovery of the attraction which by Cavendish substituting two lead balls Sir William Thompson, however, made causes bodies to fall towards the center of of known weight for the sun and moon. the interesting calculation, dependent on the earth. Notwithstanding the familiar Thus the earth with its thirteen billion the displacement of a particle of ether in story of Newton and the falling apple, this billion pounds was actually weighed. In (Continued on page 665.)

www.americanradiohistory.com THE ELECTRICAL EXPERIMENTER March, 19t6 Baron Münchhausen's New Scientific Adventures By Hugo Gernsback IF there is one thing that annoys I. M. ALIER MAKES me, it is a nosey reporter. To The Cities of Mars STUPEFYING INVENTION. be sure, they are harmless folk, are reporters, and suave and well -man- justed the Selenium Vapor Enforcer, and RECEIVES SOUNDLESS, VOICE- nered as a rule, too. But somehow their turned once more the knobs of the coupled LESS, MESSAGES FROM MARS. eyes always appear to me as gimlets inductance balancer to make sure that I and their noses as huge corkscrews, but was tuned in for 90,000 meters -the wave ALLEGED HERO, MUNCHHAUSEN, then those are the characteristics of the length used by Baron Münchhausen. SPEECHLESS WITH SURPRISE. tribe, and really they can't help it. It The chime had sounded its last stroke. is their business to drill holes right In another second the dear old gentleman's MUNCH'HAUSEN SAYS HE through your mind, and once their cork- voice would greet me as usual. AIN'T SAYIN' NOTHIN'! l screw noses have dug themselves into your Have you ever wished to "show off" to confidence they pull and pull till something your friends or to your relatives and the And so on, and so forth. The article comes up. A reporter can always dig news "show off" failed to materialize? Have was written so excruciatingly funny that I out of you, even if there's no news tc oe you ever experienced the cunning feeling had to laugh myself, despite my rage. But had. All of which might be of interest :o .tf an icy cold wave racing up and down the laugh froze to ice when my eyes had you, and then again it might not. A' any your spine, to be followed immediately by passed over the line where Snickles had rate, the editor of the Yankton Bugie, who a hot blast up and down the self same written ironically: has heard about Münchhausen, sent a re- spine? And has the perspiration broken "Undoubtedly Münchhausen was asleep porter to my laboratory in order to "write out all over you at the contemplation that at the switch!" me up" and to find out if Baron Münch- the "show off" was a fizzle? Yes? If you With one bound I was out of bed and hausen was fiction or truth. Not that it have, you know exactly how it feels. was racing madly down to my Wireless sta- was the first time that this particular re- At 11.05 p. m. I began to wonder why tion barefooted. I gave one look at the porter had called in vain. For 1 have a it was so hot in the room. By 11.10 p. m. I lightning switch in the corner of the room deep- seated aversion against the Bugle, was taking a Turkish bath. By 1120 p. m. and almost collapsed: which aversion includes everyone from the I calculated that my private temperature The switch was grounded and had been editor down to the job press. Hence I must have gone up to somewhere near 269° grounded since noon of the previous day! wasn't "in" to reporters heeetofore. But Fahrenheit, rising steadily all the while. For you may know that the Fire Under- on this occasion the reporter, who is a live By 11.30 p. m. I wasn't sure whether I writers nowadays require wireless stations one, succeeded in running the blockade. He preferred calling an ambulance or jumping to have lightning switches in order to pro- "made up" as a water meter inspector, and into the ice covered pond in front of the tect the building from lightning. Thus as both the water meter, as well as my house. when your station is not in use you simply wireless station, are located in the basement Münchhausen simply didn't "call." What connect the aerial to the ground by throw- of the house, he had but little trouble in was wrong? Why had he failed me for ing the switch, and no damage can be done "torpedoing" me. Once established in a the very first time, just when I could least by a thunderbolt. Not only that, but in this chair there was nothing to do but to sub- afford it? For the first time since I knew condition the aerial becomes really a first mit to his tortures. him I felt bitter toward him. What had class lightning arrester. Of course, he did not believe that there happened? Sad to relate, however, certain idiots are was such a thing as Münchhausen, who And there was Snickles with a sarcastic apt to forget to throw the switch over when was supposed to live on Mars just now and grin spread all over his 'bird-like face, mak- trying to receive messages, I being among who was supposed to send nightly wireless ing biting remarks all of the time. them that evening. For when the reporter messages to earth, which are relayed to me "Maybe the ether gave out, what ?" he called so unexpectedly I forgot all about from the moon by an alleged relaying plant mocked. Or: "Maybe Münchhausen has a the switch and never bothered to look located there. Martian frog in his throat and can't talk !" around to see in what position it was. However, the reporter was willing to ob- Or else: "Isn't it possible that the mes- Münchhausen had called, of course, of tain first hand evidence for his paper, and sage became lost in transit? In that case I this I was certain. The message, however, if I did not object very much he Mould would suggest that you put an ad in the had flown from the aerial directly to the stay till 11 p. m. in order to "listen in." Bugle's Lost and Found co ground, never entering my receiving instru- To strengthen the argument he pulled out That was the last straw. He didn't ments Lost and lost forever! And my some two for 50c. Perfecto's (reduced to finish the sentence and he didn't wait to thoughtlessness had made me the laughing 40e. Saturdays only at Frank Levoy's cigar take his hat either. He went out like a stock of the town on top of it! It was store on Main street). As my Nargileh blue streak, with me at his heels. But maddening. Right then and there for the wasn't working for lack of proper ammuni- reporters, among other accomplishments, next ten minutes I had what my little sister tion that evening, the argument proved must be good runners. He is. At any rate, very appropriately terms as a series of convincing and I bade the reporter, whose I did not catch him. Disgusted and in a rather violent "conniption fits!" name was Bill Snickles, to make himself white rage, I went to bed. * * * * * * at home. I explained to him all the good My ruffled feelings were not particularly That evening promptly, as always, points and qualities of Münchhausen "called," my wireless, and after He did not waste much the second Perfecto I time in preliminaries, but was willing to let him ANY of our astronomers have noted from time to time that went right to the point: photograph the station. immense sandstorms frequently sweep over the face of the "Alger, my dear boy, He called up the- office I can't begin to tell you for the staff photogra- Planet Mars. As such storms seem to cover vast areas it would how wonderful this pher, and after the flash- appear that the sand must of necessity be rather light to float in the thin planet Mars is with all light had been taken it i t s marvelous inhabi- became time to adjust Martian atmosphere. For this reason, it is reasonable to suppose that the tants. Flitternix and my- t h e instruments. I n self are as in a trance another three minutes sand is extremely fine -dust in other words. But how can intelligent half of the time. Our Münchhausen would be beings live permanently in an atmosphere loaded with fine dust? This brains simply cannot di- calling. I had placed an gest all the thousands of extra set of 'phones on instalment advances a new idea how the Martians may make life bearable wonders we see around Snickles' head and I on their desert planet. us every minute. For a could see that he was poor untrained human breathing hard with sup mind 'to be suddenly pressed excitement. I transplanted into a civi- had keyed him up to such a pitch smoothed next morning when my young lization hundreds of thousands of years that when my chime began striking the brother brought me a copy of the Bugle ahead of terrestrial civilization is no easy first stroke of eleven he jumped clear while I was still in bed. matter. At times we are positively numb out of his chair. But I smiled a very Snickles had certainly outdone himself. with astonishment and the more we see and superior benevolent smile at him, as a The whole town would choke with merri- learn the less we feel we know. Every new ' father .,. tiles at his uncomprehending babe. mnit when they would read the account, marvel opens up a dozen new unfathomable I then leaned back comfortably, toyed a there was no doubt about that. The head- avenues, each one equally puzzling. bit with the Harmonic Ultra- Amplifier, ad- lines were enough: "But to proceed. Yesterday I explained Copyright, 1916, by H. Gernsback. Ail rights reserved. www.americanradiohistory.com rMarch, I916 THE ELECTRICAL EXPERIMENTER 625

to you how we had our first Martian meal earth and Mars will have frozen down to what we saw. But Flitternix, his mind full at our host's residence and how we ex- the bottom. The vegetable kingdom will of astronomical observations, called my at- perienced that gaseous food that you don't have ceased long before that and the tention to the heavens and I followed his need to chew, is vastly more nourishing animal kingdom, dependent upon the vege- command reluctantly.

"It was found that the ordinary desert dust did not usually rise higher than goo feet above the surface of the planet. For this reason all buildings and structures on Mars, with few exc tions, are located goo feet above the ,round. . . and satisfying than solid food. It does table kingdom, will die even a more rapid "'You will observe,' said he. pointing at not overload the stomach as do solids and death. In less than two years the last the sun, 'that it appears quite a bit smaller the digestion is vastly improved. The gases surviving human on any of our planets than when seen from the earth. It also liquify, of course, in the stomach, but the will have ceased living. There can be no does not appear ellow- white, as it looks latter itself never becomes distended. Be- organized life as we know it without the to terrestrial inhabitants. You will note it sides, the Martians, trained rigidly from direct influence of a live sun. has a rather reddish hue; that is because earliest childhood, know just how much "While the Martians are by no means we are now a good bit further away from gaseous food they can assimilate. This, I sun worshippers, they nevertheless have a it, a matter of over 60,000,000 miles fur- understand, is one of the reasons why the deep- rooted feeling for our luminary. This ther than on earth. In other words, we average Martians live over 150 Martian is strikingly illustrated by the fact that the are now twice as far away from the sun as years, which is 300 terrestrial years. Planet Ruler's mansion is constructed in we are on earth. But you must have ob- "After dinner we were conducted to the such a manner that powerful machinery reserved how warm it is everywhere on Mars, roof of our host's mansion, where we made volves the entire structure silently during as far as we have visited it, and that the ourselves comfortable in the large trans- the entire Martian day; the first rays of day appears fully as bright, if not brighter, parent chairs scattered around beneath a the morning sun thus shine into the Ruler's than on earth. Naturally you will wonder, cool, green, silky- appearing canopy. As private rooms, and as the sun keeps on for on Mars, as well as anywhere else in I mentioned to you previously, the Planet rising the house keeps pace and thus the the world, certain physical laws hold good. Ruler's mansion resembles somewhat a entire day till the last sun ray creeps over Thus heat and light diminish inversely as colossal cathedral. The roof is about 250 the western horizon, the Ruler's windows the square of their distance, in other words. feet from the ground and the entire struc- are bathed in sunlight. During the night a 16 candlepower lamp two feet away gives ture rotates slowly around on its axis. This the house does not revolve. only one-quarter the light (four candle- is the reason: While the Martians are en- "The day we were on top of the Ruler's power) of the same lamp if seen at one lightened enough to have no religion what- mansion was still ur first nay on Mars. foot away. Heat acts in exactly the same soever, they know what we have known It was then in the early afternoon, after manner. Then why is it that the day is as for some time, namely, that life on all lunch time, as mentioned before. bright, and the heat as great as on earth, planets is absolutely dependent upon the "Down below we looked upon the 'city,' although we are twice as far removed? sun. Extinguish the sun to -day and all the which seemed to be laid out in form of a According to the physical law just men- planets throughout our planetary system vast semi -circle, as far as we could ascer- tioned Mars should only receive four - from Mercury down to Ncptune will be- tain. To the west we could just glimpse ninths of the light and heat from the sun come dead worlds. Without sunlight the one of the water ways. as does the earth. Why does it receive rivers will cease flowing within three "We stepped to the balustrade and more? Early astronomers on earth rea- weeks. Within six months all waters on peered down, completely stupefied with (Continued on page 658.)

www.americanradiohistory.com 626 THE ELECTRICAL EXPERIMENTER March, 1916 9ffe RADIO LEAGUE HONORARY MEMBERS CAPT. W HG. BULLARD. U S.N. NIKOLA TESLA, 9/AMERICA PROF. REGINALD FESSENDEN. DR.LEE DE FOREST.

Manager, Il. Gernsback How to Organize and Conduct a Radio Club WITH the advent of The Radio as aforementioned, is the rules of order to letter of the proper sort, addressed tt League of America, the details of he followed in forming the organization. such men. will invariably result in thee which organization were given in It may he said that many small clubs do acceptance of your proposition. It will bt full in the December, 1915. issue of The not go in for the deeper legal rules usually readily seen that a greater impetus will be Electrical Experimenter, there has beet. governing such bodies. The appointment given the club if such speakers are engaged opened up a wider and more promising field of an inspector or engineer as one of the at least for the first few meetings. A case than ever before for the formation of officers, together with the president, vice - in point is the Radio Club of America, with subsidiary or local radio clubs throughout president, secretary and treasurer (the two headquarters at New York City. This or- the country. Given the proper spark of latter officers are very often combined) ganization has been coming to the front enthusiasm, there is no city or hamlet too suffice for all practical requirements. very rapidly in the past two years. Many small in the whole United States but what It is a very good idea to select a capable of the speakers at the monthly meetings are it could support one or more such radio member to act as consulting engineer. and some of the leading instructors and en- clubs. whose duties shall cover the visits to each gineers in the wireless profession; men Possibly you, as a radio enthusiast. even member's station for the purpose of check- who also address meetings of the Institute though you may not have a very elaborate ing up his wave length. deficiencies in oper- of Radio Engineers, which body is, of wireless station (either for receiving or ation of the apparatus, etc. course, the foremost scientific radio organ- transmitting. it matters not), have often Maintaining Interest in the Club. ization in the world, counting among its thought it would he a fine idea if you Once the radio club has been formed, it members the leading wireless engineers and could band together several other similarly is not always an easy matter to maintain scientists of all countries. The office of interested I ersons either from an experi- the interest in same by the members. A the secretary of the Institute is at 233 mental, scientific or amateur standpoint. good leader in any event will help to over- Broadway, New York City. The monthly Preliminaries. come this trouble to a large extent, but of meetings are held on the first Monday of To start a radio club or society there are course he must be aided in every way by each month in Fayerweather Hall, Colum- several methods which may be employed to the other officers of the club. One of the bia University, New York City, at 8 p. m. aid the formation of such. One of the first important things to be done when start- This Institute publishes its proceedings, first things that can be done is to. write a ing a new organization is to select for the containing the more important articles pre- letter to the manager of the Radio League first few meetings, at least, some particu- sented at the various monthly meetings, of America stating briefly your intentions larly good wireless or allied papers. They four times a year; that is to say, the pro- and desires, at the same time asking for the advisedly should not be of too technical a ceedings come out quarterly and form a names and addresses of any other radio nature, as it may discourage some of the most valuable addition to any radio opera- amateurs in your particular locality. Upon younger members or others who are not so tor's or engineer's library. The dues for receipt of this infor- an associate member- mation you can then ship are $4 a year, either visit the experi- and so far the Insti- menters personally or tute has managed to a very good scheme publish its proceed- is to write each a ings and defray its letter, explaining your other incidental ex- ideas and suggesting penses with but little a date for a meeting extra financial aid at which the matters from a few of the pertaining to the for- members. mation of a local It is not intended radio club can be to dwell upon the talked over. features of such an In some cases extensive body as that such organizations now under discussion, are formed and many but it may be said details of the work that while the inter- are finished via wire- est among the mem- less, as, for instance, bers has flagged at when the "organizer" different times, nota- has a radio trans- bly several years ago mitting and receiving owing to the great. station so that he may shake -up in the busi- call up other ama- ness affairs of sev- teurs by iting their eral commercial wire- call numbers in the less companies, etc., regular Wireless Call it should be said that books. Still another those managing the scheme which can be affairs of this organi- followed out in many zation have always such cases. and also kept in mind the at an insignificant point previously men- cost, is to insert an tioned, i. e., that it is advertisement in your The Very Fine Radio Equipment of the Minnesota Wireless Association, Minneapolis, Minn. best to obtain the local news2aper, stat- Insert Photo Is That of Miss Mine Mengelkoch, a Radio Enthusiast, Who Often services of the very ing that the adver- Operates the Set Here Shown. best speakers and lec- tiser woul like very much to have all far advanced in the science. A good sug- turers in this line whenever possible. those interested in experimental wireless gestion in this direction is, whenever pos- The small radio clubs just forming, telegraphy call at his residence on an sible. try to obtain the services of an in- however, need not feel discouraged if they appointed evening for the purposes set structor in radio operating and engineer- cannot obtain a speaker of prominence or forth. ing from a local school or college, who in great learning to address them, as in many One of the first things that has to be con- most instances will be only too glad to instances there are one or more energetic sidered after a response has been had to make a short address at any time, before and capable radio men among their own such an advertisement or other campaign such an organization. members who will probably in many cases

www.americanradiohistory.com March, 1916 THE ELECTRICAL EXPERIMENTER 627

prove better as leaders for such bodies of erator appointed, and also when occasion is widely read on the subject of radio tel- youthful experimenters than a more mature demands it, someone who shall be responsi- egraphy. individual of more advanced and profes- ble for the proper maintenance of the This is a good matter to keep in mind in sional inclinations. wireless set. club affairs. Do not forget your sister or Club Dues. It is best to choose a fairly good wireless girl friend who may have scientific inclina- Speaking of club dues, this is an impor- transmitting and receiving set, which can, tions. Get her to join the club, as there is tant point. As many of these societies meet of course, be had at all prices imaginable, a wide field open, indeed, for wireless ex- at the members' houses, there is then no say from $10 up, and even for a lesser perts, and the excellent work of Miss Men- rent to be considered. The smaller clubs, amount when the club is a small one. gelkoch before cited, as well as that of of course, can run several other women along quite nicely operators, proves that with but a small bud- she can engage in this get or expense, ex- field as successfully cept that necessary as in any otl,er. for buying stationery, While on the subject having cards or liter- of amateur wireless ature printed, etc. clubs that are doing For the younger big things, we would clubs, composed of call attention to our members between the illustration which rep- ages of P. and 15, resents the excellent the dues should not wireless exhibit con- reach much above 25 ducted by the Atlanta cents a month. But Radio Club, of At- with clubs made up of lanta, Ga. The ad- older members than dress of the vice - those just mentioned president of this club, and having club quar- R. A. DeVore, is 19 ters for which rent Second avenue, Oak- must be paid there hurst, Atlanta, Ga. It will, of course, have is really wonderful to be a higher month- to contemplate the ly due levied. Most achievements of this of the larger organi- organization, which zations have an en- was started but little trance or initiation fee over a year ago. It of perhaps $1, but has received many this, of course, will congratulations on the have to be considered exhibit which it ar- and worked out by ranged and which the officers in charge formed a part of of the affairs of the Excellent Wireless Ex hibit of the Atlanta Radio Club, of Atlanta. Ca., an Example of What the recent Electrical club. This factor will a "Live" Organization Can Accomplish. Show held in Atlanta. vary in the different localities and with the In this direction we would like to call The exhibit attracted great attention. One different classes of members. the reader's attention to the excellent of the most interesting features, perhaps, photographs reproduced here and in other was an exact replica of the first Marconi Investing in the Club. forthcoming issues of The Electrical Ex- wireless set, complete with induction coil While it is not desirable in any event to perimenter showing what can be accom- and coherer. Near this was a complete work hardships upon the members of the plished by a good, "live" amateur wireless sending and receiving set of modern type, radio clubs, it should be borne in mind by organization. owned by member of the club, with which the officers of such that the organizations In the first illustration we wish to men- bona fide radio messages were received and enjoying the greatest popularity are those tion the excellent wireless set owned by transmitted. The visitors to the show were in which the members are very vitally and the Minnesota Wireless Association. of given popular lectures by members of the personally interested. This comes to the point Minneapolis, Minn. Particularly in this society on the theory and practice of wire- of having each member invest in the club. connection we wish to call attention to the less telegraphy. and, together with prac- which may be brought about by bringing the excellent work accomplished on this outfit tical demonstrations, they were made to propositions before the organization at one by Miss Aline Yengelkoch, whose picture appreciate the rapid strides made in radio of the regular meetings. A great many of is observed in the upper right corner of work the past few years. the societies to -day have excellent wireless the illustration of the station. Miss Men - The Electrical Show was held on the sets maintained at the club quarters and. gelkoch is very enthusiastic about wireless ground floor of a large office building, upon of course, in this instance the rooms are telegraphy and is said to be the youngest the roof of which was erected an aerial, invariably open every day, or at least every commercial woman operator in the United the height of which was nearly 200 feet evening, so that those members who so = States, she having just received a first -class and the total length 400 feet. sire may come to the rooms for prac' Government radio operator's license. She Another point of interest was a table 5 or training in the handling of tilt. rac1.o can transmit and receive messages at the by 15 feet, completely covered with send - apparatus. There should be a chief op- rate of 35 words per minute and, moreover, (Continued on page 664.) REVISED LIST OF AMATEUR RADIO CLUBS Akron Radio Club. 760 Damon place, Akron. O. East Night High School Radio Society. Wood- ward T. Dickey, 1649 Amsterdam avenue. New Secretary, A. A. Crum, Radio department, G. T. ward High School. Secretary, C. El. Fender, York City. & R. Co., Akron, O. Woodward High School, Cincinnati, O. Technical Wireless Association, Washington, D. Amateur -Scientists, Public School 66, room 256. Fall River Radio Association, Technical High. C. Secretary, Edwin D. Powell, 908 Kennedy Secretary, Harry Fienberg, 124 Amboy street, School. Fall River, Mass. Secretary, Lawrence street, N. W., Washington, D. C. Brooklyn, N. Y. Phelan 6 Rodman street. Fall River, Mass. Wireless Association of Central Pennsylvania. Hawkeye Radio Association, Secretary, A. B. Harrisburg, Pa Secretary. D, H. Zorger, 406 Amateur Marconi Radio Association, 619 Fifth Church, Lamoni, Ia. Kelker street, Harrisburg, Pa. avenue, Troy, N. Y. Secretary, D. Malcolm Will- Inter -City Radio Association of Allentown, Pa.. Yorkville Radio Development Association. 73 iams, 1627 Seventh avenue, Troy, N. Y. Y. M. C. A. building. Secretary, William J. East End avenue, New York City. Secretary. Bradentown Radio Club, Stockbridge avenue, Kreis. Joseph L Cermak, 73 East End avenue, New Yore Bradentown, Fla. Secretary, Hughson Hurlebaus, Junior Radio Club, Gregory street, Pensacola, York City. 439 Main street, Bradentown, Fla. Fla. Secretary, Oliver Williams, Pensacola, Fla. Notice: To ensure proper entry of club Carrollton Radio Intercommunication Club, Philadelphia Radio Association, 4810 German- registrations in our revised monthly list be Fifth Street Puhlic School. Secretary, Stuart W. town avenue, Philadelphia, Pa. Secretary, G. S. sure to send us at once the data outlined be- Pierson, 219 Maple avenue, Carrollton, Ill, Ballantine, 4810 Germantown avenue, Philadel- low. Such information should reach us not later 28th of Chicago Wireless Association, room 1010 Lake phia, Pa. than the the month for entry in Radio Club of the Polytechnic Institute of the succeeding Issue of THE ELECTRICAL. View building, 116 South Michigan avenue, Chi- EXPERIMENTER. cago. Secretary, Frederick D. Northland. 24 Scott Brooklyn, 85 Livingston street. Brooklyn, N. Y. street, Secretary, R. G. Wehle, 85 Livingston street, Name of Club Chicago, Ill. Location (street and city) Brooklyn, N. Y. Founded Colorado Wireless Association, 600 Y. M. C. A. Radio Club of Union College, Union College. building, Denver, Col. Secretary, L. P. I-tough, No. of Members Schenectady. N. Y. Secretary, Edwin A. Schah - 600 Y. M. C, A. building, Denver, Colo. Meeting Date behar, 242 Union street, Schenectady, N. Y. Power of Club Set, if any Cranford Radio Club. Cranford. N. J. Secre. Rockaway Radio Club, 296 Washington avenue. Call Letter (licensed') tary, Russell Damon, Arlington road and Madi. Rockaway each, N. Y. Secretary, L. Wagerer. Dues and Initiation Fee son avenue, Cranford, N. J The Talo Club. New York City. Secretary, El- Secreary'. Name and Address

www.americanradiohistory.com 628 THE ELECTRICAL EXPERIMENTER March, 1916 T New 500 Watt Military Radio Pack Set THE wireless sets used for military The condenser bank for this 500 -cycle day to devise the apparatus shown here- purposes, and particularly those now transmitting set is composed of six con- with. in use by the United States army, denser units of practically .002 micro -farad The old type of inductive coupler was consist of the very best instruments that each. The resulting capacity of the whole adjusted in steps, which did not give very can be purchased. These sets must work bank, after the condensers are connected in close tuning, and the presence of large under every possible condition. The ac- series -parallel, is .013 micro -farad. amounts of unused wire created the buga- companying illustration shows one of these The step -up transformer, of the reso- boo of all previous tuning apparatus, name- nance type, is of the open -core ly, "dead -end" effects, which absorb con- pattern ai.d is mounted within siderable energy and destroy the efficiency the case, 'ack of the micarta of the apparatus. To offset the above de- panel containing the measuring fects it was the general practise to use instruments, etc. Silk -enameled variable condensers to secure accurate tun- magnet wire is used in winding, and many complicated switches were ing the secondary of same, devised to prevent the dead -ends. The which is of the dry form, not coupler illustrated herewith does not re- requiring any oil for its insu- quire any taps or variable condensers, all lation. Various transmitting the wire on same being in use at all times. wave lengths may be quickly A brief resume of the principle of this in- arranged for by means of cali- strument will not be out of place. brated inductance control han- The primary consists of two coils, one dles and scales mounted on permanently fixed in the box, shown in the the front of the upright panel illustration, and the movable one shown at of the set. A regular Morse the left. These two coils are wound to key is perceived at the right have an equal amount of inductance, but of the cabinet in opposite directions, so that when the The receiving set is very movable coil is slid entirely into the fixed compact and may be observed coil the sum of their inductances will be resting on the drop front of zero, because they oppose and counteract the transmitter cabinet, at the each other. left of the illustration. The The same principle is used in the con- head 'phones are the well - struction of the secondary, which consists known adjustable -magnet type of two coils shown protruding from the supplied to the United States end of the box to the right. These coils army and navy, and in which also have the same amount of inductance, the distance between the pole - and they also counterbalance each other pieces and the diaphragm may when the inner coil is entirely within the be varied as required for dif- outer coil. It will be apparent that when Extremely Compact Soo Watt Military Radio Set. ferent strengths of signals by withdrawing the inner coil the exact balance means of an adjusting screw at of the two inductances is upset and the extra sturdy pack outfits, which at the the back of the receiver case. The receiving circuit will possess an inductance depending same time combines extra high efficiency set is a beautiful piece of apparatus, which upon the relation of the two coils. By this in both the transmitting and receiving includes a Pyron detector. The primary coil simple means it is possible to adjust the ranges attained, as well as in small space of the loose coupler is wound with 170 turns active inductance in either circuit, thus occupied. of No. 22 enameled copper wire These sets are of the portable style, divided up into two sections, one equipped with generators of the 500 -cycle of 10 turns and one of 150 turns. alternating current type fitted in a separate These are suitably connected up case, so that it is thoroughly portable and to switches, so that any combina- may be carried on separate trucks. The tion of turns, from one to maxi- cases are unique in construction, consisting mum, may be obtained rapidly: of a substantial wooden frame or base, so The whole receiving set is in- to speak, which is covered both on the installed in an oak cabinet with side and outside with a 1 -16 inch layer of hard rubber top and end, upon gray sheet fiber. This is glued to the wood which the switch points are under hydraulic pressure. The cabinets are mounted. It also contains a se- protected by hard fiber angle strips riveted ries condenser for short wave on and further protected froi.i damage by lengths, but which unit is nor- iron bumpers at the corners. mally short- circuited by a special The apparatus, such as voltmeters, am- switch. The secondary is also meters and hot wire meter, as well as trans- adjustable as to the inductance, mitting inductance control handles, etc., are and as it slides out of the primary all mounted on the micarta panel. The cabinet its graduated tubular quenched spark gap of special design, per- covering indicates the percent- ceived at the base of the panel, is cooled age of coupling. Photo courtesy by a small electric fan placed behind it. so Wireless Specialty Apparatus Co. New Loose Coupler, Adjusted Without Sliders or Switches as to blow a draft of air directly over the gap. The gap plates rest in micarta guides. A NOVEL RADIO INDUCTIVE doing away with all taps or sliders. TUNER. The secondary coils may be moved inside Their sparking surface. which is at the cen- the ter, is of pure silver. This surface meas- Since the introduction of the loose coup- of the primary coils, so that by varying sets it ures 3 -64 of an inch in thickness, with a ler there have been few, if any, radical inductance relation between the two diameter somewhat larger than that of the changes in the design of same. The change is possible to vary the coupling. metal plates supporting them and on which from sliders to tapped coils was so slight The many advantages of this apparatus they are soldered. The silver is then spun as to make very little improvement, so it will now be readily understood, for it gives over and riveted down. remained for a radio engineer of a later (Continued on page 667.)

www.americanradiohistory.com 629 March, 1916 THE ELECTRICAL EXPERIMENTER

NEW ELECTROLYTIC INTERRUP- AN UNDAMPED WAVER. can be changed by means of the jack and A great deal of speculation has been plug system ; the jacks being located on the TER ELECTRODE. seen All improved form of positive electrode made during the past two years by the ma- front of the board, as can be clearly interrupters has jority of amateurs in regard to the recep- in the illustration. or anode for electrolytic shown been perfected by a well -known New York tion of undamped waves emitted by the With the loose coupler herewith experimental supply house. The tube is powerful radio stations about the globe; in connection with the variable condensers, shown in the illustration herewith. It con- practically all the long distance transmis- sists primarily of a specially designed por- sion records have been accomplished only celain tube, which earries a thread at its by the use of undamped waves. upper end, intended to screw into a porce- The ordinary radio receiver is deaf, so to lain cover. A metal rod made of a special speak, to the undamped waves, so other ap- alloy passes down through the interior of paratus had to be developed to receive the tube, and the point of same protrudes them. Although various detector devices through a small orifice slightly larger than have been invented for this purpose, none the rod at the base of the tube proper, as have proved superior to the oscillating perceived. The metal wire point rests on audion detector. This produces "beats" a porcelain bridge, as illustration portrays, which are created by the use of properly so that excessive current will not be drawn. designed inductances and condensers linked Any electrolyte which may find its way up to the audion circuit. into the interior of the tube by working in One of the latest receivers for undamped around the metal rod will be ejected waves which employs the audion as a gen- through three small perforations in the wall erator of "beats" is herewith illustrated. A of the tube just above the porcelain skirt large loose coupler is seen resting on top of formed on the tube about two- thirds of the the cabinet. The case contains four vari- way up, as perceived. able condensers which are provided with It is claimed that this marks a great ad- long insulating handles, the pointers of vance in the design of such devices and which move across the dials on the face of New Loose Coupler and Variable Condenser actual laboratory tests have demonstrated the instrument, as perceived in the illustra- Cabinet Known as an "Undamped Waver,' coils, X tion. of these handles is to and Intended Especially for Receiving Con that for operating wireless -ray The purpose tinuous Wave Signals. coils and open core transformers up to one prevent capacity effects due to the opera- kilowatt capacity there is nothing superior tor's body. The cabinet also contains the wave lengths up to 15.000 meters can be to it. It will work on either A. C. or D. C. necessary inductances, the values of which readily obtained. circuits at 110 or 220 volts potential and on any frequency. The key may be held down for periods of one -half hour or more OVER -ALL EFFICIENCY IN RADIO waves. Claims have been made for much and the interrupter will work regularly and TRANSMITTING STATIONS. higher efficiency in such apparatus, partie- without undue overheating. An interesting Several very vital figures are given in ularly for quenched spark sets when this Dr. 75 point is found in the fact that the lower J. A. Fleming's new treatise, entitled value has been mentioned as reaching end of the rod during operation wears "The Wireless Telegraphist's Pocket Book." per cent., but these claims have not been away to a perfect sharp point. The rod We reproduce herewith an interesting substantiated. This acknowledged authori- which is consumed slowly in operation is chart as there given, covering the various ty points out that it is probably correct to fed down automatically by gravity. It of- losses in the apparatus constituting a typi- say that the properly designed quenched fers a practical solution of the power trans- cal transmitting set of the spark gap type. spark transmitter's efficiency may reach a forming problem constantly confronting the It is pointed out in the treatment of this figure of 50 per cent. wireless and electrical experimenter, espe- subject to Dr. Fleming that, while these He believes that it will not be far wrong i.1 a fairly good, modern i cially where he desires to utilize the com- values as here reiterated are of consider- to consider that mercial power circuits to operate his spark EFFICIENCY CHART FOR U. C. L. RADIOTELEGRAPHIC EXPiRIMENTAL PLANT, WITH 5 mm. SPARK GAP (From tests by Dr. J. A. Fleming, at University College, London.) Rotary input, 2620 watts

Rotary output, Rotary losses Rotary efficiency= 1481 watts 1139 watts 57%

Transmission losses, Transformer input, Choking coil losses, Choker efficiency 71 watts 800 watts 610 watts 57:

Delivered to con- Transformer resistance Transformer iron ransformer effici- denser, 445 watts losses, 302 watts losses, 53 watts ency =56%

Primary oscillation circuit Delivered to antenna, Oscillation generator losses, 351 watts 94 watts efficency=21%

Antenna resistance losses, Radiation. Antenna efficiency= 16 watts 78 watts 83% Efficiency from transformer intake to radiation =10%

able value as an over -all consideration. type spark transmitter, with queiched spark in respect to the over -all efficiency of mod- gap or gap equipped with an air blast, ern transmitting sets, utilizing quenched the power radiated from the antenna can spark gaps, etc., it may be a great deal be as much as 20 or 25 per cent. of that higher. In comparing the power radiated, given to the exciting transformer, but it is viz., 78 watts, with the power given to the not usual to find such high values as these. Interrupter mproced Electrolytic step -up transformer, i. e., 800 watts, it is In order to realize such radio transmitter Electrode Recently Brought Out. be The Metal Rod Cannot Drop seen that for this particular transmitter the efficiency, however, great attention must Through the Tube, Owing to a Por- over -all efficiency is but 10 per cent., ap- paid to the construction details of the con- celain "Bridge" Formed as Shown. proximately. In the case of a well -designed densers and also to those of the primary spark transmitter the over -all efficiency oscillation circuit and of the spark gap, as he desires to might be raised to from 20 to 25 per cent.; well as to the earth connection proper and coils and the like, and where in order utilize direct current on an open core trans- that is to say, that almost one -quarter of to the construction of the antenna, not adapted the power given to the step -up or exciting to avoid undue resistance losses in these former. Such interrupters are station. for operation with closed core transformers. transformer would be radiated as electric most vital parts of such a u www.americanradiohistory.com 630 THE ELECTRICAL EXPERIMENTER March, 1916 The Evolution of Wireless Telegraphy THE evolution of signaling without mitted without wires in this way. In one located at Wellfleet, Mass. This method of wires has been an interesting one. case, it is said, that such a message was signaling without wires has entirely tran- Since the earli,est.dawn of reason man transmitted in a few hours' time from scended the dreams of wireless teleg- has found it absohitely necessary to transmit Moscow to Paris. Of course, this distance raphy entertained vaguely by the great important intelligence through space. Par- was not negotiated by one semaphore only, scientists and engineers of even two dec- ticularly in case of war between the vari- but the message was relayed from signal ades ago. Wireless telegraphy in a practical ous tribes quick intercommunication was station to signal station, much in the same sense and for commercial requirements has desirable. As the fleetest runner, as well way as wireless messages are relayed now only been a reality since the year 1900, as the speediest rider, were soon found from ship to ship or from one ship to an- but to -day it has been developed to such wanting, methods were naturally sought to other and thence to shore, etc. an extent, involving the use of very high outdistance both. In the illustrations here It is quite surprising how well sounds powered stations, that wireless messages observed we have endeavored to show the are carried through the earth itself, espe- may readily be propagated over such dis- principal modes of signaling without wires cially in rocky soil. Signals were trans- tances as 5,000 miles. This is mentioned utilized in the various stages of the world's mitted in this way at quite an early date. to show what has been really accomplished, history. At Fig. 5 the Indians are seen making use but this is freak work. Generally speak- Perhaps one of the first mentions is made of this method of intercommunication. The ing, common ranges for moderate long dis- in the Bible, when the Israelites were led scout, for instance, tapped a rock. partially tance radio telegraphy is 2,500 to 3,000 out of Egypt and through the wilderness buried in the ground, with another stone. miles. There are a few stations working by a cloud of smoke by day and a pillar At a surprisingly long distance away this over such distances as 4,000 miles. Mar- of fire by night. Possibly one of the first sound could be heard by the Indians, whose velous indeed has been the onward and methods of signaling across an appreciable hearing was extremely sensitive, by placing triumphant march of science in the realm distance of a few miles was that involving the ear to the rocky ground. Times with- of intelligence transmission. Where and the use of fires kindled on the hilltops or out number the approach of men on horse- when will these wonders of science stop? other promontories as depicted in Fig. 1. back was heard in this way by the Indians, In this way it was quite possible to com- so that it was often very difficult for the VIA municate intelligence accurately, although United States troopers to conduct any- "SAYVILLE" TO BERLIN. not very rapidly, to be sure. This scheme thing like regular warfare, as the savages The Telefunken station at Sayville, L. I., was first used in very ancient times. would hear them coming several miles away is one of the most powerful in the world, The method of signaling shown at Fig. 3 and thus be able to circumnavigate them, or flashing messages nearly 4,000 miles direct is that employed at quite an early date. but girt to some little known hiding place. to Nauen, near Berlin. notably by the North American Indians. A mode of signaling known to most of Located near the ocean and dropped in a This consisted in building a fire on a hill us. but one which dates back to the days mosquito -infested field, the great Tele- or mountain whenever possible, so that a of the first locomotive, is that making use funken station sprawls over 100 acres. A column of smoke or a series of smoke of several distinct blasts of the steam mile away it looks like a huge spider web, puffs, could he sent up, and in this way whistle as portrayed in Fig. 6. Engineers with all its slim poles reaching into the communication was established between to -day use this scheme for calling train air, interlaced with slender wires. At the tribes. It was this method that was often crews and also for communication with gate a watchman is on guard, and all along utilized by the Indians when making war other trains. One, two and three blasts of the way to the building are posted danger on the white settlers in America. The the whistle have different meanings as- signs. fire was made to smoulder by the use of signed to them, etc. Locomotive whistles The little low building is rigged on every wet sticks or leaves. The Indians were are often used for a signal of distress when side with towering poles-antennae as they quite proficient in making fires producing a the engine happens to be located near a are called. Five hundred feet high they prodigious amount of smoke, which could large fire or when a wreck has occurred. stand -almost as tall as the Washington be seen for various distances, depending. In the latter case the whistle is usually monument. From these wires radiate the of course, upon the height of the hill upon tied down, so as to blow steadily until help electric waves that leap across space to which the fire was built, but a range of comes, but at other times it is intermit - Germany. Great blocks of cement, big as ten to fifteen miles was undoubtedly com- :ently tooted. corncribs, are set in the ground and to mon in those days with this method of Signaling wirelessly by means of a re- them are anchored the guywires. wireless communication. flected ray of sunlight, is illustrated at Fig. Inside the low, one -story building, squat- Fig. 3 illustrates a little known yet very 7. This method makes use of an instru- ting at the foot of the towers, are 18 men effective method of transmitting intelli- ment known as the Heliograph. It has working. Fourteen of these are censors gence, which is attributed to certain tribes been adopted by practically all army signal for the United States as may utilized Government, for of Indians in South America : it has been corps. This arrangement be several months the navy has been in control described by returning explorers at dif- without the aid of sunlight, wherever a of the Sayville station. Every message ferent times. It may be expressed briefly sufficiently strong source of illumination is must be sent through them and received as "drum beating," but the drum is no or- available, such as that produced l acety- through them. The Telefunken light. of the army employes dinary one. It consists of a hollow log, lene or electric Some operate the plant, but all messages have to or a log made so by burning out the searchlights now built are provided with a to that fitted be submitted to the Government censors. interior. Over the end of sane is stretched shutter arrangement, similar The message is flashed across is very the heliograph, so long and short the Atlan- the hide of an animal, which pulled on that tic the rate 25 in The log is flashes of light may be sent out correspond- at of words a minute, but tightly and bound by thongs. case of necessity it can go up to 40. The then suspended, as perceived in the illustra- ing to the dots and dashes of the Morse Rapid signaling is messages go to a small town near 'Berlin tion, so as to exert the maximum resonat- telegraph code. thus ac- called Nauen, where they beats head of complished, as it is possible to manipulate are placed on a ing effect as the signaler the land wire and forwarded to the capital. of the drum with a stick provided with a the heliograph shutter as speedily as the The charge for in with a stick common telegraph key and sounder. A sending a message to Ger- wooden head, or some cases many is 53 cents a word having at its extremity a ball formed from probable range for such devices as this from anywhere near New York. The 3 is a piece of hide and loaded with a round may be put down as three to four miles or- cents the been credibly informed dinarily. but in most cases it is used for price of the land wire to get it to Sayville. stone. We have As as the key is that this method is in successful use at establishing communication between dif- soon touched in America present, messages being actually transmitted ferent signal squads or army posts at the message is in Germany, the time oc- relay stations) over a distance of shorter distances. Signaling by this cupied in crossing being only the fraction (using a In fact, 300 miles almost every day. method can, of course, be carried on over of second. the message could Wigwagging is still in use to a great ex- a considerable range, and the more power- go around the world seven times in a tent throughout the world, especially in the ful the searchlight or other source of il- second. army and navy, where it has proved in- lumination utilized the greater the range. Every message is censored before it goes valuable in many instances. This mode of We come now to the final method of sig- out. A Government officer sits there with signaling, which usually consists of wag- naling covered by this article on the evolu- a blue pencil and if he suspects the message ging a flag or semaphore arm in different tion of wireless telegraphy, which is in- has another meaning than what is on its positions, representing the various letters dicated at Fig. 8. As is well known, for face he returns it to the sender; or he of the alphabet, was employed at quite an this method of intercommunication there may paraphrase its meaning, saying the early date. The illustration at Fig. 4 shows is invariably utilized a large size antenna same thing in different words, which would the semaphore arm as made use of for or aerial, consisting of a number of wires of course upset the code message, if it con- sending such signals over great distances. supported by highly elevated masts. The tained one. In the wonderful campaign of Napoleon illustration herewith shows roughly the On an average 100 messages a day go carried out through France, Germany and appearance of the trans -Atlantic wireless out of Sayville for Berlin. Most of these Russia numerous messages were trans- telegraph station of the Marconi company (Continued on page 670.) www.americanradiohistory.com March, t9 io THE ELECTRICAL EXPERIMENTER 631

THEEVOLUTIOPWIRELESS TELEGRAPHY

For Explanatory Text, See Preceding Page. www.americanradiohistory.com 03= THE ELECTRICAL EXPERIMENTER March, 1916 The Reception of Long Damped and Undamped Waves* By Thomas Appleby ALTHOUGH it is not generally known the speed of the tikker wheel (Fig. 1). odyne effect. We set up oscillations in the there are at least three stations in Another form of tikker would consist of receiving circuit which are slightly different this section of the country (Philadel. a revolving commutator, such as is used on in number than those of the incoming wave. plia, Pa.) now using undamped waves for small motors, with two copper brushes bear- The result is "beats," and the nearer we transmission. Two of these stations gen- ing on the sections and arranged so that make our frequency to the incoming f re- the circuit is constantly made and broken a ë i2 %ng tuning co,? /round by the passing sections of the commutator ii//th N°- 24 irke (Fig. 2). The absence of . toise in this form s"-It of tikker makes it more desirable than the I. C. first. An buzzer may be 1 ordinary electric 2 shee/s provided with an extra set of contacts well fiatai/2114' insulated from the buzzer itself and used as a ticker (Fig. 3). All of these break up 6v/ the incoming signals into a lower or audible number of vibrations, which can be easily 1 heard in the receivers. It is not absolutely necessary to use a 48 crystal detector along with the tikker, bat Rheas. is advisable, as the signals come in much fig 6 louder. Figs. 1 and z. Two Forms of " Tikker" for Re- The circuits for use with Fig. 6. Oscillating Audion Circuits. ceiving Undamped Waves. the tikker and quency the lower we will make the tone of erate the undamped waves with the oscil- our "beats." If the incoming frequency is lating arc; while the third makes use of a 100,000 per second, and we generate 99,000 high frequency generator. oscillations per second in our receiving cir- In the ordinary spark station two fre- cuit; the difference between the two, or quencies are used, one being the radio fre- 1,000, would be the frequency or tone of the quency which determines the wave length beats (see Fig. 5). This would sound like and the other the audio frequency which is the whistle of 1,000 sparks per second, as produced by the rotary or quenched spark produced by the 500 -cycle quenched gap. gap, and this determines the pitch of the Oscillations may be set up in the receiv- spark as heard at the receiving station. ing circuit by means of a near -by oscillating In an undamped wave transmitting sta- arc, or by use of an oscillating audion as tion there should be no audio or spark fre- used in cir- which the ultraaudion or Armstrong quency, as the oscillations determine cuits (see Figs. 6 and the wave length are generated by a high 7). Fig. 4. Hook -Up for Poulsen "Tikker" in Tuckerton station (W.G.G.) makes use 50,000 cycles or Re- frequency generator of ceiving Circuit. of a 'sigh frequency alternator and some- more, or by an oscillating arc which is more detector are similar to the ordinary receiv- times the arc for generating undamped or less silent in operation. waves. Sayville now uses the oscillating When an undamped wave is tuned in at ing circuits. The tikker may be connected in various places in the detector circuit with arc and Arlington also uses the oscillating the receiving station and an ordinary crys- arc at times to work with NBA. tal detector used there should be no sound nearly equal results. It operates satisfac- radio fre- torily when in series with the detector, in Tuckerton can be heard on about 8,500 in the telephone receivers, as the meters wave length; Sayville is on about quency is entirely too .'fig! for the human /00.00 freg. 9,000, and Arlington on about 5,000 to 7,000 ear. There are exceptions, however, for we o meters, considering undamped waves. can plainly hear the Tuckerton station with between 7 use Tuckerton and Sayville work a crystal detector, even though they the p. m. and 2 to 3 a. m.; as a rule, they work high frequency generator; and not only do for about one hour each, Tuckerton shut- we hear the actual sending, but we can also ting down while Sayville is working, and hear the reversed sending caused by the .9.2000 fre9 vice versa. Arlington tr,.nsmits at times compensating wave, due to the manner in during the evening, and often during the which the key is shunted around a few day time. turns of the helix. However, the signals We have received all these stations on received in this manner are very faint, com- our 300 -foot, two wire aerial, in West Phil- pared to the great strength of the signals Beat or /000freq.. adelphia, although at present we only use when a tikker is used. half of this length, or 150 feet. The load- In order to lower the frequency of the ^ ing coil in series with an ordinary loose current set up by the undamped waves; or, coupler consists of a tube four inches in in other words, to produce an audible fre- diameter and 12 inches long, wound with quency, it is necessary to break up the in- v 5 © No. 24 B. & S. enameled wire. A 43 plate &ming current at the receiving station. variable condenser is shunted around both This may be accomplished in two ways: Fig. 5. Demonstrating How "Beats" Are Pro. the loading and loose coupler primary coil. FirstNby*the use of a tikker, which consists duced by Two Slightly Differing Oscillators a Common Circuit In the detector circuit we use a 48 plate In variable condenser across the secondary series with the 'phones, across the stopping sW condenser, across the variable condenser, or even shunted around the secondary coil. Phl The second method of lowering the un- Audion/ damped wave frequency is by means of the heterodyne effect, as discovered by Prof. itllikijlQ R. A. Fessenden. 441y,

ililHti''.il . When two piano strings are tuned to slightly different tones, a third tone, or fiiliioi °beat,' as it is called, will be heard. The piano tuner does not listen to the tone of 2sheetsTiriot the strings when tuning a piano, but listens 2',4- for the "beats," which occur when the two fig 3 strings are slightly out of tune. The nearer 7Rheos the two strings approach the same tone, the 0 Fig. 7. Second Form . of Oscillating Audios Fig. $. " Tikker" Made Out of Ordinary Buzzer. slower or lower the beats become. When the strings are considerably out of tune, the Circuit. in its simplest form of a rotating gear beats are very rapid and produce a high which is wound with No. 30 B. & S. silk - wheel with a spring held against the teeth; tone of their own. covered wire. We found, however, that the the pitch of the signal being determined by In much the same manner we produce 43 plate condenser was unnecessary in the Paper presented before the Wireless Association ' ibeats" in the receiving circuit. The pro- detector circuit and when removed the sig- of Pennsylvania, Sept. 24, 1915. duction of these "beats" is called the iieter- nals could be tuned in just as strong, pro- www.americanradiohistory.com March, 1916 THE ELECTRICAL EXPERIMENTER 63 vidcd tight coupling was used. Of course be properly insulated and grounded, yet A SIMPLE VARIABLE CONDENSE we do not receive efficiently with this ar- they overlook the benefits that may result SWITCH. rangement, as the aerial is not balanced for from a little time and energy spent in The following is the description of these waves, but simply oscillates, due to making the few changes suggested in there variable condenser switch which will worl short paragraphs. on either sending or receiving types. Thy First we will consider its length ; the shorter it is the higher the amperage that is induced in the secondary circuit, and, correspondingly, the longer it is- within a certain limit -the higher the voltage in the secondary circuit. Just why this is will be apparent by glancing at Fig. 1, which shows roughly diagrammatically the voltage and amperage characteristics in the open aerial circuit. We will consider a vertical aerial set into oscillation by an incoming wave. When this aerial is swinging in resonance with the incoming wave the induced voltage is greatest at the top and lowest at the bot- Unique Switching Scheme for Adjustable Con Ill tom denser. Fig. 8. Hook -Up for Reception of Undamped or ground connection. Hence, ac- Waves with "Tikker," Including Load- cording to Ohm's law, the reverse is true plates are arranged as shown in the dia f ing Coil Cut -Out Switch. of the current, which is lowest at the top gram and are connected four two -point of the aerial and maximum to forced oscillations, and sets the loading coil at the ground. switches. The condenser plates can be o" loose coupler primary coil and shunted con- Going one step further, imagine the re- tinfoil, separated by paraffin paper for re denser circuit (which is actually tuned to ceiving set connected in at a point in the ceiving or put on glass with some shella the desired wave length) oscillating. The circuit indicated at A (Fig. 1). The cur- for sending types. The whole should bi, detector circuit also probably oscillates, due placed in a box, with the switches outsid) to forced oscillations from the primary cir- in any convenient place. One more two'1 cuit (see Fig. 8). .NiÇCo-fo/% .15 point switch and 32 more plates can b. We are now constructing the proper load- r , added and the capacity is doubled. ing coils to load up all the circuits until we Care should be taken not to put all th have resonance. The above arrangement is switches to the right, as it will short -circus so simple and can be secured with such lit- the other instruments. tle additional apparatus that the average Contributed by C. J. FITCH. I amateur will probably be inclined to give it arrent Curve a trial. The signals from Tuckerton, Say- ville and Arlington are strong, but when A TUBULAR VARIABLE COW, resonance is secured they will be many DENSER. times stronger. This condenser may be constructed al We are also constructing some loading most entirely of parts to be found abou coils for use in receiving the foreign sta- the average amateur workshop. The di;'i tions working on as high as 20,000 meters. Vollage curve mensions may be varied to suit conditions Petrograd, Russia, is said to use 20,000 me- but the author has found the followin f ter waves, as are some others. One of the dimensions most satisfactory: Length o" new Marconi in New Jersey can be stations outer tube, 51/ inches ; diameter of outer.. heard testing some evenings on 18,000 me- tube, 4 inches ; length of inner tube, 531 ters. They use an audio -frequency or spark inches ; diameter of inner tube, 3% inches system and the detector is all that is crystal j 1 A wire soldered to the bottom make necessary. A wireless authority in New fig.1 10 M JO 40 connection with the outer tube, while con, York City, and another in Washington, - dficro-amperes nection with the inner one is made to claims that the 20,000 -meter foreign stations means of a slider of phosphor bronz can be easily received on a 150-foot amateur which presses on the brass red as shown it aerial, and to the experimenter who has Fig. t. Approximat' Graphical Relation of Cur- rent and Voltage in Antenna. the illustration. tired of listening to the ordinary short layer of Empire cloth, or wave stations the writer would advise that A oiled linen rent here has ' c'- mparatively large ampere is secured around the inner cylinder by i he get busy and tune in the long wave sta- thin coating of shellac, or, better, tions, especially the undamped waves. value and a comparatively small voltage beeswax value therefore amperage predominates in The uprights are composed of oak and,. THE GROUND LEAD AND the energy induced in the detector circuit. finished with shellac. The base is bes I ITS PROPER USE this condition is best for detectors acting made of slate. This instrument possesse on the thermo- electric principle, such as great ease of adjustment, and there is n By Electron. galena, and the signals will of course be possibility of a short circuit. one amateur in a hundred Not radio comparatively loud. Contributed by The opposite tends to be the case when EARL E. NEWLIN. the set is connected at a point in the cir- indicated B. Here the voltage pre- cuit at Groove turned au/ i) lathe. dominates and the voltage in the detector circuit will be higher than in the previous case. These conditions are ideal for sets utilizing the audion. for instance. The above explains the theory. and now we will consider the application of these effects to practise. It is practically impossible to' change the connections as mentioned in the foregoing, but two alterna- tives remain. One method (A) that can be utilized to Home -Made Tubular Variable good effect is to install two ground leads, Condenser. with a switch to change from one to the other. One of these leads should run as lead. It is understood if you only us straight as 'possible to the ground connec- mineral detectors it is unnecessary to hav tion and the other should possess an in- two leads, and if audions are used ex ductance, which may consist of about 75 elusively connect the load coil in the groun turns of No. 24 C. C. magnet wire wound lead permanently. Fig. 2. Diagram of Ground Switch Change-Over on a core 4 inches in diameter. The diagrams appended show the con for Radio Receiving Set. The other method (B) is to install a nections of the switches for the use o aware of the possibilities of increasing his D. P. D. T. switch to enable one to throw those who use both the audion and miner range that lie in his ground lead. It may the load coil from the aerial to the ground detectors as receptors.

www.americanradiohistory.com THE ELECTRICAL EXPERIMENTER March, 1916 34 p_ FFICIAL LIST OF LICENSED RADIO AMATEURS NOT TO APPEAR IN ANNUAL GOVERNMENT CALL BOOK TILL SEPTEMBER, 1916. Amateur Radio Stations Licensed by the Bureau of Navigation During the Month of November, 1915. (Continued.)

I SECOND DISTRICT. EIGHTH DISTRICT. r-Call Power, Call Power, signal. Owner of station. Location of station. kilowatts. signal. Owner of station. Location of station. kilowatts. IIR Summerville, Chris. ... 4 Jones PI., Yonkers, N. Y 1 8HL Blake F. B. Cattaraugus, N. Y .5 IS Teets, Albert S. Hillside Ave., Peekskill, N. Y .5 Boardman, Thos. H.... 813 Lincoln Ave., Port Huron, Mich .5 21J Weller, William W.... 982 Linton Ave., New York, N. Y .5 8CN Burton, James F 345 Whitman Ave., Bloomsburg, Pa. 1 8IU Eaton, Floyd W 1901 Milton Ave. olvay, N. Y .5 THIRD DISTRICT. 8PE Fisher, George C 546 Utah St., Toledo, Ohio .5 3KR Anderson, Rïch'd J.. 2510 26th St., N. Wildwood, N. J. .5 8112 Goodrich Harry ...... 443 North Ave., Girard, Ohio 1 Ault, Arthuri K 1152 Columbia Ave., Baltimore, Md. 8 VU Kane, Vim. C., Jr 221 Reservoir Ave., Rochester, N.Y. .5 KSÌS Bernhard, William .. 2119 Fairmount Ave., Baltimore, Md, 8AMB Koch, Frank .,. 3402 Highland Ave., Cincinnati O.. .5 K H Don Bosco Institute. 507 S. 9th St., Philadelphia, Pa .5 Kohnitz, Harvey F 104 Maple Ave., Plymouth, Mich.. .5 KT Elder, Luciu W 407 Wayne Ave., Wayne, Pa. .5 8JG Lord Harry R 531 Beach Ave., ambridge Spgs, Pa. 1 Geiglcin, He;Iry S... 2583 W, Fayette St., Baltimore, Md. 1 80W Mitchell, Edward H 539 Main St., ÏFindlay, Ohio .5 )IK Griscom, Samuel B.. 32 Walnut St., Salem, N. J .5 8L0 Nabring, Franklin ..... 52 Foster Ave., Norwalk, Ohio. .5 KV McDowell, A. P., Jr.. 41 Carpenter St., Philadelphia, Pa .5 Newbold, James L..... 111 Orchard St., Solvay, N, Y .5 KW Mehring, Charles, Jr 414 Retly St., Harrisburg, Pa .5 SJH Nichols Raymond B. Cattaraugus, N. Y. .5 LV Podemski, Paul 1602 Beulah St., Philadelphia, Pa .5 Vonder'haar, Elliott .., 123 Valencia Ave., Cincinnati, Ohio. .5 Samaha, Edv and F 2 Oriental St., Atlantic City, N. J .5 8VA Ziska, Alfred 7704 Brinsmade Ave., Cleveland, O.. .5 FOURTH DISTRICT. NINTH DISTRICT. X IBreck, Charles 50 Logan Ave., Atlanta, Ga 1 .5 F FTH DISTRICT. 9WL Bierbach, Werner 655 S. Delaware Ave., Milwaukee. 1 sK ;Coleman, Jess B 811 17th St., Temple, Texas .5 9NO Coquilette, Glenn E 117 Hutchins St., Woodstock Ill... .5 1815 St., Rockford, Ill..,,.. IL Mount, Robt. H Pineville, Io.. 1 9WN Ferdinand, Harry P School .5 9KB Forbes, Henry C 3532 11th Ave. S. Minneapolis.... .5 SIXTH DISTRICT -None. 9W0 Garrett, Sherman 504 W. Wash. St., Champaign, Ill... 1 9WI Kelley, Eugene V 1311 W. Maple Ave., Independence, SEVENTH DISTRICT. Mo. .5 If Adams, Alit.; 1 L. Silverton, Ore, .5 Nell, Edward, Tr 2023 Talbott St., Indianapolis, Ind.. .5 Cavender, Hr. ward M 511 Terry Ave., eattle, Wash .5 9ÌG Reeder, Vern Ir 2705 Highland Pl., Indianapolis, Ind. 1 Cook, Richar.l H 324 N. I St., tacoma Wash 1 9SV Ruzek, Oscar E... Flat Rock, Mich. .5 K Gale Charles W 111 E. 48th St., Portland, Ore 9WM Smith, Stanley 1552 E. 61st St., Chicago, Ill .5 V Kraft, Vincent I 4745 11th Ave., .E., Seattle, Wash 9IM Smith, Wallace W 13 Eastover Park, Louisville, Ky. 1 IN Nelson bilkko Deep River, Wash. 9W1. Struver, Harold W 1218 Lafayette St., Ft. Wayne Ind .5 D Noel, Lionel S Snohomish, Wash. 9CIS Taferl Electric Co W. Jefferson St., Louisville, Ky 1 u O'Dell, Chari ss M 7856 Stroud Ave., Seattle, Wash .5 Teetor, Macy O Hagerstown, Ind. .5 Rasmussen, \ ïggo P 1215 Hudsn St.,Pt Townsend, Wash .5 9WK Thomas, Carroll W 746 16th St., Milwaukee. Wis .5 W Willis, Cecil D 1316 Columbia St., Seattle. Wash 9FY Zimmerman, Clinton J 117 S. Washington St., Buquoin, Ill 1 Nom-Hereafter, all power will be stated in kilowatts instead of watts. All stations using power up to and including 500 watts will be rated as .5 kilowatt ions; all stations using power above 500 watts up to and including 1,000 watts will be rated as 1 kilowatt sta ions. This will be carried out in the List of lio Stations of the t nited States, 1916 edition. Amateur Radio Stations Licensed by the Bureau of Navigation Durin the Month of December, 1915. FIRST DISTRICT. SECOND DISTRICT. all ' Power Call Power gnal Owner of cation. Location of station. kilowatts. signal Owner of station. Location of station. kilowatts.

, Allen, George i-I 16 Bacon St., Waltham. Mass .5 2GO Mulligan, Harry G 62 Chestnut St., Albany. N. Y .5 Bailey, Philip A 64 Washington St., Middletown, Conn. 1 2UV Oliver, Geo. E 511 Ave. A., Bayonne, N. J .5 Barker, Gilliam D 19 Channing St., Newport, R. I a 2JP Pruden, Harold M 142 N. 15th St., E. Orange, N. J. .5 \Z Bates. Roger 'r 184 Pine St., Wollaston, Mass 1 Ruhlmann. Ernest R 97 W. 34th St., Bayonne. N. J . .5 3A Beattie, Robent. 21 County Road, Everett, Mass .5 2ÌCQ Schaefer, Regnell C 185 N. 16th St., East Orange, N. J .5 31( Bent, Arthur .'. 84 Commonwealth Ave., Boston, Mass .5 2J B Smith, Clarence B., Jr 1017 South Ave.. Westfield, N. J 1 iS Bliss, Donald FI 12 Dcan St., Attleboro, Mass .5 2UY Squire, Milford 122 Guion Ave., Richmond Hill, N. Y .5 3 Brackett, Walter F...... 24 Maple St., Stoneham, Mass .5 2AQ Wak, Henry. 82 17th Ave., Newark, N. J .5 3J Brockington, Harry G... 69 Lincoln St., Laconia. N. H. THIRD DISTRICT. Burke, Henry M 59 Chatham Road. Everett, Mass...... 5 3L Campbell, Joni A 9 Fairlee St., Somerville, Mass .5 30J Barron, John H., Jr..... 3022 Abell Ave., Baltimore Md 5 3V Carr, Albert I 8 Decatur St., Worcester, Mass. .5 3W1-1 Berkeley, Kenneth H.... 3422 Center St., N. W., Wash., D. C .5 3T Coolikoff, Jacob 112 Broadway, Chelsea, Mass .5 3AAJ Blair, C. Drewry. 1804 Hanover Ave., Richmond. Va .5 3C Clark, Charles V 25 Pierce Ave., Beverly. Mass .5 3AEM Booz, Walter N. 237 W. Pine St., Wildwood, N. J .5 ) Crie, Oscar H Castine, Maine .5 3ADA Bott, James M 1011 W. Cumberland St., Phila., Pa... .5 3Q Crosby, Leslie W 12 Elmwood Road Swampscott, Mass. 5 30H Bryan. John D 1927 S. Salford St.. Phila., Pa .5 Donahue, Frank J 32 Whittier St.. Lynn. Mass .5 3AAG arroll, Louis, Jr S. New Jersey Av., Atlantic C., N. J. .5 30 Donnelly, Gcc:ge F..... South Meriden, Conn .5 3WI arnell, Albert H., Jr 129 S. Penna. Ave., Atlantic City, N. J. .5 Eddy, James I' 489 Common St., Belmont, Mass .5 3ADL Ellis. Edmund K Bethesda, Md .5 3D Engel, Richard B 35 5th St., Medford, Mass .5 3AKE Enslin, Louis R. 1731 N. 21st., Phila., Pa. .5 3F Fitch, Clinton o2 Cottage Pl.. Waterbury, Conn 1 3MT Gardner, Wm. L 1612 N. 4th St., Harrisburg, Pa .5 Frank, Louis C. 21 Summit Ave., Brookline, Mass .5 . 3RO Gravely, Willis T 854 Main St.. Danville, Va 1 Goularte, Manuel L..... R. F. D., Fairhaven. Mass .5 3MZ Jodry, Ray S. Quincy. Pa 1 .S Gould, Clyde 8. 123 Hamilton Ave., Lynn, Mass .5 31V\V Keller, Paul A 13th St., and Lehigh Ave., Phila., Pa.. .5 1G Graves, William S Sunapee, N. H .5 350 Kupp, Clarence L 451 Lincoln Ave., Pottstown, Pa 1 Guilmette, Edward J.... 343 Mason St., Woonsocket, R. I...... 5 3UB Lamb, Roland H 1131 Gorsuch Ave., Baltimore, Md.... .5 Hallett, Charle, E 28 Norcross Ter., Lynn, Mass 5 30A Lentz, Arthur F 18 Fairview St., West Catasasqua, Pa. .5 ;U Hertz, Wm. F. C., 57 S. Water St., New Haven, Conn .5 3UE Lindauer, Herman E 409 Piedmont Ave., Baltimore, Md.. .5 Jr.... H. 133 Keyes, Perley ii: 71 School St., Sanford, Maine .5 3QE ng, Perry Runnymede Ave., Wayne, Pa...... 5 5 Lynch, Sherm:sa AN 26 Abbott St., Beverly, Mass 3NR Maul, Gilbert E Chatham, N. J .5 McHenry. Albert T '64 Cutter St., Melrose, Mass. .5 3AAP Roehm, John A 666 Union St., Lancaster, Pa .5 3V McKinney, Roscoe H Thomaston, Maine. ,5 3V0 Schall, John R. 1318 Turner St., Allentown, Pa .5 \ Mercer, W. R v 34 Webster St., Allston, Mass. .5 3QA Stevens, Lewis D 5224 Delancey St., Phila., Pa .5 3AAC Swartz, French V 26 S. N. Ave., Atlantic City, N. 11 H Mooradian, P 144 Lawton Ave., Lynn, Mass .5 J. J.. Arum agner, Laurence E 6077 Allman St., .5 .51 Murray. James J 28 Wensley St. Boston Mass .5 3AAP Philadelphia, Pa..... Nickerson, Ed, sr W.... 16 Atlantic Ave., Beverly, Mass .5 3OR alker, Donald R 552 Kohn St., Norristown, Pa .5 BP Pope, Donalo II 2 Winthrop, Danvers, Mass .5 30Q Welke, Paul L 39 S. Stricker St., Baltimore, Md .5 Prescott, Earle M...... 6 Lincoln St., Stoneham, Mass .5 3WG Worley, Robert A. 940 Carteret Ave., Trenton, N. J .5 Reid, Ralph A. 8 Cedar St. Wakefield, Mass .5 FOURTH DISTRICT. Seibert, Leroy G Berlin, Conn .5 4CZ Ashley, Robert C 738 4th Ave., N., St. Petersburg, Fla.. 1 ) Sherman, Jose;lI E. 349 Tremont St., Boston, Mass. 0 4CY Cooper. Frank P 717 S. Edison St., Tampa, Fla .5 Simmons, Minot A. 124 Beech St., Roslindale, Mass 4DD Emory University. Oxford, Georgia 1 )Y Snow, David F 15 Lincoln St., Arlington, Mass .5 4DA Fogarty, John J 707 Azeele St.. Tampa. Fla. 1 3R Stevens, Charles L 19 Lincoln St., Stoneham, Mass 5 4DB Lesley, John L 114 Hyde Park Pl., Tampa. Fla .5 I Stevens, Louis \V 394 Riverway, Boston, Mass 4DE Moore. Thomas H., Jr... 321 N. Spring St., Pensacola, Fla .5 BE Taylor, Fredetf: W...... 30 S. Main St.. Attleboro Mass 4DC Peer, Emmitt E 419 Duval St., Jacksonville, Fla 1 Turner, Edwin E 72 Wyman St., Jamaica Plain, Mass. .5 Wallace. Wm. II 30 Hastings St., Cambridge, Mass.... .5 FIFTH DISTRICT. pl Wells, Herbert a 32 Nelson St., Dorchester, Mass .5 SDN Collins, Wm. A 328 Arabella St., New Orleans. La .5 Wetherell, Fred L. 37 Peck St.. Attleboro, Mass .5 5BO Floyd, Preston M., Jr 213 E. Blvd., Baton Rouge, La .5 Z White. I. Davis Peterboro, N. H .5 SDP Geren, A. Blanchard 1815 W. Gary St., Shreveport, La .5 5DM Reid, Kenneth M 1001 Columbus Ave., Muskogee. Okla .5 SECOND DISTRICT. 5D0 Volover, Wm. H 624 Eastside Blvd.. Muskogee, Okla .5 Adams. Earl F 1048 Julia St., Elizabeth, N. J. .5 Atwater, Charles K 40 Oakwood Av., Up. Montclair, N. J. S XTH DISTRICT. iS Bergner, James A. 206 High St.. Brooklyn, N. Y .5 6GA Andrews, Gaylerd 4734 Shattuck Ave., Oakland, Cal. .5 B Booth, Sherman F 30 Center St.. New York, N. Y. .5 6DV Bales, Edward M 1006 N. Main St., Napa, Cal. .5 tR Byrne, William 85 N. 120th St., Rockaway Pk., N. Y. Bascom, Carleton V 1020 E. 27th St.. Los Angeles, Cal .5 Carruthers, David 135 Waverly Pl., New York. N. Y .5 6EW Bertin, Edwin 917 Ave. A, Coronado, Cal .5 Foster, Dudley E 423 4th Ave. Neward, N. H .5 6BE Birkeland, Andrew 22 Fairmount St., San Francisco, Cal .5 Fricke, Wm. B 156 N. Arlington Av.. E. Orange, N. J Carter, E. Stewart 1639 Formosa Ave., Los Angeles, Cal .5 Garity, \Vm. E 324 Reid Ave., Brooklyn, N. Y .5 6JP Clark, John H 316 E. 55th St., Los Angeles, Cal .5 R Haight Russell P. 18 Spruce St., Bloomfield, N. J... 1 6CF Curtis, Burbank 519 E. 9th St., Long Beach, Cal .5 Katz, Frederick. 1464 Seabury Pl., New York, N. Y... .5 6DE Davidson. James D 462 W. Grand Ave., Pomona, Cal .5 Lockwood, Nelson W 237 Prospect St.. E. Orange, N. J .5 6RD Deardorff, Ralph W 202 Cypress Ave., Santa Ana, Cal 1 McClintock, Ralph W 125 High St., Nutley, N. J. .5 6D., Duffey, Guy H 1622 W. 24th St., Los Angeles, Cal .5 (To be continued.)

www.americanradiohistory.com March, 1916 THE ELECTRICAL EXPERIMENTER

...... _THE v v _l0000 0000_

The Use and Construction of a Decremeter By Milton B. Sleeper

WHILE most experimenters are fa- The handle in the center is for the though it is far better to keep all the parts) I' miliar with the measurements com- variable condenser. At the right is the inclosed, this instrument will work as well monly made in radio work, not switch, represented in the diagram of con- if the essential parts are made according many understand the measurement of "dec- nections by the numbers I, ', :j, 4, 5, G. to the drawings, but mounted on a plain base. The Variable Con- denser. The condenser is o the rotary type an ut about !0005 mfds. capacity. It is much Icetter in most cases to buy a condenser than to make one1 ilowever. the home- made one described here will be satisfac tory if the instruc - lions are closely followed. A list of part:; is given to help the builder in getting th material ready. From perfectly flat No. 2 gauge aluminum sheet, cut out 1(' pieces 21/ x11A, inches. These are for the, rotary plates. On tw mark out the shape" of the plates asI!!:

Fig. I. Front View of Finished Decremeter. shown by 17 in Fig ; Clamp the stack rement." Since the sharpness of the radi- Below the switch are binding posts for of plates between two blocks of wood ated wave depends upon the decrement (or connecting any suitable 'phones. Across the the marked pieces on the outside. Usiit damping), this value must be measured if top is arranged a slider which projects these as a guide, cut along the liner the tuning characteristics of a transmitter through the slot in the hard -rubber front. with a fine hand jig -saw, well lubri. are to be predetermined or made known. The damping decrement can be read dicated with kerosene. Drill the holes foi To reduce the interference as far as pos- rectly from the scale. If it is desired the the shaft, too, while the plates are stil sible, the law requires that the logarithmic decrement shall not exceed 0.2. Several kinds of decremeters* have been developed. but the one described here is the simplest. This type was first used by the Marconi Co.: the formula on which its operation depends is due to V. Bjerknes. The construction of the instrument will first be taken up; then its use. Construction of the Decremeter. Fig. 1 shows the front of the instrument, while Fig. 2 gives the connections. At the left of the front view is the detector. Any mineral is suitable if it holds Fig. 5. Rear of Decremeter Switch Board, Showing Slider, Change its adjustment well. =Ober Switch, Etc., in Position. decremeter can be calibrated at the Bureau clamped. From rectargles 3xl% inches cut This decremeter was actually built and of Standards, Washington, D. C., but if out the nine checked against a standard instrument. With a the thin stationary plates and tht little care a faithful duplicate can be constructed. decremeter is carefully constructed it will two thick ones, acccording to the draw -EDITOR. be accurate enough for all purposes. Al- ings. Drill the holes around the edges, but

www.americanradiohistory.com 1 636 THE ELECTRICAL EXPERIMENTER March, I9tu

,1 do not drill the holes for the bearings in to the front of the case. The threaded shown. The connecting wires have been the thick plates. If there are any burrs on washers, 9, are to hold the rotary plates in omitted to make the drawing clearer. Fig. the plates, rub them off with emery cloth. position on the shaft. To make sure that 5 shows the condenser in position on the Washers can usually be purchased. They both sets of plates have been tightened up back of the hard -rubber front. The con- must be between 0.063 and 0.062 inches in the same amount, try the edges of the as- nection wires are left out in this drawing thickness. Test each one with a microm- sembled rotary plates against the assembled also.

!I 6-32 t v O ,- 6s2t

I .i U`8-321 24 spring. ©

k o O B-32t 6.32Í 021 30'

Mho 4.0* 6321 rh á'

s' 33

Fig. 3. Details of Decremeter Variable Condenser Parts. eter. In drilling the bearings, 14 and 15, stationary ones. Finally, slip the rotary The Inductance Coils. clamp them to the thick plates and drill plates between the stationary ones, put the The inductance coils and contact slider the holes in all of them at the same time; bearings on the shaft, and screw them are depicted in detail in Fig. 6. Wind the otherwise the bearings will not be in align- down in place. When it is time to put the long coil, 32, with No. 22 double cotton ment, and the plates will touch. Now tap condenser on the hard -rubber front bend covered copper wire. By soldering a piece the holes for the screws, 7, which hold the the spring, 1, to a bow shape. It belongs of copper foil to the bared wire take taps bearings to the thick plates. on the shaft between the front and the at the 26th and 52d turns. Wind the small- When the stationary plates are finished handle. This spring, pressing against the er coil with 26 turns of No. 22 double cot- sz turns 2610/rIS-.r /tap tap

/O C // 26 qr re turns /7!' 0/e

Q © e St Ira' _4_ 1 t

s _ ,1d 43 21 z" fi

hol. 44

1 /6 6 9 3 d' O so--1,1,1141A1d/h1a146Vlrl,1/l/l-S.i. /6 t/7ictr,

Fig. 6. Inductance Coils, Slider, Rod and Scale for Same, and Other Details. ssemble them on the screws, 8. The ends handle, will hold the plates in any position. ton covered copper wire. The completed f the pieces 11, which have the smaller The nuts, 6, hold the plates from being coils are shown in Fig. 4 as they appear holes, go on the screws 8 to keep the plates pulled out of alignment by the spring. In when held in place by the straps 40. !':fight ; the ends with the larger holes are the side view of the assembled instrument, Be very careful in laying out the scale 45. Iior the screws 7, which hold the condenser Fig. 4, the complete condenser is clearly Divide the 8 -inch space into 100 equal parts.

www.americanradiohistory.com rMarch, 1916 THE ELECTRICAL EXPERIMENTER 637

Then make the divisions for the decrement This makes a place for the narrow part of sired on cupboards, little closets and shop readings as given in the table below: the slider handle, 34, to fit in. Solder the doors to keep out undesirable parties. The Number of Graduation Marks on the Scale with contact, 39, to the bottons Decrement Readings. of the tube. Now fasten Deere- I leery. Decrc- Scale. nient. Scale. nient: Scale. men:. the handle to the slider 30 0.378 40 . .. 0.2 00 49 ....0.15'1 by means of escutcheon 31 0.344 41 ....0.194 50 ....0.146 32 0.314 42 ....0.186 55 ....0.123 pins or small rivets, put 33 0.292 43 ....0.1811 60 ....0.110 through the holes in the 34 0.272 44 ....0.174 65 ....0.104 handle and the side pieces 35 0.258 45 ....0.168 70 ....0.096 36 0.242 46 ....0.162 80 ....0.082 42. Fit the pointer, 36, 37 0.230 47 ....0.158 90 ....0.07.2 tightly in the Bole of the 38 0.220 48 ....0.154 100 ....0.064 handle. Be sure to put 39 0.210 the completed slider ou 'Legal limit. the rod. 44, before bending When the scale is in position on the the rod in the shape in- hard- rubber front move it until the pointer dicated 'by the drawing. is on the zero mark, when the slider con- Make sure, also, that the tact is on the 26th turn of the larger in- contact is on the right i side of the rod. k These parts finished, we may start construct- fly. 4 ing the change- over switch. Fig. 4. End View of Decremeter with Cabinet Board Removed. [fit the second part of this paper on the common method of opening these locks is "instruction of a dccremeter to use secret contacts, such as two nails, the Ile. Sleeper explains how to circuit being closed by a coin or niece of use saute for measuring wave metal. length, decrement, etc. Don't The lock herewith described has many miss it!-Ed.] of the advantages of the above, but is in the forni of a combination and can be WAVE LENGTH AND opened by no one save those who know DAMPING. the prearranged setting of the lock. It is a little known fact that The materials needed are 3 switch levers, the Government pays little or 30 contact points, 1 push button, 2 or 3 no attention to a highly good dry cells and an electric door opener. damped wave under 200 meters, The circuits and wiring diagram are shown whereas it reprimands and in Fig. 1. A, B and C are the switch punishes amateurs who use a levers. Ten contacts are used per switch wave length in excess of 200 and arranged on a 1 -inch board, 81/zx4% Pig. z. Wiring Diagram for Parts of Decremeter. meters. Select the lesser evil inches. After the levers and contacts are ductance. This must be done carefully if to avoid fines. However, for maximum arranged the combination is to be decided the meter is to be accurate. range the decrement should be kept down. upon and hooked up accordingly. In the illustration the combination is 6-3 -1. It LIST OF PARTS. will be seen that unless switch lever A is Drawing on contact 6, switch lever B on contact 3 Number Name of Part Size Pieces Material and switch lever C on contact 1, it will be impossible, upon pushing the button, to 1 Spring to go on shaft under handle. 1 x y x p4 gauge 1 Spring brass open the upon which the electric lock 2 Pointer for handle 9/16' x 1 /16 diam. 1 Brass door 3 Washers to hold connection wires 1 /3ry' x b/16" diam. 9/64 hole 2 Brass D is fastened. A great variety of combina- 4 Connection piece for bearing 13/16 "x 34 "x 24 gauge 1 Brass tions can be had. it being possible to ar- 5 Screw for making connection to No. 4 y ". 6-32 thread 1 Brass 6 Nuts to adjust plates..... 8-32 thread 2 Brass range 1.000 different settings with the 7 Screws to fasten bearings to outside plates 5/16 ", 8 -32 thread 6 Brass scheme illustrated. 7 Screws to fasten No. 11 to front of case 5/16 ", 8-32 thread 3 Brass The appearance of the finished device 8 Screws to hold stationary plates together; goes in No. 11 1". 6-32 thread 3 Brass 9 Washers to hold rotary plates á/32"x 34' diam. 8.32 T 2 Brass will be as shown in Fig. 2. It should be 10 Shaft for rotary plates 23f ", 8-32 thread 1 Brass screwed, or preferably, bolted, to the door 11 Pieces to hold stationary plates to front 3,4''x 3/16" diam. 8-32 and 6 -32 it is All thread 3 Brass upon which placed. wiring is 12 Separators for fixed plates 1 /16 "x1.364" diam. 9/64 "hole 30 Brass 13 Separators for rotary plates. 1 /16"x34 diam. 5/32" hole 9 Brass 14 Bearing nearer front of case 34 "x 1 4" diam. 1 Hard rubber 15 Bearing at back .¡"x 134" diam. 1 Hard rubber 16 Handle 34 "x 13.f" diam. 1 Hard rubber 17 Rotary plates 25 gauge, 21/" diam. 10 Aluminum O 18 Outside stationary plates; fasten bearings to them 16 gauge, 3" diam. 2 Aluminum oyf obi 19 Inside stationary plates 25 gauge. 3" diam. 9 Aluminum os Os so Os p 20 Nuts to screw on either side of No. 30 8-32 thread 2 Brass OQ 21 Pointer for handle 34"x 1 /16" diam. 1 Brass A Oa `O Os A 22 Switch contacts 1 "x , 24 gauge 2 Spring brass dbw O'd°o aro 23 Spring to go under handle 1 "x34" 24 gauge 1 Spring brass 24 Washers for connections 1/32"x 52/16" diam. 5 -32" hole 12 Brass Roo ddrav p 25 Pins to stop contacts. 34 "x 1 /16" diam. 2 Brass 26 Screws to hold No. 31 to front of case. Y ", 8-32 thread 2 Brass, round head 27 Screws to hold connections. ", 8 -32 thread 6 Brass, round head fig. 2 28 Shaft 1 't 8-32 thread Brass 29 Handle. 4x y"" diam. Hard rubber 30 Movable contact holder sá x 13t diam. Hard rubber 31 Stationary contact holder 34 "x 2 5/16" diam. Hard rubber 32 Core for large coil 11 "x 34 diam. Well- seasoned wood .! 09 33 Screws to fasten coil holders to case x3á' diam. Brass J o 34 Handle of slider x 9/16 "x i" Hard rubber : W, i 35 Tube for slider 1 x3g sq. i.d. 3/16" sq. o.d. Brass ; 36 Pointer for slider handle. 34/x 1/ 16" diam. Brass e 37 Screws to fasten slider rod to front of case 5/16' ,2-56-56 th ead Brass. round head 38 Support for slider handle 3f "x 3 /i6 "x 3/16" Brass Pu.róa//o/7 39 Contact for slider 3' x 34" 24 gauge Spring brass 40 Coil holders 2tx 3'x 1/432" Brass IIII 41 Screws to hold scale to front of case. 3/16' , 6-32 hread Brass, round head .ed? 42 Pieces to hold slider handle 34"x 3i "x 1/32" Brass 43 Core for small coil 2"x 3 i diam. Seasoned wood 44 Slider rod 11 "x34"x3¢" Brass 45 Scale 9 "x 34"x 1/64" Celluloid /r9 / n 46 Front of case 1234' x 534'x 3/16" Hard rubber 47 Back of case 1134 "x 435 3x 34 Mahogany 48 Top and bottom of case 1245, "x 2 11/ 16 "x34, 2 Mahogan Handy Electric "Combination" Lock for Draw- 49 Ends of case 2 10 /16 "x 414' x3á" 2 Mahogany ers, Tool Boxes, Etc. To assemble the slider, first solder the AN ELECTRIC COMBINATION taken to the inside of the door to prevent piece 38 on the middle of the tube 35. To LOCK. anyone meddling with the circuits. opposite sides of 38 solder the pieces 42. A secret electrical lock is frequently de- . Contributed by A. R. DARLING.

www.americanradiohistory.com 638 THE ELECTRICAL EXPERIMENTER March, 1916 An Electro -Magic Skull By homer Vanderbilt MOST readers of this journal are un- lay can be advantageously used. The trans- These latter schemes are merely sugges- doubtedly familiar with the "rap- mitter is of the supersensitive type and tions that may be used to give the appara- ping skull" used by stage magi- which can readily be made by following the tus a professional appearance. A final cians, but are possibly doubtful as to how instructions given in the November, 1915, word; it is absolutely necessary to mount it really works. Several of these schemes issue of this journal on page 333 in an the cabinet on a solid support, otherwise article entitled "How to Build a Dicta- vibration will cause it to operate of its own phone." After these various instruments are made they should be properly arranged Pivot as portrayed in Fig. 1 and connected as shown in "D," Fig. 2. The instrument is now ready to be used. The only thing necessary to operate the jaw of the skull is to talk or blow a whistle, which will affect /teight.r the transmitter and in turn the jaw, there- Jku//Jow by causing it to rap very mysteriously. In conclusion several points may be mentioned which if followed will make the apparatus work and appear much more professional. Firstly, the contact disc had best be geared up to the motor, so that it Jorr makes about one revolution to 20 or more Lever rod of the motor shaft. Again, the skull should be arranged so that it may be picked up Tob/etop) /ron disc A Z from the stand and shown to the audience. At Fig. 3, "E," is indicated how a separa ble rod joint, X, may be contrived, enabling the operator to remove the skull easily for inspection. An indirect electrical method is fig. 3 the best way in which to actuate the jaw. At Fig. 3, "G," is perceived how the elec- Fig. z. Circuit Arrangement for the Mystic Skull. tro- magnet D may influence magnetically rig. 3. Details of Jaw Actuating Mechanism an iron disc, X., joined to the movable accord and spoil the whole illusion. have been developed by different workers jaw, as usual, by a lever or wire. This in the field, and one of these is herewith described in detail. VALUE OF RADIO TO VESSELS IN The general principles upon which this DISTRESS. trick works are as follows: A sensitive mi- During the fiscal year 1915 the radio in- crophone, A (Fig. 1), of the carbon ball spectors of the United States Navigation type, is connected in circuit with a relay, B / Bureau reported 26 cases of vessels leaving (see also Fig. 2, D), and its armature cir- our ports whic'i met with accident or dis- cuit is linked with a motor, C, and battery. aster, requiring the use of wireless to sum- Upon the motor shaft a proper circuit Stall1 mon assistance. Four of these were from breaker is placed and the latter is con- .!-AC¡i.. fire; 12 were from running ashore, strand- nected in series with a powerful electro- ing, or getting into an ice jam; 3 were magnet, D', actuating an iron armature, E, CLo/h cover - from the breakage of machinery; 4 resulted . which is connected to a rod, F, operating from collisions; 1 from shifting of cargo; 1 lever G, which is fastened to the (bal- -t 1 vessel was storm -battered and water- anced) lower jaw of the skull, as per- logged ; and 1 was torpedoed. Excepting ceived. Now, when you speak or produce in the case of the "Lusitania," which was any sounds near the instrument, the micro- torpedoed, the assistance thus rendered re- phone will be disturbed, operating the resulted in but two lives being lost. Since lay, which will connect and work the mo- the close of tie fiscal year the following tor, and in turn the circuit breaker. Con- disasters have occurred: sequently the electro- magnet D' is put in On Sept. 13, 1915, the Fabre Line steam- operation andSthe result is that the jaw is ship "Sant' Anna," bound from New York pulled up by the action of the rod F, actu- p - to Naples with 1,700 Italian reservists and ated by the magnet. When the current is crew aboard, caught fire in mid -ocean and released the slightly overbalanced weight E...,:. all persons on board were saved. The of the jaw will cause it to drop back. The S O S call 'brought the steamship "Ancona" arrangement herewith shown will only to the assistance of the disabled vessel and cause a double rap of the jaw, but the 1118 600 persons were taken off. The "Sant' number of them may be varied by increas- gi Anna" then proceeded to port, convoyed by ing the number of segments on the circuit the "Ancona," and the entire 1,700 pass- breaker. engers and crew saved. The writer will unfold the details of his Six days after the "Sant' Anna" disaster, apparatus and thereby the experimenter -' II II -__ __ _ the Greek liner "Athinai," bound from will be enabled to build such a device for New York to Piraeus, caught fire in mid - amusing his friends. It is certainly very ocean and was abandoned by the passengers amusing to witness the astonishment ,I of the " ...... I and crew, numbering 470. The call for as- visitors when the skull is operated. Df sistance was answered by the steamships The constructional details of the indi- "Tuscania" and "Roumanian Prince "; 341 vidual apparatus are shown in Fig. 2. The persons were taken on board the "Tus- electro- magnet "A" is made to size, as per- cania," the remaining 129 being taken off ceived, and is fully wound with No. 22 B. Fig. I. Assembly Details of Mystic Skull in by the "Roumanian Prince." The vessel & S. copper magnet wire. The circuit Cabinet. was entirely destroyed. breaker "B" consists of a disc revolved by The use of radio apparatus on vessels a motor and which makes contact with a permits of minute inspection by the audi- carrying passengers, or with 50 or more brass strip located at the bottom of the ence. Again, the effect can be attained by crew, is now accepted as essential to the base, as depicted. The relay "C" is made placing an aluminum ring in the jaw (prop- safety of those on board, and the report of of two bell magnets actuating an iron ar- erly balancing the jaw to make it work the "Athinai" shows conclusively that many mature carrying a contact point which co- easily) and an alternating current electro- persons might have been lost and perhaps acts upon a second point, as seen. Connec- magnet, by induction, will repel the ring the cause of the disaster never known had tions for the various parts are shown in (and hence the jaw also) whenever it is not this vessel been equipped with radio drawing "D." Practically any kind of re- energized. apparatus.

www.americanradiohistory.com March, 1916 THE ELECTRICAL EXPERIMENTER 639 0 RHEOSTAT FOR SMALL MOTORS. How to Build a Photophone This rheostat is composed of a base- with the center of the back fur securing a brass board, eight hardwood blocks and a strip Those who arc experimenting for piece, used a binder. manometric flame tube B. This tube should be well soldered of wood the top as selenium will find this The blocks are % inch thick, 1'/, inches very useful in their research work. It can on the back and is used for transmitting tip. Another tube C of the wide and 4 inches long. A hole is made be employed in transmitting wireless tele- the gas to the of block, beam size is secured on the bottom of the through both ends the through phone messages by the use of a light same which one end wire is passed. The case, and this a l s o of wire is then wound around the block, tak- should be soldered, wind leave and is connected to ing care to it evenly and about an acetylene gas generator by means of a rubber tube. The diaphragm is next provided, which con- - sists of goldbeater's _° or pig's bladder skin \C`.'SC%i-'% .C.C`\` of very light quality. %...CCC.- First the latter is laid .. across the case with . its cover removed 0 and the skin is then tightly stretched across the edge of the box, and finally the cover is placed over the diaphragm. This is firmly pressed into its proper place. The edge of the cover is next soldered a 11 around the case in order to make it perfectly gas -tight. Parts and Assembly of Rheostat for Controlling Having finished all Small Motors. this, a hole is made Mc inch between each strand. Put the wire Fig. I. The Completed Photophon,. in the upright wooden standard 10 inches through the opposite hole and clip it off, acting upon a selenium cell. It can also from the bottom and 2 inches from the leaving just enough wire so that connec- be successfully employed in recording voice side. The tube B is now carefully inserted tions may easily be made. This step is sounds by the addition of a revolving mir- through this hole and firmly held in place shown in Fig. 1. ror. by applying some sealing wax around the When the eight blocks are wound mount The complete apparatus as shown in Fig. tube. An ordinary acetylene gas tip is pro- them at the rear on the base -board ; cut in the design shown in the drawing, the rear 1 was built by William J. Hammer, of New cured and placed over the end of the tube cell is placed behind the as measuring 9 inches from A to B in Fig. 4. York. A selenium observed. strip one blocks -tip as perceived and is connected in A small selenium cell is placed in Screw the to each of these flame now as shown in figure. The switch may be series with two batteries and 'phones, as back of the flame tip. This is held in made of suitable metal 3 inches longs photograph shows. In Fig. 2 the con- position by means of two brass strips, glee half of a spool given. The very which are screwed inch wide. At one end structional details are on to the hase by wood in Fig. 2. When completed it is the which con- as shown first thing to build stand, screws. Two binding posts are next look like Fig. 4. sists of two strips of well- seasoned wood placed on the upright support and these are should The connections are made as follows : either oak or mahogany. It should be connected to the cell, which in turn is con- of 1 2 at details of Coil Nos. and are connected the bot- made of 3/4-inch stock, and the nected in series with a telephone receiver tom, Nos. 2 and 3 are connected at the top, same are given in both figures. and several batteries, as the photograph and so on to the end. The leading -in cur- The most important apparatus of this depicts. rent is connected at pole H, and so on to outfit is the instrument A, which causes The experimenter who is not familiar J, while the leading -out wire is made fast variations in the flame at the tip, and this with the working principle of this instru- to pole I. is made from an old shoe blacking can. ment will .find the following simple ex- The switch arm is moved over to he first The can is first thoroughly cleaned by ap- planation quite satisfactory: At first, when contact point, which starts the current the gas enters the chamber, a through wire A down through coil 1, up .se/eniumcei/\ straight flame is produced at coil 2, down coil 3, up 4, and thus through the tip; but as soon as one be- ,acety/Pne,burner Con gins to talk near the diaphragm t40 at A the volume of gas is in- terrupted, and consequently the SR/i7 diotrorA flame is varied in brilliancy, this being directly proportional to the intensity of the sound against the diaphragm. There- /'ubbertubing fore the change in the voice will be reproduced in the flame, and in consequence will affect the sensitive selenium cell, which then operates the telephone the Bicycle receiver according to oce/y/ene variation of resistance. As generator ME this is governed by the gas MEI flame, therefore the voice is ac- MEN curately duplicated at the receiver by merely talking against /O the skin diaphragm. Of course, Wiring Diagram for Rheostat Resistance Units it should be understood that G and out wire G. Should this offer too the selenium cell can be placed much resistance, move the switch to con- Fig. z. of Photophone and Assembly. Details at any distance from the flame, tact 2, which sends the current through plying hot water and a rag; after this is light will be required. This principle, great- wire B, up through coil 2, down 3, up 4, etc., done a 1 -inch hole is made in the cover, as ly enlarged upon, as by using an electric arc and thus out wire G. seen in Fig. 2. This can be made by lamp, has enabled speech to be transmitted The contact points and binding posts may either drilling or else sawing it out with a for several miles; one record attained by be made or bought at very low cost. jeweler's saw. A A -inch hole is drilled in the late Herr Ruhmer having been 14 miles. Contributed by JACK CRANDALL. ri _ www.americanradiohistory.com 640 THE ELECTRICAL EXPERIMENTER March, 1916

This department will award the following monthly prizes: FIRST PRIZE. $3.00: SECOND PRIZE, $2.00; THIRD PRIZE. $L00. The idea of this department is to accomplish new things with old apparatus or old material, and for the most useful, practical and original idea submitted to the Editors of this department, a monthly series of prizes will be awarded. For the best ideas submitted a prize of $3.00 will be given; for the second hest idea a $2.00 prize, and for the third best a prize of $1.00. The article need not be very elaborate, and rough sketches are sufficient. will make the me. chanical drawings.

FIRST PRIZE $3.00. SECOND PRIZE $2.00. THIRD PRIZE $1.00.

A SIMPLE DOOR BELL ALARM. USING WINDOW -LATCH AS A POST CARD PROJECTOR. SWITCH. The materials required for this device are An easily made switch for ringing a bell two electric lamps and two sockets. Also to let me know the A window -latch can be used as a single - when anyone opens two ; by connecting pieces of tin 5x5 inches, "B" two door of my shop is here described. pole, single -throw switch strips of tin 1x4 inches, "C," bent as A metal strip (A), preferably of cop- your wires as shown in the diagram or by shown two small hinges, "D" ; a lens hav- per, should be bent into a small circle at ing about 5 inches focal length, "E," and the middle to fit over the doorknob bar. some pieces of hard wood. A small bolt will draw it up tight around From the hard wood construct a box II this bar at (B). Place between the prongs x51Yzx51/2 inches, as shown in illustrations. and fasten to the door a metal strip (C) Then put the lamps, reflectors, lens, door and the device is complete. with post card holder and hinges on same By connecting a battery and bell as an i conne't lamps with batteries. To oper- shown a slight turn of the knob either way ate put the postal or other picture in holder, will throw one prong or the other against close the door and take the machine into a (C), completing the circuit and ringing the dark room. Then hang a curtain 7x5 feet bell. on the wall and focus the lens. Contributed by ARTHUR PAUL. ,1 _. ,., , l: , i , Logt Door- /rt7ob '' e ® r--' C sing Window Latch as Burglar Alarm. l Beii s Ocbr . connecting the wires as on an ordinary r i` single -pole, single- throw switch. The latch i / may be of any metal. This is useful for ,- ia closed -circuit alarm \ ` 1 / e--e burglar circuits. Contributed by BERNARD COHEN. A SOMEWHAT DIFFERENT ELEC- Par/ cord,-- TRIC BELL. The bell herewith illustrated is very simple, but a few words may make its con- .C struction clearer. It differs from the ordi- ç nary style of bell in that it has a hinged J'J't/q B_ot-- armature instead of a spring one. The ref/ec%r clapper holder A is made from a piece of heavy copper. A hole is drilled and tapped Small lobe /n Qr - ' one Perm// I i) .b/g -1 focu.sing. !fr¿i. , NoliÍa,C,ri,,,,J,,14,,:L Home -Made Post Card Projector. Electric Call Bell Attachment for Door Knobs. DRY CELLS SHOULD BE DATED. Contributed by C. REX GILBERT. Dry batteries are useful for many experimental purposes, but have the disadvantage of giving no external indication of METHOD OF THREADING HOLES being ruts down. It is a good plan, there- IN CARBON AND OTHER fore, to label each cell with the date on MATERIALS. which it was put into use. This is espe- The following is a suggestion for thread- cially useful in connection with electric ing holes in pieces of carbon and other bells, for if a defect occurs one must sus- material without taps. Bore a hole in the pect either the bell, the battery or the wir- carbon a little deeper and with a larger ing. If the battery is seen to have been diameter than the length and diameter of in service for a long while, it will be ad- the screw you intend using. Then nick the visable to try a new cell rather than spend edge of the hole with a file or saw. Melt much time testing the wires or adjusting sufficient lead to pour into the hole, and the bell. while the lead is still in a molten state in- Contributed by H. J. GRAY. sert the screw. When the lead has hard- ened the screw may be removed with a nut should be put on the screw for con- screw -driver. venience in making the connection. In Contributed by PHIL TAUB. O O operation the bell works as follows: \\Then a current flows through the magnets the the pole 111111111111111111111111111111111 armature is drawn up against pieces which actuate the clapper. When the THE INITIAL STEP. should An Electric Bell of Radical Des gm clapper strikes the bell the arm of A "I hear, old man, that you are going in just barely be clear of the armature, thus wireless. for?" What have you got toward to take an 8 -32 brass machine screw. A breaking the circuit. The armature drops it further hole is then made in the base into back before the clapper and when the latter "A catalog, two binding posts and a which the screw will fit very tightly. Be- drops the circuit is again completed. buzzer." fore putting the clapper holder on a brass Contributed by SELMER WICK. ,

www.americanradiohistory.com March, 1916 THE ELECTRICAL EXPERIMENTER 641

AN ELECTRICAL WATER LEVEL HOW TO MAKE A PARABOLIC electroscope that has been charged with INDICATOR. REFLECTOR. electricity of known sign, either positive or negative. When the charged body which is A novel forni of electrical water level \\'hen making up electric bicycle headlights, etc., amateur mechanics are in need to be tested is brought near to the instru- gauge is described by a writer in Power. ment the leaves diverge more widely if the This arrangement is particularly adapted sign is the sanie, or collapse if it is opposite. to gauge the depth of water in shallow The usual method of giving the initial pans or reservoirs, where, for instance, the charge to the electroscope by induction is total depth is only 5 inches froni'the over- inconvenient, 'because the induced charge is flow outlet to the bottom of the pan. A of opposite sign to that of the charging float of the usual type was tried, but found body. By use of the device shown in the to be impracticable. As the illustration illustration either a positive or negative shows, a 200 -watt, 2 -coil A. C. transformer charge may be given direct, and, while was connected with a pair of lamps, which strong enough for the purpose, there is no were in turn connected in multiple to the risk of tearing the gold leaves by over- water level in the pan. The terminals in charging.

Tronsf

Parabolic Reflector Made from Brass Fistur. Canopy. il of a parabolic reflector, which can be mad, very easily as follows: Procure from any dealer in electrical supplies a brass fixture canopy of the size = 6 required and cut off part "A" as shown in illustration. Part "B" will then serve as 4C-supply the reflector. Then polish the interior and fE proceed to silver -plate same. A silver - plating fluid can be made by dissolving 1 Miniature Static Generator for Exciting Electro- Unique Water Les el Indicating Scheme. ounce nitrate of silver in 12 fluid ounces of scopes. soft water and adding 2 ounces cyanide of the tank were a pair of arc lamp carbons, A thin brass tube A closed at one end is potash. Mix this with enough fine whiting attached to a glass handle B with a little one having been adjusted to make contact to make it the consistency of thick cream, with the water just before the pan became elastic glue or other non- conducting ad- and with a piece of clean rag or cotton hesive. A broken "thistle" funnel with the dry. One side of the transformer was apply same to the polished interior of grounded as perceived. One of the lamps stem cut short and closed in a blowpipe your reflector. Let it dry and brush off flame makes a capital handle. The open was red, while the other was left plain; a the whiting and you will have a good, sil- red light indicating overflow, while a white end of the tube must be rounded, or what ver- plated parabolic reflector. amounts to the same thing from an elec- light denoted safe water level. No light Contributed by GEO. NIEDERHOFF. indicated no water in the tank. trical point of view, turned in so that the Y sharp edge is inside. This must be lined A SAFETY CHICKEN -COOP. with fur. the skin side of the fur being If one has a chicken -coop and is troubled secured to the metal with glue. A smaller A SHORT DISTANCE TELEPHONE. with chicken thieves, he may avoid this by metal tube C, similarly rounded at the open Chums can communicate with each other constructing a safety coop. end, is secured on the end of a glass rod very easily, using the following system, Take an abundance of wire screen and D, which serves as an insulating handle. provided the distance between their houses surround the coop with it. Fasten it to Mark the large tube "positive" and the small is not much over 200 feet or so. the ground so that it is firm. Then take one "negative." The small tube should be Connect the following apparatus accord- another screen of the same length and kept inside the larger one when not in use. ing to the diagram: B', electric bell; Sw. fasten it to the ground so that it is about If quickly withdrawn both become oppo- S. P. D. T. switch; R, 75-ohm telephone 1 inch away from the first screen. Take sitely charged, and either may be used for receiver; B', batteries; P, push button; G', batteries and a bell and connect them with charging the electroscope or for any other ground (connected to water pipe) ; L', line the screens as the diagram shows. When- purpose requiring a very weak charge of or wire running from one house to the ever a thief comes to eliminate some of known sign. other. your fowls, he brushes up against the out- Contributed by H. J. GRAY. Operation : When the phones are not in side screen or leans against it, and thereby i closes the circuit, ringing the bell which UNIQUE TELEGRAPH SYSTEM. may be located at any desired place. Contributed I thought that it might be of interest to by J. 'MARCHETTI. some readers to know that around Spo- i (The author of the above doesn't state what happens when a strong wind blows or when a 'non-burglar" accidentally leans . PI n w .. against the fences! Ed.) l\/% 0

1 elegraph System Utilizing Three Sounders and Common Battery. Distance Telephone Set. A Simple Short kane, Wash., some of the farmers use the use place the blade of switch on L. Now wire fences for private telephone lines. if you wish to talk to your friend push the The following connections were used by button P several times and then throw the three of us boys on a telegraph line. In blade to G. Your friend, hearing the the diagram herewith, S.S.S. are sounders, bell, also throws his blade to G and K.K.K. the keys, F.F.F. the ground con- says, "Hello!" through the receiver R, and nections, and B is a battery of either wet Pressure Against Outer Screen Rings Bell of this or dry cells. The chief advantage of this you hear the reply in your receiver. (This Chicken Thief Alarm. being used both for transmitter and re- is that there are no switches, also it is an open circuit system. ceiver.) EXCITER FOR CHARGING ELEC- When the conversation is over the blades Contributed by JOHN B. MOORE. of Sw. must be thrown back to L, making TROSCOPES. the line ready for calling again. It is often necessary to test the polarity . Shaking the transmitter will 'oftentimes Contributed by JAMES R. HOPKINS. of an electrostatic charge by means of an improve the enunciation on the telephone.

www.americanradiohistory.com 1642 THE ELECTRICAL EXPERIMENTER March, 1916

FUSE FOR BATTERY CIRCUIT. AN ELECTRIC IGNITER. pleting the circuit and the alarm is While a fuse block is not essential for This apparatus is intended for the ex- sounded. a battery circuit, there is a certain satisfac- perimenter who does not possess a spark Contributed by tion in following out the general plan of coil with which to ignite fireworks or WILLIAM WILLIAMS. large power stations, where a properly pro - chemicals at a distance. First wind two small magnets with No. 20 D. C. C. wire portioned fuse is quite indispensable. The A HANDY A. C. GENERATING SET. illustration shows a simple fuse block that I give herewith brief description of a can be made by any experimenter, the fuse Yee fblch/orate useful A. C. electric Arm. Test/ude generator which can itself being quickly renewed when neces- /ron and .rogar; be made from the parts of an old tele- sary. phone. Referring to the diagram A is a The several parts are mounted on a block telephone magneto, B a telephone induc- of wood A that has been well impregnated tion coil to step down the high voltage of by soaking it in melted paraffine wax. Two the magneto to that of small motors, bat iL109/le/J tery lamps, etc. One of the secondan =f

l'seful Electric Igniter Subject to Remote Con- trol. and make an iron armature with a spring brass arm and a clip on the end of the armature. This clip holds the test tube from overturning. When clip is released, gravity upsets the tube which contains a few drops of sulphuric acid. This falls on Tinfoil Fuse and Block for Battery Circuits. a mixture of potassium chlorate and sugar. Take equal amounts of sugar and potassium Small A.C. Generating Plant with Transformer. bolts B, B, are passed through the under- chlorate. This mixture ignites and sets fire wires of the coil is connected to the con side, the holes being countersunk to accom- to a fuse. tact D, the other to the magneto frame. modate the heads. The bolts may be an inch Contributed by tinfoil The primary wires are connected to the apart, and serve to hold a strip of ROBERT CHANDLER. binding posts EE. The base is of wood C, two brass washers shown at D being and should be of a suitable size. If the ' to avoid tearing the foil when tighten- used MOTOR RAISES AND LOWERS generator is run by a motor small inducing up the nuts E, E. The strip of foil tion coils can be operated nicely. should be of uniform width, except at the WINDOW CURTAINS. A unique device for raising or lowering Contributed by I ends, one -eighth inch or less being suffi- AN EXPERIMENTER. cient for the middle portion. If a small strip of glass F can be cut from an old negative or microscope slide and let into A SIMPLE BURGLAR ALARM. the wood between the bolts it will be an This simple burglar alarm can be at- advantage. tached to any door with very little trouble. Contributed by H. J. GRAY. A string, B, is fastened to the knob, A, by winding it around the knob a few times BUZZER TELEGRAPHS TWO then tying. The string is then attached to MILES. a switch, C, which makes a circuit with the In the October issue of your magazine contact when the knob is turned. I noticed in an article where an English Contributed by CARL HANCOCK. experimenter had sent messages over water pipes for one- quarter of a mile. He used a Raising Window Shades by Motor. a number of window curtains has been adopted by a large W.stern school, says a writer in the Electrical World. As perceived, each curtain has a cord secured to same, and these all pass over a series of pulleys down near the floor, and the cords, in turn, pass to the motor- driven drum, as indicated in the illustration. In this way a few turns of the motor will lower or raise the curtains, according to the direction .swding in which the motor is driven. These refinements are not, of course, practical in the ordinary house or hall, but in school or other buildings where there are a large number of windows which are to have their shades repeatedly changed during the day this scheme should find considerable favor. AN AUTOMATIC "FIRE" ALARM. Telegraphing by Buzzer. This device is very practical for giving sensitive galvanometer to receive signals an alarm of "fire" in any room or shop. Burglar Alarm Employing String to Connect with. It works on the same principle as the fuse; Doorknob and Switch. My method is cheaper and more efficient. I use a common buzzer and an ordinary REPAIRING SMALL TUNGSTEN 75 -ohm telephone receiver. Both gas and LAMPS. water pipes are used, and the danger of a Don't throw away your burned -out flash- short -circuit by using only water pipes is light bulbs. If the bulb itself is not cracked averted. or broken connect it across the secondary Connect the instruments as at A. The of a % or 2 inch spark coil and close the signals come in exactly like wireless buzzes. primary circuit for an instant, not longer. The farthest distance we ever tried was When you test your lamp on a battery cir- 114 miles, and the signals came in loud and cuit you will find that the two ends of the clear. Electric Fire Alarm Using Sealing Wax Fuses. filament have been welded together and the We also tried this method along the rail- a bit of sealing wax being used to break light is as good as new. road tracks. B, and it worked over a dis- the circuit. With very little heat, the wax (This does not always work, but it is tance of two miles. is melted, the steel spring then snaps worth trying.-Editor.) Contributed by B. SCHUMM. down on the conductor terminal, thus corn- Contributed by C. M. CROUCH. www.americanradiohistory.com March, 1916 THE ELECTRICAL EXPERIMENTER 643

Shellac, 5 parts of Turpentine, 100 parts of A GOOD SILVER WASH. best Spirits. Take 1 ounce of pure nitric acid, 1 silver I 10. For Russet Leather Ilaruess. -Mix dime (or, better, a Canadian five -cent piece, together 1 part of Point Oil, 3 parts of which is also silver) and 1 ounce of quick -' Common Soap, and heat up to 100° F., then silver. These ingredients are now placed add 4 parts of Oleic Acid and 1% parts of in a glass vessel and left until they are Tanning Solution (containing at least 1 -I6 completely dissolved. Then add a pint of of Tannic Acid.) Stir until cold. water and next enough powdered whiting S. G. to make the whole into a powder. This silver wash may be used on brass, copper, German silver, etc. EMERGENCY BLUE -PRINTING. Recently I had occasion to make a blue- CEMENT FOR ATTACHING GLASS print drawing in a hurry, but found I did TO METAL. not have either a frame or the blue -print large enough for the work at hand, Take about 2 ounces of a thick solution EDITED BY'S:GERNSBACK paper so the following kinks may come in handy of glue and mix with it 1 ounce of linseed Under this heading we will publish every month for some readers of your magazine. To oil varnish and 1/i ounce of pure turpentine. useful information in Mechanics, Electricity and This mixture is next boiled in a covered make frame I took down a I/ Chemistry. We shall be pleased, of course, to have the picture crock is our readers send us any recipes, formulas, wrinkles, from the wall and removed everything ex- and then ready for use. The articles being cemented should be new ideas etc., useful to the experimenter, which cept the glass and frame. I then screwed after clamped will be duly paid for, upon publication, if acceptable. four copper together for several days to allow the ce- pieces of spring on it as shown ment to set properly. in the drawing. The size of the picture FORMULA NO. 19. frame was 16x20 and, having two backs Blackings and Polishes for Leather Har- for the regular 8x10 photographic frames, A GOOD SOLDERING SOLUTION. nesses, Etc. I fixed them up as shown. This frame Procure about 5 cents' worth of muriatic s. L Harness Blacking. -Melt together 2 oz. proved to be very serviceable and filled the acid and add as much pure zinc as it will of Mutton Suet, 6 oz. of Beeswax. Add 6 requirements which were needed. dissolve. If a little rain -water is added it oz. of Sugar Candy, 2 oz. of Soft Soap, 2'' To make the blue -print paper proceed as will somewhat improve the mixture. The fi oz. of Lampblack, 112 oz. of Powdered follows: Obtain a fairly good grade of articles to be soldered should be thoroughly cleaned of every trace of dirt. The solder- Indigo. Mix thoroughly and add 14 pint drawing paper (Rives or Saxe paper, if it is with of oil of turpentine. ing solution next applied a wire g 2. Harness Blacking. -Melt together 4 oz. brush to the cleaned surface. With this of Gelatin, 3 oz. of Gum Arabic, % pint solution the solder will stick every time. t . Contributed by WM. A. of Water. Add when dissolved 7 oz. of CA\WLEY. Molasses, 5 oz. of Fine Powdered Animal Charcoal. Heat gently, stirring all the SILVER PLATED PENNIES. time until the compound is of proper con- In a solution of mercuric nitrate place a sistency when cold. Must be kept corked. cent so that the coin will be completely 3. Polish for Carriage Harness. -Dis- covered by the liquid. A chemical reaction solve 3 sticks of black sealing wax in '/> immediately takes place ; the copper. having I pint of Alcohol and apply with a sponge. a greater affinity for the nitrate than the 4. French Blacking to Restore Soiled mercury, forms a copper nitrate, causing 1 Harness.-Take 41, lb. of Stearine in thin the mercury to he deposited on the cent, sheets. Mix with 6% lb. of Turpentine. which gives it a silver- plated appearance. Heat in a water bath, during continual If mercuric nitrate cannot be bought it

stirring; then add 3 oz. of Animal Char- can easily be made by dissolving a small ' cod, place the whole in another vessel and globule of mercury in a little concentrated stir so as to prevent its crystallization. It nitric acid. warming, if necessary, to start must be warmed when using and rubbed Making an Emergency Blue -Printing Frame of the reaction. on with a cloth as quickly as possible, giv- Large Size. Contributed by PAUL JENKINS. ing it a very thin coat, and when nearly dry polish with a silk cloth. can be obtained), and cut down to the required size. Next a blue ÿ 5. Waterproof Harness Paste. -Put into make up -print HOW TO CUT BRASS AS WELL AS as : a glazed vessel and melt over a fire 28 oz. solution follows GLASS IS CUT WITH A Solution 2 ; of black resin, when dissolved add 3 oz. of A.-Water, ounces potassium DIAMOND. Beeswax. When this is melted remove ferricyanide (red prussiate), l20 grains. With a quill pen dipped in a strong solu- from the fire and add % oz. of fine Lamp- Solution B.-Water, 2 ounces ; ammonia tion of alcoholic corrosive sublimate (care- black, % drm. of Prussian Blue in Powder. citrate of iron, 140 grains. (Any propor- ful; strong poison) draw a line on the Stir well together and add Turpentine, tion of the above can be made.) brass. After letting this dry. go over the When they are thoroughly dissolved, enough to form a thin paste. Allow to mix line with the pen dipped in nitric acid. >I cool. Apply with a sponge and polish and filter, and always keep in a clean bottle. Then the metal may be broken as glass is ï with a soft brush. Be careful not to let too much strong light cut with a diamond. 6. English Ball Blacking for Harness. act upon this solution. Contributed by - The best way to sensitize is to 1 oz. of Lard, 1 oz. of Beeswax, 8 oz. of the paper JOHN SCHMELZEIS. Ivory Black, 8 oz. of Sugar, 4 oz. of Lin- work by an orange light similar to the light seed Oil, 2 oz. of Water. Melt the wax used in bromide printing in photography. MISCELLANEOUS FORMULAS. and stir in the other ingredients, and when Float the paper on this solution until it lies perfectly flat. Do not take it out of the A good metal polish may be made as cold roll into balls and use. follows : Take wood alcohol, 3 parts ; aqua 7. Vaseline Harness Composition. oz. solution carelessly. but slide it out by grasp- 1/ -% ing two ammonia, 1 part; prepared chalk, part. of Prussian Blue in Powder, 4 oz. of corners, sliding it over the surface of water. is Apply the polish with a flannel and when Lampblack, 2 oz. of Molasses, 2 oz. of Soft the If it desired to keep some of the paper for future use this can be done dry wipe off. Shake the polish before using Castile Soap. Warm and mix together in to get the chalk stirred up. a mortar. Then add 6 oz. of Vaseline, 5 by rolling it up, with the sensitized surface on the inside, and keeping in a tin box free Carpet soap can be made as follows: oz. of Ceres, 1/a oz. of Yellow Resin. Melt Three small bars of good white soap, 2 gal- 4 together and add sufficient turpentine to from light. If any part of the above instructions Ions of water, 1 10 -cent bottle of house- give proper consistency. Mix thoroughly. are % 10 not clear I shall be very glad hold ammonia. box of borax and 8. Oil for Farm and Team Harness.- to try and cents' worth of tartar. Dissolve the soap Melt 3 lb. pure Tallow, but do not heat it explain anything in doubt upon receipt of a self- addressed envelope. in water on top of stove; then add other up to a boil; then pour in gradually 1 lb. then I Contributed by A. WILSDON. ingredients. Let boil 10 minutes and neatsfoot oil, and stir until the mass is remove from the stove. cold. If properly stirred, the two articles A silver plating for steel can be made as will become thoroughly mixed and the follows: Lunar caustic, 11 parts ; sodium grease will be smooth and soft; if not well To Remove Oil Stains from Leather. - hyposulphite, 20 parts; sal ammoniac, 12 stirred, the tallow will granulate. Add a Cover the spot with Spirits of Sal-ammo- parts ; whiting, 20 parts, and distilled water, little bone black for coloring. niac; allow it to act for a short time, 200 parts, mixed together. Before applying t 9. Lacquer for Harness.-5 parts of cleaning with clear water; repeat until the silver plating to the article clean off all

Colophony, 1 part of Lampblack, 2 parts of the spot is removed, taking care not to grease. 1 Mastic, 5 parts of Sandarac, 20 parts of affect the color of the leather. Contributed by SAUL MARCUS. .i www.americanradiohistory.com 1 644 THE ELECTRICAL EXPERIMENTER March, 1916

Our Amateur Radio Station Contest is open to all readers, whether subscribers or not. The photos are judged for best arrangement and efficiency of the apparatus. To increase the interest of this department we make it a rule not to publish photos of stations unaccompanied by that of the owner. Dark photos preferred to light toned ones. We pay each month $3.00 prize for the best photo. Make your description brief. Address the Editor,

AMATEUR RADIO STATION CON- LAKE PARK RADIO CLUB. RADIO TIME SET OF J. B. TEST. The accompanying illustration portrays MACKEY. Monthly Prize, $3.00. some of the apparatus in use at the main About seven months ago, after having the Lake Radio This month's prize winner. station of Park Club at read several interesting articles in The Des Moines, Iowa. Electrical Experimenter on wireless and wireless time receiving stations and being ARTHUR CHURCH'S PROGRES- a jeweler, I became very much interested SIVE WIRELESS STATION. in a wireless time receiving station. I present herewith photograph of my Our city gave me permission to attach wireless station. The transmitter con- one end of my aerial to the water tower, sists of a 1 -K. W. Thordarson trans- which is 110 feet high. This tower being former and line protector, moulded con- 275 feet from my store gives me an aerial denser, rotary spark gap and hinged type 253 feet between spreaders (I used four oscillation transformer. wires in aerial). My store is a two -story The receiving set consists of a special building, so I only had to erect a 70 -foot loose coupled tuner of my own design and mast to make it 110 feet at that end. Now construction, three variable condensers and comes the interesting feature to the jew- fixed condenser, audion detectors and E. I. eler. On top of this mast that stands 110 Co. "Government" type 3,000 -ohm receivers. feet high over my store I installed a 500 - A pair of Brandes superior 'phones are watt Ruby electric light. I made a little also seen in the photo. A special switch attachment that you may notice in the on the left end of the cabinet throws the E. I. Co. .01 M. F. variable condenser either in series with antenna circuit or across the primary winding of receiving transformer. Radio Station of the Lake Park Radio Club. The is the type and con- Arthur Church and His Ex- aerial of "L" cellent Radio Sending and tains four wires. We can receive the fol- Receiving Set. lowing stations easily: Ames, Iowa State Teachers' College, East and West High Schools, and we also hear many near -by amateurs. The following gentlemen hold office: Roy Smith, president; French Holebrook, vice-president; James R. Allen, treasurer; Kerby Moran, secretary. LAKE PARK RADIO CLUB, Per James R. Allen, Sec'y. Des Moines, Iowa. RADIO STATION OF CHARLIE BARE. Herewith are presented illustrations of my wireless set and myself. I am using a one -half kilowatt, closed core transformer at present, with a quenched spark gap of my own make. The detectors are also of my own construction. My switchboard is placed 40 inches from the wall, thereby allowing space behind it for tools and materials necessary for making repairs. The aerial consists of four stranded wires, each î :i feet long and 70 feet high. Wireless Time Station of J. B. Mackey. A Mignon vario- selective coupler is sometimes used with very good results, but is picture, which I attached to the pendulum intended especially as a portable receiver of my regulator, making a contact every in which capacity it is admirable indeed. I time the pendulum swings back and forth, am using a multi- audifone equipment, and flashing the time out to the public in per- the received signal strength at this station fect synchronism with the time signals is simply wonderful. N.A.R. comes in at given out by Arlington (N. A. A.). The noon loud enough to be read with 'phones last minute preceding the hour of time the off -a distance of over 1,500 miles. W.H.K. light is made to burn continuous by means and several other stations are audible at of a two -way switch, going out absolutely times 40 feet from 'phones. Regular com- on the hour. This feature of wireless time munication is carried on with various sta- has proven a big advertisement for me, and tions within 300 miles. I believe it will for any jeweler. People Two aerials are employed; one for 200 in a neighboring town about five miles meter work and the other for longer wave away are able to get correct time regular out. This method of trans- length. The latter is 300 feet long, Well Arranged Station of Charlie Bare. as it is flashed stretched from a 100 -foot mast to a 60- mitting time has been reported as far as foot pole at the station. I hold a second I am also carrying a line of wireless sup- 15 miles from my store. Many people on grade commercial radio operator's license plies in my office and use my station exten- the streets, when the time is being given, and my official call is 9.W.U. sively for demonstrating. stop and compare their watches to the ARTHUR B. CHURCH. CHARLIE BARE. second. J. B. MACKEY. Lamoni, Iowa. Mt. Carmel, Ill. Uniontown, Ala. www.americanradiohistory.com March, 1916 THE ELECTRICAL EXPERIMENTER (i45

WIRELESS STATION OF ROY THE IONIZED UPPER AIR. MAX CLINCH A RADIO ENTIIUSI- WUENN. The theory that the upper layers of the AST. I am submitting herewith a description atmosphere are ionized and therefore con- As I am a regular subscriber and photograph my the Amateur to The of set for duct electricity, first suggested by the late Electrical Experimenter I take this oppor- Wireless Station contest. The transmitting Professor FitzGerald in 1893, has been ex- tunity of tendering photo of my station set consists of 11/2-inch and 2 -inch coils, tensively utilized in recent years to explain and myself for entrance in your amateur helix, rotary and stationary gaps, two con- the law of decrease of the intensity of radio- station contest. densers (one a Leyden jar condenser and telegraphic signals with distance. In an the other a glass plate type, connected to- article in the Revue générale des Sciences gether) and a key. The receiving set has Professor H. Nagaoka, of the University a De Forest rotary variable condenser, of Tokio, attributes this ionization to two Blitzen variable condenser, sliding plate causes. The first is the ultra -violet light condenser, variometer, tuning coil (800 of the sun, which he believes is capable of meters), transformer (3,000 meters), trans- ionizing the atmosphere down to aLout 40 former (5,000 meters), two fixed condensers kilometers from the earth's surface. The and three detectors, galena, commercial sili- second is the stream of electrons emitted by con and Radioson detector. The aerial con- the sun, which, owing to the magnetic fields sists of six strands on 12 -foot spreaders. It of the sun and the earth, describe paths is of the inverted "L" type, 150 feet long, far from straight and account for tl.e ioni- suspended between a 60 -foot pole and one zation of the upper atmosphere at night. on top of the house. The greater height of the reflecting layer at night and the consequent reduction in the number of reflections of the waves at Max Clinch Enjoys His Wireless Outfit Thoroly. the ionized layer and at the earth's surface account for the better transmission of sig- My aerial is of the "L" type, 300 feet nals at night. The under concave surface long, 6.5 feet high, composed of four strands of the ionized layer above a station at of antenium wire, spaced 21/2 feet apart. which the sun is rising focuses the waves My receiving set consists of Murdock from the west near the surface of the receiving transformer, variable condenser, earth, and so gives the good signals at crystaloi detector with cohering inductance, dawn. A similar focusing of the waves fixed condenser and 2,000 -ohm Brandes from the east occurs at sunset. The effect 'phones. of solar eclipses is explained in the same My transmitting outfit includes a New Complete Radio Set of Roy Wuenn. way, and Professor Nagaoka points out York spark coil, spark gap, condenser, key I purchased some of my instruments that as the period of an electrical oscilla- and 12 batteries. from the large wireless station that was at tion on the sun is 6.5 seconds, there should I have no trouble in getting Key West Michigan City. I have received many long - be a corresponding period in the stray sig- and can hear Arlington 20 feet from distance station signals, having caught base- nals at terrestrial stations. He hopes 'phones. I get most of my ideas from ball scores sent from New York to Chicago. radio -telegraphic observers will succeed in The Electrical Experimenter and could not I shall be glad to communicate with any- detecting this period exactly. This opens an afford to be without it. one within my range. ROY WUENN. interesting field of experiments for the ama- MAX CLINCH. Michigan City, Ind. teur interested in such work. Lakewood, N. J. Amateur News Radio Talks 600 Miles cussion were Mr. Pacent, vice -president of the club, of Pittsburgh Reopens Wire- Experimenter on and Mr. Greeley. University 1,320 Watts. At the December meeting Mr. William Dubilier less Plant. F. M. Corlett, wire chief of the Automatic Tele- delivered a paper on the "Construction and Opera - The University of Pittsburgh department of phone Co., at his home at 1101 East Eighth street, ion" of his well -known direct -current vibrating electrical engineering reopened its wireless plant for Oak Cliff, Texas, recently talked by wireless to nterrupter. public communication recently. With the co- the Christian Brothers' College in St. Louis. Mr. operation of the Radio Society of Western Penn- Corlett has a regulation wireless apparatus erected sylvania, the wireless work during 1914 and 1915 in his back yard which he has but recently com- was satisfactory and a number of interesting ex- pleted. periments were carried on. The plant is similar Mr. Corlett talked to St. Louis, a distance of in design to the immense Government station at 600 miles, with 1,320 watts of energy, which is Arlington near Washington. considered unusual. Radio engineers generally An extensive program is being prepared for figure 10 watts to a mile, which would have given the spring. A number of experimental tests are to Mr. Corlett a range of only 132 miles. be arranged with long distance stations. A plan is He picks up_ the time signals from the station being arranged whereby many university stations at Arlington, Va., and often "listens in" on pow- throughout the country will be organized into a wows between the United States transport "Bu- radio society. ford" and some Gulf of Mexico neighbor, A large correspondence was carried on with amateurs during the past season and it is expected this service may still be continued. The fol- Radio Club of America Meeting. lowing program has been inaugurated and will Several interesting papers were delivered at a be in force Wednesday and Saturday nights until recent meeting of the Radio Club of America, further notice: held at Columbia University, New York City, Mr. 7.30 -7.32- General call to all stations, call Q. S. Emil Simon, a noted radio engineer, read a paper T. signed Pitt; 7.32. 7.50 -Athletic results; 7.50-8 on Professor Pupin's testimony in a wireless suit Items of interest to the public (12 words per min.- between the Marconi and the Telefunken Com- ute); 8 -8.10 -News items at speed of 20 words panies. He expressed his ideas lucidly on the whole subject. per minute; 8.10 -8.30- Special tests. Due to the present patent litigations, no discussion was permitted after the paper was read. Chair- Scientific Class Organized in West man George Elty, one of the engineers who installed the radio telephone apparatus at Arlington, Hoboken, N. J. described the system and methods involved in this A Scientific Class has been organized in School wonderful radio No. 4, West Hoboken, N. J. Anthony Marino is engineering achievement. He president. The staff of workers stated that the received wireless telephone message Hook -up for Talking Wirelessly with Audion. research are John was amplified and then brought back to N. A. A. Saldavini, George Matterichi and John Reinert. on a line. We would be very pleased to correspond with simi- Mr. lar organizations. All mail should be addressed to Sadenwater, radio inspector, described a Anthony Marino, 511 Traphagan St., West Hobo- method and gave a circuit for using a regular N. J. audion receiving set as a wireless telephone trans- ken, mitter and receiver and he proved with this circuit RADIO CLUBS ATTENTION! that a distance of over a quarter of a mile can be MEETING OF Y. M. C. A. RADIO readily covered, utilizing an ordinary audion bulb. We The diagram of the connections is herewith repro- are always pleased to hear CLUB OF VINCENNES, IND. duced and it consists of an ordinary from The Y. M. C. A. Radio Club of Vincennes held Armstrong young Edisons and Radio its first meeting at the Y. M. C. A., Tues. hook -up, with a telephone transmitter connected in day, series with the ground lead. It should be under- Clubs. Send a write -up of your Nov. 30, and was well attended. The club stood that the audion must has a very able instructor, who has worked as an oscillate before it will Club with photos of members and operator on the Great Lakes. The following officers transmit any current. By placing a short circuit- were ing switch around the transmitter it is possible to apparatus to -day to: Editor "Ama- elected: Walter A. Horner, first operator and receive messages with the same circuit. president; John W, Surbaugh, second operator and teur Gossip" Section, The Electri- secretary; Clinton E. Simpson, third operator and Mr. Whitting, president of the Worcester Radio treasurer. Club, of Worcester, Mass., described in a very cal Experimenter, 233 Fulton St., All radio simple manner the exact effects that take place in correspondence from radio organiza. a complete radio transmitter employing a quenched New York City. tions and interested Individuals should be ad- spark gap. dressed to the secretary, 912 Broadway. Those Among the members who participated wishing to confer with the president will find him in the dis- at 1225 North Second street.

www.americanradiohistory.com Ç4TE5tPTENT S

Novel Electric Arc Lamp. D. The indications are given on a shown. The best feature is that of cial construction of the coherer tube. curve drawing, electric voltmeter E, the control switch. The granules when lifted by the (No. 1,159,383; issued to Richard which may be specially calibrated to magnet coil 5, will be dropped again Holsten, assignor to Siemens- indicate results in "horsepower" di- unevenly, thus conducing to the reg- Schuckertwerke G. M. rect. ElectroHydraulic Gun. ular and reliable resetting of the B. H.) (No. 1,167378; issued to Rollie device. A constant and sharp criti- Electrical arc lamp employing for Calvin Hill.) cal voltage value can be obtained the lower electrode a suitable cup - Holder for Crystal Detectors. This patent covers the use of with this improved coherer it is shaped chamber A, into which a con- water or other fluids in combination claimed. tinuous and properly regulated (No. 1,162,765; issued to John J. with an electro- magnetic propelling stream of fine particles such as pure Gliegan.) mechanism for the ejection of pro- carbon (or any desired mixture of jectiles from a cannon. The patent carbon with other substances which describes a double solenoid arrange- emit a strong light, such as me- ment whereby a switch can be tallic salts and the like), are fed. thrown so as to push or pull an iron The arrangement is apparent from plunger within the solenoid. When the illustration. The changing length pulled backward, it sucks in the liquid from a tank 15 and when the An improvement in wireless min- solenoid is switched to the firing po- eral detectors giving great ease of sition, the plunger is rapidly pro- adjustment by virtue of the ball pelled forward, simultaneously clos- joint support of the vertical pillar, ing a check valve in the suction pipe carrying the cat- whisker contact. The 14, and ejecting the projec ile 17, by horizontal arm is also pivoted so as virtue of the sudden, rise in the hy- to be adjustable to any position de- drostatic pressure thus obtained. sired. The contact wire can thus be swung up, down, or sidewise, also forward and backward. Electric Hand Lantern. (Na 1,163,887; issued to Charles F. Burgess, assignor to C. F. Burgess Laboratories. Heavy Current Microphone. An ingenious electric lantern at- (No. 1,165.255; issued to Charles D. tachment suitable for use with Herrold and Emile A. B. standard dry cells is here shown. Portal.) The inventor provides a small rheo- A clever design of water cooled, stat in the end of the handle at 17, heavy current microphone is here to protect the lamp when first used depicted. This patent covers the on a fresh cell. 23 is then thrown arrangement for utilizing a multi- in contact with the shell 19, leaving tude of water cooled chambers on tbe resistance in series with the the end of each of which there is lamp. As the battery begins to mounted the usual microphone lose its energy the switch is pushed chamber with carbon grains, etc., 4. into a vertical position and the lamp These microphone uniti are all se- burns direct. This attachment can cured to a common metal diaphragm be adapted for use on two dry cells 3. The various water cooling sham. with a strap around them. hers are so piped that water enters into the first one of the group and of the arc controls a magnetic clutch F'p ! which feeds the pulverized carbon from a hopper E through the medium of a worm M. The metal salts may be injected separately through a hopper D, controlled by the magnet IV. A very interesting patent. .6

An Electric Fly- Catcher. Electrical Horsepower Indicator (No. 1,165,712; issued to Frank for Engines. Rea, assignor of one-half to (No. 1,159,769: issued to Walter IL Arthur M. Sheakley.) Ilolistein.) Another electric fly- catcher is In electrical forni of steam engine here shown which involves the use indicator for ascertaining the horse- of a small fan of special design. power developed is covered in this -The metal chamber about the fan is patent. It appears to be quite feasi- of peculiar shape and terminates in ble and a distinct advantage in this a metal wire cage 13. The appara- line. As perceived from the illus- tus may be plugged into any lamp then passes consecutively throughout socket and consumes but little cur- the entire number before it leaves rent. In service the flies or other the transmitter. The design should prove efficient if the size of the Pr; diaphragm 3 can be kept down with- Telephone Cord Guard. in normal limits. (No. 1,164,563; issued to Oadville Yates, Sr.) Portable Electric Lamp. The inventor of this attachment (No. 1,166,003; issued to Adolph C. for taking up slack telephone cord to Recker, assignor to Waterbury avoid abrasions, provides for the Mfg. Co.) purpose a spiral wire spring with This patent relates to portable small hooks on each loop of the electric lamps, particularly of the spiral. The telephone cord is candlestick variety. Flashlight bat- wound around this spiral on the in- tery of the ordinary type fits within side of it. When the 'phone is un- a shell or chamber 7 The flash- moved, the spiral appears as in the light bulb is seen at 8, and the cir- illustration, but when the 'phone is cuit from the battery is completed through a switch 11. This switch

insects are drawn in through the opening 11. The fan blade appears Fr 1. at 10. tration the piston rod or cross -head a' controls a belt secured to it and Coherer and De- Coherer. also to the shaft of a small dynamo (No 1,167,163; issued to Crosby C. The current from this dynamo field Frank assignor to passes through a resistance D. The General Electric Co.) changing steam pressures in the cyl- A reliable form of the filings type inder A, actuates the spring con- coherer suitable for transmission trolled rheostat arms b° and b10 by line signaling or for other purposes. means of pistons. These rheostat The patentee mentions the use of arms slide over contact points as blade is pushed against the end of granules of nickel specially prepared. shown in Fig. 2, which lead to the the battery by a convenient thumb- The de- cohering is done by means of moved, it expands. A guard is also different turns in the resistance coil actuated pin, pivoted in the manner a magnet coil shown and by tbe spe- indicated for protecting the cord. COPIES OF ANY OF THE ABOVE PATENTS SUPPLIED AT 10e. EACH

www.americanradiohistory.com March, 1916 THE ELECTRICAL EXPERIMENTER F).}q Phoney Patents Under this heading are published electrical or mechanical ideas which then you haven't a smell of the Patent yet. Alter they have allowed our clever inventors, for reasons best known to themselves, have as yet the Patent, you must pay another Szo.00 as a final fee. That's $40.00 I I not patented. We furthermore call attention to our celebrated Phoney WE PAY YOU $)w1/ and grant you a Phoney Patent in the bargain, Patent Ofnzz for the relief of all suffering daffy inventors in this coun- so you save $.tt.00 I I When sending in your Phoney Patent application, try as well as for the entire universe. be sure that it is as daffy as a lovesick bat. The daffier, the bet- We are revolutionizing the Patent business and OFFER YOU THREE ter. Simple sketches and a short description will help our staff of DOLLARS ($ .00) FOR THE BEST PATENT. If you take your Phoney Phoney Patent examiners to issue a Phoney Patent on your invention Patent to Washington, they Charge you $so.00 for the initial fee and in a jiffy. PHONEY PATENT OFFIZZ No. 40' 15' 7" N E by E. Patent Applicated Feb. 30, 1916. THE ELEGGTRICAL EGG EGGSTRACTOR

Be it a secret to all: 11 and without warning swings h onto con- then suddenly lands on conveyor 21 and That I, Egg S. Natcher, of Yolkville, in tact 12 and then continues its explorations. gets a raise up, up and over into receiver the State of Remorse, have devised certain The switch 11 cuts off compressed air sup- 22. It rests here awhile from its labors

improvements worthy of notice by egg ply and resets switch 6 by means of electro- but is quickly awakened by the alarm clock, . swipers who desire to eggstract the eggs magnet 13 and also rings bell in house to which closes a circuit, energizes magnet 24, from a nest without eggciting the egg - warn the reception committee of the ap- and drops it down through tube 25 into the makers. proach of their guest of honor. tomb 26, wherein it is stored. The alarm The attached specifications and drawing The egg, then, egglike rolls against the advises the house of the arrival of the expose all the inards of the machination wheel 11 and turns it one notch. On the newly born. and lay bare the devilish details of my wheel is arranged a projection that as the In testimony hereto, thereof, I attach my method of coercing the feathered bipeds to wheel completes a revolution makes con- handcuff and seal -packerchief this yester- deliver up their contraband goods without tact with 16. Instantly electro-magnet 17 day of to- morrow in the City of Yolkville. the necessity of de- claring a blockade. Considering the details of this night- mare, at 1 is shown an ediffice known as a hen house, named after the inhabitants who abide or reside therein. The chicken on becoming ambi- NAY// / //////// / / / 11.1 / / / / N 4 VI ll/AY/ r t // / / Af tious mounts corru- gated pathway 2 leading to the nest. The weight of her wait on the board com- presses bellows 3 and thus pumps air into tank 4 and is there stored. The hen then passes into the boudoir 5, at which point, dear reader, we gently draw the curtain. A few minutes and the click of the switch 6 is heard as it is pushed onto contact 7 wiBSO!) by the egg. The clos- arv+iMi+ wr YGbaflzd`óii ing of the switch re- %///A7A MO//% I/G leases a stream of 1/111///1 !(llArrrua yr/ r/, y/. 7 f C r/// .' compressed air from r/ / rOl / I I////// . %N / I L tank 4, which flows 1/////1//4 %// %/H//tr/i through pipe 8 and gently but firmly Time -saving Invention for Eggstracting Eggs from the Nest Without makes it evident to the hen that her pr esence is no longer 'acts, opens door 18, allows feed to flow (Signed) Ecc S. NATCHER, required. from hopper 28 into pan 19 which, on be- By his attorney, 1 The lonesome and unloved egg rolls then coming full, settles gently down on the Geo. M. Gray, onto conveyor 9 and thence through under - spring, opens contact 20 and thus hopper Needham, Mass. ground tube 10. With a rising and fall- door is closed by its own weight. Witnesses: Sol. Idivory, Hen Nery, R. ing, sinuous motion it approaches switch But to follow the egg. It is rolling along, O. Oster. THE "ARLINGTON" BUG? ton was sending, what? -Ed.) "Vis, sor." was the calm rejoinder of This is an introduction to one of Dame Contributed by Pat. "We talked over the tilephone, sor." PAUL SHNEY. Nature's curiosities and mysteries! X- ?? F. The other night I was awakened by a HEARD OVER THE TELEPHONE? THE TUNELESS SOLO. shrill -. .-, and thought I must have Pat was called into court to testify to Signor Marconi. the wireless inventor is dreamt it; but I heard it twice before going a talk that he had had with the defendant likely to prove of great value to his coun- to sleep. The next morning we found a in a civil suit, and everything went along try in the present crisis. large green winged insect which I sus- as swimmingly as a flock of bullfrogs un- An amusing story is told about a reply pected of working its "transmitter" on til the lawyer attempted to bring out the that the celebrated inventor once made to Arlington's call. (N. A. A.) important points of the conversation. a lady who mistook him for his equally I would not believe this story myself, if "Now. then, Pat," said he, encouraging- famous compatriot, Mascagni, the com- someone else told it, but would like to ly, "please tell the court what you and the poser. know if anyone else among the Electrical defendant talked about." "Oh," she said, gushingly, "I'd love to Experimenter's readers has had the same "Iris sor," answered Pat, willingly. "We hear you play your beautiful 'Intermez- experience. talked about 15 minutes." zo!'" (If the "green" bug had an "antenna" it "No, no, no!" interposed the lawyer. "I "Madam," replied Marconi gravely, "I'll probably was tuned to the tune of "N. A. mean what did you and the defendant talk do it with pleasure if you've got a wireless A.," which caused it to sing when Arling- over ?" piano."

www.americanradiohistory.com 648 THE ELECTRICAL EXPERIMENTER March, 1916

This department is for the sole benefit of the electrical experimenter. Questions will be answered here for the benefit of all, but only matter of sufficient interest will be published. Rules under which questions will be answered: t. Only three questions can be submitted to be answered. a. Only one side of sheet to be written on; matter must be typewritten or else written in ink, no penciled matter considered. 3. Sketches, diagrams, etc., must be on separate sheets. Questions addressed to this department cannot be answered by mail.

WATCH DEMAGNETIZER. but this can be lengthened by using the than any other form of aerial, but the same (448.) William H. Kelly. Holyoke, filament at a lower incandescence, i.e., by amount of wire used in a single line would Mass., wants to know the number of feet using a rheostat. make a far more efficient antenna for your of copper wire required to build a 110 -volt A. 3. Your storage battery will operate receiving purposes than most other types. a.c. watch demagnetizer. the audion bulb for about 40 days if used A. 2. Although this loose coupler with A. About 1,000 feet of No. 30 B. & S. but two hours each day, without recharging. both windings wound with No. 26 wire gauge copper wire would be necessary. would be almost as efficient as if wound This should be wound on a brass form or WIRELESS BOOKS. with No. 24 and No. 28 wire respectively, bobbin, having an opening large enough to (452.) Fred W. Jameson, Leavenworth, yet it is advisable to have the windings of admit a watch. The length of the spool Kan., asks for information on the follow- different sizes of wire. This depends upon should be about two inches. ing: 1. The title of a book on the con- the type of detector employed, i.e., whether struction of high grade wireless apparatus. potential or current actuated. TRANSFORMER. 2. Whether the primary of a loose coupler (449.) C. L. Bauman, Cherokee, Ia., should be wound with stranded wire, and PROBLEMS IN ELECTRICAL asks whether he can employ a 16 -cell bat- if the loading coil used in connection with WORK. the coupler should he wound with the same (454A.) Jas. A. Davis, Pittsburgh, Pa., size wire. 3. The location of an antenna sends us several electrical problems: 1. in regard to a high voltage transmission How many amperes will a 22 h.p. dynamo line. produce, the output of which is 120 volts? A. 1. We can recommend two excellent What is the resistance? 2. A relay has books covering this subject, which are pub- four windings of 10, 20, 25 and 80 ohms lished by The Experimenter Publishing connected in parallel. What is the resist- Co. They are "How to Make Wireless ance of the relay? 3. If .08 amperes flows Sending Apparatus" and "How to Make through a keyboard lamp, what is the dif- Wireless Receiving Apparatus," which are ference of potential? sent prepaid for 25 cents each. A. 1. This dynamo will produce 136.7 A. 2. The primary of a high grade amperes. The resistance is .087 ohms. loose coupler should be wound with These results were obtained by multiplying Mechanical Break for Spark Coils. stranded wire. While the loading coil may the 22 h.p. by 746 watts and dividing the tery plant of 32 volts and 120 ampere hour be wound with the same size wire as the product by 120 volts, which gives the am- capacity to operate his flexible step -up loose coupler, it is better to use a larger peres. The resistance is obtained by sub- transformer. size wire for this instrument. stituting the values in the following E A.. The transformer can be successfully A. 3. It would be all right to place a operated from this plant by employing a 200-foot aerial directly over and at right formula : R = - suitable interrupter. This interrupter may angles to the 2,300 -volt line. It is also I be of the independent magnetic or mechan- advisable to use means to prevent acci- R in ohms, E in volts and I the current in ical break type. The accompanying illus- dents resultant from having the antenna amperes. tration gives the connections for the inter- fall on the transmission line, which would A. 2. The answer to this problem is 4.9 rupter and transformer. be dangerous in the extreme. ohms. This result was obtained by substituting the values given in this formula: LOUD SPEAKING RECEIVER. WAVE LENGTH OF COUPLER. 1 (453.) Leonard Mabbott, Aberdeen, S. R= ( -150.) Buran Studdard. Leavenworth, D., wishes 1. wave length 1 1 1. 1 Kan., asks us several questions which he to know: The of his loose coupler. 2. The reason he can would like to have answered. 1. The cost -+ -+ - +- a with one hook r r, ra rr of a telegraphone, as described in the hear certain station -up and June. not another. 3. The positions the where r and r,. etc., stand for the given 1915, issue of The Electrical Experimenter. with of slider of a loose coupler when it is at its resistance values. 2. The price of a loud speaking telephone A. 3. We cannot say what the difference receiver. lowest and highest capacity, respectively. A. 1. The maximum wave length of potential is as you do not state the re- A. 1. that The cost of the experimental can be obtained loose coupler sistance of the circuit. It is necessary in be in the from the you telegraphone would neighborhood describe is 1,800 meters. order to obtain the difference of potential of $75, although this amount would be re- A. 2. The reason for your not being of any circuit to give both the current and duced if built by yourself. able to amateur you men- resistance. A. 2. A. loud speaking re- hear the station telephone with loose is ceiver would cost $25 of type be used tion the coupler circuit that the to the wave length is longer than the trans- PUMP USED FOR GROUND. in place of an 75 ohm ordinary receiver. A mitting wave from the other station, but (455.) Experimenter, Jackson, Mich., plain independent type loud speaker com- wishes to know: 1. Whether a pump could plete microphone rheostat for bat- this can be remedied by connecting a with and variable condenser in series with the tery circuits costs about $5. ground. A.. 3. When the sliders are at the start- AUDION BULBS. ing end of the winding of a loose coupler, (451.) Edward Law, Clarksburg, W. the instrument is being used at its minimum Va., wants to know: 1. Whether a 6 -volt capacity; conversely, when they are at the 40- ampere hour storage battery will operate opposite end of the winding the maximum an audion as well as six dry cells. 2. The wave length capacity is reached. average life of the tantalum filament of the audios bulb. 3. The length of time ANTENNA QUERIES. - Q455. such a storage battery will last. if used (454.) George D. Hankins, Yorktown, but two hours per day in connection with Ind., 1. Sends us a diagram of his antenna, Ja fra/7srniffer EE the audion. and wishes to know whether a better type A. 1. The 40- ampere storage battery could be designed with the same amount will successfully bulb 2. Hook -up for Eight -Wire Aerial, with Change. operate the audion of wire. The efficiency of the loose Over Switch. and, in any case, it will be more satisfac- coupler described in the September, 1915, tory than the dry cells for this work. issue of The Electrical Experimenter. be used for a ground. 2. A. diagram for A. 2. The average life of the tantalum A. 1. A straight four -wire antenna an eight -wire aerial constructed in such a filament in the auction is about 400 hours, would be more efficient for transmitting (Continued on page 650.)

www.americanradiohistory.com March, 1916 THE ELECTRICAL EXPERIMENTER 649

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It contains the largest assort- I t contains 658 illustrations, 2,000 = ment of Wireless and electrical articles, complete Code Chart experimental shown apparatus of Morse, Continental and Navy in any catalog published. In addition are shown Commercial Codes. sixteen- page "TREATISE Wireless Sending and Receiving ON WIRELESS TELEGRAPHY," Outfits, Electric Motors, Dyna- list of Call Letters of U. S. Gov- mos, Flashlights, Medical Bat- ernment and Commercial Ship = teri es, High Frequency :Apparatus, Plating Outfits, Toys, Printing ELECTRO and Shore Wireless Stations, Presses, Tools, Sporting Goods IMPORTING besides a great many useful SP' COMPANY t. and the LARGEST Scientific s' tables, and formulas. This val- section published. This 236 Fulton Street, Book New York City, uable book is will you 6% x 534 inches a book give as much M- I enclose herewith 4 N formation as many books that cents in stamps or coin for in size and 3,4 inch thick, and you $1.00 which please send me your well bound. IT IS FREE cost or more. SEND latest Cyclopedia Catalog No. 16 SENT FOR THIS WONDERFUL containing 275 pages, 658 Illustra- FOR 4c. TO COVER POST- BOOK TO -DAY, WHICH IS .4/ tions and diagrams, including Treatise on Wireless Telegraphy, complete list of all AGE ONLY. FREE. YOU TO PAY 4c. % U. S. Wireless Call Letters, and 20 coupons for FOR POSTAGE ONLY. your 100 page Free Wireless Course In 20 lessons. \1 E.E. 3 Name

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QUESTION BOX. (Continued front Page' 648.) Watch for Watch for manner that four wires may be used for Our New Electro -Set News Our New transmitting and the whole number for Catalogue Catalogue receiving. Published by The Electro -Set Co., Cleveland, 0 A. 1. The pump can be successfully employed for a ground. A.. 2. The MARCH, 1916. 1874 EAST SIXTH STREET diagram herewith shown gives the constructional details of an eight - wire aerial to be used in the manner you specify. ANTENNA EFFECTS. Auction "B" Batteries -50 Volts!! (456.) John Bedford, Morsemere, N. J., to know: 1. Whether a 110 -volt FOR THE NEW MODEL AUDION DETECTORS a.c. line would affect the reception of messages through an antenna placed four feet THE ELECTRO -SET COMPANY announce the development of a new, high potential battery for distant. 2. Whether a '/ k.w. transformer Audion Detectors. would transmit 40 These batteries have been developed for us in the most complete laboratory of its kind in the world. miles. They are especially designed for long shelf life and voltage main- A. 1. The 110 -volt a.c. line would affect tenance and are a long step forward over the old makeshift flash- your receiving antenna if they are parallel light batteries formerly used for the purpose. Dry Storage Cells effi- to each other. You could eliminate this Electro-Set Audion B" batteries will not only increase the CAN BE RE" a trouble by ciency of these splendid wave detectors, but will also prove consider- _ tet CHARGED 300 changing the position of your able saving over the old type, both in initial cost and maintenance. TIMES. aerial so as to be at right angles to the The open circuit potential of these bat- One 50 one -Set charge a.c. line. Another way of eliminating this teries is about volts; Electra has ergy of Audion 'B" battery replacing 12 flash- sevendry cells. trouble would be to erect a second antenna light batteries. 400 ampere. of a larger size The new model Audion Detectors have gn1'hshort at right angles to the 110 - longer celi. are volt line and ground same. This will been reduced in price and are no fur- the newest de- ab- nished with batteries of any description. velopment in the sorb the effects from the a.c. line and thus Our new "B" batteries will, therefore. be a welcome product to the trade. forage battery the smaller antenna will be freed from They are recommended over any other form of battery for the field. the They may he disturbance. purpose. used in any posi- Price, each, 50 volts tested and guaranteed $3.50 tion, are easy to A. 2. A 1 -k.w. transformer can readily Shipping weight 8 lbs. transport, cannot transmit 40 miles, and would generally NOTE: Electro -Set Audion "B" batteries are designed only for MOM or corrode, have be used for any other continuous duty. and are ideal for a longer range if properly connected Audion use. They are not to experimental and work of any description. tuned. Why Buy Minerals on a Gamble? Each cell develop. twn volt. in The least expensive and the most important part of your wireless full charge and has, a capacity of 20 ampere hours. They are con - RADIO HOOK -UPS. equipment is the mineral in your detector. in shape being about of An expensive receiving equipment will do only mediocre work if the the tenta me dimensions and eise as (457.) Sidney Rosenthal, Brooklyn, N. detector is not sensitive. Don't Neglect This Important Point. an Binary dry battery. Y., 1. Wishes READ WHAT OTHERS SAY! The price is so low that any ex- us to give him the hook -up A few letters selected at random from our files. perimenter n for a receiving set comprising a tuning coil, e long run, theya much le Milan, Ohio. expensive than dry cells and any fixed condenser, galena detector, buzzer The Arlington Tested Galena Crystal that I bought of you some time garage will charge them at very ago has given the best service, by far, of any crystal I have yet used. low cost. Yours very truly, RALPH H. SAYLES, Jr. If you have 110 volt direct Ind. house current, these batteries may 4.14 FL. N. Manchester, be merely L- N A A Tested Galena. It is more satisfactory than charged by I received your ing them In series with 1 -100 advertised. Yours truly, EUGENE SMITH. watt lamp or 4 -25 watt lampe in Purcell, Okla. multiple J'=l I received the N A A Minerals last week, and I want to tell you that USES: Audion detectors (filament bat. 4 iNVJ better results have been obtained with them than with any other. tericel. ó t Yours truly. JACK GILLETTE. Portable and Stationary Wire - It costs mighty little to get extremely sensitive minerals. But it re- leea Sete. quires caution. Look carefully where you buy. To be sure accept only Automobile Lighting. ElectroSet !fireless Minerals. Every package marked thus Experimentalpile. Hand ne. -C. Stationary Engine Ignition. In fact, these batteries may be ÿ. Buzzer/es/ 0 GENU E ECTRO-SET MINERAL used in place of any other type of 457 storage cell. Allow 1 cell for every 2 volts required (i.e., for 6 volte use 3 cello. 04*`Cat/Yba{4/PgFS. e) Shipping weight 51hs. Simple Wireless Receptor-Circuit With Tuning Price. each...... 52.00 Coil. SEND FOR CIRCULAR. THE PRICES ARE HIGHER. test and receivers. 2. Also if They have to be. Our buyers scour the world for these supremely two persons good minerals -but remember. after all. that even Electra -Set Minerals The Mineral Detector can operate separate receiving sets from are not too high priced for the smallest pocketbooks. the same aerial. ARLINGTON TESTED MINERALS A. 1 The illustration herewith shows INDIVIDUALLY PACKED AND TESTED. the connections for the instruments you N A A Galena. each crystal carefully tested by experts for distant stations. Individually wrapped and packed in wood containers. Postage mention. paid 23e. At 2. It is possible for two receiving N A A Silicon, individually tested, wrapped sets to be operated from the same aerial, and packed. Postage paid "Sc. N A A Zincite Couple, specially selected, but the energy received in either one set tested and packed. Extremely sensitive. We have greatly improved our would be considerably reduced, unless the Postage paid 50e. popular No. 1603 Detector with no in price.Thia wave lengths utilized are quite different in Triple "A" Grade Electro-Set Minerals type mineral detector is the most convenient and easily ad- value. Packed in convenient one, four and six- iueted ever produced. teen ounce cartons. In connection with our famous L These ultra- sensitive minerals are the only super ROTARY GAP. ones you should buy. ook for the original signature on the wrapper. Sensitive detector ease your coould (458.) Rudolph Wensko, Cleveland, O., PRICE LIST OF TRIPLE "A" GRADE MINERALS in appearance and 1. 1-oz Can 4-oz Can 16-oz Can generous in sise. inquires: Whether a rotary gap will Galena 25e. 60e. $1.50 The cat whisker wire is easily work on a V2-k.w. transformer coil. 2. At Silicon. 75e. removed, and replaced the 25e. 2.50 Special Chuck Holder. what speed must an amateur be able to Bornite. 25e. 75e. 2.50 Minerals are readily inserted in obtain Copper Pyrites 25e. 60e. 1.50 and are firmly held in good con- send and receive signals order to Iron Pyrites 25e. 50e. 1.50 tact. Any degree of pressure may an amateur license. 3. The manner in Mo!ybdenite 25c. 70x. 2.00 be brought to hear on the min which the taps of a Navy loose coupler are Carborundum 25c. 60e. 1.50 m. Price, paid 51.25 2 incite, Pure, per % oz. Can, 50e. Prices are prepaid postage connected, so that one turn at a time may be obtained. A. 1. A rotary gap can be successfully 1874 E. 6th St. operated on a 1, -k.w. transformer coil, but Dept. 510 v/P Electro-set Co. Cleveland, O. a quenched gap is best. A. 2. An amateur must be able to receive and send at least 10 words per minute SEND 4c. IN STAMPS FOR CATALOGUE to obtain a government radio license. He must also be familiar with the technical li You benefit by mentioning "Tite Electrical Experimenter" when writing to advertisers.

www.americanradiohistory.com March, 1916 THE ELECTRICAL EXPERIMENTER 651

details of radio apparatus to a fair extent. A. 3. A description of the Navy type loose coupler was published in the Septem- ber, 1915, issue of The Electrical Experi- menter, which included the method of connecting the taps so as to obtain single turns Multi -Audi - Fone at a time. The new wonder in the wireless world. It increases the Audibility 1,500 Times RADIO TELEPHONE. (459.) Edward C. Jones, Jr., Fairmont, W. Va., wishes information as to: 1. We Guarantee Everything We Make! We Guarantee Everything We Say! Whether there is an inexpensive wireless telephone set available that can transmit three miles. 2. If it is possible to construct Every Business a wireless telephone with a 1 -inch spark Man should have coil, microphone, etc., and obtain good re- Every County At- of the one of our Detec- sults. 3. Whether a dictaphone, should have torphones if he type described in a recent issue of The torney one of our Detec- wants to know Electrical Experimenter could he used as which of his em- an amplifier. torphones if he ployees is plan- A. 1. As far as we know there is no wants to know what ning and plotting cheap wireless telephone for the use of the offenders are plot- tobringonastrike. amateur on the market, but we would sug- Radio Telephone ting. Every Detective gest that by writing the should have one and Telegraph Company, of New York find EveryHotel should of our Detector - City, you would no doubt be able to phones if he out ifi any such telephone is for sale at a have some rooms wants to succeed, price within your reach. equipped with our for you can tell A. 2. It is possible to construct a simple just what the fel- wireless telephone outfit by employing a Detectorphones in order that they low you are after 1 -inch spark coil, microphone. etc, but is saying even the results would be very poor on account may detect and in the faintest of the unequal sparking rate of the gap eject objectionable whisper, fort y which gives irregular sounds at the receiv- characters. feet away, in the ing end, and also due to the low frequency garret or in the of the sparks. Although the results may cellar. be bettered by using several spark coils Price, $35.00. connected in parallel so as to form a multiple sparking gap, which will increase the sparking rate of the complete device of UN- DAMPED -WAVER. TWO STEP MULTI -AUD1- course. Even then the speech at the re- FONE. ceiving end will not be clear. This outfit Do you want to get Nauen. Han- will transmit over a short distance of, say. over, Sayville, Tuckerton, San Are you a jeweler? Do you want about a mile or more. A very short spark Francisco, Honolulu and the Naval Arlington time shouted to your gap must be used, about the thickness of Arc Stations on just a good, or- visitors every day at 12? Are you the paper of this page. dinary Aerial? Do you want to a teacher of wireless? Do you become thoroughly familiar with want your 500 students to read the DIAGRAM FOR UNDAMPED WAVE the action of the new valve cir- signals? Both of you men should RECEIVER. cuits? Then you want our Un- have our Two Step Multi -Audi- (460.) Reginald Pink, Bronx, N. Y., Damped- Waver. Fone with its Trumpet Horn with wishes us to give him the following in- specially wound Head Set. Price, $100.00. formation: 1. A, diagram of an undamped Price, $75.00. wave receiver employing the audion. 2. The size of wire employed in winding the various coils. 3. Whether the Electro Im- MULTI- AUDI -FONE. porting Co.'s Mignon Vario- Selective coup- TELEPHONE VOICE MULTI- ler will receive undamped waves with an Do you want to get a lot of stations PLIER. audion. you do not hear now? Do you want Are you hard of hearing? Are your A. 1. The accompanying illustration to get those you now hear Telephone lines or connections poor? gives the proper hook -up for the reception only of undamped waves. employing the audion. faintly and unsatisfactorily, clear Are your long -distance calls weak? The capacities of the various condensers and strong, often even audibly? Do you want to know exactly what are given. Condenser X is optional but is Do you want to enter a new Wire- the fellow at the other end of the strongly recommended. less World? Then you want our line is saying? Then you want our A. 2. The secondary loading coil is Multi-Audi-Pone. Telephone Voice Multiplier. wound with No. 28 B. & S. copper magnet Price, $30.00. Price, $15.00.

Everyone of these instruments is one hundred fold better than any other instrument of its kind. If you don't believe it -try them. If after a ten days' trial you are not surprised and more than satisfied-we will return your money. Will any one else do this? Tear this out and ask for information about the instrument that interests you by writing its name Audion Circuit for Reception of Undamped Waves. here wire on a tube 4 inches diameter, 30 inches long; while the winding of the Send for circular "wing" coil today 273 Morris is of No. 30 B. & S. copper magnet wire MULTI Ave. Ask your dealer to- morrow wound on a similar size tube. -AUDI -PONE ELIZABETH, N. J. A. 3. The coupler you mention may be successfully employed for the reception of You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. www.americanradiohistory.com 632 THE ELECTRICAL EXPERIMENTER March, 1916 undamped waves with an audion, with the addition of the inductances just described. BREAK -IN SYSTEM. Chicago Wireless Headquarters (461.) Elmer C. Lundy, San José, Cal., asks: 1. The length of time for which an CLOSING OUT LARGE LINE OF RAW MATERIALS, PARTS, Etc. amateur license is issued, 2. What device ROTARY VARIABLE CONDENSERS will eliminate the flickering of the lights when operating a transformer on 110 volts Only transparent rotary variable condenser a.c. 3. The connections for a satisfactory made that can be screwed down, filled with oil break -in system, using a rotary spark gap. to increase capacity and has binding posts on A.. 1. An amateur operator's license is where issued to cover a period of two years, while bottom they belong. The 43 plate con- a station license is given for one year only. denser has a capacity of .001 m.f. The 17 plate These licenses may be renewed by applying has a capacity of .0003 m.f. to the chief radio inspector of your district, sending him affidavits to the effect No. 9240 -17 Plate Rotary Variable Condenser, $2.25 that the applicant's station has been in No. 9241-43 " " 46 3.75 operation for the preceding six months. A, 2. A kick -back preventer will sometimes help to eliminate the severe flickering No. 125. TUNGSTEN of lights caused by the operation of a NICKEL VEST POCKET transformer on 110 -volt a.c. lines, but a FLASHLIGHTS with Tung- sten bulb and Ever-Ready choke coil is invariably required in series No. 10. TUNGSTEN FLASHLIGHT Battery complete. 45e. with primary circuit. 6 inches long, complete 650. Extra bulb, 15e. 'Extra battery, 200. A. 3. The illustration herewith shows Extra battery...... Oc. Extra bulb 150. 60 and 100 Watt Nitrogen Lamps use FINE 50e. POCKET CIGAR LIGHTER less current; give white light. Turn the wheel. Flint good for 5,000 lights. 60 Watt ß5c. 100 Watt 90e. (2 for 250.1, or each 15e. New Flints, 50. 6 for 250. We carry a very complete line of Wire ess Apparatus in stock, being Chicago headquarters for the Electro Importing Co. Same prices, same goods and Free Wireless Course. Lionel Trains. Motors, Transformers, Wireless Outfits. Structo Metal Building Material, Automobile and Electrical Supplies. Send 4c. in stamps for complete catalogs.

LA SALLE LIGHT COMPANY, 134-136 N. La Salle St., Chicago, Hl., Opposite City Hall NEW WIRELESS WONDER THE INSTANT RADIOGRAPH Greatest invention of the Age. The result of years of experimentation. Break-in Hook -up for Radio Sending and Receiv- Abolishes detector troubles and adjustments - ing Circuits. No more delays -no more lost time and messages Pick up your receivers any time. Summer or Winter, in any atmospheric conditions and- the connections of a break -in system, including a rotary spark gap in the trans- You Can Receive Instantly Without Any Adjusting mitter. 3,000 miles is latest record of the Instant Radiograph. It is wonderful, but .rue. you cannot get the Instant Radiograph out of adjustment no matter how you knock it about. Try it yourself, hit it with a hammer while in use. KITE AERIALS. Vibrations, jars, knocks cannot affect it as there are no fine adjustments to make -no batteries-. (462.) Ira Hull, Zenith, Kan., wishes nothing to wear out -no operaung expense whatever. advice: 1. As to the size of wire suitable INTRODUCTORY for an aerial that is to be supported by a PRICE FOR Malay kite. 2. The number of feet of wire MARCH 3.00 which said kite can support. 3. The wave length that can be tuned with such an an- The Instant Radiograph is more efficient than any detector on the tenna, one loose coupler and one loading market. as there is nothing to adjust. The Instant Radiograph is beautifully and solidly constructed on a coil. heavy base of hard rubber 4 x 4 inches square with rounded cornera and A. 1. No. 22 B. & S. bare copper wire 43á inches high; binding posts are made of non -corroding metal, heavily can be used with for the aerial sup- silver plated, and have heavy rubber -covered thumb screws, preventing success current leakage. All contacts are large, non- corroding. heavily ported by a Malay kite. silver plated, of large size and will last a lifetime. This Is a A. 2. The kite will be able to carry wonderful instrument of distinctive appearance that yo u will be Cut i- Actual Size. wireless station. about 1,000 feet, although this length could proud to have in your finer wire. The Radiograph is the greatest recent invention in the Wireless field. Its value is priceless and as we be increased by using want every professional and amateur operator on land and on board ships to use it, we haie decided to A.. 3. The wave length .to which you make an introductory price of $3.00 tor a.limited time only. This is only one -third of the price at which it could tune with this outfit would be about should be sold. Send your order at once. Send for free Catalog E of the Instant Radiograph. You need this new book. "Radio Stations of the World." A complete authentic list of call signals 8,000 meters. of every public wireless station. Price, only .50c. UNIVERSAL WIRELESS COMPANY, 19 New REGARDING WAVE LENGTHS. East 32nd St., York (463.) Henry Gerke, Westwood, N. J., wants to know: 1. The wave length of W. C. C. 2. The wave length and the time This New Tuner Only $8.00 at which W. H. B. sends "press." 3. Where he can obtain copies of (a) United "Your New Receiving Transformer States Naval Radio Regulations. (b) Regu- having 20 taps on the primary and 9 on the secondary is very efficient. a n d lations Governing Radio Communication. worth twice as much as the one with Act of A,ug. 13, 1912. (c) Berlin Inter- sliders, although that timer does great national Radiotelegraphic Convention and work. Gordon F. Danforth, Syracuse. Regulations. We also make n 10.000 meter tuner, A. 1. The wave length on which W. Send 2-cent Stamp for Bulletin 107. C. C. operates varies from 12,000 to. 15,000 lust Out meters. A. 2. The time at which W. H. B. Colby's Telegraph School usually sends "press" is 10.15 p.m., and the Auburn, N. Y. wave length on which he operates is 600 meters. You benefit by mentioning "The Electrical Experimenter" when writi ,y to advertisers. www.americanradiohistory.com Dlarch, 1916 THE ELECTRICAL EXPERIMENTER 653

A. :3. The copies of these books can be obtained from the United Statcs Printing Office, Washington, D. C. TELEGRAPHONE TALKING HEAD. 5000 miles - (164.) Radio Amateur, Irvington -on- From Hawaii to Hudson, N. V., wishes us to tell him: 1. Can the armature of a telephone magneto Richmond, Va.- be used in the construction of a telegraph - with .one, if a hole is bored lengthwise through the center of it. 2. is a pair of 1,000 ohm CRYSTAL 01 receivers more sensitive than a single re- On Dec. 23 I made what I believe to be a ceiver wound up 2,001) ohms. new record for the Crystaloi Detector. About 11 P. M. 1 heard the station at Lahaina, A. 1. We do not believe that the arma- Hawaiian Islands, a distance of 5.000 miles. Heard the station four different times. ture of a telephone magneto can be uscd (Signed) RALPH J. ROBEY, 3314 Floyd Ave., Richmond, Va." in the construction of a telegraphone head. A. 2. A pair of 11:00 ohm receivers are We Guarantee Every Claim Made for more sensitive than a single receiver wound to 2,000 ohms. This is due to the fact that the two phones act on both ears simultaneously. CRYSTALOI CHEMICALS. The Highly Sensitive, Permanent (463.) K. 13eymer, Dayton, O., wishes us to give him the name of a house where WIRELESS DETECTOR he may obtain chemical apparatus and 3 TYPES chemicals. What It Is What It Does Crystaloi. A. Eimer & Amend at 211 Third avenue, Crystaloi offers a large Crystaloi will work New York City, should be able to supply surface of highly sensitive TYPE O- Dimensions 21,1"" x under the heaviest 1 /n"T your wants for chemical apparatus and mineral, which is brought static conditions Price, $3.50. Postage 10e chemicals. We would suggest that you into contact with a finely - TYPE Equipped with a will AA- write to them for prices and catalog. Also divided alloy-thus giving not burn out - cohering inductance- Dimen- refer to our advertising columns. and proper sions 4 'x3!í ". innumerable contact with use Price, $6.00. Mad. lt'gbt. 21 hs. will last a BULBS. points. By rotating the lifetime. TYPE BB- Equipped with SPECIAL ELECTRIC With it every mes- cohering inductance, fixed con- (966.) J. H. Kahler, Rochester, Minn., cylindtr the most sensi- denser. buzzer, test, batteries spot is found imme- sage will come in and control. Dimensions 7tí" wants to know: 1. Where he can obtain tive x534" x special electric light bulbs. 2. Where he diately. strong,and clear. Price, $12.00. Mail.Wght. 416s. can have special mercury vapor arcs made. :3. Whether a variable condenser is better Send 5c. stamps Catalog -than a fixed type when it is used in shunt in for with wireless 'phones. "C" fully describing Crystaloi A. 1. For these bulbs we would refer and all of our other high you to General Electric Lamp Works. Har- Class Receiving Apparatus. rison, N. J., who will doubtless be able to make them for you. .A. 2. These lamps could be built by the firm mentioned in Answer 1,' or by the Eugene T. Turney Co. -Cooper- Hewitt Electric Co., Hoboken, N. INCORPORATED J. The latter company would probably be better able to do this work, as they make 2595 Third Avenue a specialty of manufacturing mercury vapor lamps. -SENSITIVE New York City A 3. It would be far more- advisable TYPE -AA. SUPER for you to connect a variable or adjustable condenser in shunt with the receivers than a fixed one.

/U/ You looking TOOLS. /iii /odi Are for Quality - (467.) Godfrey S. Bloch, New York uwimmov, v,,,. Design and Workmanship con- wishes know what we consider the /%v City, to I!IIIIIIIII!IIIIIIIIIIIIIIIIIII 12 most important hand tools used by a ! sistent with price ? machinist. A. The 12 most important tools used every day by machinists and electricians are If you are, then get our catalog as follows: Hammer. screw- driver, pliers, No. 8833. Dandy No. 36E. Illustrating and hack saw, hand drill, dividers, calipers, Receiving Transformer, $5.40 chisel, wrench, drill, blow -torch and vise. describing We also Manufacture about 300 INDUCTION MOTOR. Telegraph and Fire (468.) Ervin R. Musgrove, Longmont, of Colo., asks several questions relative to Alarm Apparatus, articles induction motors: 1. About a motor to be Ama teur- operated on a.c. and having an armature Dry Batteries, composed of copper bars and laminated Medical Batteries, Radio Tel e- iron discs, but not fitted with any commutator or slip rings. 2. On the construc- Bells, Line Equip- graph appara- No.8654. Dandy tional details of such a motor. 3. The ment, Novelties, Rotary Variable Condenser, $3.30 tus. reason why different results are obtained when applying Ohm's law to a.c. circuits Etc. as compared to d.c. A. 1. The motor you are interested in falls into the category of induction machines. No commutator or slip rings for J. H. Bunnell & Co., Inc. conveying current from the outside or feed circuit to the armature winding are neces- 32 Park Place sary as the armature or "rotor," as it is Broadway Block NEW YORK No. 8834. called, has currents induced in its short - Jove Receiving Transformer, $7.50 circuited windings from the magnetized

You benefit by a,catinnin 7 7,e I la trical L.,-p nerf, r" Tchen riti),, to n:hvrtisrrs. www.americanradiohistory.com 654 THE ELECTRICAL EXPERIMENTER March, 1916.

field. This field is provided with a plurality of windings which are connected to the external source or exciting energy. Induc- "Mignon System" tion motors are supplied for either single km., s sîEM .R A D ' 0..x, Apparatus of Scientific Construction Varfor the Reduction of Static Interference High Resonance - Unapproached Selectivity .a..A.a-

NO TICKERS NOR ARMSTRONG CIRCUITS REQUIRED -.E... for the reception of CONTINUOUS wave signals if you own a -sPEe.

MIGNON - SYSTEM Assembly and Parts of Induction Motor.

CABINET or multi -phase circuits ; the larger size motors being invariably supplied only for two. I or three -phase supply. Special windings. and starting provisions De Forest Audion Detectors and have to be made for such motors, when adapted for use on Amplifiers single -phase a.c. circuits. A. 2. Herewith the illustration showing BRANDES RECEIVERS the make -up of the induction motor. The: rotating member consists of a number of Crystaloi Detectors, Etc. soft steel discs mounted rigidly on a shaft in the usual manner. These are slotted similarly to a d.c. motor R6 Catalog. Dept. "ll" armature, but in- Write for stead of being wound with coils comprising a large number of turns of wire, each slot MIGNON WIRELESS receives a single, heavy copper rod or bar. CORPORATION Two heavy copper rings are placed ont either rotor end and the copper bars in the N. Y., U. A. slots are firmly riveted or soldered to these ELMIRA, S. TYPE RC2 rings; thus there are provided a plurality of closed electrical circuits through the end connecting rings or discs and the inductor bars within the slots. A four -pole field, made up of laminated annealed steel discs, is here indicated, but Reliable Supplies for Working Models this is only used in most cases for small, The following are just a few of the hundreds of items with single -phase fan motors and the like. In

which we can supply you. Every "Ideal" article is priced . larger multi -phase motors the field has a_ as low as is consistent with the quality. If you don't see large number of slots in the periphery of what you need listed here, write us and tell us lust what you the rotor opening, which resemble almost. want. Your order will receive our row t and careful I identically the peripheral appearance of the f ' attention. Satisfaction guaranteed or money refunded. J rotor. In the stator slots appropriate wind- l ings are placed, consisting of coils of mag- PROPELLERS net wire. The rotor is moved or pulled_ \ 1 accurately made of carefully selected wood. All types carried in around by the constantly changing rotating `tack from 6 inches up to 24 inches; made to order up to 7 feet. a.c. magnetic field set up by the stator windings. .t A.. 3. The reason that you obtain dif- Lt ferent results when using Ohm's law with. a.c. circuit is that this law does not apply AXLES "Ideal" Ball Bearing Propeller Shafts to a.c. circuits but only to d.c. circuits, due Made of best quality steel rod. Doing threaded are perfect miniature Bearing to the former manifesting marked capacity Shafts eetion on both end.. and having nuts, they are very hoe b Bad iron and inductive effects, which throw the cur- teb,nee. They r ikeithtly on tructed, bare solid for CONNECTING TU NEIIS' ENDS AND tnroedhearingasadthehoostetcelbalte andraces. Flanges rent and voltage out of phase or syn- LOOSE COUPLER SECONDA RTES. Also made re drilled and ends of shafts are threaded and supplied with in bra at extra charge. I/ 18 in. Azle. up to n in nuts and washers.ashen. Flanges and upper ball -bearing e ases are chronism. 10e.: 7 to 10 in.. 15c.: 11 to 15 fa. 200. 1/ 8 in. in solid piece of brass: of soldered and Ihrrefore unbrrakohle. axles up to n i0., 15e.: 7 to 10 in.. 200.: 11 to 15 in.. No. 1 -1/lß in. steel shaft. weight 1.2 oz. Price. 50e. No. 2 -1r8 in. steel abaft. Weight 1.2 oz. Price, 60c. 200. Footage. 2o. extra. Postage. 2c. extra. GEARS Build a FLYING Clean cut, made Model War Aero- g ng _ right; run smoothly without noise or pane :'1. friction. Have 1/ 10 We can supply E- - - in. shaft hole but - can be furnished you with accurate with 1/8 in. hole at scale drawings, in- 10c. each additional. '.." -- Postage, 2c. extra structions and all . - t.f for each gear. parts for the well - size No.of Teeth Pitch Price known types. For prices see our interesting new 50- 5/8 in ..18 32 .15 page catalogue. All our experimenter's supplies are 3/10 in 10 40 illustrated in 20 40 .20 and described in this booklet. Write to-dayy 4/5 in 30 40 .25 for a copy. Price, 5c. postpaid. Radio Receiving Hook -up. are promptly and carefully executed by our Mechanical Department. Submit SPECIAL ORDERS us your drawings and specifications for quotations. THE TESLA PLANT. Port IDEAL AEROPLANE & SUPPLY CO. 76 -82 West Broadway, New York (469.) Chas. W. Squires. Jeffer- son, L. I., N. Y., wants us to give : 1. The correct hook -up for a receiving set consist- Yon benefit by in ens io nin, "The Electrical F.rprrinr r to r" wirr,, wert,, a to advertisers. www.americanradiohistory.com i march, 1916 THE ELECTRICAL EXPERIMENTER 655 ing of two slide tuning coils, two detectors, silicon and galena, two -point switch to throw on either one, test buzzer for detectors and 75 ohm receiver. 2. The wave MARKO STORAGE BATTERY length of a two -slide tuning coil wound with 198 feet of No. 94 bare copper wire. 3. The location of Nikola Teslá s plant on Long Island. A. 1. The illustration herewith given shows the proper connections for these instruments. A. 2. The wave length of the tuning coil would be about 450 meters. A. 3. This plant is located at Shoreham, L. I. STEEL WIRE. (470.) Edward L. Jewett, Sullivan, N. H., inquires of this department: 1. Where he can obtain long lengths of steel wire for use in the telegraphone, described in the June, 1915, issue of The Electrical Ex- TYPE 6WT3 perimenter. 2. The difference between No. :12 steel piano wire and No. 39 B. & S. Type Volts Amp. hr. Length Width height Special price to gauge wire. capacity wireless engineers steel used in the tele- 4WT4 4 40-60 5y 7y 8 $7.87 A. 1. The wire 6WT2 6 20-40 5% 7Y8' 8 $8.25 graphone can be bought in any desired Especially adapted for Audion use. length from most hardware stores. It is a well -known fact among up -to -date wirelecs engineers and experimenters that the Audion operates at a higher efficiency when controlled by a storage battery that gives con- A. 2. There is a difference between the stant voltage. diameter of wire designated as "No. 39 MARKO Batteries are fully guaranteed, and designed to meet these conditions. steel piano wire" and "No. 32 B. & S. wire, Descriptive circular on all types of MARKO Storage Batteries upon request. wire Guaranteed highest quality and lowest prices. as the gauge used for measuring steel MARK O' QUALITY is not the same as that used for copper. The latter refers to the Brown & Sharpe PAUL M. MARKO, 1191 Bedford Ave., Brooklyn, N. Y. standard gauge. WIRELESS SCOUTS HONORED. H. B. Thayer, president of the Western Electric Co., gave a dinner at the Hotel "SOME" DETECTOR! Astor recently in honor of the men who went to the far corners of the earth to re- Absolutely the simplest and most ceive the wireless telephone messages re- practical Detector of the Cat cently sent from Arlington, Va., and which Whisker type yet devised. Lac- were heard in Paris and Honolulu. quered Brass for the metal parts ELECTRICITY ON OCEAN LINERS. and Polished Fibre for the base. (Continued front page 611.) Has the usual merit of the "Winger" products. in the house. There are two complete sets one for transmitting and one of apparatus, ACTUAL SIZE Winger Electric & Mfg. Co. for receiving messages, the latter being placed in a sound -proof chamber in one POSTPAID, 50 CENTS 711 So. Dearborn Street, Chicago, Ill. corner of the house. There is also an independent storage battery and coil. For submarine signaling apparatus is provided for receiving signals from submerged bells. Small tanks containing mi- Arnold Navy Type Loose Coupler crophones are placed on the inside of the PRICE, $15.00 hull of the vessel on the port and starboard Owing to the peculiar court ruction and wind- sides below water level and connectedby ing of this instrument it is possible for those de- wires to receivers situated in the port navi- siring to hear the Arc Stations, to do so on this instrument. A special Hook -up is needed in order to gating room. The whistles are electrically get up to the brave length. actuated. The boiler -room telegraphs, stok- To those ordering an Instrument such'Hook -up ui:1 ing indicators and a number of auxiliary be furnished gratis. -- It is as in the past the Right instru- appliances, such as rudder indicators, clocks \ ment to do all first class receiving with. and thermostats, are also electrical, and the Workmanship and material the best. water -tight doors are released by electro- Send 2-cent stamp for Bulletin No. 3, which describes fully, also shows the magnets. finest line of Switch points, Rubber There are complete emergency circuits knobs and accessories on the Market. provided on all ocean liners. A separate Send two-cent stamp for Bulletin J. F. ARNOLD installation is and distinct fitted in all parts No. 3 135 East 119th Street, New York City of the vessel, deriving current from two " THERE'S lTONEY /NIT " Ñ =LEARN TELEGRAPHYE M MORSE AND WIRELESS TEACH YOURSELF in half usual time, at trifling cost, with the wonderful Automatic Transmitter, THE OMNIGRAPH. Sends unlimited Morse or Conti- nental messages, at any speed, just as an expert operator would. Adopted by U. S. Gov't. 4 styles. Catalogue free. OMNIGRAPH MFG. CO., 39L Cortiandt St., New York You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. www.americanradiohistory.com 656 THE ELECTRICAL EXPERIMENTER March, 1916

30 -kw. sets and the 3,500- ampere -hour battery, so that in the event of current from the main dynamos being unavailable an independent supply is obtainable. Con - Y ©u nected to the emergency circuit are about 500 incandescent lamps, fitted throughout all passenger, crew and machinery corn-. Can Get Type AML partments, at the end of passages and near stairways: also on boat deck, to enable anyone to find the way from one part of the Results The Precision Yaricoupler ship to the other. The following are also connected to the emergency circuit by means with a small l'at, eted .Var. 7, 1916, foreign patents pending. of change -over switches: Five arc lamps, condenser and Up -to -date receiving circuits require im- seven cargo and gangway lanterns, wireless UNMOUNTED proved apparatus. You can't get super- apparatus, boat davits, mast, side and stern TRANSFORMER this transformer sensitiveness with old style couplers. The lights and all lights on bridge, including Precision Varicoupler is PERFECTION those of navigating and chart rooms, wheel It is a 1 -2 K. W. size and is built on the in receiving tuners. It has house, telegraphs, compasses and Morse same specifications as to material and signaling lanterns. workmanship. etc.. as our big central No Taps No Sliders Very soon, it is freely predicted, ocean station transformers. No Switches No Delicate Parts liners will also be driven by electric power, the Government having ordered such an No "Dead Ends" All the Wire in electrical equipment from the General Elec- Hundreds of stations are No Contacts Use all the Time tric Co. to drive the new battleship Cali- now using these trans- fornia, the largest in the world. formers. This transform- and is finished in mission oak, genuine er gives you 13,200 volts. cut hard rubber, finished wire, etc. silver ELECTRICITY, THE BENEFICIENT. 5 Styles, $10 to $25 (Continued from page 619.) Let us tell you how you can do part of trans- For detailed information write for bulletin PL. he work yourself and get this great aluminum industry with all its former at a remarkably low cost. The Precision Radio Equipment Co., Inc. branches, for instance, is directly dependent upon the electric current for the General Office: 868 Putnam Ave., Brooklyn, N.Y. production of the aluminum itself. Acety- THE PACKARD ELECTRIC CO. lene gas which is now used for so many 555 Dana Avenue Warren, Ohio purposes is obtained from calcium carbide, which is I means I I I I I I I I I I I I I I I I I I 1 1 1 1 I I I I I I I I produced by l l l l l l I I I I 1I I I II I of the elec- ' l l l ü l C:I I i; l N;'.11 f;; I:I' I f; l I II I II I II I I I I I II I I I I II1111111II1 L III I II I I I L tric current. Carborundum, the well - known and widely used abrasive. is a $11.00 Guaranteed Amplifier Coils $11.00 product of one form of the electric fur- AUDIO IRON nace. The electric current is used in re- fining copper on a vast scale, for the pur- úßA SFOO RKES BULBS $6.50 pose of purifying it and for the separation SENSITIVENESS GUARANTEED of the precious metals, Numerous other Built for Wireless chemical industries are founded upon the 200 PER CENT. MORE Wireless Equipment SENSITIVE THAN ANY OTHER MAKE use of the electric current. Fixation of The Pittsburgh Co. OR ANY OTHER FORM OF DETECTOR atmospheric nitrogen for producing nitrates are under new management at SEND FOR INTERESTING LITERATURE for fertilizing and other purposes is now accomplished on a large scale by means RIDGWAY, PENNSYLVANIA CHELCO ELECTRIC CO. of the electric current. and it promises to become in time one of the vastest indus- and are on DECK to give you a SQUARE 948 N. TRUMBULL AVE., CHICAGO. ILL. tries in the whole world. In fact, power DEAL and 100% value in our LARGEST DISTRIBUTORS OF AUDIO TRON BULBS plants of approximately half a million kilowatts, or more than three -quarters of Superior Radio Apparatus a million horsepower, concentrated in a for every dollar's worth purchased single station are now being considered for such production of nitrates. The time Send 10e. for our complete catalog. 8,000 MILES Parts catalog free. is coming when the whole world will be is the record (amateur) with our Audio - affected by this industry through food Tron Detector production. PITTSBURGH WIRELESS EQUIPMENT CO. THE AUDIO -TRON Such a catacylsm as the complete cessa- Department "R" DETECTOR-AMPLIFIER-OSCILLATOR tion of all electrical activities would there- RIDGWAY, PENNSYLVANIA fore in result such changes as greatly in- 1111,1111' "'11111111 1 III ": :'.'Ill'I: Price postpaid . . . . $6.50 .1111011111 11 IIII19,111rcna1Ll11C III :f1I III :IIli 1111 Ill' 1111 III'. III creased concentration of population around industrial centers, the city and the country Jensen Electric Co. would be pushed farther apart, many in- QUENCHED RADIO APPARATUS dustries would be disorganized and some "MONOTONE" and SUPPLIES would be stopped completely, many great SPARK GAP establishments would have to be recon- SEND STAMP FOR CATALOG Why-dissipate your structed, types of buildings would be radio energy in sound 1949 Huron Street CHICAGO, ILL. changed, and light waves? methods of business would be Carry it to the dia- modified, the producing capacity of indi- phragm of the dis- viduals be tant re on pure A NEW and of industries would greatly waves of Radio En- reduced, methods of living would be modi- ergy. Every station eh ld be equipped No. 44, PRICE ONLY $4.50 fied, methods of transportation would be wi th ' Monotone' LOOK! Quenched Spark Positively un- changed and for the worse : in fact, all con- Gaps for penetrating ditions of life and fields of endeavor would great distances. Span equaled for that "freak^ distance the money. Is be influenced, either directly or indirectly. every night. Silent in operation. Ardes,. In single 6^ high, 6" Myriads of times it has been said unite as illustrated for spark coils. Two unite in aeries wide, and 14" that and multiple for every quarter K. W. power of trans- over all. "electricity is in its infancy," until people former. Price per unit, $1.50, prepaid. Wound with have come to believe that it is a perpetual Commerce Bldg. E namele d infant like Buster Brown instance, but RICHARDSON COMPANY, ERIE, PA. wire, and has for a very unique it has now grown to robust stature and slider. Wood- unostentatiously has assumed a goodly work mahog- share' of the world's burdens. Its efforts 11r-"I 'd "Alar.'12:0:111 ü any finished. Try one, you will not be disap- have been productive and not destructive. pointed. Make your own "Wireless," also Dynamos. Bat- 5c. in stamps brings our 64 -page illustrated cata- In this sense it has been one of the most teries, Mottos. Telegraph, Tolephone, Lights. Bells. logue, B -B-24. None otherwise. beneficent agents of mankind. In Arabian Alarms, Coils, Current Reverser. Electric Engines, etc. Book with i5 Illustrations; by experts so anyone can Nights' parlance it is one of the good understand it. With Catalog. Ali 1Oe, a for 25c pp F. B. Chambers & Coe Philadelphia,Ph° Pa. genii.. J.C. Dorn, 705 So. Dearborn St., Dept. 118. Chicago, IIL You benefit by mentioniad "The Electrical Experimenter Whin writing to advertisers.

www.americanradiohistory.com March, 1916 THE ELECTRICAL EXPERIMENTER 657 PATENTS IF YOU HAVE AN INVENTION Edited by H. GERNSBACK which you wish to patent you can In this Department we will publish such matter as is of interest to inventors write fully and freely to Munn & Co. and particularly to those who are in doubt as to certain Patent Phases. Questions for advice in regard to the best way addressed to "Patent Advice" cannot be answered by mail. Sketches and descriptions must be clear and explicit. Only one side of sheet should be written on. of obtaining protection. Please send sketches or a model of your inven- FREIGHT CAR LOCK. and is supposed to have a much larger ef- tion, and a description of the device, (47.) Elmer D. Gehman, Macungie, Pa., ficiency than other generators of the same explaining desires to have our advice on a freight car kind. its operation. door lock which he has invented. He sub- A. As stated before in these columns, All communications are strictly confiden- mits this journal advice tial. Our vast practice, extending over a description and illustrations of same. cannot give as to the period of seventy years, enables us in many A. The idea to us seems novel and as financial value of an invention. We stated cases to advise in regard to patentability far as we have ascertained by a careful ex- before that even if we were to put down without any expense to the client. Our Hand - Book on Patents is sent free on request. This amination of our files and reference books a figure this would at best be but a crude explains out methods. terms, etc., in regard nothing like the idea submitted is in ex- guess, as it would be practically impossible to Patents, Trade Marks, Foreign Patente, istence so far. We would, however, ad- to approach the true value within 90 per etc. vise our correspondent to get in touch at cent., no matter what the invention was. All patents secured through us are described without once with a patent attorney to find out As far as the dynamo is concerned as coat to the patentee in the SrmreAr Amer:ran. what has been done in the art before. It submitted by our correspondent, we must will only cost a small sum of money to get say that we have been very favorably im- the references of other patents that have pressed with the idea. We have never seen & CO. been obtained on such locks, and they per- anything like it, and from a careful study MUNN haps will show our correspondent how to which we have made of the device we are SOLICITORS OF PATENTS $o about getting a valuable patent on the quite convinced that it will work as stated invention. by our correspondent. It is certainly the 699 WOOLWORTH BLDG., NEW YORK most ingenious invention which has been and 625 F STREET, WASHINGTON, D. C. NON -REFILLABLE BOTTLE. submitted to us so far, and should prove (48.) Ralph H. Zimmermann, Sutton, of great interest to manufacturers con- Neb., desires to know if there is such a structing generators. As far as we are thing as a simple and practical non- refill- aware of, there exists to -day no machine able bottle, and whether one is on the mar- nor patent on a generator of this kind, and T YOUR IDEASI ket and in actual use. He also wishes to we would advise our correspondent to get ',f'- There Is Constant know if it is worth while to spend time and in touch with a patent attorney at once 41É Demand for Good Inventions money in the invention of such a bottle. and see what has been done in the art be- A ff A. As stated before to another corre- fore. There is a chance that a similar idea `WHAT TO INVENT spondent, several thousand patents have might have been patented before, although and " How to Obtain a Patent" been taken out on non -refillable bottles, and we very much doubt it. These Hooks sent FREE as far as we are aware, there are not We have been so well impressed with this III If you have an invention, send sketch for free report regarding patentability; if not, six being used at the present time. The invention that we would like our cor- send for free hook, "What to Invent." ones that use them are mostly the liquor respondent to advise us what results he From our advertisements in newspapers manu- people, has had in connection facturers are constantly writing to us regarding to whose interest it is to see that with the device. the purchase of patents. Their names and ad- the bottle is not refilled after its contents dresses are furnished our cliente free of charge. have once been emptied. EDISON DEFINES GENIUS. We advertise your patents for sale at our expense. We have DON'T WAIT! Your invention will never do stated the case clearly above "Stuff! I tell you genius is you any good If some one else patents it ahead and hard work, of you. to us NOW. our advice to inventors of non- refill- stick- to- it -ive -Hess and common Write able bottles is that they se ..e !" CHANDLEE & CHANDLEE should not waste In this short and sentence Est. 20 years. 822 F Street, Washington, D, O, a lot of trite Thomas time and money inventing one, as A. Edison, the wizard, sums up his success- practically everything has been attempted ful career. But this in this art, versatile and brilliant and several very good ideas are inventor should have added genius is in- in actual use to -day. defatigable in research, experiment and dis- As far as we are concerned, there is no covery and exhibits intense concentration such thing as a non -refillable bottle, as any PATENTS of mind love non -refillable and of learning. THAT PROTECT AND PAY bottle, no matter how well Thomas A. Edison was born at Milan, constructed, can be refilled if anybody O., Books and Advice Free really in 1847, but when he was seven years wants to do so. of age his family moved to Port Huron, Send sketch or model for seareh. Highest Rat We know of a case where an unscrupu- Best Results. Promptness Aoured. Mich., where he passed his boyhood. Edi- WATSON E. COLEMAN, Patent Lawyer lous bartender removed the label of a son spent but liquor bottle, three months in the public 624 F. Street, N. W. Washington, D. C. the brand of which had a schools, but received a thorough schooling very wide sale. After removing the label, at his mother's knee. Before a small he reached hole about aft in. in diameter was the age of twelve he had read Gibbon's SOMETHING drilled into the bottle, and by using an ordi- "Rome," Hume's "History of England," INVENT It May Bring Wealth nary suction pump the bottle could thus Sears' "History of the World," and the Our Free Book tells what to invent and how to obtain a be refilled quite easily with Datent through Our New Credit System. an inferior "Dictionary of the Sciences." D. C. brand. The small hole was plugged up WATERS & CO., 4287 Warder Building, Washington, with cement and the label again placed on the bottle. Consequently the non -refillable Patent Buyers bottle could be refilled in spite of the fact Write for List of who that PATENTS WANTED desire to purchase patents and What To this was about the best bottle of this Invent with kind on the market. While such cases are valuable list of Inventions Wanted. $1,000,000 its prizes offered fo inven- of course infrequent, it goes tions. Send model or sketch for Free Opinion as to patentability. We have a still to show in to that where there is a will there is a way. Special Department devoted to Electrical Inventions and are a position assist and advise inventors in this field in the development of their inventions. COMMUTATORLESS D. C. GEN- MODERATE FEES -WE ASSIST INVENTORS TO SELL THEIR PATENTS ERATOR. Write To -Day for our Five Books sent free to any address. (See attached coupon:) (49.) Clarence Ray, Kokomo, Ind., has submitted to us an elaborate set of draw- ..FREE COUPON! -. ings and description about a commutator - I VICTOR J. EVANS & CO., Patent Attorneys l less d.c. generator, and he wants to know I NEW YORK OFFICES: desist Broadway PHILADELPHIA OFFICES: 1429 Chestnut St. I what demand there would be for a ma- I Main Offices: 779 9th Street, N. W., WASHINGTON, D. C. chine of this kind, and, if possible, its value I GENTLEMEN: Please send me FREE OF CHARGE your FIVE Books as per offer. financially. The dynamo in question works I NAME ADDRESS , without commutator, as its name implies, You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. www.americanradiohistory.com 658 THE ELECTRICAL EXPERIMENTER March, 1916 BARON MÜNCHHAUSEN'S NEW SCIENTIFIC ADVENTURES. (Continued from page 625.) I SOLDERALL I soned with a similar logic, and they had thus come to the conclusion that as Mars MCP Price is so far removed from our sun the tem- YOU SOLVER SULIrR WRX StlCtRt u'g perature on Mars must necessarily always be far below the freezing point. Accord- [Sal:DERALL ingly they reasoned that life on Mars as the understand it was not possible. But 50c. then the telescope suddenly revealed that the Martian 50 MENDS for snowcaps do melt every spring, REAL METAL and if this is the case the temperature even 50 CENTS SOLDER in With an ordinary match it easily monde and stops all the arctic circles at times Faust be above leaks in pots. pane, tinware, metal ornaments, agate the freezing point. But why? ware, toys, umbrella, (broken ribs) and a hundred other things. Automobiliste, mechanics and machinists use it "`The answer is simple enouph. The regularly. Indispensable for wiring. A child can stop or mend a leak with i t a t once. earth has a very dense atmosphere with NNN many clouds. On Mars the reverse is the case, where we have a thin atmosphere and What You Want practically no clouds all year around. SOLDERALL TRADE MARK i When You Want "'Professor Lowell estimates that over It- the earth as a whole the proportion of ac- and where you want it-on the ;oh boring tual to possible sunshine Blow Torch trite or in your pocket awaiting call to for the entire action. year is 50 per cent. In other words, the FITS ANY POCKET sun only shines practically one -half of the No pumping Or blowing nccese.ry. time it might if there were no clouds. On Generate, its own pressure. Burns MILLERS FALLS wood or denatured alcohol. It is Mars, on the other hand, the sun shines 99 absolutely anodes,. Can't Explode. AUTOMATIC PACKET RORER Noll per cent. of the time. There are no cool- PRICE, 51.00 Handsome nickeled steel. Magazine han- ing rains or snows in the temperate zones Dealers write for Wholesale Price dle contains eight drill points from 1/16 to either to cool the atmosphere, consequently List 11/64, also screw driver bit. By special a great deal more heat is and device one bit can be removed front handle absorbed re- THE EMENAR CO., Inc. without disturbing others. Grip of chuck tained on Mars than is the case on earth. 45 E. 23d ST., NEW YORK is Positive. Further, an enormous amount of energy is Length 73Ç" extended. 4;," compressed. lost on earth, where the suet rays must Write for pocket catalog. travel through a dense blanket of air, which BUILD YOUR OWN FALLS CO. is not the case on Mars, where the air is MILLERS thin and clear. For this and other rea- Grandfather's "Toolmaker to the Master Mechanic" sons too technical to dwell upon, we find Millers Falls, Mass that light and heat are practically the same Clock N. Y. Office, 28 Warren Street on the two planets, with several points in WITH OUR HELP favor of Mars.' We furnish blue prints, finishing material and In- "While I was still turtling these facts structions. Buy the works, in dial, weights and pendu- over my mind, Flitternix suddenly lum from us at surpris- pointed to the sky and shouted rather ex- ingly low prices. Yoa citedly: make a fine profit bond- ing artistic clocks t o t "'Look at the moons!' I followed his your friends. For Better Work Complete works. WOO. finger and I saw the wonderful spectacle Others with chimes at all you precision tools of two full moons shining in the sky. It prices. If want that Ask for attracnvs tree will work faithfully for you under was still light and for that reason the ef- offer. El conditions, that stand harder fect was not as wonderful as we have wear than others, that enable you to since Clock Company do better work and do It more easily, witnessed when we see Phobos and Deimos 1661 Runner St. then you want during the night time. At that particular PHILADELPHIA, PA. time the moons shone rather pale as our "RED DEVIL" TOOLS own moon does in a bright afternoon with "RED DEVIL" Diagonal Nipper No. 542, 6 the sun still up. GROBET SWISS FILES in., THE MOST POWERFUL NIPPER Are the standard of excellence 20 "Phobos, the larger of the two moons, is It MADE. One pound handle pressure = files, and have been for over 100 lbs. cutting pressure. Sample 85c. but 4,000 miles distant from Mars and, as years. We send postpaid as an In- Tool Booklet Free I mentioned before, it revolves around reducer 48 files especially adapted Mars in the incredible short time of 71/... for tool makers and machinists on Smith & Hemenway Co., Inc. receipt of $5.00. This Is a Chance to get u set of 153 Chambers St., New York City hours. In a single Martian day it there- files you'll appreciate and we'll get future orders. fore revolves three times around Mars, MONTGOMERY & CO. consequently it rotates faster than Mars 100 :Fulton Street New York City BRASS GEARS Cut by an entirely new process. The itself. Although it revolves in the same noel accurate made and at otiose direction as Mars and the rest of the ¡i that cannot be equalled by .then. Every gear ha* a huh, .rater planets, namely, from west to east. on ac- EXPERIMENTERS -INVENTORS painted ebony Week, *demo turned count of its greater speed it appears as if Let us develop your inventions and make 3 True, highest grade red brow. and your working modele. much heavier than oth.re. the it were moving from west to east. Its Our well equipped shop and etsi of ram- Derry the largest stook In the speed to an unaccustomed human observer noosed model builders are at your envite. world, d every gear Meted I. We carry a oomplets stock of gears. ainer.hipOed on dale Of Order. is really disquieting. While we were look- Shipment made Same day order received. BEND FOR CATALOGUE ing on the could actually see how terrifically Send 4o in stamps for booklet Inventor.' CHICAGO STOCK GEAR WORKS Supplies. 20a So. Filth Ave. .. Chicago fast Phobos moves. When Flitternix had UNION MODEL WORKS, Established 1882 first called my attention to it it was quite 119 S. St., Chicago high up in the sky. Ten minutes later we Clark REGISTERED PATENT ATTORNEYS watched it plunge with express speed below PATENTS AND TRADE MARNE the eastern horizon I It is positively un- canny to see a heavenly body that looks as Experimental and Model Work big as our moon perform such celestial ELECTRICAL INSTRUMENTS AND gymnastics, but the fact remains. Deimos, FINE MACHINERY at a Inventions developed. Special Tool., Dis, 252 Ouray Bldg. Washington, the smaller of the two moons, revolves D C. distance of 12,300 miles from Mars. But Gear Cutting, Etc. Beek Inventions-Patenting and Prmtfnq" Fr.. it Improvements wanted-Send ter free bulletins & advt.. as it measures but 36 miles in diameter HENRY ZUHR naturally appears quite small as seen from 32 -34 Frank! New York City WANTING Mars, even when full. At that afternoon INvENToRS when we saw it it did not appear very at 1 -2 rate. and U.S. priority tights cot EX (goy., FEE be the Classified Adv.rtisments In this Inventor.' League of U.S. expert tt'y. get our latest much brighter or bigger than the evening They are small but contain terms. BUREAU of Patente. It Broadway. New York. issue, star as seen from the earth. As a matter READLiAU big bargain and opportunities. WESNOwHaW TO SELL YOUR PATENT of fact, it does not look like a moon at all Fou benefit by mentioning "The Electrical Experimenter" when writio g to advertisers. www.americanradiohistory.com March, 1916 THE ELECTRICAL EXPERIMENTER 659

to Martians, as we understand that term; it looks rather like a very bright star. Even during the night its face does riot always appear as a disc to the naked eye, even YOU BE THE BOSS! when it is full. It is too small and too far Become a master of men in this removed. Nevertheless it is a true moon. wonderful new profession. Get the "Having finished our contemplation of the big job -climb to the top in the great electrical industry. Electric sky, we turned anew to the view directly Lighting Plants must have Meter below us. Of all inspiring and majestic v Engineers. Nearly eight million sights 1 do not think that there is one electric meters now in use need constant attention. half million that can rival a Martian 'city.' I once more being installed yearly. thought that New York as seen from the Woolworth building was about the grandest Earn $1200 To view one could ask for, but it appears positively ridiculous compared with any of the $3000 a Year Martian great centers. "To begin with, the Martian cities are As Electrical Meter Engineer not built upon the ground for a very im- The supply of trained men does not begin to meet the demand. The field is tremendous-growing greater portant reason. Nearly all of the Martian and greater. \York is interesting, fascinating, profitable. The marvels of electricity interest and hold only in you captivated, as you study our simple, concise and complete course. Experience unnecessary. Just continents arc deserts, irrigated common school Earn while you learn. comparatively small sections and near the education. great waterways. The land, therefore, Big Demand for Trained Men which is absolutely flat without even small %Ye help you to a position when ready. Our graduates command respect everywhere. Only school teach elevations, is sandy, as are all true deserts. ing Meter Engineering. Get into this new profession -get the high -salaried job. YOU be the boss. For ages upon ages this desert sand has been rolling back and forward over the FREE -New Literature Fort Wayne Correspondence planet till it has lost the characteristics of School Tells all -explains proves all; terms. outline of course. real desert sand as you know it on earth. all- Ft. Wayne, Ind. Dept. 343 faculty, money -back guarantee and the story of King's rise from Gentlemen:-Send me absolutely It has become a fine, impalpable dust, ex- Newsboy to Meter Engineer. Mail the coupon to -day. j free and prepaid, your new literature tremely choking if it finds its way into on Meter Engineering. the lungs. Fort Wayne Correspondence School Name "This fine desert dust is the greate t bane , .lddres: of the Martians and they fight it constantly Dept. 343, Ft. Wayne, Ind. and heroically. But as nothing but vegeta- tion- which, again, is dependent on water - will permanently stop the dust, the fight is almost hopeless, for the Martians lack secure the best in FLASHLIGHTS water to irrigate the entire planet. Natu- and BATTERIES by insisting that rally the dust is not quite so bad near the You Can Only waterways, but the large centers spreading this trade -mark for a few miles inland are not thus pro- is on tected, especially if the wind blows f rom flash- Beacon Flash- the land side over a broad expanse of light -case and lights and desert. Even the slightest breeze brings its battery. If Batteries are clouds of choking dust and a strong wind sometimes obscures the sky. your dealer made in a wide "But when it storms pity the poor Mar- cannot supply variety of tians ! Through the large telescopes on you with our product styles and shapes but earth 40 million miles away astroromers llave frequently seen huge sandstorms write directly to us only one quality - sweep over sections of Mars as large as for Catalogue A2. THE BEST. France! Can you imagine what such a storm means? We witnessed one yesterday and it was awe- inspiring, terrific indeed. Hours the storm the Martians ran .THEIUEA ..°?l!hlúht[[ihl 45` - ahead of mpTSVT771914 _r-OTHERS PENOIaG -- - - for their sheltered lofty houses and closed everything airtight. All traffic on the "Ideal Fountain Light." canals, on the ground, as well as in the air, 118 -20 DUANE STREET ceased for two hours while the storm was Beacon Electric Works of National Carbon Co., NEW YORK in progress. From the eastern side of our host's windows we saw the approach of BRANCHES: CHICAGO, SAN FRANCISCO the dust. It came rolling on in gigantic red clouds like an ocean, and although it was in the forenoon the sun was blotted out in almost entirely. The dust is so fine that The Newest Thing you could hardly hear it as it was hurled Flashlights against the thick window panes in immense quantities. On and on it came, seemingly Your watch on one end of your without end; sometimes we would get a chain, your WATCHLITE on glimpse of sunlight, but oftener we were the other. plunged in total darkness. After the storm had lasted for two hours it stopped as sud- Not merely a novelty, but a use- denly as it had appeared and the sun ful, serviceable flashlight. smiled down on us again as always. "Within ten minutes after the storm Bright Star Battery Co. myriads of aerial flyers could be seen spray- Factory and Main Office: ing the buildings and structures with com- NEW YORK pressed air to clean out the red dust from Branches: the corners where it had accumulated. CHICAGO MONTREAL " WATCHLITE" When we looked around this morning there was hardly any evidence of the terrific sand- Make Your Own storm of yesterday. Of course, such DYNAMOS storms as the one we witnessed are rare MOTORS ELECTRIC LIGHT and do We make a specialty of dynamos and motors. We an not occur more than six times a n furnish parts for same, finished or unfinished. Anyone with engine can oper- 'year; nevertheless, all Martian houses and sizes. ate a dynamo. Saves current Commutators and armature discs of all bills. Costs little to operate. 30 structures are built with a view of get - Transformers from 25 watts to 5,000 watts built to order. Send stamp for circular "B" for quota- light. $60. Movie Arc )ynamo. ling rid of the dust as quickly as possible tions. $95. Sold on easy monthly pay- when it ments. does come in avalanches. F. R. HEILMAN 442 Ni St., Buffalo. N. Y. "Accordingly all buildings have sharp BOBART BROS.. Boa S. Troy, Obis You benefit by mentioning "The Electrical Experimenter" when writing to advertisers.

www.americanradiohistory.com THE ELECTRICAL EXPERIMENTER March, It)It)

gable or pyramid roofs, and every wall =IIIIIIIU111111111111IIIn1111111111111111111111111111111111111111111111111111111111111111111111111111111111!Illllillllllllll IIII IU'- and balustrade is built with a gable. Every window sill points downward at an angle. There is not a structure on Mars that is Brilliant Light in a Jiffy exposed which is flat, or which has a single Everybody appreciates the value of Franco flat it. Flashlights. Around the home at night; projection extending from Every- motoring; out-of-doors; tor boy scouts; me- thing is built to get rid of the dust as chanics; farmers and postmen, Franco quickly as possible, for this fine and ex- Flashlights are indispensable. At a pressure tremely dry sand slides down a sharp in- of the finger they throw a brilliant stream cline with great rapidity. of white light just where you want it. "From the foregoing you will easily understand that the Martians cannot permanently dwell near the ground. It is an Franco Flashlights exceptionally calm day when your Martian can walk on his planet without his respirator hood over his head. From this it fol- are guaranteed absolutely to give you worth. while service and satisfaction. The Radio lows that as he cannot dwell upon the Battery inside is the finest flashlight battery ground, and as intelligent beings as a rule produced, will give more light and last do not care to burrow themselves into the longer. At the Panama Pacific Exposition Big Money Franco Flashlights were awarded highest ground, there is but one thing to do, and honors -Gold Medal and Blue Ribbon. that is to go above the surface of the ground. Indeed, this is precisely what the in Martians have been forced to do for thousands of years back. Electricity "It was soon found that the ordinary dust did not usually rise higher than 400 feet above the surface of the planet. At The electrical industries offer won- this altitude the air is sandproof except derful opportunities for boys with for such severe storms as the one we wit- a liking for electricity. The sala- nessed yesterday. ries paid to trained men are large "For this reason all buildings and struc- -promotion comes rapidly, and, tures on Mars, with few exceptions, are located 500 feet above the ground in order Flashlight illustrated is 554 inches long, best of all, the profession is not fibre covered, nickel trimmings to make life bearable. Thus all 'cities' are and will throw light a long dis. overcrowded. built high up in the air, and it is this fea- tance. Patented "Wireless" ture which gives the stranger his greatest feature prevents short -circuit. The opening of new lines, from = ing when in contact with surprise. metal. Complete with Radio time to time, (such as wireless tel- "Imagine immense metal towers stretch- Battery and Tungsten Lamp, egraphy and telephony), promise ing skyward mile upon mile, supporting a at 7;1.00; everywhere. attractive and paying fields to those vast city raised 5011 feet up in the air. s Imagine these towers partly roofed over Write for our Big Catalog who wish to specialize. The will with metallic roadways and buildings and No. 9. to do and Special Training will you have a faint idea of how a Martian bring success to you. 'city' appears. _= Interstate Electric Novelty "When we had first 'landed' on Mars we The International Correspondence naturally thought that we had touched the Company Schools of ground. As a matter of fact, we had not Scranton can help to _= 29 -3I Park Place,NewYork City make you an expert in electrical 'landed' at all, but we were still 500 feet away from Mars proper. We simply had Chicago San Francisco Toronto work. Hundreds of boys have descended in the aerial Martian city, but Illill II II II II IIII II IIIII III I IIIh= already won success through this we did not know till later. IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIÍIIIIIIIIIIIIIIIIIIIiIIIlu111111111111111111111111111II I. C. S. help. You can do the "Every building is constructed of the same. Everything is made so clear universal transparent material Tos, giving that you can learn in your spare the structures a curious but pleasing appear- Electric "Pullers" for Boys time, regardless of ance. The transparency of this wonderful where you live material is so great that it is possible to or what you do. No books to actually look straight through an entire buy. building, wherever there are no obstructions of opaque objects. I might say that the latter are rare, for the Martian loves There's big money in electricity. Get nothing better than transparency and for after it by marking and mailing the that reason he builds nearly every object attached coupon today. Finding out of Tos; from a table down to the floor, costs you nothing. which, of course, is transparent, too. You might think that such a h,use, open to Mark the Coupon -NOW everybody's curiosity would bring with it many delicate as well as embarrassing situ- No. 390 Just what they have been looking for. Transfers ations, but this is not the case, at least the high speed to great power at slow speed. INTERNATIONAL CORRESPONDENCE SCHOOLS not for the Martians. These peoole have FIVE CHANGES from three pullies and two winding drums. Boa 5306, SCRANTON, PA. long since learned that anything worth doing cannot possibly be open to criticism Price $2.00 IExplain. without obligation to me. how I can I Live dealers everywhere. Order direct. or ask qualify for the position before which I mark X. from fellow inhabitants; while closeted, your dealer to show you the Knapp Line and nothing insist on getting Knapp Goods. Dealers not non -transparent rooms make for already handling the Knapp Line should ask for iAutomobile Running tenog. &Typewrit'g but laziness and vice. When all of your prices. Motor Boat Running kkeeping Catalog illustrating many specialties on request. Electrical Engin'er'g R. R. Accounting actions are open to the entire world you _ Electric Lighting Good Hagfish for E,'yooe are more apt to lead an upright life than KNAPP ELECTRIC NOVELTY CO. Electric Railways Civil Service reason no false, make - Dynamo Running Architecture otherwise. For that 523 West Stet St., N. Y. City Telep. & Teleg. Eng. Contracting & Build. I believe civilization exists on Mars as is Mechanical En¢'r'g Structural Engin'g the case on earth. For that reason, too, Mechanical Drafting Plumb'¢ & Heat'g is an healthy, truth - Shop Practice civil Engineering the Martian upright, Steam Engineering _Salesmanship loving individual, not a hypocrite as are Mine Pore. & Supt. Advertising nine -tenths of the human race. The Mar- Chemistry Agriculture tian has no secrets, he knows no vice, he OSTON WIRELESS Name has no scandals, and he has little occasion Rotary Condenser, 43 plates, 001 M.F., $3.75 B Tuner 0. Spark 33'00 Be- to feel ashamed of himself. Why? bote .00Ó SÌ.l60e. .0OÓ Street and No cause everyone can see at all times what Loose Coupler, $7.50, 1500 Meters Agent for A. W. Bowman h Co., Adams -Morgan Co.. he is doing. Manhsttan[Bnark Coil.. Catalogue for 2e. /tamp. ICity State "Pick up any one of your newspapers. M. MUELLER,18 Devonshire Street, BOSTON, MASS. Present Occupation What do their text pages contain? Seventy

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per cent. scandals, murders, war, law suits, gossip; 10 per cent. sports; 10 per cent. business; 5 per cent. science and advancement, and 5 per cent. miscellaneous sub- I jects. If you place your whole humanity in transparent houses the scandals, murders, war, most of the law suits and the gossip ' Z-_ -- '^"r".. will disappear automatically. Think it ( over! "The great Martian 'cities' are laid out in semi -circles, or else rectangles, always one side quite close to a waterway. More- over the 'cities' are not detached, but they arc continuous; by that 1 mean that they run unendingly along the whole length of nearly every waterway. Thus on both sides of the waterways you will lind the metal towers bearing on their top the Martian buildings. The so- called 'running cities' are only about one mile wide, running par- Because allel with the 'canals.' Every 50 or 100 1 want ambitious men to become high salaried Draftsmen miles we find a large center. which spreads through my practical working training- therefore: out in form of a semi- circle or a huge rectangle, some of these large !'cities' re- cede from five to seven miles from the waterways. Of course, these large 'cities' IWìllGíveYou are connected on both ends with the 'running cities'; for that reason there is no This Set of Drawing Instruments no end Martian beginning and to the The Chief Draftsman of a large and well -known company will 'towns.' Nor do they go by any particular give you this complete draftsman's outfit absolutely free. It does not cost you a name. Each spreading city has a number penny. Besides these Imported regular draftsman's instruments shown here, I also while the running ones, located between the give you absolutely free a 20x25 inch drawing board, a 24 -inch T- square, a draftsman's triangle rule, supply of drawing paper, 2 triangles and French curve, pencils spreading ones, have a figure and a symbol and erasers, drawing thumb tacks, etc., in fact a complete and first -class regular Draftsman's Working like our letters. Thus the Martian Capital Outfit as soon as you enroll. This is just the same kind of an outfit f use myself. Genuine working on this special I which we is 1. instruments. You could not get this outfit for less than $13. But now offcr. will give it at reside at present termed to you absolutely free. The first large 'city' toward the south is termed 2. The 'running city' which con- nects city 1 and 2 is termed 1A. Of course, And Train You for a $200 Position the Martian symbol is not 'A,' this is mere- I am Chief Draftsman of an old and well -known company. There is a con- ly my equivalent or my own translation stant demand for trained draftsmen all over the country and I will give you just the kind of training for it. The numbers of the houses for quick that will qualify you to hold one of these big paying positions. $125 to 5200 a month straight orientation are teemed in 'fractions,' ac- salary is an ordinary pay for a good draftsman. I will give you just the kind of training that you need to hold one of these fine jobs, right in your own home during your spare cording to their location. Thus, for instance, time. Start earning money as soon as you are my personal student. a house located in the 'running city' lA is I know the kind of training that you must have in order to get the highest SPECIAL! salary -and that is just exactly the kind of training that I will give to you. lA For a limited time I am During the last twenty years I have trained some of the highest paid men. numbered This means that it is the making a special price Their success in the profession is well known. You can do as well -or -. offer in order to com- better than they. 10 plete a new class ready tenth house south, counting from the 'city' to start. Send for free F book at once, to -day. FREE 1. As every Martian knows the location Send Me the Coupon NewNor Book of every 'town,' the numbering system is I both simple and does not lend itself to con- Put your name and address in the - I sa MIN MIME ar3111a, fusion. coupon or on a letter or postcard now and send to Chief Draftsman Dobe me at once for my new book "Successful Draftsman "As nearly all of the land on Mars is ship." Find out about the golden opportunities that' Engineer's Equipment Co. practically desert, except that near the await you in our procession. Find out how you can' Division 3383, CHICAGO, ILL. waterways, it follows that no 'town' ever get just exactly the kind of training that you need to hold a position paying from $125 to $200a month Without any obligation to me what- reaches more than 10 miles inland. This at once. Absolutely no obligations in getting the 1 soever, please mail your book "Suc- fully explains the vast 'connecting cities.' book. Just put your name and address on the cou- cessful Draftsmanship." and full par- pon. But send it now-immediately while I am ticulars of your liberal "Personal In- "All the streets run perfectly straight making this special offer. struction" offer to a few students. It and cross at right angles, American fashion. is understood that I am obligated in no nay whatever. All buildings and houses are detached from CHIEF DRAFTSMAN DOGE each other, none are ever found built close Value together. Usually eight buildings constitute Div. 3383 Engineers Equipment Co., Chicag a 'block,' three to each side, with the center space left open. "The 'blocks' are separated by wide arched roadways ; wherever two of them big cross each other, there are usually two at the subscription offer bridges flung diagonally across which meet LOOK shown on page 669 of this issue in the center. "The roadways themselves are of a heavy metallic construction and are entirely per- forated with round conical holes about one inch in diameter with about one inch of Handy Binder metal between them. By this method all dust and dirt falls through the streets to for THE ELECTRICAL EXPERIMENTER the ground 500 feet below. Thus the Holds and preserves 12 issues, each of which can be roads appear clean perpetually, even aftcr inserted or removed at will, without tools. Will 'keep a sandstorm. The houses but, your magazines perfectly for all time or just 'preserve hello, my chronometer tells me that 1 have them like new till you bind them permanently. Made of but ten seconds left to talk 'before the heavy material, extra strongly reinforced telegraphone wire on my radiotomatic on at the back and covered with handsome the moon will be full to capacity. Well, green cloth, suitably lettered in gold good night, my boy, till to- morrow, good Shipping weight 2 lbs. Add sufficient postage, other- 41 night! * * * * * wise we will have to send binder by express. The usual rap, r- r -r -ap, f -flum, f -flumm Order a BinderTo -day and Preserve Your Magazines. and everything was quiet once more. This serial started in the May, 1915, issue. Experimenter Pub. Co., Inc., 233 Fulton St., N. Y. Bark numbers are supplied at 10 cents each. Book Dep't. (To be continued.)

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Here's YOUR Chance to Learn THE UTILIZATION OF THE SUN'S ENERGY. DRA F T/NG (Continued from page 606.) This Complete $15 Drawing Outfit and Full Instructions FREE a partial rotation to the ratchet wheel w. In Mechanical Drawing As the current ceases the armature is re- tracted by the spring b, without, however, moving the wheel w. With the stoppage of the current the plates t t cease to be attracted and separate, thus restoring the circuit to its original condition. Coming now to later developments of a practical nature in the line of solar engines and boilers, we may take up the work of Mr. Shuman, of Philadelphia, Pa., who later collaborated with a Mr. Boys, of Eng- land. They were able in their final de- There's a good job waiting for you. velopments to operate a 100 horsepower The country is facing greater engine by means of solar energy. This plant was built at Meadi on the Nile, prosperity than Egypt, and is shown in the large illustra- - rr it has ever before tion here reproduced at Fig. 3. Prior to experienced.Far - this excellent work, however, the may consider briefly the early solar engines de- seeing men are veloped and tried out at Philadelphia. Pa., THE N. Y. ELECTRICAL SCHOOL le the pioneer and getting ready for by Frank Shuman, upon which work he premier school of the 'Learn by Doing " method. When you have completed this Course you shall be fully boom times. Get started in 1906. qualified to handle ALL branches of Electrical ioduetry. A year later he had running at Tacony, The equipment of this School le unequalled and up-to-the- this training now minute. No preparation needed to become a "learner" in Pa., a practical plant of this type, which this school. You can start to learn on any day of any and share in the developed about 31% horsepower by using week throughout the whole year. Send for catalogue. 1,200 square feet sunshine was CHARLES W. MOREY coming prosper - of that al- New York Electrical School Peooldent of the costee. lowed to fall on a fixed, horizontal water d head of a Large Chicago ity. We make 29 West 17th Street New York City Find box. This box was fitted tvitll a glass ElrclrcaliEnidneea e'od the way plain. Contractors. top and a series of parallel horizontal black pipes were immersed in the water. These pipes, containing ether, exposed 900 square LET SAM BROWN feet of surface to the solar radiation. The Men Wanted water also became heated and carried the TEACH YOU THE heat to the underside of the pipes, thus AT BIG SALARIES realizing a greater efficiency. The ether This is rare chuce for a few wide -awake young men. boiled and its "steam" drove a small ver- AUTOMOBILE On account of the rapidly increasing demand tical, cylinder for trained draftsmen Pres. Morey has issued single engine. The exhaust orders that instructions be furnished to a ether vapor passed into an air surface limited number of young men who are inclined condenser and the liquid ether from this BUSINESS along engineering or architectural lines. He'll a Job as Read about this great offer below -then mark was pumped back into the tubes of the sun fit you for good chauffeur, teet- and mail the coupon. It worked er, repair men, salesman, etc., In 3 to 5 weeks. boiler. was found that this plant Pam teaches you personally -le right ou the well even with snow on the ground, which Job years. STUDY AT HOME your spare every minute. Established six hours for short rt is explainable from the fact that the per- only and learn this profitable and pleasant is about 20 per profession, and get in the class drawing the big meability of the atmosphere Earn $75 to $300 a Month pay envelope. Hundreds of men are in daily cent. greater in winter than in summer. Good Jobs everywhere are waiting for good men. attendance at this old established college. In Further tests and refinements to the Complete equipment to work on; 4, 6 and 9 your own home you can do the same work these cylinder ears for students' work. No theory. men are doing, and the same experts that teach Tacony plant by Mr. Shuman resulted in Bam is practical. Short on lectures -long on them will guide you toward the big job. These actual, practical work. When you finish you well -known 1911 in an engine and boiler which showed engineers prepare your instruc- in their de- are ready to tackle any auto problem. You're tion matter. Your work is examined and ap- considerable strides forward as good as the best, Sam does a good Job. proved by them. They know exactly the sign, the ratio of 245 square feet of sun- Learn from a practical mechanic. I have a line practical training you need and they train you. shine per one brake horsepower having I story building, at 1513-21 Prospect Ave., and No books to sell. Live, up-to -date blue prints 1620 -26 Brownwell Court. Welding and Bronz- of work in actual construction. In your own been attained. ing Depts.; large, well equipped machine home you work with plans of machinery, build- it may be mentioned here that the pipes shop; Radiator, Fender and Tire Depts. Start ings, steel works,etc., actually being construct- to at once. Drop in and see me, or write -Saa ed in Chicago, New York and constituting the sun boilers have invariably other large cities. been blackened. For low temperatures Brown. Electrical Drafting and Design lampblack has been used as the absorber, Ohio Auto School No other similar correspondence comes in America has but where high temperatures were required a resident college of National reputation back of It, nor Dept. 201, 1521 Prospect Ave. a faculty of active experts actually engaged in muni- platinum black was used. cipal and corporation engineering work. These men CLEVELAND, O. know exactly the kind of training you need because The illustration Fig. 3 is that of the solar they are in constant charge of big work. energy plant built at Meadi on the Nile, Egypt, by Messrs. Shuman and Boys in conjunction with several English scientists, Learn Music $45 COURSE FREE including Mr. A. S. E. Ackerman, B.Sc. IN MECHANICAL This plant made use of a 100 horsepower ! DRAWING Shuman engine coupled with suitable auxil- At Home This College has gel aside a limited number of Free ew Method -Learn To Scholarships and will give the regular $46 Comae in iary apparatus, as before mentioned. Five Play By Note Piano, Mechanical Drawing Free with any one of the Home - Study Courses absorbers of the reflection type were util- Organ, Violin, Banjo, to the complete $15 Drawing OntSt which is ized. as the illustration portrays. Each Mando l in, Guitar, Cornet, also furnished to students free. Take advantage of this Harp, 'Cello or to sing. unusually liberal offer today, as one measured 15 feet wide by 205 feet long. when it will be withdrawn Special Limited Offer of free the allotted number of Free Scholarships has These were placed north and south geo- weekly lessons. You pay only been awarded. It costs you nothing to get full infor- music mation. No obligation on you. and for and poetage,which graphically speaking, were automatical- is small. No extras. Begin- ACT NOW -FILL OUT COUPON TODAY ly heeled over, by being placed on suitable ners or advanced pupils. wheels, from an easterly aspect in the Everything ill ustra.ted,plain, simple, systematic. -Electrical Drafting -Builders' Coures one in the evening, Free lec- -Machine Drafting -Plan Reading morning to a westerly tures each course, 16 years' -Architectural Drafting - Estimating so as to actually follow the sun. This success. Start at once. Write -Strnctnral Drafting -Sheet Metal Drafting for Free Book let Today -Now -Civil Engineering (1060) -Surveying caused an approximately even absorption V. S. SCHOOL OF MUSIC, Boa 173 Name of solar rays all day. the 225 Fifth Avenue, New York City Address...... The total area of sunshine so collected Town ...... State at this plant was 13,269 square feet. Cast BINDERS FOR THIS College or Home Study Course ...... iron boilers of suitable design were placed MAGAZINE at the focus point of the reflectors, as ISSUE CHICAGO TECHNICAL COLLEGE shown in the illustration. They were WILL PRESERVE EVERY 1060 LAKE VIEW BLDG. CHICAGO, ILL. covered with a single layer of glass which SEE PACE 661 }'orr benefit by n entioning "The Electrical Experimenter" when writing to advertisers. www.americanradiohistory.com AIarch, 1916 THE ELECTRICAL EXPERIMENTER 663

enclosed an air space around the boilers proper. The concentration value of this WIRELESS arrangement was 4141 to 1. The maximum pounds of steam generated was 12 pounds Per 100 square feet of sunshine, or the Going up? equivalent, to 183 square feet per brake SUPPLIES horsepower. The best hours' run developed, at atmospheric pressure, 1,442 pounds of LARGE STOCKS steam. I -knee (allowing 22 pounds steam per brake horsepower) the maximum out- of Electrical and put for an hour was 55.5 horsepower Wireless Apparatus (about ten times bc'tcr than any previous AGE 30- results I. This means 63 brake horsepower sum AND INTELLIGENT SERVICE per acre of land occupied by the plant. As agents for The Electro Importing Co. and J. H. Bunnell g Co.. we assure you of quality mer - Moreover, no marked reduction in the Chandlse at lowest prices. horsepower produced was noticeable in QUAKER LIGHT SUPPLY CO., 728 ARCH ST., PHILA., PA. the early hours of the morning or ill the late hours of the afternoon. The engineers of the concern which Auto Throttle Governed made these tests at Meadi recommended AGE A0 -se0o Engine for Every Work that such solar plants were feasi le and AGE 305700 Them is no other four. AGE 20$ 600 cycle engine with auto - practical and that undoubtedly they would matio auto typo ut throttle be a very good thing in such arid regions governor on the market -or down? AGE 504500_ , near the price. Unlike for irrigation purposes. One argument ordinary low priced en- tines it is not hit-once-in- 'brought against them, however, was that n- w hito governed with jr. the power 'would not he available in regular speed and wasted cloudy HERE is your future charted for gasoline. weather, but then the irrigation would not It fires every shot with you, based on the actual aver- speed regulated by exclusive auto -throttle be necessary, was the reply. govenor which eans even, economical power. Thus the fight goes on between Dame age earnings of trained and un- It win operate electric light plant, pump water. run feed, Nature and the scientists. \Vhedier we ery. ntacchurnis theengine for e work.p'machin- trained men. H pper Cooled comploto shall ever have an efficient solar boiler and only rs unDi2 H. . to 'you from the factory. Write engine is a problem worth thinking about Which way will you go? You'll for catalog. and a very interesting one at that, as we either go up, through training, to a C. Benningholen & Sons possess no greater source of natural energy, Dept. 110. Hamilton. O. to be had without taxation or special leases position that means good money and from some money- grabbing coal, oil or more comforts as the years go by, other baron, than that of the sun. Some or you'll go down, through lack of day we may be able to derive all necessary PORCELAIN light and power, for our homes at least. training, into the ranks of the "THAT'S OUR BUSINESS" by means of a solar- electric plant located poorly paid. on the roof, and who shall say that we Standard and Special Shapes, Regardless must be taxed for utilizing such energy? It rests entirely with you which way of How Difficult you go. You can make or break your own We Illustrate one hard shape we make. THE TESLA HIGH FREQUENCY future. And now is the time to decide. A pair of rolls 734" long and 15S" in diameter with 8 holes on ends and middle. OSCILLATOR. Not next year, not next month, but now. They must be perfectly straight and we (Continued from page 615.) can go up you make them so. It's hard but not for us. You if want to. You can We can make your difficult, designs also. get the training that will command a Send us blue print for quotations. thousands of horsepower ? However, this trained man's salary. The International iiguïes out better than might be expected Unioi Electrical Porcelain Works offhand. With an input of 300 kilowatts at Correspondence Schools have helped hun- TRENTON. N. J. the Tesla coil primary exciting such a dreds of thousands of men to qualify for 1 structure and considering that this amount advancement. Let them show you how you of energy is discharged through the earth can prepare yourself, in your own home, in six- thousandths (.006) of a second, then for the position you want in the work START NOW the rate of liberation of the energy will be 120,000 horsepower. you like best. TELEGRAPHY Many perhaps would doubt that even At least, find out what the I. C. S. can do ith their small experimental high fre- for you, by marking and mailing this coupon. and WIRELESS quency sets. where a high frequency am- It will be the first step. upward. Choose your meter placed in the high frequency circuit future from this list, then get this coupon into iR Studen a who e net now reap the ad- NI vantages of he wonderful opportuni- may register but r ampere effective current, the mail today. ties created by the war and which will yet an average maximum surge for the os- multiply when peace is declared. cillation passing through the circuit may I. C. S.. Box 5305. Scranton, Pa. (ff Our book on "Telegraphy and Wire - and often does reach the value of over rró T OUT HrPE - - --.- 'II less as an Occupation" sent on re- amperes. As the amplitudes of each suc- ceipt of IOc. It gives much necessary I INTERNATIONAL CORRESPONDENCE SCHOOLS 1 and valuable information.. ceeding high frequency alternation is less I Box 5305, SCRANTON, PA. than the one preceding it, of course the Explain. without obligating me, how I can qualify for first oscillations are much higher than the the position, or In the subject, before which I mark X. BOSTON SCHOOL OF TELEGRAPHY ELECTRICAL ENCISEER ADVERTISING MAN average amplitude just mentioned. and con - Electric Lighting Window Trimmer 18 Electric Car Running Show Card Writer Boylston St., Boston,'Mass. sequently the peak value of the current Electric Wiring Outdoor Sign Painter which flows through the electrode and into C Telephone Expert ILLUSTRATOR MECHANICAL ENGINEER DESIGNER a person (who may happen to be connected Mechanical Draftsmen BOOKKEEPER in series with a 110 -volt, 32 candlepower Machine Shop Practice Stenographer and Typia Gas Engineer Pub. Accountant TELEGRAPHY lamp for demonstration purposes) may I CIVIL ENGINEERR Railway Accountant and Mapping Commercial Law Taught by retired railway officer.eANDr. RailwRailway wires in reach a very much higher figure than 116 Surveying ad d rooms. Expenses earned. All graduates MINE FOREM'N OR F.SO'R GOOD ENGLISH Placed direst In the telegraph service. amperes. Metaller gist or Prosperlor Teacher STATION tiff ENGINEER Common School Sableeis Send for Folders and_Rates Marine Engineer CIVIL SERVICE ARCHITECT Railway Mail Clerk of Telegraphy, Madison, Wis. Peinar School electric lamp on the front Contractor and Builder AGRICULTURE dmeriec'. Scientific Roiloao Tr ininoSchool A tiny porch Architectural Ilraftrnaa POULTRY RAISING the back porch, left burning Concrete Builder Textile Overseer or Rapt. and another on Structural Engineer Navigator Spanish all night, will keep night prowlers and PLUMBING AND HEATING Chemist German $12500 to $30002 a Month burglars away, because no thief cares to Sheet Metal Worker AUTO RI'NNING French Write at once. Moat wonderful opportun- SALESMANSHIP data Repairing Italian ity for the am- take a chance in the light. Theo need dark- bitious man. Name Railroads need ness and black shadows for their protection. of One two -candlepower lamp for the front Occupation Signalmen -will pay Big Money. & Employer porch and another on the rear porch can I Street Special Offer v,o rrt, he turned on all night for a few cents a Iand No Wnta Tester forour fi e..loat nd particulars of ourbigoüúr. is cheap burglar in- DEPARTMENT OF SIGNALING month, which certainly City State IBlO W Ilson Ave.Room3383,Ravenswood Station.Chicego surance.

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www.americanradiohistory.com '04 THE ELECTRICAL EXPERIMENTER March, 1916 Oh, You Skinny! HOW TO ORGANIZE AND CON= Why stay thin as rail? DUCT A RADIO CLUB. You don't bave to! Andn you page 627.) don't bave to go through life (Continued from w itb s chest that the tailor YPNOTISPII cites you; with arms of ebild- ing and receiving sets constructed entirely Be a HYPNOTIST and MAKE FUN and MONEY! i:.b strength; with leg, you It takes but a few hours to learn. o on. The study Is both easy and hardly stand And by members of the club. The crowds of fascinating. Hypnotism is an endless source of fun and wonder. what about that ato.narh that If you know how time visitors evinced great interest in this par- to Hypnotize you can perform some of the Mashes every you try most marvelous feats Imaginable. You can do a hundred amazing square meal? Are you s ticular feature of the exhibit. things that other people cannot do. Toucan surprise you rMends pat- Ierder? and make yourself popular. Do you aspect Health The Atlanta Radio Club has an active You can place others under this and Strength in tabloid strange and mystic spe1L You can compel them to think, act lor.n- through pills, po- membership of 25, each member possessing and feel just as you wish. if you want to make money you can tions and other exploited piffle? a complete sending and receiving station. A may án m others nW!ir Ywork for others, when you mayysion sot in. ` You can't do it; it can't sleeting is held every two weeks, at which van gate SOw!On so easilyleasily? lrn .. be done, t SOW! to fie well is many subjects of interest are discussed. You may learn ( e fd .r The up way at your own hone. 1 to build will send g1 'l l' itt% The members converse every night with m free treatise for the ask- //Agjll," ' r it-through nttanature's methoh f youg. Its tells you about ens d -not by pampering the eah other, the length of conversation, form in 4 d how you may 1 ,, stomach. It is not fate that of calling, signing, etc., all being done in team nd It is Iny illustra. bt is making you a failure; it's ted it that poor, emaciated body of and writtenwrider a simple 1'' 1 strict conformance to certain by -laws of the easily understood by all. ttypNOTJLNG Anybody a f 't [h Oeand club's constitution. Lows plain your face d the Hypnoticthe, Spellegra sways the me its the or the world loves healthy who reformspositron the degraded, overcome So be healthy- strong- The club has a special operator, bashfulness,bashfulndsg helps to trade or vital. lining. Don't position, amuses an audience for ndfia, and for the oper- That's sends out official notices to all members on ator himself and hap, mess. and ameull to health, welt- think too long; send 4 cents ( and happiness. in stamps to cover mailing of a certain day and hour, and also has an Itr a so treats fully on Meg - r book, "INTELLIGENCE I netisro and kindred objects. solutmberthisSim-this IN PHYSICAL AND inspector of stations, whose duty is to ad- rise for t,t het. Sim- HEALTH CULTURE," just each station so that it will cause a ply write for lt, Mari it will be written 1,3, the strangest physi- At( sent byneztmail all charges cal ulture instructor in the minimums of interference, and also to see +; oe.t Don't send any monay 1ri r o tamp, butsrndyour name warf.d that station the Govern- eecpl each conforms to S/ tß,1 and address today. Address: LIONEL STRONGFORT ment radii.) wave \? Dept. C36 H ,Cuba regulations regarding )d C M. D. BETTS, length, power, etc. . t IN6 Sta. 663. Mich. A Club La'toratory. Jackson'. THE PANDICULATOR Many amateur radi, organizations have arranged in one way or another to fit up `1:4I, ,- ARMY AUCTION BARGAINS shoo facilities for the use of the members. Saddles $2.00 np Army Revoivers $1.55 n ',`- g Bridles .90.' 11.1. Rifles e . .95 F Specia' appropriations, obtained by outside D f Teem Harness 21.55 e' ` Sword. . .3S " contributions by levying an assessment 41, Leggings. pair 15' 7 Shot Carbine S.60" or Tents . . . 2.86' New Uniforms . 1.50 oil the :!embers of the club, have served to t' Colts Cal. 45 Revolver $2.45. Otg.. le each. 15 offset the cost of the machinery necessary. 7.,;.,5 ,ii., Acres Government Auction Bargain. Illustrated t' 1.,4'11 fr end described in 420 largo page wholesale and A small lathe is probably one of the most fl I( . retail cyclopedia catalogne, mailed 25 cnts This 30 University discovery is the most im- useful articles which a club should purchase .Beat and cents West of the Mississippi Meyer. portant health invention of the century. It re- I Francis Bannerman, 501 Broadway, New York, makes and rejuvenates the Human Body. It for such a laboratory. This may be fol- produces normal spines. It frees impinged and lowed by a small drill press, another neces- irritated nerves, corrects contracted muscles, sary accessory which the individual mem- DSuper- Conscious shortened ligaments; eliminates congestion, it - proves circulation and drainage of the leek II bers would probably not have the good for - WILL INCREASE TILE BODY'S 1.L: ,III. EEP BREATHING tulle to have the use of in their own homes Over 50,000 Satisfied Patrons or laboratories. Aside from such machin- my super l method of "Su r- Conscious DEEP THE REATHING"Bf warrants my claim that it w the only PANDICULATOR CO. ery necessary in winding coils, making up correct method of -vitalizing the bloodscientifically. building force and constitutional Cleveland, O. special apparatus parts, etc., there is a very strength. tlwyenaablinganyone, with a few min- i practice, to throw off fatigue. d presston and urgent need for a good wave ureter, and brau s ffag. Send for my FREE book on DEEP BREATHING.. Paul You Boeckmann Respirator" also, when possible, a decrenreter. From Nerve 2840Tower Bldg 1 West the various magazine articles, particularly and New in The Electrical Experimenter for Novem- A ber, .1915, it is possible to build a fairly ;1 DON'T ME accurate wave meter without a special cali- Lilt i. bration against a standard wave meter. Any BASHFU ,r- wave meter can be calibrated at a nominal Are you timid or self-conscious! .--Do you blush, lose your nerve ands, expense by the Bureau of Standards, Wash- become confused ee ;1:y? Are you bashful Obtain free hook showing ho, QUINN WRITTEN ington, D. C. The secretary of the club and unsuccessful In love, social or business affairs? METHOD saves three -quarters of time and money My illustrated FREE TREATISE tells how these faults usually necessary to learn piano o organ. Scien- should write to the bureau, obtaining in may be promptly and permanently overcome. Address: tific and systematic method. yet practical and M. DeBETTS, ' Station 55, JACKSON, MICHIGAN simple. Play chords immediately. and a reply information as to the cost for cali- complete piece within a few lessons. Suc- .brattng the particular instrument in hand. cessfully used by Dr. Quinn for over 25 CET ON THE years. Endorsed by leading musicians./ Likewise, it is possible to have a decremeter STAGE Successful graduates everywhere. Learn at calibrated. If access is had to any local VAUDEVILLE home either as a social accomplishment or for I tell you bow! Fascinating profession for teaching. Practise in spare time whenever school or college having such standard in- S, ,- sex. Big Experience you wish. For either adults or children, biro either salaries. un- Special terms this month. Send today for strument on hand, it is possible that ar- necessary. Splendid engagements always FREE hook "How to Learn PianoandOrgan. rangements can be made with the instructor waiting. Opportunity for travel. Thee - No obligation. M. L. QUINN CONSERVA- V trical agents and authorities endorse my TORY, Box 650- DO,CHICAGO. h in charge to compare and check up the , methods. Thirty years' experience as club's instrument with same. manager and performer. Illustrated Month IBe to the conclusion book "All About Vaudeville" sent FREE, 50 a sure read of this Frederic La Dane, Sta. 177Jackson, Dish. The master- important article in the April issue. It piece of watch takes up such timely subjects as the "Rules Manufacture-adjusted to the second, positions. tem- for Conducting a Meeting," "Order of De- perature and isochron:sm. En- dirt cased at factory into your choice bate," "Formation of Club Library," "List of the erpuisite new watch case.. of Most Desirable Books," etc. -EDITOR.]

19 Jewel THE CHORALCELO, A WONDER- There is an' ever inereat- Learn Wireless Telegraph y tag demand for Compe- FUL ELECTRIC PIANO. tent operators-this profession offers steady employment. at a good salary- wireless operatoretravel all over the world. and women. Burlington (Continued front page 607.) Th PAINE Uptown BUSINESS SCHOOL The great Burlington Watch sent on simple request. 1931 Broadway. (65th) New York. Send for CatalogueE Pay at rate of 52.50 a month. You get the watch at the same price even the wholesale jeweler must pay. necessary to place within them a small piece Write Today for Free Watch Book of iron, so that the electromagnets may ,t_ :is Classi fi ed AdveethI:m n s In t See handsome color illustrations of all the newest attract them. Instruments which are op- ssue. They are sertismall but con tai n designs in watches that you have to choose from. READ big Your name and address on a postcard is enough. erated by this method are depicted in Fig. bargains and opportunities. Get this offer while it lasts. Write today. 3. The one toward the right is an instru- Burka on Watch Co. De t. 3383191h& Marshall Blvd. Chicago ment which imitates a flute. The electro- You May Learn Theory, Code an. magnets are placed underneath the tubes, Laws of Radio Communication which are made out of wood and act as In Our School or at Your Home. MUSIC LESSONS FREE fitting you for podtione paring good ear resonant chambers. The magnets are worwith wonderful also. to travel tb a caused to act on iron discs mounted at the ld er. lt. the mostinterestingpre ....1re aIr fession known and the demmd for skild 9oe can 185+4. Trio lower end of the tube. Another style of operators ia neresaing. Send st am p for oaslogr ttkt quitli. ich at Your Nom.. Write today for our booklet. F. tells flute instrument is illustrated in Fig. 4. give* full Information. bow to learn to play Piano. Organ, Violin, Mandolin. NATIONAL RADIO SCHOOL. 1405 U St Guitar, Banjo, tc. Beginners or advanced pupila. This employs a different variety of tubes, Washington, D. C. AMERICAN SCHOOL OF MUSIC,70 Lakeside Bldg-Chicago ranging from a very high tone to a very Q You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. www.americanradiohistory.com March, 1916 THE ELECTRICAL EXPERIMENTER

low one. The smaller pipes emit the latter tone, while the larger ones produce the former. WANTED The instrument shown in the center of Fig. 3 illustrates a brass chime. The tones are Railway Mail Clerks produced by hammers, each of the tubes being supplied with $900 to $1800 a Year one. These are operated by ($75 to $150 a month) Pleasant Work -Continually Traveling electro-magnets, as perceived Rapid advancement to bicker Government Positions. "No lay- Franklin Institute (The offs" because of STRIKES, WAILS, FINANCIAL FLURRIES Pathway to Plenty), Dept. F254, Rochester N.Y. in the bracket of the or Thin coupon Oiled out as directed, entitles the s.nder tel tree specimen questions; upper the WHIMS OF SOME PETTY BOSS. TILE POSITION IS of our book. l ;o n sitio ii how ehn true .,rnmen .r ' lletof These are also con- YOURS FOR LIFE. cod ialneLle and t c nde [ion for Free CoehÌOt for stand. tÍ..,v.nnnnr Country residents and pity resident, stand the saine chanco for ns her sclerli CO dONn nected to the same keyboard. immediate appointment. Connoueenee education sufficient. ..Railway Mail Clerk.$900 to 51800 ...Customs Positions.$800 to $1500 Political influence NOT REQUIRED. ..Bookkeeper 900 to 1800 ...Stenographer .... 800 to 1500 The very deep tones of an ..Poslothwe Clerk 800 to 1200 ...Internal Revenue 700 Write immediately for schedule showing the places and datte of ..Postofflce Carrier 800 to 1200 to 1800 TILE SPRING GOV'T examinations. Don't delay. Every day ..Rural MairCarrler ...Clerk In the Departments organ are produced by vibrat- S00 to 1200 1 Washington. . BOO to 1SO0 you hose means the lose of iust so much coaching before the ..Auto Chauffeur ...Canadian Gov't Positions ing diaphragms placed beneath vidly approaching esam,natlons. metal horns. A pair of elcc- FRANKLIN INSTITUTE, Dept. F254, Rochester, N.Y, Name Address F264 tro- magnets are held a minute Uw the before you lose it. lynt, plainly. distance away from the diaphragm and serve to vibrate the latter when the pulsating current is applied. The volume of the tones are powerful and are very pleasant, although Extraordinary Prices on they are very low. By increasing the power in the electromagnets the strength of the tones are so much increased that it is almost impossible to These Oliver Typ ewriters imagine the effect. "Echo" combinations also may be installed without limit wherever their effect may be most beautiful at any distance Here's Your Chance! from the master instrument. Thus the greatest cathedral el) Must Sell a Thousand Machines Quick may be filled with a glory of . sound. The tower may be c The great European War makes it impossible to used to flood the surrounding ship typewriters to Europe. We have 1,000 No. S Oliver country with the same divine machines which we must sell quick. And we are determined melody. It may also be carried to dispose of them in this country at prices which defy com- to the quiet cloister and to the petition. These grand typewriters must be sold at once. private room. An instrument Here is a great opportunity to secure an Oliver at bed -rock played in one place may repeat prices. You will never have another chance like this, as its music elsewhere. the small number of Olivers at this ridiculously low price The Choralcelo was devel- will be sold to the first thousand readers sending in the oped and its wonderful basic coupon. Are you going to be one of these fortunate people? principle discovered by Melvin Act now if you want a good typewriter. Investigate today. L. Severy, of AQlington, Mass., and George B. Sinclair. These savants have been working for Genuine Oliver Typewriter twelve years to bring this mu- Guaranteed a Lifetime sical instrument up to the per- These machines come to us fresh from the factory. Money will not fection which it has reached buy greater typewriter value. They have all the wonderful Oliver advan- to -day. One cannot predict its tages- visible writing, U- shaped type bar, built -in tabulator, marginal release, possibilities or limits, as it is universal keyboard with six extra characters, etc., etc. Each full standard size, complete with every accessory and full instructions for operating. really still in its early stages of The Oliver has the lightest touch and greatest durability of any typewriter made. development. Anyone can operate the Oliver successfully. We are indebted to Wilber We will sell you one on the easiest terms ever known. Better still, we cover every E. Farrington, of the Choral - single machine with a lifetime guarantee. Other machines are guaranteed for one year. ceto Co., for our illustrations. But we have such confidence in the No. 5 Oliver that we will guarantee it for life. When you buy an Oliver you buy "for keeps." MARVELS OF MODERN PHYSICS. Half the Price of Other Machines (Continued front page 623.) Payments Just Like Rent These 1,000 machines must go at once. And the price we make is so low that we do not a heat wave, that it had a dare even publish it. We can quote this price only in a confidential letter. Ask for it, t.A density of about 513 x 10 -'° if you need a machine. Don't wait until they are all gone before investigating. Mail L'1` pounds per cu. ft., which would the coupon or a post card today. Our price and terms will surely astonish you. '' make a volume of ether the And remember that this is a regular $100 machine, with many thousands in use size of the earth weigh only a all over the world right now. We can always undersell manufacturers, because ~Oe v small fraction of we have no salesmen with their big salaries and expenses. All of our ma- a pound. chin es goo direct to the consumer, and he getsets the savinsaving. a Whether the ether is con- IlkAnd right now we are going to cut our own low price clear to the bone. ` y0 tinuous or discontinuous, at Seize this opportunity while you may. for we doubt if it ever can be a .`$ r°s least it is not matter in the repeated. At the astonishingly low price we are quoting, these 2 Cj Oro c`ó° ordinary sense, and it certainly thousand Oliver Typewriters will all be vroa{. of in a time. , D. is not atomic; that is, divisible disposed very short O ° into particles akin to atoms. _ ° There are no gaps as would ec a°ao;` c o exist between such particles, Our, ,e. tee oQ and the shortest light waves Get Amazing Price and Qor are carried by it as well as the longest. Likewise we now see FREE Trial Offer! rr Send for our offer today. Use the coupon or a post card. Find tS, ,cc° e.'"`O f , that it is the universal medium ont all about our sensational cut in prices. A few cents a day V %Q of action for several different will buy your Oliver. And we will let you try one free, without C o' 04V and sending us a single cent. M ail the coupon now, whether you're l,4Sta'N'a`om :f wonderful forces. rad: to buy or not. Then youwill kn whether you can : To gain a mental picture of afford - without a standard Oliver an longer. 440A í this medium let us consider a TYPEWRITERS DISTRIBUTING SYNDICATE 4Qv s,en6See ,Iás', J hollow sphere H, W, as in 1510.871 Wabash Ave.. Chicago iFt; (Continued on page 667.)

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www.americanradiohistory.com 666 THE ELECTRICAL EXPERIMENTER March, 1916 Thousands of dollars were gladly spent

to compile this book

NOW OFFERED to you for the unusual price of 35c. Postage on 1lb. extra CONTENTS Tells you quickly and accurately either call letter or station name and location of any and every wireless station in the entire World. Obviates that irritating moment when you hear an unknown call and have no means of quickly knowing who it is. Makes it worth while sitting up late at night to hear that faint and far off foreign call, for with it, at least, you can tell whom you hear. Contains 222 pages of information worth its weight in gold, lists over 15,000 ship and shore stations by BOTH nationality, location and call letter being cross indexed to give location, ownership and station designation. A REALLY REMARKABLE OFFER Imagine a finely cloth bound book 5%. x8 inches and 7g inch thick in size, our illustration is full size, containing 222 pages of information obtainable nowhere else and printed on an excellent grade of book paper and from type unusual for clearness and ease of reading. Not only is it up to date, but provides means for the insertion in their proper places of new calls of every nationality whenever assigned. Positively the best work of its kind ever offered and WORTH $2.00 PER COPY. HOW IT IS POSSIBLE This remarkable offer is possible only because of the financial difficulties which prevented the publishers from marketing a book which cost them thousands of dollars to compile alone, while thousands more were spent in editing, composition, printing and binding. Being exhausted the printers came to us as the logical outlet and we offer you these books at a price less than they actually cost to produce. AUTHORS The book was compiled by FRANK A. HART, Chief Inspector of The Marconi Wire- less Telegraph Co. of America, and H. M. SHORT, resident Inspector (U. S. A.), Marconi International Marine Communication Co., Ltd. Need we say more as to the authority which these men have at their command to compile so noteworthy and necessary a book? DELIVERY We have on hand a very limited number only of these books and NO REPRINTS WILL BE MADE. We cannot, therefore, urge too strongly that you send in your order at once. All orders will be filled in the order of their receipt. Better send for it TO -DAY and make sure of getting the greatest book value possible to get. When you get the book you will say we've under- estimated the value we offer. NOTE! POSTAGE IS EXTRA ON A SHIPPING WEIGHT OF ONE POUND. So include sufficient postage with your remittance which should be in cash or-by money order.

EXPERIMENTER PUBLISHING COMPANY, Inc., DEPARTMENT, 233 Fulton Street, New York, N. Y.

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MARVELS OF MODERN PHYSICS. 61/ ;í(tii,,,, (Continued from paffe 0;5.)

Fig. 3, consisting of two hemispheres connected by a coiled spring on the inside. Now we may consider these hemispheres as uncharged or rather the positive and negative charges exactly balancing each !ti h other when they arc together. / rn .+t 1. Ile i\ ti o. 4./1r tpl Iit 1;', Itr t\\ ke Or et i If now the hemispheres are electrically charged in a suitable manner, we may consider Earn $2500 to $4000 a Year the positive as separated from Your CHANCE has come! Your chance for big money. Your the negative. and the two hem- chance to do the kind of work you'll be proud of. Your chance to go ispheres as stretched apart. into business for yourself. Think of it! You can now qualify AT HOME There is a strain in the ether for that most wonderful of all fields open to the ambitious man -the great between these two charges that field of ELECTRICITY! Yes, no matter who you are, where you live or is analogous to what ou do, I will take you in hand and make you an EXPERT ELECTRI- here the ten- $2,500 $4,000 more. sion of the stretched spring. CIANso that you should easily earn to a year and And Take A.W.Wicks, I'll do it so quickly and with so little effort on your part that you'll a charged Leyden jar wonder how it was possible. for example. Here we have E. E. two opposite charges bound to Formerly with each other by the strain exist- the General LEARN AT HOME ing in the intervening medium. Electric Cotn- What if you don't know a thing about electricity! What if The mechanical illustration of pany:former General you've never had a bit of electrical experience. All I ask is that you Manager of company this in Fig. 4 is almost self - give me a little of your spare time. I will instruct you personally and manufacturing Jen- make the whole matter so simple for you that you can't help but learn. You don't explanatory. A rope attached ney Electric Motors: have to buy a lot of books or equipment. You can master MY personal instructions to two springs passes over two also formerlywithFh ir. easily right at home. I've solved this question of teaching electricity. 1'l1 shove . banks. Morse & Co.: you I have by giving you 20 personal lessons ABSOLUTELY FREE. Almost pulleys. The weighted ends of now Consulting En- from the very first instructions you will have the knowledge and skill to do the rope are the coatings gineer and Director for doing. of of Elec- practical. electrical work -work that you can demand good money the Leyden jar, and an excess trical Institute. You can earn as you learn -more than pay for your instruction as you go along. of weights on one side or the other constitutes the charge. Here the strain between the Be An Electrician coatings is shown by the Think! When you have finished my instructions you are an EXPERT springs again, and if the ELECTRICIAN! You are right then and there ready to take a big paying weights are suddenly evened job or start in for yourself. I will train you until you consider yourself up, the oscillatory nature of competent regardless of the time it takes. I not only show you how to do expert electrical the spark discharge would be work but show you how to estimate on jobs so you can take contracts at big profits. That's what it means to be personally trained by a man of my practical experience in every aptly illustrated, f or t lI e phase of electricity. Decide today to take advantage of my big free 20 personal lessons springs would vibrate back and offer. Don't let the question of money bother you. I make the cost so small and the forth "charging" and "dis- payments so easy that you won't miss the money. charging" the coatings till Wherever you go there's always urgent demand equilibrium was reached. Now MEN WANTED for Expert Electricians and at big pay. That's it is very much a question of because the watchword of the age is, "DO IT ELECTRICALLY." Electricity advances whether electricity is a func- eo feet that there's a big shortage of competent electricians. And the demand is constantly increasing every day. tion of the ether or vice versa; that is, whether the electric charge causes the ether- strain or whether the ether- strain 20 Complete Lessons FREE! causes the charge. One is eer- tainly the accompaniment of That's the sensational offer I am making now to a few more ambitious men. Send this Coupon the other apparently. I I make it for two reasons. 1st. To show you how easy my personal instru -f 1 The fact is evident, however, 11 w tions are to master. 2nd. To secure quick action on the part of a few / E É, Director. students. This offer means 20 WICKS ELEC. Dim it. Mthat the ether is a medium for more prospective that you get complete/ W.at Rands the exertion of forces, either personal lessons ABSOLUTELY FREE! But yyou must act trick Dept. 92 Chicago, t ., The offer closes in 23 days. Send coupon or postcard at once. I'll Without any obligation on electric or magnetic, and it /me whatever, please send me send full particulars immediately. Mail coupon today -sure! foil description of yourperaonal seems that gravitation is still Electricity do. 'particulars your special of a third form of ether -strain. A. W. WICKS, E. E., Director ars of y free. Little direct connection is seen Wicks Electrical Institute, ou yet between it and the other $1 West Randolph St., Dept. 92 Chicago, ill. two, but then it must be re- dle Name membered we know but little of the exact nature of any one ' street and N. of them or even of the "ether." We must content ourselves to E ty live and learn, even though the Send Now nranr sçnow, learning at times seems slow. 5 t a year ART MAGAZINE vayóú ro 10e. a copy [This is the second of a series of FREE DEVELOP, ISTS and ART eootf How To papers specially prepared for The STUDENTS , VITALITY ENERGY, ENDURANCE. Electrical Experimenter by Mr. Publishes Cash Art Assign. NERVE STRENGTII.MUSCULARSTRENGTH Rusk. Part 1 appeared in the mts, lessors and articles on Cartooning. illus. .PERFECZPHYSIQ!U1E February issue.- Eprroa.L [sting. fettering. Designing and ChalkTalk. Mg. Criticises amateurs' work. interesting. My FREE BOOKS. "The Whys of Exertise"and "The helpful. artistic. UNIQUE. Clare Briggs, Itvaa First and Last Laws of Physical Culture," tell you, if you are noted antsts contributors. Walker and other weak or underdeveloped, how to grow strong; if Wong, how A 11.111 please SI pips,. Send NOWSlamps or baneI. NOVEL RADIO IN- you. to grow stronger. They explain how to develop lungs and DUCTIVE TUNER. LOCKWOOD PUB.CO.. Dept 140 Zalamazoo,hlich./ muscle, the strong head and vigorous digestion -in short, how (Continued from page 628.) to improve health and strength intemally a, well u externally, Send TODAY -- NOW - for these FREE BOOKS. xtremely sharp tuning with - Enclose 4c. in stamps to cover postage. t the use of variable eon - PROF. H. W. TITUS ensers, and no dead -end ef- Rene. writer prices smashed l Underwood.. 'ton.. Royal. L. C. Smnhe. Vox. 56 -58 Cooper Sq. Dept. 51 New York City fects etc. -your choice of any standard factory will be experienced. rebuilt machine at bargain. Everyone terrrttu renie. orasey This instrument is the inven- There's a Book tion of Charles Horton, a eider tells how to save 40 per cent ''to 60 percent on each machine. You Need on Page 666. well -known experimenter in Write for it. C. E. GAERTE, President the field of radio telegraphy. DENISON( TYPEWRITER EXCHANGE, DEPT. 623, (=CAW. WW1 LOOK FOR IT. ti.sers. 1 on benefit by mentioning "The Electrical Experimenter" when writing to ad.et www.americanradiohistory.com 668 THE ELECTRICAL EXPERIMENTER March, 1916 I ooks You Must Have

THE EXPERIMENTERS LIBRARY NE I TWO REMARKABLE BOOKS

HOW TO MAKE How to Make Wireless Sending Apparatus WIRELESS HIS book will surely be welcomed by every wireless enthusiast and by everyone who is fond of making his own 1 apparatus. SENDING APPARATUS This book contains more information on how -to -make up -to- HY date sending apparatus than any other book we know of. 20 RADIO EXPERTS I hirty different pieces of apparatus can be made with materials can .00 PAGES 88 ILLUSTRATIONS that most anyone obtain without much trouble; the illustra- t..ns and descriptions being so clear and simple that no trouble will be experienced in making the instruments. Only strictly modern and up-to -date apparatus are described in this book and if we asked you 50 cents for it we are sure that you would consider it a bargain. This book has been written by twenty radio experts who know how to make wireless sending apparatus and for that reason you will gain by their experience as well as by their experiments. The 'size of the book is 7x: Inches sub- stantially bound in paper; the cover being printed in two colors. Contains 100 pages PRICE and 88 illustrations. There are quite a few full page illustrations giving all dimensions, working diagrams as well as many photo- 25c. PUBLISHED EY graphs showing the finished apparatus. THE EXPERIMENTER PUBLISHING CO.. INC. PREPAID 233 FULTON ST.. N.Y. CITY.

100 PAGES, 88 ILLUSTRATIONS THE EXPERIMENTERS LIBRARY N_ 2 HOW TO MAKE How to Make Wireless Receiving Apparatus WIRELESS WE know that this book will surely be a boon to every RECEIVING APPARATUS "How-to- make -it" fiend. It has been written and FIV published entirely for the wireless enthusiast who makes 20 RADIO CONSTRUCTORS Iee PAGES 90 ILLUSTRATIONS his own receiving apparatus; the twenty radio constructors who have written the articles are well- seasoned in the art and know whereof they speak. You consequently profit by their experience. Only strictly up -to -date and modern apparatus are described and only those that the average experimenter can make himself with material that can be readily obtained. We believe that this book contains more information on how to make wireless receiving apparatus than any other boot¿ in print and you will find that it is easily worth double the price we are asking for it. The size of the book is 7x5 inches, handsomely bound in paper; the cover being printed in two colors. Contains 100 pages and 90 illustrations. PRICE There are a number of full page illustrations

giving all dimensions, as well as photographs PUBLISHEO BY 25c. THE EXPUMENTER PUBLISHING CO.. INC. showing finished apparatus. 233 FULTON ST.. N.Y. CITY. Send for these two books today. PREPAID 100 PAGES, 90 ILLUSTRATIONS THE )n,XPEIRRMENTER PÚ EILISHliNG CO., Moo Book Dept. 233 Fulton Street, New York

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www.americanradiohistory.com March, 1916 THE ELECTRICAL EXPERIMENTER (,ill

KILLING THE SMOKE NUISANCE tended fire, but such is not the case, due ELECTRICALLY. no doubt to the inbred pride that all ne ! doing (Continued from page 610.) chanics take in their work oroierly jl`1ATER AND WEATHERPROOF lately in precipitating acid mists, such as 'Arab/or are generated in acid producing plants. .lfe%/s1ocit Figs. 7 and 8 illustrate an experimental outfit for such a purpose. The large dr- cular drum carries a helix of wire which serves the purpose of a ground, while another terminal is placed inside the drum, in the usual way. The connections from the high tension transformer are made to the helical coil and the interior conductor respectively. The pan on which the pre- 120exc. cipitator is placed is used for collecting O the condensed mist which is being gen erated by the acid making apparata. Fig 7 shows the precipitator when the current u.wr.,ata. is off, what. Fig 8 depicts same when the Bonn cotaon current is on. Note the difference between these illustrations. When will ekes, wonders cease? Elec- tricity cleans our doors, washes our dishes, Master batterie, are impervious to and now by .ts power we can filter out atmospheric and temperature influences as they are absolutely water the fine solids from smoke without creat- Fig. I. Diagram of Electrical Smoke Precipi- ing a back draft or in the least affecting the tation. and weather proof. The zinc cell is operation of the furnaces. Besides most up -to -date port" r ¡ila'ats are sealed within the outer waterproof it may be thought that when these equipped with recording chi rts, r: linen: reg- container its the same manlier as a smoke precipitators are installed a will ister the smoke produced. steam pressure thermos bottle leaving a dead air cause the firemen to get careless, as it gradient, etc.. for every minute of the 21 space which acts as a temperature smoking stack is evidence of a badly hours. equalizer. The lithographed carton has an insulated metal button to insure the rigidness of the battery. MEN We HAVE TAUGHT ARE NOW SAILING THE SEVEN SEAS! LEARN RADIO, COMMERCIAL OR RAILROAD TELEGRAPHY

BEREL'S SCHOOL OF TELEGRAPHY, 343-345 LENOX AVE. (127TH ST.), NEW YORK CITY s DAYS A WEEK-5 EVENINGS A WEEK -OPEN ALL YEAR -START AT ANY TIME DAYS, 117.50 A MO. -EVE., $5.00 A MO. -FREE TRIAL ATTENDANCE SEND FOR FURTHER PARTICULARS-NO CONNECTION WITH ANY OTHER SCHOOL a The complete line of quality at prices that are right.

UNITED BATTERY CORPORATION 162 John Street BROOKLYN, N. Y. CARAWAY FACTORY :ASIATIC FACTORY. SS West King st. 22 Escolta, Toronto, Ont. Manila, P.1. Will you take a 20 lesson Wireless Course absolutely FREE -even postage charge prepaid ?

Just as you A c o u r e e that tells you everything you can possibly will receive it, wont to know about "Wireless starting off in Lesson No. 1 by explaining the Principles of Electricity. The Second Stop Using a Truss cloth bound, and Third Lessons are devoted to magnetism. motors; generators and wiring. And then, by simple easy stage, STUART'S PLAPAO -PADS size 7 x 1014 this wonderful Course takes you into "Wireless." The are different from the truss. being ins., 160 pages, mysteries of Wfrelesé' are unfolded to YOU by the use of medicine applicators made self. such simple language go skillfully used, that of necessity adhesive purposely to hold the 20 lessons, 350 you must understand every word. The subject is not parts securely in place. No straps treated superficially, however, for there is a whole lesson or buckles attached -no Obnoxious illus., 30 tables, devoted to the Theory and Mathematics of this epoch springs. Cannot sap, so cannot with every bit of marking subiect. To lend charm to the Course, the last chafe or press against the bone - Leeson (No.20) is devoted to a history of Wireless and the Thousands have successfully information on men who developed it. The wireless course positively treated themselves at home with- Wireless can cannot be bought, but will be sent absolutely free with a out hindrance from work- most you full yeafe subscription (12 numbers) of the Electrical obstinate cases cured. Solt as possibly want, be- Experimenter at 31.00. It's the biggest dollar's worth velvet -easy to tumid-Idea. in- ST :..Aw..RT. pensive. Awarded Sold Medal. sides valuable today enclosing S1.ä0. Sendnow before you forget. Process of recovery is natural. formation on Elec- The coupon below is a convenient voy. But do it so anerwards no further use now. for trusses. We rove It by tricity, Magnetism sending you Trial of Plapao and Theory of them THE EXPERIMENTER PUB. CO., Inc. absolutely tree. Write t -and it's FREE as Publisher RAPS) CO.. Shtk 221 St. lob, Me explained. `The Electrical Experimenter Magazine." THE BOYS' OWN LABORATORY EXPERIMENTER CHEMCRAFT PUB. CO., 233 Fulton St., New York A Complete Outfit of Gentlemen : CHEMICALS (39 Chemical Reagents) APPARATUS (All Necessary Apparatus) On your absolute guarantee that your 20 Lesson Wireless Course is just as INSTRUCTIONS (The Chemeraft Book) described by you, you may send me same FREE. You are to, send me this Course for performing over 50 Different Experiments. Each at once, experiment can be repeated many times. all charges paid, and enter my name for a full year's subscription to the Under the heading "Chemistry and Its Applica- Electrical Experimenter, 12 numbers, for which I enclose *$1.00, the price of the tion to the Industries" are many experiments in Electrical Experimenter alone. which the products of our great chemical industries are really manufactured on a small scale. Every- (If a 2 -year subscription is desired, enclose $1.85.) thing is explained in a clear interesting way. Chemeraft also contains 30 mysterious experi- My name is ments in Chemical Magic. It's great fun to show these to your friends. If your dealer does not have Chemeraft we will My address is send yours direct. Price $2.00 postpaid. Descrip- tive literature sent on request. (3) *Canada and Foreign Countries, $1.50 -2 years, $2.85. THE PORTER CHEMICAL CO., Hagerstown, Md.

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VIA "SAYVILLE" TO BERLIN. Practical Electrical (Continued from page 630.) LEARN the AUTO EDUCATION go at night, as the sending conditions are Our practical course in Electrical then better. When Germany gets these BUSINESS Science and Engineering trains you to get and keep the big -pay messages she sends back the letter "R." re- Earn Splendid lobs. Eater at any time, no peated time after time. This means that Salary or Have a matter what your education. Ad- vent., as fast as you maeter what she has received the message and under- Business of Your we teach. Course combines theory with actual practice in all stands. Own - branches of electrioal work. The Auto business is growing by leaps and Individual instruction. Positions paying Messages come in to Sayville written in hounds; there are better opportunities now than 31,500 a year up. waiting for graduates. all kinds of languages -English, German, ever before, for properly trained men as Chauf- WRITE FOR FREE ILLUSTRATED feurs, Demonstrators, Mechanical Experte, etc. CATALOG. Russian, French, Portuguese. These are Over 3,000 of our graduates are making good HOME STUDY COURSE -If you cannot come to us Most Up -to-Date Years or do not want to give up yout present occupation. we translated into English and turned over to money. -12 of Suooess. will furnish you, by mail, at small cost, our theoretical the censors, who examine them carefully Including 12 cyl. cars: latest tines mmare course. Will apply all payments made for Home Study and lighting trt Course on reguln tuition, in ease yaw eater out school for hidden meanings before they are put on Individual instruction. Tuition and Board reasonable. Write at once. at Milwaukee later. Get full particulars. the tape. CLEVELAND AUTOMOBILE SCHOOL SCHOOL OF ENGINEERING OF MILWAUKEE 2343 Euclid Ave. CLEVELAND, O. 238 Stroh Building, Milwaukee, Wis. When the Government sends a message DOHTAKE to Germany it goes by code. As soon as his A COURSE IN MACHINE DRAFTING Secretary of State Lansing has affixed The Largest, Lill you've rand my proposition. You want to learn the signature the message is taken by the clief We kind of drawing that enables you to earn money. I can Best Equip - prove by mimerous references that my Course is best. clerk of the State Department to the cipher Guarantee No picture books for children, but a business proposition rooms. The different pages are distributed ped and ONLY for business young men! lostrumcnts I send free are First Grade guaranteed best furnished by any concern. Terms very among the cipher clerks, who begin turning Practical reasonable. Pay a part in position as draftsman. Commercial Mention "The Experimenter;' and inclose stamp. a"1 I the words into code. After the message Radio School will send a copy of "Straight Dope," a set of engineering it is Operators' tamp has been deciphered turned over to in New MACHINE CRAFTSMAN, 252-254 S. CORONA. DENVER. COLO. another set of clerks, who check it care- Licenses fully. England LearnQarnAtN SNOW CARDS The secret code books of the De- t6 State l.11teacmyou partment are guarded most carefully. Life LEARN WIRELESS personally by ;. Last year everyvone or our graduates success- 17 year,: successfulteach- is to be expended at any time to defend GNSeien. field for men end fully passed his required commercial Government Yo them. In fact, they are guarded as care- Examination upon the first trial. Send a stamp EARN $18 TO $45 A WEEK fully as the code books of the navy, whose for new fall prospectus. Winter classes now forming. Williamson (Ind.t Ability 1 have r. developed under yourWtuition is surprising." ty covers are so heavy that when thrown into Will you learn. Write: Eastern Radio Institute DETROIT SCHOOL OF LETTERING the sea in case of emergency they will sink B. Chas. J. Strong, Founder Dept. 370. Detroit, Meet. instantly. 899 Boylston St., Boston, Mass. Scientific Exchange Columns you have at the present time some things for which you have no further use. Do you wish to exchange them UNDOUBTEDLYfor something, for which you have immediate use? There is no surer and quicker way to do this than by advertising your articles in these columns. The Very people, the Only people, who could possibly have a use for your things read this journal. More than agora interested people will see your ad. It is furthermore the cheapest advertising medium for you in the country. Dealers' advertising accepted in Opportunity Exchange Columns only. The rates are; Two cents per word (name and address to be counted) minimum space 3 lines. Count about 7 words to the line. Remittance must accompany all orders. No advertisement for less than tOC. accepted. We reserve to ourselves the right to refuse any advertisement which we consider misleading or objectionable. Advertisements for the April issue should reach us not later than March 5th. The Classified Columns of "The Electrical Experimenter" Bring Positive Results. Subscribers experiencing trouble in dealing with any advertiser should notify the publisher very promptly.

FOR S.11.E -11/2-pint Leyden jar, % -k.w. sine FOR SALE - Braudes Snprior bend set, 2.015) WILL EXCHANGE $5 electric wirroscope, good slmrk gap, Leyden jar discharger, books on ndven- ohms. $:3.50; lt. I. Co.'s single (lend set. 1,001 o11ms, condition; want pair 2,000-ohm Murdock 'phones 111re; everything practically new. For list and $1.75; t -lu. Manhattan coil. excellent condition, with double bead band. All letters answered. Fred- prices, write to Robert S. Zimnuers, 2522 Broad $3.511; n ISO other wireless goods. Send for list. Wm. erick Walters, Amityville, N. Y. M,Cnrter, 4718 N. Cmnac St., Philadelphia, Pa. Ave., Altoona, I'a. POlt SALE-Two 1 -k.s', laboratory transformers, $4.50 TAKES parts of loose coupler advertised in FOR $ALE- i4 -k.s'. transformer, electrolytic In- never used; in steel cases; 110 to 50 volts; for mov- February Popular Science Monthly. page 131, ex- terrupter, and oscillation transformer. new and to ing picture arcs ur electric furnaces, $7.50; several venting Mahogany front. instead of hard rubber. line smith tiol: will sell cheap for $9.50. Russell reels Moving picture film, $1.50 each; one 1/16 Urban McMlller, 3107 211th Ave., Minneapolis. 'linls. Hell, 219 North Ave., Washington, Pa. horsepower Diehl motor, 220-v. A. C., new, $8; will trade. FOR SALE OR EXCHANGE-One orchestra sante FOR SALE IIR EXCHANGE-CM Clapp -Eastman For more information write Gregory Fay, 11)24 Bellevue Ave., Syracuse N. Y. drum M st irks and erns., drum slightly ship. -l: 1 -k.w, transmitting set. $15: ylm'doek $15 loose gas post nl yard projector, 1 double slide tuner arty, cnnielel-, $6; two 43 -plate notary condensers, $2.511 SALE OR EXCIIANGE -No. 3 folding' Brownie, 1 pair 2s 000 -ohm revolvers new, one hot -air enge.in each; high glade, 2,000 -ohm heard set, $3.75: $5 complete outfit, two 23t s3)< Premos developing rums by hot air only; wallt wireless sending bistro. perikon detector, $2.50: all equal to new. Send tank; films to both: 32 revolver, $5 Waterman pen, meets or navy type receiving transformer or loading $tamp for photo and particulars. II. Butterworth, Crusader bicycle $20, unused; large amount of 5c. toil in good rnudi t lull. Chas. W. Stanter, 3400 Ro- 15 K.iseLusko St., Brooklyn, N. Y. novels, good pair troller skates; want 2,000 -mile anoke Ave., Cleveland, O. EXPERIMENTAL transformer: t -k. w, capacity; Electro receiving set; will sell other things. What / have you'[ M. lleudricke, Ingleside, FOR SALE OR EXCHANGE-Type SS dynamo. Will give and take all voltages 1 to 501. new; will Ill. 20 -ohms telegraph set, :3 lbs. nuteuilnm wire; want exchange for lathe. Johnston, West End, Pitts- FOR SALE- Two-cylinder, 12 horsepower, air - electrical or photo supplies. Edwin Vullcor, Mor- burgh, l'a. cooled automobile engine, complete with magnets, risville, Vt. FOR SALE 2,5300 -meter cabinet loose coupler, earbureter crank, $15; Adams Morgan $6 loose coup- - 6411. 1.1. $5 $10: will exchange for two 4:; -plate variables, must ler. $2; water motor, $2. Clarence Vaughan, SELL OR EXCHANGE - For Crystaloi Middletown, N. Y. American Mmlel Builder, loose coupler, oil color he DPW, and audioli bull; 2,t00-rtlm Brandes head outfit. telegraph set. S0 -ohm 'phone. stamp collec- set, $3.50: will pay cash for Imntt -nut nudlnn bull; FOR SALE-Yrk.w. transmitting set With Pack - tion and others. What have you? Khu. Manley, oleo have other instruments. Write for particulars. nid transformer, Murdoek condenser and oscillation Fall River, Mass. II. Underhill, 78 S. Hamilton St., Poughkeepsie, transformer, gap and key; worth $30: condition perfect; sell or exchange separately for receiving ap- WANTED -A printing press, not smaller than 5,cS jtáratus. Tbomas Hunt, Abingdon, Mass. inches. J. E. Joues, 203 Mary Ave., Carnegie. l'a. WANTED -High grade manufactarell wireless re- eelving lowest Full SALE OR EXCIIANt ;E- Complete wireless amt transmitting apparatus. State WANT National automatic Morse transmitter or (trice and rendition. Crocker Mann, Dover- Iluss, an omnigntph cheap. for looks and cash, and in receiving outfit with wire, insulators, key, buzzer, good etc.; everything necessary: never used; $11: cost $15. VARIOMETER base, 1B -point order. J. 1f. Keating, 8 West Center St., type tuner. warble Beacon, N. Or will exchange for static machine and other good switch on primary, 30 -point switch on secondary Y. electrical apparatus. Howard I'armele, 1727 Marcus wound with green silk sin., tunes up to over 2.500 FUR SALE -One 2,000-ohm telephone ringer and Ave.. St. Louis, Mo. sorters: first $15 takes it. Chas. W, Mallory, Box hells, never need, $1.30: 1 type S. motor, armature FOR SALE CHEAP -Loading coil. loose coupler. 127, Monongahela. Pa. needs rewinding, $1.50; 3 Its. No. 36 enameled wire, detectors, condensers and helix. Write. Everything FOR SALE -Small wireless outfit for $5. Harry $3.50; primary and secondary for Blitzen loose coup- new and in perfect condition. L. W. Houlrvyd, 34 Ilxtner's, (fiver Fella, Wilt. ler wound with hare wire, never used, $1; 4,000 - West 50th St., Bayonne, N. J. meter landing coil wound on tube 6 inches diam- WANTED-%- horsepower, air cooled upright gaso- eter S FUR and inches long, 50e.; complete parts for SALE - 2.n00- anter receiving transformer, line engine, second -hand, without spark roil. State Blitzen variable condenser, minus ease, army detector, ceondenser, aerial switch, Meaco rabic dimensions, weight and price. Wilbur Guen- never used, $2: 1 dustproof detector case, 7yx1:3 %x4 inches, $1. "standard" gap, 1 -fu. roil, storage battery, "O. K." ther, Shelby, O. All the above sent postpaid motor, speed key: reasonable Slices. anywhere in the United Joseph Ma- SELL OR EXCHANGE- ylaudelette 1- minute cam- States. Edw. C. Schnrch, Deer Lodge, Mont. 1 Ines. 164 East 82d St., New York City. era, in excellent condition; want 2,000 -ohm head SELL OR TRADE 38 revolver, belt and bolster, FOR SALE OR EXCHANGE -Ives Miniature rail- stet. loose coupler or other wireless instruments. If $5; 32 revolver, belt and holster, $3; Kodak with way trains, for transformer or 1 -in. spark coil. A. interested. write. St pben McIntosh, Meredosia, III. Laug, 495 East St., New portrait attachment. $7: 4x5 camera, $3; 22 special 164th York City. FOR SALE OR EXCHANGE -Large electric train 13 -shot ritle, $10; 25 volumes Dumas novels, part FOR SALE-Loose coupler. detector, fixed con- outfit, cost $19: sell for $10; algo Mascot tuner, leather, $25. All above articles are in excellent denser, Brandes Superior bend set, all new and un- 90e.; Crystal detector, 60e would like loose coup- condition. Want complete wireless receiving sta- used; pair rubber (soots, Winslow ball -bearing ler and Brandes Superior 'phones and $3, or Crysta- tion. Must receive 1,500 to 2,000 miles, or what skates, Meccano No. 3. in excellent condition. E. loi type AA and Brandes Superior 'phones and $3 have you? Inclose stamp for reply. Mr. H. E. L. Turner, 240 Hart St., Brooklyn, N. Y. for train. Henry Cole, R. R. 13, Broad Ripple, Ind. Nelfe, LaFarge, Wis. Von benefit by mentioning "The Electrical Experimenter" when writing to advertisers. www.americanradiohistory.com March, 1916 THE ELECTRICAL EXPERIMENTER 71

W11,1. SELL 'iridium detector and one -step ampli- FOR rt. 1.I.1': Olt I:X(:IIAN( ;F.- 2,500 linter loose 1.150 WA'rT nitrogen light, good ruwlilinu; will fier Set for $35; will pay cash for 1 -k.w., 25 -cycle coupler, D. l'.. motor, and other items. Send for exchange for 6-64 »torn ge' raillery or one -i orb sport, transformer. Ourdou Obersteimer, Station O, Buf- lint aid ',amen. \Vaut variable ruudenserx and roil and voltmeter , ammeter. Albert betinedy. falo, N. 1, offers. J. W. Kidd, Niles, O, 11452 1:. 75th, l(alln11n 1 City, Mo. BAiAfN$- 1urdock loose coupler, $4.50; Tur- H.CVI! telegraph, $1; lungdiatnlne telephone re- CASH paid for andion Maim. Ali-ply E. W. Fann- lock loading coil, $1.80; Eat) man Kodak. No. 1. Jr., ceiver and cord, 75e.; Uso I -foul rods :11141 sliders, er, Itux 4111, Farnham, Quebec. Correspondence an- $4; all lu excellent condition. \Vm. Ranft, 4107 50e.; all for $2, or trade for wireless lust rntnents. swered. Md. Ruston, Belle Ave., Baltimore t'. Flieh, Ilusa_ ILIA VF: Type S dy usu., polishing head and tele- EXCHANGE - Complete McGraw -Ms Power FOR SALE CHE. \P- Cnwplete', uro seven -picee graph iusumuenls: will trade for god receivers or Plant Library, 8 volumes new, cost $12, for MI winless reeriVhlg set, trilli large aerial: lande by Type AA ,- rystnlui, , what:' OIln,r articles for type audio' or sanitary rolltop desk. Meade, 975 Ifieetru hnp.l'liug Co. Albert Grout, Toms River, trade. Tried I;. Egan, oMissortri Volley, la. Ave., Brooklyn, N. Y. Putnam FOR. SALE a '1 ilr.A l' -W irelss teeei ring set. crou- EXCII.\NeiE- Two -iucb Bulldog coil rond $5 Mes - FOR $AIAl-Several 111111111Vó empara or "Golden sistiug of double slide littler, silieou detector, two co adjustable wireless key for ItJ type amnion. 'Mara" mud "Golden Days." Sand stamp for lists runlenaers, buzzer lest ,ritll key awl , No. : Meade, 975 Putnam Ave., Brooklyn, N. Y. and prier's. Samuel Olnhnuseu, 824 dress rr . \ve., I,Gia-olnn rrreiv,t; all ue,v: lirst $3 takes rset. L. Itnst Liverpool, O. J. 1(nitt1, f t \Vilkius st., Rochester, MIGNON cabinet tt. L. C., 3 special 1O,Ik Me- N. Y. ters, including 3,000 -ohm telepl 's; sacrifie' for FOR SALE Olt EXCII ANGE- l'uutplele sending 1\.a N'l'KD -.tudinu bulbs, burnt ont or good; va- $29; excellent condition. Is. lt. Meeker, 1632 Uni- sud receiving set, cost $101: sell $40, or exchange riable. , IId,11se1'n, (env pnnmis No. :to silk insnlatc. versity Ave., New York_ for \'ietrnl.n. Frederick tlillelbo''r, East Ruther- rapper Wire fur cash. . \II Ici tors nuns. nod. Wits. ford, N. ,1, Bohn, 151:, Seeoud Ave., New Vulk HAVE one new Promu Joidor ó,slnk, '%x:t /; 1 city_ type S dynamo; would like to exchange for water EXCHANGE-Pair of Whislotv's locker skates, WILL rxeh:algc a u, -W $23 lieu'tocsin roil (,jr n motor, not less than six inches. 'l'houuls Alsobrook, flaunt, rant $'t; watt; llkbump, llghhulug switch. W. lltll. \\'illebest'i or Remington pomp gun, equal Boston', Fla. N,_(hirrv, Sweer SI jogs, Mn, value un ylurdoel, s riding eoudrna,r, motinndeteet- or or l nnpiili,r, st'nuded Lenau,. Win', or $10 cash. RECEIVE NG set iloose coupler, two variables, olio FOR SALE -Toc ::,51st -meter, navy type lave momite,l eoiipkera, $10 each; %kilowatt useillalinu trans- John B. Hawley', .1r., 912 College Ave., Ft. Worth. fixed coideuser, loader, pers kas detector> air soars. in cabinet, tines 4,100 meters; $12, $12.51; Win- former, $1.50; Nid nI II -volt Knapp tor, ntancia 5 chester 20 -shot, 22 rifle, good condition, $7, or ex- inches high, $1, Henry Forbes. 3332 Eleveml ln Ave. 1. tilt S ALF. Ill i tzen r'e,ivhng cabins set; band value; va riameter, $1; want aONe- So., ilhuenpolis, lliuu. !smell pinauL, w,igld 130 Ilia.; metal splitting shear, change for equal Wright ueck unction socket. Murdock bander, variables. Fran- EXCII.tNGE- Six -inch Leurh chuck, psi lbs. Writ.. for particulars. C. F. Ive, IntLr, slide 1417 Dellephnin Ave., Chicago. cis Pray, 102 sleuth St., Somerville, Mass. rest, all -nnit dynamo, 0 -v. buttery charger, 2- Lors,- FOIL $.41.E-Four FOR SALE -Complete wireless transmitting and power Indian engine; want miltap desk. Ford blas- galena detectors, ^.Or.. auch; poatuge- If receiving sets, including 4< -k.w. 'yhordnrsn trans- ter vibrator for $5 dy nmuo, iterniy mnguet r and roll ,sien. lintou St:ud,y. 153 Mariner St.. former, rotary spark gap, Bunnell brass key, oscil- ' -eyl in,,r, $12: Briggs 4 eyl imlcr and coil, $8: 4x5 Itnffalu, N. Y. lation transformer, 2 sections Murdock condensers, box 'n nuera, $2; 2- hursel s,'rrr dynaalu ell/Sting', 1.0111:! -A bargain. complete navy type loose 2 Leyden jars, kick -back ',revolters, lightning (rough). $10. Inclose stoup for description. G. F. coupler rec'eiviug outfit: ulunnt,'il on Cabinet type switch, loose coupler, Murdock variable condenser, Silllman, Sardinia, N. Y. Lase, mahogany finish throughout; users switches for E. I. Co.'s fixed and variable condensers, Ferras FOR olt all tuning, also has dead ,end switch type SALE EXCHANGE-Westinghouse re, I detector and Crystal detectors, Jimmies Trans-Atlantic tiller. A. C. 110 -volt, D. C. 25 -volt, 10- ampere; goal shunt; very serom to turning possible; pria,- only $10. 'phones; in same condition as when bought, cost condition; $:35, or will take motion deteetnr as part George W. Hansen,loen, canal Ave.. Marinette, Wis. for photo. $82.50. Make an offer or scud stamp in exchange. J. Il. Wll "t, 014 N. Lombardy St., FOR SALE-(' poet, tiro- kilowatt transmitting B. D. Arata, 5154 Cates, St. Louis, Mo. Richmond, Va. outfit for $35; opera tea ein 111) volts, 00 cycles, al- SALE OR TRADE -One $5 medical battery, 2 tel- FOR SALE OR TRADE-One pedometer Columbia ternating Irrent; consisting of transformer, con- induction coils, 1 22 -cal. rifle, 1 pair ice denser, helix, spark ephone list. bicycle Munn, small meeh:t nient drawing set. tir pia gap awl 10- ampere hot wire skates, 30 25e. hooks, etc. Send for complete for flashlight, fountain pen flashlight, potentiometer; meter. Or will sell instruments separately as fol- A. Edington, 424 Butler St., Ft. Wayne, Ind. all in good condition; want X -ray hull,, variable lows: Two-kilowatt trnusform,r, $25; 14 copper- WANTED -One double pole. 1,000 -ohm receiver, condenser, Crystaloi detector. All letters answered. plated Leyden jars ill ease, $30; helix with spark head hand and cord; have gum hoots, site 5%, worn Ennuis Croup, Jr., Columbus, Ind. gap inside, $6. Everything in test class working skates. cnidi than, Are you a bargain hooter? twice, fine condition; 1 pair new $2 ice SALE OR EXCHANGE -22 Stevens rifle, $3; long ITere is your Write H. F. Happoldt, 2743 Germantown Ave.. Phil- telescope, thaws,. Write to -day. Sidney Friedrich, 350 East $2; winter motor, $2; wire telegraph set, ('u_mmrrcw St., San Antóuio, adelphia, Pa. TSe.; parts of telephone, $2; parts 1án. spark coil, Tex, WANT 1/2-k.w. wireless transformer (used E. I. $1.75; revolver, nickel, fountain pen, flashlights, Sue. FOR SALE-An E. I. Co. 8-volt, 10- ampere dyna- Co.'s also high frequency adjustable con- each; silienu detector, rotary disc ear cushions, 75e, nno; new and slightly used; will sell for $5.50. Win- preferred), ston denser; will pay cash. C. Ehreuberger, First Na- each; want transformer e 11, Edelman's "Experi- Coleman, R. R. 7, Lexington, Ky. tional Bank, Chicago, Ill. mental Wireless" and "Experiments," variables, EX CI L\NI ;E -Rep, rifle, watch, coil, parts of navy receiving 2,000-ohm Bunnell giant sounder, new; 1 Little transformer, burnt or broken 'phones, Ele,. and Mech.'s from 190; to 1913; want SWAP -One motion bulb. L. Mason, Alden, Minn. "Amateur Hustler motor, almost new; 1 4 -in. horseshoe magnet. Work" magazines; can pay cash, Harold E. 1435 for 1 -in. Bulldog spark coil in good condition. E. FOR S,CLE OR EXCHANGE- Several A. C. and hickey, Howard St., Philadelphia, Pa. Servan, Lumberton, N. J. one D. C. are lamp; will sell or exchange, Burgess FOR SALE OR EXCILANGE-Single harrel shot- HAVE violin, accordeon, flashlight, harmonica, Stewart, 222 Main St., Huntington, W. Va. gun, No. 12, value $0; 2,000-ohm douhle head set, hooks, chemical laboratory supplies with chemicals I HAVE many things to sell or exchange. Write value $5, for a 1 % -in. transmitting and loose coup- never used; will trade for receiving and sending for list now. All letters answered at once. George ler receiving set, or what? Harry Thomas, Mound station, must receive at least 1,500 miles at night Sharp, 73 Everett Ave., Providence, R. I. City, Mo, and send 10 miles. What have you? Write for de- BARGAIN for $5- i/- -in. spark coil, 1 in excellent condition. Ad- HAVE single and 16 -shot 22 rifles, portable drill - Gernshack scription. Articles all tog machines. coastorbrake bicycle. 414- horsepower gravity relay, 1 zinc spark gap, 1 enherer and de- Schroeder, Box 31, Wisner, Neb. coherer 1 dress J. G. engine, clutch transmission gearing. all gears for and strap key. all E. 1. Co.'s make, cost A BIG BARGAIN -Will give a $4 horn free with attaching to buggy. Write for description. Want $7. Waldo C. Buck, Britton, S. D. a Smith motor wheel for $40; un trades. Arthur motorcycle or cash. H. Reagan, Box 95, McBrid,s, FOR SALE--Gasoline engine with stand, coil and Sager, 941 Superior St., Appleton. Wia. Mich. gas mixer. Write for photo and particulars. Irvin Weaver, 1(137 Xenia Ave., Dayton, O. FOR SALE -$6 Meccano set in good condition with FOR SALE -1.4 Premo camera (24ix4 %), $2, cost $1 worth extra parts. F. (Yapser, 418 Jamaica $3: Type SS dynamo, $2; 22 rifle, Winchester, $2: WANTED -To buy or trade wireless goods or Ave., Brooklyn, N. Y. film pack tank, $1, Al condition. L. A. Madison. Mende bicycle for , omplete electric lighting outfit WANTED -% or y k.w. transformer; have for Kingman, Me. for small house, small gnsrdine, kerosene or motorcycle engine. L. Fulton, exchange mandolin, stamp collection $3). spark coil. FOUR-STRAP switchboard to exchange for spark Pluses Bottom, W. Va. hikemeter, Stevens 22 hooks, small typewriter. All coil; also have telegraph sounder and 150 -ohm re- SELL nr exehnnge 2x2 -in. vertical. one -cylinder, letters answered. Adelmer Bryon, Ridgefield, Coon. lay. H. Linee. Allegan, Mich. air cooled gasoline engine: has new piston, cylinder, EXCHANGE-Xylophone. two netaves chromatic coil and carhureter, Fisher Ames, Masseua Springs, FOR SALE OR EXCHANGE-SA Eastman Kodak N. Y. scale for "Edison" cylinder machine with recorder; in case fitted with Ziess Tosser LIB lens, multispeed motorcycle for or motion picture cam- trade glider shutter, 1 sec. to 1'500111, plate adapter, 2 new TO TRADE; for gond long -distance time receiving era. Robert Bullock, York, Neb. plate holders, ease 6 extra lenses, 4- section telescope set. Mark Stern mandolin with case, small' brass HAVE number of 2 -point rubber base switches, tripod, cost $110.80; also Gibson mandolin almost upright microscope mid Mandel one- minnte baby new detachable key; bargains: 25e, each. John new, "flat," in black leather case, cost $57.50. No postcard camera. All inquiries answered. Robert Means, 44 Zachary St., Atlanta, Ga. reasonable offers refused. G. H. Dodson, 2011 Syl- Bray, Big Timber, \loot. EXCHANGE -1/10 horsepower speedy. variable van Ave., Leonia, N. J. FOR SALE- Lathe, water motor. and several speed General Electric motor, almost new; would WIRELESS receiving set, comprising a single wireless instruments: cheap. Call evenings or write, like rotary variables, or what have you? Zadig, 33 slide tuner, new silicon detector, condenser and 75- H. A, Gilman, 150 Jerome St., Brooklyn, N. Y. Vernon Ave., Long island City. New York. ohm receiver, $4. Elmer Baier, 444 Seventh Ave., FOR SALE CHEAP- 14/, -in, coil, new 6 -enp de- Brooklyn, N. Y. tector, tested 1 HAVE 30 -in., 8 plate Waite & Bartlett static mineral, piano finish base. gets long machine, full set of elcetrrales, X -ray attachment WANTED -Six Mdrdock molded condensers. Write distance; at half price; guaranteed satisfactory. with no use same. No reasonable telling funny Poil Write D. M. Danvers, 1109 N. Francis, Oklahoma tube; for offer hou' have and whist you orant. Okla. refused. All letter answered. Make offer, money llave Urn qurneIed gaps, etc., or will pay. R, D. City, or exchange. Harry P. Noll, 1000 Packer, Will- Zuekcr, 411 Clinton )'lace, Mt. Vernon, N. Y. HAVE two watt meters, one folding vest pocket iamsport, Pa. EXCHANGE new $113 audio]) receiving set for camera, one box camera. 2,t Brownie; want pair wireless receivers, 3,000 ohms: FOR SALE OR EXCHANGE -One small receiv- twin motorcycle. 1913 model or later. Must be in must he in good eon - first ,-miss condition. Photo sent to interested par- dition. What have you? Lowery Simmons, Van Al- ing set, 1 four -forty storage battery, 1 large 2.500. styne, Tex, meter cabinet receiving set. Write or call. C. E. ties, also loose coupler for 'phones or hot wir, me Littlefield, 2G72 Mansfield Plnee, Sheeimhend Bay, ter._ Wm. Lobe, 592 Miller Ave., Columbus, O. FOR SALE OR EXCHANGE-4E. I. Co. goals: New York. Transatlantic 'phones. rotary and fixed condenser) FOR SALE-Complete T. C. 8. Reference Library 5-disc omnigraph, sets or Dock's Ferrol' detector. large FOR SALE. OR EXCHANGE Electric train, en- the Structural Engineering, Gas Engines, home -trade loose coupler and spark colt, gine, three cars, 16 sections of track and one pair Surveying sud Mapping. and Spanish Language helix, key; 5 volnulca Musical Edneata. Would consider T. C. of switches, cost $9 when new: will sell for $5, or enurses. Italian bonne study outfit. Text books n S. steam engineering, what electrical? shorthand, mechanical and nrehiteetn- vnonmes. eucineera or mechan- have you rincen(e Paulus, Kallp- typwriting, iea' tnnla- .Tnhn ifethven, Box 171, Ronald, Wash. meier St., Burlington, Ia. drawing, foreign languages. etc. Colt 32 -cal.rat n utaaatic pistol and 3s-cal. police positive special FOR SALE -$4 Massie wireless key, or will ex- FOR SALE OR EXCHANGE- t/ -k.w. sending set, revolver. No. 2 11.I1'a -4:ye k,dak. Several sets change for Brandes Superior receivers; will pay ex- Boston key, etc.; Blitzen receiving cabinet set drawing instrumenta, seules, protractors. slide role. tra. Emmet Faacks, 413 Fourth Ave, S., Minne- (new), and Brandes 'phones, cost $33; andion With ,te. Mandolin, metronome. music stand and satchel. apolis, Minn. X grade bulb and batteries (6O volts), for -k.w. Pope twin motorcycle. No. 5 L. C. Smith or ' typ- ANXIOUS to get and will pay cash for Issnnd Hightone set, what have you? Frank Marshall, writer. No exchanges. Write for description of nr- 517 W. Delaware, Toledo. O. volumes 1 and 2 of "The Electrical Experimenter." tieles interested in and prices. Eugene Lewis, Ha- James Donahue, 857 Vernon Park Pl., Chicago, Ill. I WANT a static machine, omnigraph, 8 to 12 -ion. le,v Rond, Kittery Depot. Ile-, FOR SALE- Eleetro goods in fine cnuditlnn. Ga- spark roil, storage batteries 6 to 10 volts, 60 to 100 FOR 90e.; amperes, wire SALE -W. B. Dnek's Code Learner, lena detector, opal glass hase, (lair.; 2,010 -ohm Ju- hot ammeter, Teals cil, fluoroscope, U. S. S. detector, $3; one Buys' Magazine, 75e.; tape register, coheres, electrolytic interrupter, an- year nior wireless 'phones, $2.90; 5,001 -wave meter load- tenna or 211 Modern Elettrica and World's Advance, $2.90; ing coil, $1.90: zinc spark gap, 30e.; telegraph key, switch, dynamo, generator (10 to 50 volts). 5 -inch neat motion longuet. 10e. T. Red Devil water motor, rotary pole -changing p'rnm Waldie, .Tuninr tuner. $1.00; Junior fixed eondenser, gait, Jr., 21 Woodbury St., Beverly, Mass. 4Oe.; one spark sepa- switch, galvanometer, 110 -volt meter and ammeter, -inch Bulldog coil, $3.25; sold of -k.tv. transformer. with oil condenser and helix. I EXCHANGE- Shotgun, rubber shot's, bracelet, 6-v. rately, or all for $11. Ralph Thompson, Wooster, O. will pay cash for these nrtlrles or will trade. What motor, fishing rod, Hampton watch works, razor, WILL TRADE an E. I. static machine for a duo you want? R. W, Williams, 820 First place, looks; want violin, protectogrnph, coil, most any- small variable condenser. II. W. Relehle, riso F,v- Plainfield, N. J. thing. Write. Itux 322, Glasgow, Mo. cutli Ave., Pittsburgh, Pa.

Yon benefit by mentioning "The Electrical Experimenter" when writing to advertisers.

www.americanradiohistory.com 672 THE ELECTRICAL EXPERIMENTER March, 1916 FOR SALE-Two tuners, value $7.50; sell for FOR SALE -$6 Radio Equipment Co. loose coup- FOR SALE -Electro Importing Co. instruments,. used one week. Loading coil, lead peroxide detec- $3.50, or $2 each; $5 Ferron detector, $2.50; $5 ler brand -new, tunes 2,000 meters, $4,50. Mac - Murdock variable condenser, $3; $3 aerial switch. lamald, 36 East Tulpehocken St., Philadelphia, Pa. tor, potentiometer, 50 -ohm relay, half -inch spark coil, small spark gap. Write for bargain prices. C. $1.50; $9 cash for whole outfit. All bought new and SWAP - Brand -new Eastman's 3A Postcard Alleman, 1408 Madison St., La Crosse, Wis. in good condition. Ellsworth Davis, Morrice, Mich. Brownie ramera for about 2,500-mile range wireless WANTED-Second -hand dynamo cheap (MO v., receiving set. E. Haugerud, Scappoose, Oreg. FOR SALE -BIG BARGAINS. send descrip- $7.50 Electro Loose Coupler about 10 amp.) or smaller machine; FOR SALE 1,000 -ohm single receiver, $1.50; in,) $3.75 tion, Clarence L. Robinson (Curtis Rte.), Waynes- -New $5.50 Electro Spark Coil 04 Mo. first elass sounder and key, $1; Marlin 22 -cal. re- .s4,50 Radioson Detector $3.00 ville, peater, fair order, $4. Sidney Cook, Victoria, 111. 4.00 Mesco, 150 -ohm Relay (new) $2.75 HAVE telegraph set, step -down transformer, 110 FOR SALE -Wireless which receives 2,500 miles; $2.50 Electro Sending Condenser (new) $1.75 A. C. to 8 D. C., and drawing set; want 2,000 -ohm Scat $10 takes It: also a half -inch coil, $1. Ken- $2.50 Electro Loading Coil (new) $1.75 head set. Write. Stephen Kent, 92 Campbell St., neth L. Jennings, Mattapan, Mass. 2.00 Omnigmph and 5 dials $1.25 Pawtucket, R. I, All the above are in perfect working order and con- FOR SALE -No. 3 Brownie camera in excellent AUDION detector and one -step amplifier combi- dition. Sent within 24 hours of receipt of order. condition with portrait attachment for same; devel- nation, $35; complete K -k.w. transmitting set has Eckstein, River Road, Hoboken, N. J. rotary gap; Blitzen transformer. etc., $22.50; other Address Fred oping and printing outfit with instructions. All for apparatus. L. Gebhard, 1121 Ellicott St., Buffalo, FOR SALE-One -inch Bulldog spark coil, $3; elec- $7. Write. Walter Curnutte, Rivesville, W. Va. N. Y. trolytic Interrupter, $1.25; electrolytic detector, 75e.; MOTOR WHEEL WANTED -Have up-to -date re- FOR SALE- Practically new wireless lustruments; potentiometer, 50e, Will pay cash for audiou. Robt. ceiving outfit, complete In every way, including au- Blitzen, Ire Forest. and other reliable makes; also Sandifer, Eldorado, Kan. dion, Blitzen variable, Brandes 'phones, commercial FOR outfit, of a 2M -in. loose coupler, etc., 1 -k.w. quick -throw aerial switch books and magazines. Write. Withers Gavin, Cor- SALE-Sending consisting also included; want inth, Miss, coil. navy rap three, condensers, key, and storage and 600 -volt lightning switch battery of 8 .oils, 80 amp. hours, for $18; or sold to exchange for Smith motor wheel in good condi- FOR SALE -2.500 -meter loose coupler, 1 -in. spark separately. Fred Carlotte, 78 Christopher St.. New tion. All inquiries will be answered. Edward J. coil, detector, spark gap, key, switches and parts French, Peekskill, N. Y. for a cabinet set. Inquire of Karl Haberstick, 74 York, N. Y. 14th St.. Wheeling, W. Va. FOR SALE-Four- horsepower motorcycle engine iu HAVE $12 mail -order course, $5 stamp collection, fine condition with carburetor and spark coil. Has $3 "Solid Receiver"; want good receiving set, or HAVE brand -new Scout No. 2A with printing and other wireless instruments. Mort Calcott, East Liv- outfit, connections for carbereter and oil, and is just the developing cost $6: will exchange for E. I. thing for cycle ear or air wagon. Price $15. L. E. erpool, O. Co. 1 -in, spark coil. Bulldog type. J. Howard Kel- 3A ley, Franklin, N. H. Beckley, Ukiah, Cal. FOR EXCHANGE -- Cameras 5x7 Century outfit, I HAVE for sale or exchange 2,000 -ohm Brandes Eastman Kodak, Premo Filmplate outfit, pair prism FOR SALE -Loose coupler, $1.50; 22 ride, $1.50: binocular field glasses, a $20 electric postcard pro - $2.50; $5 'phone, qt. Leyden Jar, $7.50 loose coupler, type- violin, football, $2: 4-in. roil without vi- writer Rem. No. 0 in Al condition, 2-cylinder gaso- 22 brator, $1; two 1,000-ohm receivers, $1.25 cash. John twoohammerlessore olversSetools,diec.e15want elec- McComb. Miss. line engine. 14- horsepower, air ccthd, In good run- W. Carroll, ning shape, 12 -gauge Remington snot gun. pump trical goods, open core transformer, or 1 -k.w. closed FOR EXCHANGE -A Colby receiving transform- action, hammerless, as good as new, P.9merous elec. core, a Tesla coil, or what have you? Odell, Op- er, tunes 5.000 meters. and a 14 coil for a Nation- trical and mechanical books. All the above Is in tometrist, Fremont, Mich. al automatic telegraph transmitter with records. practical, Al condition. I will trade fo_ anything FOR SALE OR EXCHANGE -Experimental lab- without key or sounder. Frank Spencer, 289 State electrical or mechanical, or sell very cheap. Don't oratory equipment consisting of volt meters. gal- St, Auburn, N, Y. hesitate to write me, for 1 have some bargains. I vanometers, Wheatstone bridges, and other electri- with large of tel. I. had rather sell the above articles. E. A. Haim, Mc- cal Instruments, together quantity BARGAIN -E. Co. electrolytic detector and Nary, Ky. et.hone relay ?, drops, jacks, transmitters, receivers, rheostat, $1.25: peal condition. L. Loase, 4704 carbon, carbon electrodes, Park Ave., Bronx, New York City. FOR SALE OR EXCHANGE -One complete =uud- magnet wire, granular tug and receiving wireless set with 2x01)-nnm chemicals, small dynamo, lathe, drill press, filing FOR SALE- Flectro potentiometer, 95e.; electro- cabinets and other equipment, State what you want. 'phones; will sell ut a sacrifice. For full particulars S. C. lytic detector. 55e.; single slide tuner, $1.25; ales- write me. Would also like to buy or swap acces- H. It. Van Deventer, Box 591, Sumter co double slide, $2.50; mineral detector, $2.75. Vin- sories for 0 Gauge Electric trains. George Adams. FOR SALE CHEAP- Complete amateur station, cent Nataliste, Jr., 071 West 56th St., New York. 601 North College, Charlotte, N. C. sending and receiving set. and large aerial; will sell FOR SALE-Receiving outfit, receives 2,000 miles; MUST NELL- Circumstances fore we to sell my for $15; worth twice as much. If interested, write. will receive time from Arlington. Make offer, John %k.w. Cackard; used two months; $8.51 brings it Ed. Guilmette, 343 Mason St., Woonsocket, R. I. Fouhy, 1428 Blue Hill Av,.., Mattapan, Mass. prepaid. L. A. Walker, 1716 South 20th St., St. FOR SALE OR EXCIANGE- Complete volumes 4, 5. 6; BIG SNAP Ives Joseph, lilo, of Popular Electric magazines, Nos. 2, 3, -One Elettrie train; practically make reasonable offer; all ready for binding. Will- new, 3 pieces, 8 straight track, 8 curved, value HAVE Excelsior printing press with outfit, cam- St., Newark, N. J. $5.75: want $3. H. Annulant-a, 700 W. Washington era outfit, Roller organ, postcard projector, wireless iam Kirsch. 782 Bergen St., Los Angeles, Cal. apparatus. What bave you? Nathaniel Leek', Ama- POWERFUL 11 -in. water motor, $4.25: $15 Erec- gansett, N. Y. tor outfit with $3 motor, $8; 22 rifle, $1.75, cost FOR SALE OR EXCHANGE -A 6-v. 6A dynamo $4.50: will exchange for audion bulk, 8.000-ohm motor that cost $12.80; three 2 -volt, storage bat- FOR SALE -Brandes Superior 'phones. One 'phone King, and head band new. Other 'phone in good condi- 'phones, Mott(- Audi -Fone and aerial. Archie teries, never used, $2 a piece, and 6 different -sized North St., LeRoy, N. Y. flashlights without batteries. Kenneth Jennings, tion, $3. Arnold's special make loose coupler, pri- Mattapan, Mass. mary 12-in. long, line instrument; can be used COMPLETE "Talking Head" for the construction three different ways, $7; Murdock $3 variable, of a telegraphone, will be exchanged for any of the HAVE No. 2 camera; Stevens "Cracksbot" rifle, $1.50; large cabinet. good mahogany finish; has two following instruments: A hot wire ammeter, Wes- $8; medical coil; canut telegraphs, Kodak, photo al- tap switches and taps also test detector, $1.50; ton or Keystone voltmeter, small dynamo. opera bum, wireless or boxing gloves. Elwell, 115 Cox complete set for $10.65. Edwin Cohan, 601 West glasses, variable condenser, or what have you? Sam- Bldg.. Rochester, N. Y. 150th St.. New York. uel Cohen, 1936 Pitkin Ave., Brooklyn, N. Y. Opportunity Exchange Advertisements in this section 4c. a word for each insertion. Count 7 words per line. Name and address must be included at the above rate. Cash should accompany all classified advertisements unless placed by an accredited advertising agency. Ten per cent. discount for 6 issues, ao per cent. discount for ra issues from above rate. Objectionable or misleading advertisements not accepted, Advertisements for the April issue should reach us not later th an March 5th. EXPERIMENTER PUBLISHING CG., INC., 233 Fulton S , New York, N. Y.

BEFORE you try to wind secondaries for a coil BOOKS or transformer get our prices; we can save you STAMPS AND COINS time and money. State your wants plainly. Eureka Secondary Co., 6937 S. May St., Chicago, Ill. STAMPS -100, all different, free: postage 2e. Mention paper. Quaker Stamp Co., Toledo, O. THERE is but one telegraph school that places all grades direct in the railway telegraph service. $2 TO 500 EACH paid for hundreds of coins It Is Pelnars, Madison, Wis. dated before 1010. Send 10e. for our New Illus- It Depends trated Coin Value Book, 4x7, showing guararteed FILMS developed free: send negative for sample prices, Get posted at once. Clarke Coin Co., print und particulars. New Lex Novelty Co., New Box 14, Le Roy, N. Y. Lex(ngton, O, BARGAIN, 58 different stamps from warring on yourself WANTED -Young electricians In every city and nations, 19e. C. Martin, Iroquois, Ontario. town to install thermostats. A chance to start in to become quite prosperous and independent inside busiuess. Beers Bros. Thermostat Co., 1166 Port- of 10 years Of you hold on to something good) by land Ave,. Rochester. N. Y. WIRELESS investing the Introduction- nomival price of 25e. (stamps are not exchanged at the P. 0., and there- CALIFORNIA little suburban farms for sale. 2,500 METER loose couplers. $5; other wireless fore cannot be accepted) Terms write E. R. 1Valte, Shawnee. Okla, bargains. Send for circulars. Cliff lffg. Co., Brook- -in "Warnings and Advice field. Mass. to the Small Investor "; original price, $1 net. Why H.P. 24 lb., air cooled aluminum gasoline should you not make yourself independent? Satis- engine $18. Sent C. O. D. for $1 with order, TESTED SILICON, 15e. ounce. Gress, Pitman, faction guaranteed or money refunded. Address Gasoline and steam N. J. Box 3034, M. T. Dept., Middle City Station, Phil- with privilege of inspection. adelphia, Pa. engines, engine castings. model engines. Com- SPECIAL BARGAINS-Switch points, brass, 40e. plete small electric Iight plants. Tools, gears, per hundred; stop pins, brass, 50e. per hundred; sil- HAVE YOU SEEN A COPY ?-Amateur Photog- pulleys, experimenter's supplies, etc. Send 5c. for ver plating, double above. E. F. Ball & Co., Buck - rapher's Weekly, $1.50 per year; weekly prize Manufacturing laud, Coon. competitions; criticisms; print exchange; illus- catalogue and circulars. Dynamic trated; many features. Three months' subscription, Co., First National Bank Building, Chicago. $10 COMMERCIAL KEY for $4. Money refunded 40e. Amateur Photographer's Weekly, 915 Scho- if not satisfied. Massie Wireless Telegraph Co., field Bldg., Cleveland, 0, PATENT ATTORNEYS 77 Washington St., Providence. R. I. WESTERN AGENT for Multi- Audi -Fone, Un- BRAZING AND WELDING PATENTS without advance attorney's fees. Not damped -Waver and Mignon apparatus. Special prop- due until patent allowed. Send sketch for free re- ositions. Arthur B. Church. Lamont, Ia. BRAZING TIIRCIIE&, 40e., postpaid: will heat port. Books free. Frank Fuller, Washington, D. C. GALENA detector, 35e.; cat whiskers, 3 for 5c.; one inch bar red hot in three minutes. Send condenser, .006 -Mf, 60e. Walter Patch Co., Klemme, stamps or money order. Auto. Welding & Mfg. IDEAS WANTED- Manufacturers are writing for Ia. Co., Omaha. Neb. patents procured through me. Three books with list, hundreds sent free. Advice GALENA DETECTORS -Complete with crystal on REGULATORS for oxygen or acetylene gas with of inventions wanted black fiber base, 45e.; parts, 35e.; postage, 40. Par- free. I help you market your invention. R. B. N. fittings for standard tanks with single gauges, $8 Owen, 130 Owen Washington, D. C. ticulars on other apparatus. A. Bullock, 3121 each; with double gauges, $14 each; welding torch Bldg., 220. Kansas City, Kan. with four tips, $10, postpaid; guaranteed for one PATENT SECURED or fee returned. Send sketch SOMETHING NEW -"Eterno" insulation for re- year. Auto, Welding Sr Mfg. Cn.. Omaha. Neb. or model for free search and report. Latest com- foot and plete patent book free. George F. Kimmel, 254 ceiving and transmitting sets, 15e. square MISCELLANEOUS np. Better than rubber or fiber. Stands 2,80n deg. Barrister Bldg., Washington, D. C. F., 1,000 -75,000 volts. Used by Government and DRAWINGS made for inventors. Consulting En- JOHN M- McLACHLEN, attorney -at -law- Patent Marconi Co, Send 4e. for sample and catalog. Manuel gineer, EE -3240 Seminary Ave Chicago. causes. Union Trust Bldg., Washington, D. C. Rattner & Bro., 36-38 Union St., Poughkeepsie. N. Y. Von benefit by mentioning "Tile Electrical Experimenter" when writil g to advertisers. www.americanradiohistory.com Murdock Wireless Receivers PROVED SATISFACTORY 99.8%

of the Murdock Special No. 55 1 leadsets deliv, red WITH REGULAR BAND duction to the wireless world Complete Double Set HAVE BEEN KEPT 2000 Ohms - $4.00 with the undersL nl 3000 Ohms - 5.00 by the purchasers. who bought clear oli' FOURTEEN DAYS' TRIAL offer and MONTY H. \( K I l 1 1 I l l t l (' With Coronet Band that we are delivering RL.11_ \.irtlrss etc,', \ ' i h $ .50 additional This PROVES fully satisfy 99 out of 100 wireless operators in sensititenc.} a/,p ut - once and value. This PROVES that we have 99 out of 100 chances YOU that our receivers are the best in the world, prie( cons d. t, d IOU CANNOT BUY BETTER RECEIVERS AT THE PRICES. YOU MAY PAY MORE BUT GET LESS IN ACTUAL VALUE. IT'S YOUR TURN TO TEST OUR CLAIMS. DELIVERY AT GLACE. OUR CATALOG IS FREE. WM. J. MURDOCK CO. 55 Carter Street Chelsea, Mass. WITH CORONET BAND 221 Second Street, San Francisco

WE ARE HEADQUARTERS FOR ELECTRICAL AND WIRELESS GOODS OUR NEW BIG 216 PP. ELECTRICAL AND WIRELESS

tIañbtitylQB i CATALOG

IS THE EXPERIMENT- ER'S REFERENCE BOOK. Stearn Engine, 50c. No. 7729. Is olio:, at bargnm urlove u, Telegraph Set, $1.00. our Ctitnlug THE AMCO NAVY TYPE RECEIVING TRANSFORMER

t g Represents fhe I u t est advances male towards the ideal tuner and embodies the greatest f perfection yet obtained. No grvatott can be secured where accurate selectivity. s, and finish are desirable. The illustration shown herewith cannot possilily do justieejust to tl '191e itself. primary winding is eu,luseI in a tabiuet. the '1 1 l top of which ar., polls Led hard rubber. Two 15-point switches are mounted on the trout. On switch controls the pre: of several turns and the other controls , turn at a time. 'rile entire variation of unypi thus se, trod by the rotary motion of two k ne elect knobs rather than the tuoveuient of :, > tray be varied from 1 to 225 turns in steps of one turn at a time. The wimlings t Ily ndapnd to long wove lengths. v7tráéistnhe$etYa,l;Ias3' in The secondary is wrouud with green silk covered wire. The .t HARD RUBBER, turned and polished. vurintìou is by a =ee w hlrl Spark poi!. a complete receiiug amt makes it possible to secure eery fire adjustment. PRICE, ONL Y $15.00 4weo p k r, In transmitting outfits. Dort kuowldged the hest. l huy until you see our SEND 6 CENTS FOR OUR CATALOG. DO IT TODAY. YOU NEED IT. Catalog. IF YOU ARE BUILDING SOMETHING, WE HAVE JUST WHAT YOU HAVE BEEN LOOKING FOR Our No. 6 CATALOG shows several hundred parts and sets of materials 1,,r bnildi,e you own apparatus at home which have never before been listed. Al'e do all the dilli e t is e rk ú ,t tar,,.rA- and Dien you pen them together. (' plete description and prices of the latest Electrical and E cperimen t al A ppa rat n.- Stern_, Batteries, Rectifiers, Transformers, Induction Coils, Wireless APparnins, Lamp. Flashlights, X -Rays, hooks, Tools, Electric Railways. Steam Engines, Water Motors, Ucnamos, Motors. 't'. d.._ g anila, Telephones, Electrical Supplies, )Indel Aeroplanes and Farts t'orbuilding y - tus. A Treatise on Wnr,'less Telegraphy, telling how to put up an aerial. eonneet apparatostn:,pl,:,r meth, with a ('all list and Wiring Diagram, FREE with every catalog. tie. in shuup, will bring you this Light O, 'fit. 75c. wonderful hook. The bust eats log of wireless apparatus, etc., published. several hundred mini' ti Lure Ill tuns, sockets, etc., Experimenters"' in our rat- ADAMS- MORGAN CO. [ThsSupply House 13 Alvin Place, Upper Montclair, N. J. slog.illustrated

Crystal Dete tor, g2.25. 6 they styles from 30e. up quenched Gap, $15,00. Fun With Magnetism. Fun With Electricity, 50c. Rotary Gap, $12.00.

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