Submarine Escape Apparatus

SUBMARINE ESCAPE APPARATUS

PRINCIPAL CONTENTS

THE BEGINNING OF FLYING SIMPLE HYGROMETER STUDIES IN ELECTRICITY MAKING AN ELECTRIC HEATER HARDENING PLASTER CASTINGS LIGHT PUNCHING MACHINE FACTS ABOUT GENEVA STEEL PASSENGER HAULING MODEL LOCO.CYCLIST SECTION When / wantaCL/AIturn to TERRY'S (the 5,o people) I go to TERRY'S for all kinds of CLIPS-steel, bronze, stainless, etc. When I want a clip made to specification, Terry's Research Department is a big help in the matter of design (Terry's with 96 years' experience should know a thing or two !) 7.77:7737rrrr,

Nos. 8o and Si come from 1" to z" from stock. No.300,anexcep- tionally good drawing board clip, costs 5/- a doz.(inc. p.t.)from stock. Want to know all about springs? Here is the most comprehensive text - book on springs in existence.

No. 80 Post free to/6 No. 81 No. 300

Sole Makers:HERBERT TERRY & SONS, LTD., REDDITCH London Birmingham Manchester

IIT4F October, 1951 NEWNES PRACTICAL MECHANICS 1 A COMPLETE TRAIN SET FOR YOUR BOY The Prince Charles train set is not just a toy, but a real " live" scale model that will give years of joy to its owner.

Areal " live " BASSETT-LOWKE train set. The finest model train ever offered (clockwork or electric). A layout of track, an engine and its wagons or coaches bought now at a moderate cost, grows in time by the addition of " extras " into an enthralling miniature railway system that never loses its fascination.

.. Acompleteclockworkset,inc. PurchaseTax. A modern style of station exactly in scale with Bassett- Price£7.17.6 Lowke stock No. 1005/0. Length, 341in.; width, 51 in. ; height,51in.Price, 881-. Acomplete electric set,incl. Purchase Tax. Price £20.12.6 The most comprehensive Gauge 0 Catalogue yet Published STATION STAFF, includes (Ready for connecting toA.C.House Mains.) Guard,PlatformMaster, Writenow(orBassett-LowkeGauge'O'Railway 2 Porters, 1 Luggage Barrow Complete sets delivered, post paid, to any address Catalogue (ref. GO/12) Price 1,'-, which contains details and Spiecesof luggage. of a host of accessories for use with these train sets. Price, the set, 318. in the United Kingdom. BASSETT-LOWKE LTD.

London : NORTHAMPTON Manchester : 112, High Holborn, W.C. 28, Corporation Street.

Order nowfor immediatede- DO YOUGETTHRILLING SNAPSHOTS ? THIS BOOK livery. Every WILL SHOW YOU HOW tool full size and fully guaranteed. NEW HOME PHOTOGRAPHY Brick Scutch Ham- mers,8/6 ; Stick Even if you only possess a box Choppers, 3/-; 10in.Broad Brick camera this book will show Trowels, 9/6; 1 1 in. you howto turn out first-class BradesBrick Trowels, 15/9; 6in. photographs. Written by two GaugingTrowels, experts, a photographer and a 6/9 ;8in. Gauging Trowels, 8/3 ;7in.Gauging Trowels, 6/9 ; 5in.Pointing Trowels, 4/6 ;6in.Pointing Trowels, 14/9 ; 7in. scientist,theinformation is Pointing Trowels, 5/3 ;Lath Hatchets, 9/6 ;11in. x 4iin. Plasterers impartedina way you can Trowels, 11/6 ;kin.Conduit RingSaws, 7/6 ;tin. Capacity Enclosed Gear Breast Drills, 37/6 ;10in. Paper Hangers Scissors, 11/9 ;12in. easily follow. There is nothing ditto, 12/6 ;54in. Footprint Wrenches, 3/- ;Sets of Cramp Heads, too stodgy or too technical for 9/ -set ;; 6in. Woodworkers Vices, 11/6 ;6in. Quick Grip Vices, 15/- ;7in. Record Quick Grip Vices, 43/- ;5ft. Light Tee Bar Cramps, the average camera user to 38/. ;6ft. Heavy Door Tee Bar Cramps, 59/- ;Top Action Floor Cramps, 66/- ;Unbreakable, 4in. Heavy Gee Cramps, 4ft. Heavy understand. Tee Bar Cramps, 19/6 ;7in. Combination Plyers, 4/9 ;6in. Insulated Nearly100pages, with 130 Combination Plyers, 6/-;7in.Insulated, 6/9 ;8in. Combination Plyers, 4/10 ;6in. Carpenters Pincers, 2/9;7in. ditto, 3/-;8in. ditto, illustrations, packed with practical and easy -to -follow hintsand 3/6 ;12in. Bevels. 7/9 ;10jin. Bevels, 7/3 ;9in. Footprint Wrenches, dodges. How to take good photographs both out ofdoorsand 5/3 ;5tin. Snipe Nose Plyers, 4/3 ;36in. Levels, 23/6 ;18in. Bushman Type Saws, 8/6 ;Plugging Chisels, 2/9 ;/in. Electric Drills, £13/7/6 ; by artificial light; hints on portraiture,film developing, contact fin. Electric Drills, £6/10/0;7in. Hand Grinders, 41/- ;American print making and enlarging are all explained. Get a copy as soon Hand Vices, 6/9 ;Expansive Bits for wood, tin. to3in. 19/6 ; " Yankee" Push Screwdrivers, 34/6 ;66ft. Steel Tapes, 55/9 ;50ft. as you can.It will bring a new pleasure to your hobby. Steel Tapes, 46/- ;4in. Engineers Squares, 5/- ;10in. Tenon Saws, 9/- ;12in. Tenon Saws, 9/9 ;Best Dovetail Saws, 8in., 17/6 ;}in. OBTAINABLE FROM ALL PHOTO- CapacityBreast Drills, 32/6 ;6ft. Two -Man Crosscut Saws, 31/6 ; One Pint Paraffin Blow -lamp, Swedish, 49/6 ;One Pint Paraffin PRICE GRAPHIC DEALERS OR SENT Blow -lamps, British 36/- ; Iron adjustable Rebate and Fillister Planes, POST FREE BY JOHNSONS OF 26/3 ;Genuine No. 45 Stanley Planes, £12/7/- ;7in. Electric Saws, HENDON AT THE PUBLISHED £32/10/- ;tin. Bench Drilling Machines, 62/6 ;18in. x 3in. Treadle 2/6 PRICE IF YOU MENTION OCT. Grindstones,f11/10/- ;Steel Roofing Squares, 24in. x 16in.,32/- ; " PRACTICAL MECHANICS." C.12 Ten Rivet Finishing Trowels, 25/6 ;C. 12B ditto, 27/6 ;Super Ratchet Braces, 15/9. Goods to the value of 50/- and over carriage paid, if your order is JOHNSONS OF HENDON LTD. under that amount send 2/- for postage -any excess will be refunded. ROSS and ALEXANDER (LONDON), LTD. 165-167, BISHOPSGATE, LONDON, 335, HENDON WAY, LONDON, N.W.4 Tel.:BlShopsgate 2220 2 NEWNES PRACTICAL MECHANICS Odober, 1951 Most sizesavailable- from stock! I.C.S. TRAINED MEN ed MICRO- arein Greater Demand DRILLS STRAIGHT FLUTE DRILLS. Awell -designed drill par- -Maximum production ticularly recommended for drilling brass. Range than Ever of sizes: .35 mm. (.0138") to 3.0 mm. (.11131") depends onhightechnicalskill,such asthatacquiredbyI.C.S.Students PIVOT DRILLS Widely used by watch FLAT DRILLS TENS OF TH OUSANDS MORE TRAINED and clockmaking Similar topivot drills MEN ARE URGENTLY NEEDED NOW tradesfordrilling but made in larger very small -BUT THERE IS NO WORTH -WHILE holes. sizes. Rangeof Range of sizes : sizes:.25 mm. .05 mm. (.002") PLACE FOR THE UNTRAINED (.0098") to 3.0 to.5 mm. Ambitious men everywhere have succeeded through (.0197") mm. (.1181") Home -Study Courses.So also can you. The man with an I.C.S. Training inany one of the subjects STANDARD SPIRAL listed below knowsitthoroughly,completely,practically. SINGLE SPIRAL And he knows how to applyitinhiseverydaywork. FLUTE DRILLS FLUTE DRILLS Ageneral purpose drill Motor Mechanic For drilling small Accountancy Draughtsmanship ofimproved flute Advertising Drawing Office PracticeMotor Vehicle Elec. holestoextremely Air and Vacuum Electrical Engineering Municipal Eng. design for easy ejec- Brakes ElectricPower,Light-Plastic tion of swarf. fine limits.Range Air -Conditioning ing, TransmissionPlumbing Range of sizes: .1 of sizes:.1 mm. Arable Farming Traction Production Eng. Eng. Shop Practice mm. (.0039") to (.0039") to3.0 Architecture Fire Engineering Quantity Surveying 3.0 mm. (.1181") Architectural Drawing Foremanship Radio Engineering mm. (.1181") Auditing Fuel Technology Radio Service Eng. Boiler Engineering Heating and VentilationRefrigeration Book-keeping Horticulture Sales Management Building Construction Hydraulic Engineering Salesmanship WRITE FOR STOCK LIST Building Specifications Illumination Eng. SanitaryandDomestic Business Training Industrial Management Engineering S. N. BRIDGES & CO. LTD. Business Management Lettering Sheet -Metal Work Carpentry and Joinery Machine Designing Short -Story Writing BridgesPlace, ParsonsGreen Lane. London,S.W.6. Chemical Engineering Machine -Tool Work Steam Engineering Chemistry, I. & 0. Maintenance Eng. Structural Steelwork Civil Engineering Marine Engineers Surveying Clerk of Works Mechanical Drawing Telegraph Engineering Coal Mining MechanicalEngineeringTelevision Technology Commercial Art Mine Surveying Welding, Gas and Elec. Concrete Engineering Mining Engineering Woodworking Drawing .113=110) Diesel Engines Motor Engineering Works Engineering Students intending to sit for the above examinations in Architec:ure, Quantities, Civil Eng., Mech. Eng., and others, should enrol NOW for preparatory Courses. Using a specially prepared Study Programme, the student studies in his spare time, at his own pace and, with time for revision, sits with full confidence of success. Courses are also available for most other Technical, Professional, Commercial, and Civil Service Exams. (I.C.S. Examination Students are coached until successfu..) GENEROUS DISCOUNT GRANTED TO ALL MEMBERS Oi H.M. FORCES. Ifyou needtechnicaltraining,ouradvice on anymatterconcerning your work and yourcareerisyoursforthe asking-free cnd without obligation.Let us send you our special free booklet on the subject in which you are specially interested.DON'T DELAY. Make ACTION your watchword.

The successful man DOES to -day what the failure BecauseoftheirHigh The S. G. BROWN Type Sensitivitythe S. G. " K " Moving Coil Head- INTENDS doing to -morrow.Write to us TO -DAY BROWN Type " F" phones supply that High Use this Coupon (Featherweight) Head- Quality Reproduction so phonesare a popular essentialfor DX work, INTERNATIONAL CORRESPONDENCE SCHOOLS LTD choicebyallrequiring monitoring, laboratory Dept. 95, International Buildings, Kingsway, London, W.C.2. efficient,longandde- purposes, etc. Please send me the free booklet describing your Courses in pendable service. D.C. Resistance 4,000 ohms. D.C.Resistance47ohms. Impedance14,000 ohms at Impedance 52 ohms at Name Age 1,000 c.p.s. Weight 9 oz. 1,000 c.p.s. (USE BLOCK LETTERS)

Address SEND FOR BROCHURE " P.M." ITGIVES DETAILS OFALL TYPES OF S.G. BROWN HEADPHONES. Addresses for Overseas Readers Australia ;140, Elizabeth Street, Sydney.

Egypt :40, Sharia Abdel Khalek Sarwat Pasha, Cairo. - Eire :13, Anglesea'Street, Dublin, C.4. .9ArnAVAttriA India:Lakshmi Bldgs., Sir Pherozsha Mehta Rd., Fort, Bombay. - SHAKESPEARE STREET, WATFORD, HERTS. New Zealand 182, Wakefield Street, Wellington.' Telephone : Watford 7241 N. Ireland : 26, Howard Street, Belfast. ICS South Africa :45, Shortmorket Street, Cape Town. October, 1951 NEWNES PRACTICAL MECHANICS

DRAWING INSTRUMENTS

IESLIDE RULES We are thelargestmanufacturers of high-grade Drawing Instruments and Slide Rules in the British Empire, andourKinwestDrawingMaterials have gained a reputation throughout the worldfor superbqualityandaccuracy. " Rather !I turned Insist on using only Thornton's for complete my Wolf Cub Electric Drill satisfaction. into a lathe and it only cost me £3.12.3." Bia Our illustratedCatalogue, whichincludespar- ticulars of Drawing Instruments, Drawing Boards, "That's very cheap-how do Wolf do it?" Tee and Set Squares, Scales, Curves, etc.,is sent Post Free on request. " I had a Wolf Cub (that cost me only£5.10.0),then I bought thisLathe Set for

A. G T+-FORN TO N LTD I inthe Litaiving butt/Lament Spectal..astt4 £3.12.3. clamped W YT44c.N./44AW-E, MANCHEITER. Wolf Cub - and there you Tel : WYThenshawe 2277(4lines) are, a real electric Lathe Kit !"

SELECTED MISCELLANEOUS ITEMS "Is that all Wolf Cub Home Constructor Equipment?" EX -GOVT. PRISMATIC BINOCULARS Best British makes, including Kershaw, Ross,etc. "Oh no !next I shall buy a 6 .x30. Eye -piece focusing.Complete with Web Saw Set like this for £2.16.6, Case.Guaranteed condition. Post 21- extra. 17-15-0 fit. my Wolf Cub and I shall have a real Electric Saw Kit!" "How marvellous! " U.S. Govt. Yes, and thats not a// the story STAR IDENTIFIERS Writerite at at once Consists of Star Base and seven Templates. Can be used to spot or identify stars.Complete with instructions and leatherette Wolf Cub fully wallet.Postage 9d. extra.4/6 picturised folder, PRISMATIC ELBOW "Profitable TELESCOPES HOME CONSTRUCTOR KITSPleasure." Power 7 x.Weight 6 lb. Image erect.Definition is crisp and free from distortion. Post free. 27/6

REFLECTOR SIGHTS Beautifully constructed instrumentconsistingof lamp -house with INTERFERENCE dimmer -switch attachment and condenser Nit RADIO of 3 lenses in housing.Readily adapted f/T A as film -stripviewer,etc. aft (including postage). 15/- PRISMATIC NV* °ZURATEL OPTICAL UNITS No magnification but can be SUPPRESSOR adapted for use as prismatic Specially designed for use with Wolf monocular, rifle -sight. etc. Cub Drills. Supplied ready to attach Television Suppressors also available Weight only 14 ozs. (including postage). 10/6 to " Cub" lead. Conforms fully with for fitting by Wolf Service Engineers. SATISFACTION GUARANTEED OR FULL REFUND official regulations. Only 23,'6. 8/6 inclUsive. * Prices and descriptions subject to alteration without notice. Phone : CHARLES FRANK BELL 2136 WOLF ELECTRIC TOOLS LTD. Instrument Makers and Dealers since 1907. PIONEER WORKS, HANGER LANE, LONDON, W.S 67-73, SALTMARKET GLASGOW, C.I Te/ephone PERIvale 5631-4 BRANCHES: BIRMINGHAM MANCHESTER LEEDS 'BRISTOL GLASGOW 4 NEWNES PRACTICAL MECHANICS October,1951

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No finer range of Drawing Office Furnitureisavailable than the Halden range.Every up-to-date refinement making for greater a:curacy. greater easeinuse, and economy of MORE skill at space has been introduced to the Halden designs. The range includes Drawing Tables, Cabinets, Drawing Boards, Filing your fingertips! Cabinets,TrestlesandGlassTracing Tables. Large size boards made to customer's own specification. For all office furniture and accessories consult :-

Haldens ® OF MANCHESTER j. MALDEN & CO., LTD., 8, ALBERT SQUARE, MANCHESTER 2. Branches at :-London, Newcastle -on -Tyne, Birmingham, Glasgow, Leeds and Bristol. PRECISION MADE BURNERD CHUCKS * Extreme Self centring 3 -jaw geared Independent 4 -jaw scroll (Reversible) No. 86 accuracy. 21in. Model 28 ...10719 3,jin. Model 35A 4916 3jin. Model 29 ... 11212 4in. Model 35B 51/S TOOL CHEST Almost a workshop841 - * Powerful grip. 4in. Model 30 ...12219 4iin. Model 35C 61/4 Sin. Model 30A ... 174111 6in. Model 34 9714 in itself.A complete assortment * Minimum weight 6in. Model 31 ...207111 of toolsin handsome, fined and overhang. Self centring 3 -jaw lever With rboarcdk pml atue;Ritattehde f o r wooden chest. scroll Sin. Model 33 ... 7913 Model 30 ... 171616 t. * Hard wear and 4in.Model 33A ... 118110 Model 34 6511319 long life. Self -centring, 3 -jawscroll(Reversible jaws), 2(,in.Model 32 991 - * Quick,smooth Postage extra. Illustrated literature gladly sent. A 6d. stamp will bring you a copy of our comprehensiveillustrated catalogue operation. for 1951. A. J. REEVES & CO. " The choice of 416, MOSELEY RD., BIRMINGHAM, 12 Grcms : ReevescoBirmingham " experience" Phone:CALthorpe 2554

No. 5 KNIFE No. 2 KNIFE mEw! No. I KNIFE tk, for heavy duty. With for normal cutting. With for delicate work. With one No. 19 blade 0,0 one No. 22 blade 3,6 one No. 11 blade 3/ - THE Replaceable faces of non-inflam- Try the perfect balance of X-acto knives, test the scalpel -keen mablecellulose. High impact strength. Retainsshapeand sharpness of X-acto interchangeable blades and you'll soon be TNOR never damages the work.Solid convinced that X-acto makes creative hands even more skilful. steel hammer body with knurled Call at your dealers and see the complete range of knives, face - retainingpegs at SOFT HAMMER both ends. Standard blades, tools and attractive kits or write for illustrated folder. IL Hammer hascylindrical faces.Six weights (4 ozs. * X-aclo blades are available separately in packets. 5 short blades, to 2 lbs.).Dome, cone, taper, or wedge shapes also supplied.Ideal straight 216, five short blades, curved 3,'9 and 2 long blades 2/- for machine shop use and general assembly work. Write for details.

TRIX LTD., 1 1, OLD BURLINGTON STREET, LONDON, W.I. THOR HAMMER CO" SALOP STREET, BIRMINGHAM, ENGLAND. 'Phone :ViCtoria 0987-8. 'it a October, 1951 NEWNES PRACTICAL. MECHANICS The acid -free cored solder for every, handyman This new non -resin cored solderisanindispensable addition to every home workshop, replacing sticksolder and fluid and paste fluxes.It MAKES MANY contains two cores of Arax Flux, a flux so fast that Arax Multicore Solder can even be PERMANENT used for soldering blued spring steelwithoutpre -cleaning. MODELS Flux continuityisassured, and utility objects, there is no waste, and no extra from simple instructions in illustrated flux is required.If desired, Booklet-please the flux residue can be easily read below. washed off with water. SIZE 8 CARTON5 -EACH A COMPLETE RANGE OF MULTICORE SOLDERS IN THIS SINGLE HANDY KIT The Multicore 2 - Solder Kit contains two specifications of Arax Multicore for metal soldering and two specifications of Ersin Multicore for electrical 2 KIT and radio work. MULTICORE SOLDERS LTD. MELLIER HOUSE, ALBEMARLE ST., LONDON, W.1 REGent 1411

6 MARLCO KNURLING TOOL Range 0-4in.Allsteel, case-hardened. Can be assembled to operate in front or ONLY4D behind work. Will exert great pressure without strain tolightlathe.Floating IN STAMPS jaws will follow workpiece and enable BRINGS BOOK knurling to be started in its middle. Diamond and .. . showing how suchmodels as those above, and many others, straight cut knurls available. can be made, without skill or special tools, from Sankey's PYRUMA Full particulars on request. Plastic Cement.Ready for immediate use initsplastic state, W. H. MARLEY & CO., LTD., Pyruma sets or bakes to stone -hardness, and can be painted or Eng. T Dept., New Southgate enamelled inallcolours according to instructions.Therefore Works, 105 High Rd., London, realistic natural -colour models can be made from Pyruma, including N.I I.Telephone: ENTerprise 5234 HOUSES, BUILDINGS FOR MODEL RAILWAYS, DOCKS AND AIRPORTS, SHIPS, MODEL FURNITURE, ANIMALS, FIGURES, RELIEF MAPS, Etc. as well as utility objects such as ASH TRAYS, BOOKENDS, MENU HOLDERS, PAPER WEIGHTS, ORNAMENTS THE CRAFTSMAN'S SUCCESS and DECORATIVE OBJECTS. ... lies notonlyin his own skill, enthusiasm Pyruma is inexpensive, and easily obtainable in tins from Iron- mongers, Art Material Dealers and Hobbies Shops.Send 4d. in and concentration, but also in his choice of tools stamps to the address below for illustrated Instruction Book. and materials." CRAFTSMEN THROUGHOUT THE WORLD PREFER SAN KEY'S MYFORD PYRUMA LATHES AND ACCESSORIES. PLASTIC CEMENT

ML7, 31in. x 20in. Metalworking Lathe. ML8, 4in. x 30in. Woodworking Lathe. See Your Local Tool Merchant, J.H. SANKEY& SON,Ef? ILFORD EsT. 1857 ESSE:: 6 NEWNES PRACTICAL MECHANICS October, 1951 HIRE PURCHASE TERMSLOOK! On all your requirements! We are now able to offer a unique arrangement whereby you may purchase your equipment on low cash deposit. For example, we detail below the terms available gvent eeoa on the famousAVOMETERrange : 12 monthly.LIGHT WHERE AVOMETERCash Deposit payments ofYOU NEED IT! peARteeceate 'Avo Model 7,8 or 40, With a List Price, £1910s. Od. UniversalAvo Minor, £600 44 5 6 FLEXIBLE List Price, £10 10s.Od. * TYRE INFLATION Signal Generator (mains£3100 15 0 TABLELAMP orbattery),ListPrice, Avoid eyestrain with good UP TO 40 lbs. £30. £1000 El 17 6light. For reading, writing, UniversalBridge, List typing, close work, odd jobs * SPRAYING Price, £26. £900 fl12 6-for fireside and bedside, ElectronicTestMeter, the ideal lamp. List Price, £40. £1200 £2 12 6 Flexible stemforexact Valve Characteristic adjustment.Complete with Meter, List Price, £50. g16 0 0 £35 0shade, flex and switch. Green * DRILLING Similarly, we can supply all other gear in stock on equalorcream - pleasestate terms.Write for details and quotations on your require-preference. ments or send order with small securing deposit to avoid PRICE ONLY ACi_ disappointment in view of the expected demand. Plus 1;6 carriage. * GRINDING TERMS AVAILABLE on equipment made byS. G. I BROWN ;COSSOR ;E.M.I. ;B.S.R. ;B.P.L. ;COL- LARO ;COSMOCORD ;DECCA ;EKCO ; EDI- SWAN ; G.E.C. ;GOODMANS ;HANDY -UTILITY ; * BUFFING MARCONI ;MU LLARD ;TAYLOR; TRUVOX ; VALRADIO ;WOLF ;VORTEXION ;ETC., ETC. Price £16- 12-0 BEAUTIFY BRITISH & YOUR AMERICAN No handyman or model engineer can be without this useful and adaptable HOME! tool.It is driven by a .1 h.p. A.C. motor and the power cost is infinitesimal. A beautiful VALVES A 13 ft. airline enables the job to be reached without difficulty.Complete Table Stan- We are ,tow able outfit, including A.C. motor compressor, 13ft.airline, cycle pump or dard in highly to offer any type finished of valve required Schrader valveconnector and attachment fordrilling,grinding and grained at B.V.A. prices. buffing.Write today for full details, stating current available and whether Tufnol-looks We will dispatch Schrader valve or cycle adaptor required.A larger compressor can be like waldut-wears like byC.O.D.post ebony ! Ideal for bedside, uponreceiptof supplied if required. dressing table, study or your order. living -room. Complete withplasticized THE OVERSEAS ENGINEERING CO. LTD. fabric shade and MAIL ORDER SUPPLY 6ft.flex. Postage The Radio Centre 194-200 BISHOPSGATE, LONDON, E.C.4 and packing It I. MOS (Dept P.M ;10) Tel.: EIShopsgate 9878 (5 lines) Cables :MYCAMYN, LONDON ONLY 12/11 33TOTTENHAM COURT RD., LONDON, W.1

PRECIMA Drafting Mach. for 32in. x 23In., used in many thousands of Drawing Offices. Serves as T -set, Setsquare, Ruler and Pro- tractor. Code P1 with Setsquare 1/161n. div., HOME HOBBIES WILCO ELECTRONICS 63/- post paid ;Code P3 with Setsquare, Motor cyclist to Sidecar Passenger, 2 -way communicating telephones, very i-itn. scale, 63/- post paid.Add. inter- loud ;no batteries, no complications, 1.716 per set, inc. post. 204, Lower Addiscombe Rd.. Croydon. changeable Setsquares, 14:6. For Summer Painting buy a Goblin spray -gun ;will fit to almost any make WALKIE-TALKIES. Type 38. 7.4 to 9 mis. of cylinder vacuum cleaner and can be used for distempering walls, painting and New, but less ATP4 valve and Yaxl Y UNIVERSAL BALL JOINT DRAWING varnishing doors and skirtings, cellulosing furniture, or with soapy water 'for switch. 25/-, post 1/6. BOARD HOLDER.One movement of MOVING -COIL lever locks board rigidly. Any angle (0-80°). shampooing carpets, washing down walls, etc. Also good for spraying the car or HEADPHONE lid Turns clockwise 360. bike.13/9. plus 9d. postage. Microphone set. Brand new. 10/6, post 1 6. Just clamped to Still in Stock -the popular small motors suitable for sewing machines ;supplied 0-1 MILLIAMP METER. 2in. Complete table. 55/- post paid. complete with on/off Switch and fitted belt. 21/6 inc. post. on paxolin panel with instrument rectifier. PELIKAN GRAPIIOS INDIAN INK Treat Yourself to an electric blanket to warm the bed on chilly nights :price 17/6, post 1/-. FOUNTAIN -PEN.Saves 50-100 fillings of £16. complete, or we can supply the infra -red warming unit for attaching to your METAL RECTIFIERS. -12 volt1 amp, drawing pens. Uninterrupted flow, uniform own blanket at only 22/6. plus 9d. post_Unit is 6 yds. long by I in. in diameter. 1216 :6 volt 1 amp, 10/6: 48 volt 150 m./>;s, lines. Great choice of Nibs up to lOmm. and comes complete with on,bil switch and 2 -pin mains plug ;during the summer 10/- :All Bridge, post 1/-. forTechnicalandFreehand Drawing, when the Ideal boiler isn't working the unit can be used to warm the airing cupboard. ACCUMULATOR CHARGERS in Stencil and Artwork.Standard Case G.81, For 220-250 v. mains, A.C./D.C. crackle case with fuses and meter. 6 d velvet lined : Pen. 12 Ruling Nibs 0.1 to 2.5 Convert Your Radiogram into a magnetic recorder ;easily done, with no per- 12 volts at 4 amps. Bargain Price.all mm., 3611: 12 Pelikan Black Ink Car- manent parts or screw -holes to disfigure gram. Complete kit Including spool of Pkg. and carr., 5!-. tridges, 18/6. Other sets and accessories on tape, £8.2.44. Details and circuits, Parts in stock for the simple recorder shown TWIN FLEX in black braided covering, enquiry. in June issue.Other recording accessories, EMI -tape 25/. etc. G.E.C. tape, 301- approx. 25 -yd. coils. 7/6, post 1/-. per half-hour spool, spare spools 4/6.45Kc. Bias oscillator coils, 5/6.Record/ SLOW-MOTION DIALS. gin.Scaled playback and erase head kits, with instructions, 7/6 the two.Constructional 0-100, reduction 200 to 1 or direct, ideal for data on Magnetic Recording, 5/-. wavemeters, signal generators, etc.Our TAPE RECORDER DECKS with fast forward and reverse speeds, sup- price, while they last, 5/6 each, post 1-. plied complete with spool of tape and spare spool, very nicely finished article, POWER PACKS. Input 110-233 volt A.C. £25. Demonstrations at our workshops. Output 250 volt, 80 m/amps. 6.3 volt I amp. 0 6.3volt .5amp.Complete with 5Z9G PARKRADIO OF MANOR PARK, valve, in steel case. Only a few left at the 676/8, ROMFORD ROAD, LONDON, E.12 amazing price, 50/-, carriage and packing. Ater 28. PRE -AMPLIFIERS for TN., including EF50 valve.15/- each, post 1/6. HAND TELEPHONE. Brand new with cord.15:- each. post 16. IrePeVect Pkaivinyan AIRCRAFT CLOCKS with splendid 8 -day jewelled movement, flange type, made to WITHREMOVAL KEYS THERMOLECTRICS LTD. stringent Govt. specification.Brand new guaranteed. Ideal for car, study, bedroom, CHAPEL WORKS. HAMPTON -ON -THAMES. etc., will withstand vibration and shocks. Special offer, 65/- each, post free. ENTERPRISE, THE IDEAL DRAWING " ELF " CIRCUIT BREAKER. 220 volts, PIN. Needle -fine point, perfectly flush, flat Here is an opportunity for the amateur engineer to acquire 2 amps., size 3 inches round. 10!6, post 1/-. rim, 2 Removal Keys in box of 48 pins.1 box, aprecisionBi-metal Thermostat, capable of controlling 4/6 ;3 boxes. 12/6 ;9 boxes. 36/, KLAXON GEARED MOTORS No. A.C. currents of 1 AMP within the temperature range IK5S13,3-W7. Torquelbs./in.15. R.p.m. CURVIMETEIt CONTOURMETF.M. for 50 degrees Fahrenheit to 200 degrees Fahrenheit. 175. Motor r.p.m. 1.400 at 230 v. A.C. Split measuring Maps, Blanks and Presspower. phase induction type, £10 each. BA50 :I Dial. reg. 391n. by Um, 24/6 post KLAXON CAPACITOR INDUCTION paid ;BA54, 2 Dials reg., 481n. by 1/32in., MOTORS with 41n. fan, 1/40 h.p. 220240 v. 36/9 post paid. ASBESTOS FLEXIBLE HEATING CORD. A.C., 2,700 r.p.m.No. EM5CB2 with. con- yd.Various Resistances :15, 25, 60, 200, 400 ohms denser, 551- each. PRECIMA MAJOR per yd. PRICE The new outstanding Drafting Machine for 3/9EACH 24 -VOLT D.C. MOTORS with double ended DE and Anti -size.215/15/, ASBESTOS SLAGWOOLfor the thermal insu- shaft 2in. x 31n.. 8/6, postage 1./-. lation o. hot-water tanks.II- lb. TIIERMOSTAT SWITCH. -Bimetal type Drawing Instruments. Slide Rules and full in sealed glass tube, 211n. x Lin. 30 deg. range of equipment on enquiry. THREE HEAT SERIES PARALLEL LINE CORD Cent.Ideal for Aquariums, Wax and Oil SWITCHES. IAmp. 250v., "off" position each end. 716 each. Baths, Gluepots, etc. Will control 1 amp. ;in.7 B.A. FINE SILVER -TIPPED CONTACT SCREWS6d, each. at 240 v., 5/- each. W. G. PINNER & CO., CUTTER HEADS.-" Recording "high BI -METAL,6in. wide x .036in.40/- per lb. impedance. Amazing bargain at 55/- each. 1, YORK ROAD, BIRMINGHAM, 16 post 1/-. WE INVITE YOUR ENQUIRIES FOR ASBESTOS MILLBOARDS AND SPECIAL P.M. SPEAKERS.-61In. Rola in case with ALUMINIUM FOIL -BACKED THERMAL INSULATION. transformer and volume control. 401-. Edgbaston1251 post 1/6. October, 19 51 NEWNES PRACTICAL MECHANICS 7 A Perfect Model for only

That's allit costs for a complete kit of materials to build theMary Every time this door slams a little cement, stone, plaster, wood, metal, Fortune, one of the first ships of the British Navy. more of the mortar or putty drops tiles, glazed earthenware ... Aperfect miniature for out. Why ? Because it sets hard and A Seelastik seal costs id. to !Ad. a thediscriminating modeller. shrinks and does not really stick. foot, depending on its width. It is There aremany other Hobbies GalleonKits, too -all equally They should have used Seelastik. light-coloured, and can be painted good value for money.For example, there's another miniature Seelastik forms a watertight, air- 24 hours after it is put on. -the galleon depicted on the back of the present-day halfpenny -" The Ha'penny Galleon.- The complete kit costs 513. Two of tightseal and remainsflexible You can buy Seelastik-packed in the larger models are the Elizabeth Jonas (complete kitI71-), and elastic when set ;itsticks handy ca rtridges, and applied by the and the Golden Hind (24!-).All can be made easily with a fretsaw and a few Hobbies tools. tenaciously even to highly polished Expandite gun (50/- with two noz- From leadingstore;, Hobbies zles) -or in 2/- and 3/- tubes, which surfaces, such as glass, as well as BranchesinLondon,Glasgow, toany combinationofbrick, are self-contained sealingtools. Manchester, Birmingham, Leeds, Sheffield, Hull, Southampton and Bristol -or post free from Hobbies Ltd., Dept. 7, Dereham, Norfolk. SEALS THE GAP Freeillustratedleafletsof Yftead ft complete range on request. EXPANDITE LTD., CUNARD ROAD, LONDON, N.W.10 ELGAR 5151

Slip a "MASON -JOHN FARMER MASTER " into awheel - HaveYou "A.A.*" ? brace andturn. No matter Inc. The Mail Order Dept. 0/ the if it is brick, tile, concrete To 5,4. 3o co« o.oc. MIDLAND INSTRUMENT CO. or marble the carbide tip Items from our 20pp. May Catalogue and penetrates easily a n d June Supplement. quickly and gives a clean 39. VEEDER COUNTERS, 0-9993, last round hole. digit is 110ths.Direct side shalt Ain. Sizes from 5132in. togin. dia.,5!-, post 3d.. 48:- doz.. post 8d. 61. NUTS, BOLTS & W'ASkIERS. The" GLAZEMASTER " B.A. & American sizes.5lbs. assorted. bores holes in glass of any 12/6,post1.3.12lbs., post1 6. thickness without fear of 91. AERIAL RODS. Consist of three 4ft. tubular steel copper plated sections splinteringorbreakage. screwing into each other.Base lin. You justletthe drill do dia., tapers to Ain. dia.Make superb flshir.g rods. New. in cardboard water- thework. Type B as r RNs proofedcontainers,76,carr. illustrated for craftsmen. 3 for 20', carr. 1 6. 182. ALTIMETERS Type A for the handyman. containing high grade aneroid mote- ment. suitable as ordinary barometers, Soul for l.'. its: Booklet ' L.' This reduced reproduction of a sub- brand new, 7.6, post 8d. 210. WINCHES Agents in most countries. assembly from one of our series of Worm dive 187.5 to 1 by On. sq. shaft. unique. life-size, " Easy -as -A B C." For hand or motor dperation. Clutch JOHN M. PERKINS Construction Sheets shows how simple and release, quick rewind, triple steel MASON MASTER GLAZEMASTER & SMITH LTD. radio construction can be/ II YOU have cable 6Ift., fitted shackle.Size 8in. x Braunston, Near Ituu.'hy, average ability (A.A..) and could wire 6in. x 5in. For loads up to 12 cwt. New, 'S' DRILL GLASS DRILL Phone: Braunilon 7.33, this unit then you can tackle any, or unused. 376. post 1 8. 211. BELL all,of the TWELVE GUARANTEED BATTERIES. exU.S.Army,Glin. CIRCUITS given in our "HOME CON- long. Jan. dia.. with brassterminals. OBTAINABLE FROM ALL GOOD TOOL STOCKISTS STRUCTOR'S HANDBOOK," knowing 6 for 811. post lg.213. FLEXATEX that failure is impossible! DOSE. Tough yet very flexible, smooth Our world-famous book has ONCE bore,resistsheat,petrol,oil,etc. AGAIN BEEN ENLARGED and now (a) fin. i.d.. 1.6.(b) fin. 1.d., 213.(c) contains the following FULL PAGE lin. 1.d.. 3 -.id! 1 in. i.d.. 316. All prices circuits,with descriptions.illustra- per yard. post 6d.Max. lengths 8ft. tions, full parts lists and details, and a (e) liin.i.d.. 46 per yard, poet 9d.. MATCHBOX RADIO RECEIVERS host,ofusefulinformation.data, max. lengths ert. (1) 2tin. i.d., 6'- per formulae, etc. yard.postMd.. max. lengths14ft. FULLY ASSEMBLED RECEIVER. Tunes B.B.C. Long 3 Valve. 3 wave FEEDER. 214. IIOSI' CLIPS, worm drive, taken 4Valve,3 wave FEEDER (with from unused equipment. (a) lin. to llin. and Medium Waves.Fitted with station selector switch and " hi -fl " switching). dia., 6'- doz.. post 4d.(b) Sin. to 21in. 5 Valve, 3 wave A.C. SUPERSET. dia., 91- doz., post 5d.(c) Sin. to 21in. non-linear impedance unit.Price, 15-, post free. 5 Valve, 3 wave A.C.ID.C. SUPER. dia., 12'- do7., post 8d.215. WIND- Feeder amplifier and Power Pack, SHIELD WIPER MOTORS. 24v. 6 Valve. 3 wave A.C. SUPERSET. D.C. 8.4 amps., l'6th h.p.. 5.00()-10.000 KIT OF PARTS. Fully illustrated instructions andkit 6 Valve. 3 wave A.C.,D.C. SUPER. r.p.m.For flexible drive, continuous SIGNAL TRACER. rotation.Standard base fitting.Size containing everythingnecessary for building the matchbox 4 Valve BATTERY SUPERSET. 6in. x 4/in. x Min.New. unused. CO 5 Watt AMPLIFIER. post 1,4.216. DELCO FANS. 230 v. receiver.Price, post free. 10 Watt AMPLIFIER. A.C. A beautiful 4 bladed fan with SIGNAL GENERATOR. removable castalloycircumference Remember. all components, resistances. guard for panel mounting, also rear INSTRUCTIONS ONLY. Full step-by-step instructions, condensers, etc., supplied by US are wire guard.Overall size 121n. dia. by fully marked and identified. 5in.Silver finish, new, 36', post 1;8. working drawings and theoretical wiring diagram.Price, 3/-, The price for all this information ? Send for our 20 -page lists. also supple- post free. 2.6 ON1.11, which makes it just about ment, direct to : the best value obtainable anywhere to -day t ! ! Many thousands of Con- structors now utilisethissplendid JOHN FARMER (Dept. A.2), JOHN O'BEIRNE (P), Rook so SEND NOW for YOUR copy, The NEW ISSUE is obtainable ONLY 194 HARBORNE PARK RD., 137, COTHAM BROW, BRISTOL, 6. from BODING LABORATORIES HARBORNE, B'HAM, 17 (Mail Office MO) Orders by Post only. 694. Lea Bridge Road, London, Eat) Tel , IIARborne 130" 8 NEWNES PRACTICAL MECHANICS October, 1951 EIMERT ADVICE ON YOUR CRIMER 144 -PAGE BOOK -Free! An unusual opportunity you cannot afford to miss

Are you looked upon as an up-and-coming man in your job ?Have you already been noticed by the right people-or are you just one of the crowd, plodding along in a rut that leads nowhere ? YOU have it in you to succeed-to be somebody, but only experts can help you find out where YOUR opportunity lies.Fill in this Confidential Advice Form and our Careers Experts-they have helped thousands of men just like you-will send you a frank, personal letter of advice on your best method of achieving success in Engineering. Whether you act on our suggestions will be for you to decide.But you owe it to yourself to find out what you COULD achieve...... ---FREE CONFIDENTIAL ADVICE FORM..., Please send me a copy of " ENGINEERING OPPORTUNITIES " andyour expert advice on how I can best advance my career and make the most of to -day's opportunities.I understand that the details given on this form will be treated in strict confidence andassume no obligations whatsoever.

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IF YOU PREFER NOT TO CUT Complete and post this Advice Form today ! THIS PAGE, COPY THE FORM THE ADVISORY MANAGER OR WRITE A LETTER BRITISH INSTITUTE OF ENGINEERING TECHNOLOGY 41 OA, SHAKESPEARE HOUSE, 17/19, STRATFORD PLACE, LONDON W.I. THE 13.1.E.T.IS THE LEADING INSTITUTE OF ITS KIND IN THEWORLD October, 1951 NEWNES PRACTICAL MECHANICS

EDITOR IL_TYLs\257-1 F.J. CAMM OCTOBER, 1951 VOL. XIX. No. 214M ECIATA E.4 Owing to the paper shortage "The Cyclist," " Practical Motorist,'and "Home Movies " are temporarily incorporatel. FAIR COMMENT By The Editor Is Interplanetary Travel Possible ? EVER since the imaginative fictionto offer a substantial improvement onthe crewatadistance of too km. of Jules Verne and H. G. Wellsthe chemical rocket because of limitationsAlternatively, alongcylindricalcon- therehasbeenanincreasingof temperature and power rating, whichstruction might be adopted with a shield belief in scientific circles that in timeprevent the achievement of very highat the end of the pile facing the control we shall be able to visit the moon andexhaust velocities and the high thrustscar.The atomic pile might use a heavy some of the other planets which are partneeded to lift vehicles against planetarywater both asa moderator and as a ofthemysteriousUniverse. Ourgravitational fields. working fluid to drive a steam turbine knowledge of them at present is scientific In the case of an interplanetary shipandaD.C.generator.Wasteheat conjecture.Practice has been made tooperating between a circular orbit aroundfrom the condenser would be dissipated fit theory.Our only knowledge of theone planet and a similar orbit roundby radiation from a fin 1,000 sq. metres planetsis what we have gained byanother without making a landing, it isin area at 45o deg. K.The heat would calculation and by visual examinationpossibletoemploy a new principlebetakenintotheworkingfluidat by means of an astronomical telescope.which might effect great economies in900 deg. K. to ensure so per cent. Perhaps beforethiscenturyclosesathe amount of propellants and materialsthermal efficiency. space ship will enable us to visit thewhich must be carried up into the orbit. Nitrogenwouldbeusedasthe moon, whichisonly240,000miles This principle depends on the factpropellant, since it could be collected distant, and we shall have ascertainedthat such a ship can be propelled byfrom the atmospheres of a number of how far our conjectures have been right.very low thrust, whence it is possible toplanets.A potential difference of 740 From a practical and from scientificusehighexhaustvelocitieswithoutvolts would be required to accelerate points of view aspaceship whichinvolving excessive power production.nitrogenionstoavelocity of 100 could make thejourneyisnotanThe high velocity exhaust stream wouldkm./sec. and a total current of 2,000 impossibility.The experimental workbe -obtained by accelerating a beam ofamperes would be required to produce would be costly, of course, and no doubtions in an electricfield, power beingthe necessary thrust. This potential in the attempt there will be loss of lifeprovided by a nuclear reactor.Professorwould be applied between two mesh as in the early days of flying.Such aSpitzergaveasan exampleashipscreens1 mm. apart, and thermionic risk would not act as a deterrent. Theredeveloping an exhaust velocity of iooemission of electrons from the outer are plenty of volunteers who would bekm. /sec. and a thrust sufficient to providescreen would ensure electrical neutrality. willing at the present time to undertakean acceleration of o.3 cm./sec. Such aThe area of cross-section of the beam the journeyif the spaceshipwereship could undertake atotalvelocitywould need to be about 7 sq. metres available. change of 3o km./sec. with a mass ratioto avoid space charge limitation.Com- munication between a space ship of this BritishInterplanetarySocietyof only 1.3.The useful mass ratio of The the vehicle would be 15o kW/tonne.type and a planetary surface would be has been steadily examining the problem achieved by means of a satellite vehicle Its membersThis ship would be a small one weighing over a long period of years. to tonnes, the energy source being aof conventional type.The interplanetary aretrainedscientistswellableand ship would have to be carried up to the qualified to undertake the design of an tonne U235 or a PU239 reactor producing heat energy at the rate of 4,500orbit in the first instance by means of a interstellarship.Themovementis booster rocket weighing perhaps a few growing in importance, as was evidentkW. To avoid heavy radiation shields one envisages the vehicle as a separatethousand tons.In making alanding from its recent lecture session in London, on a planet such as Mars a winged rocket where prominent interplanetary specialistspilotless power section, towing by means of thin wires a light control car containingmight be used carrying to the surface gave lectures disclosing the present state the propellants needed for the ascent. of our knowledge and progress. Thesuggestionhasalreadybeen the ProfessorLymanSpitzer,of SUBSCRIPTION RATES made in America that astratospheric Princeton University Observatory, agrees including postage for one year platform should be built as a sort of that while it appears possible to project Inland - --- I4s. per annum. starting -off point and on which would a multi -step rocket into a close orbit Abroad- - - - I4s. per annum. be " land " instruments, radar apparatus, about the earth, the next step of pro- Canada- - - - I3s. per annum. and transmitting and receiving equip- Editorial and Advertisement Office :" Practical ceeding from this orbit to the surface Mechanics," George Newnes, Ltd., ment so that communication could be of the moon or another planet and back Tower House, Southampton Street, Strand, W.C.2 maintained between the aerial platform would requireatpresent prohibitive 'Phone : Temple Bar 4363 Telegrams: Newnes, Rand, London. and the crew of the space ship. quantities of conventional propellants. Registeredatthe G.P.O.fortransmissionby Of course, there are other suggestions In other words, we shall have to discover Canadian Magazine Post. for space ships, such assteprockets, Copyrightinalldrawings,photographs and a new propellant. Perhaps atomic power articles published in " Practical Mechanics " is that is to say a series of rockets joined will supply the answer. specially reservedthroughout thecountries one behind the other to the control car, The application of nuclear energy to signatorytotheBerneConvention and the eachrocketbeingfiredatcertain U.S.A. Reproductions or imitations of any of heat up a propellant in a conventional these are therefore expressly forbidden. intervals of time in order to complete the type of rocket, however, does not appear space journey.-F. J. C. 10 NEWNES PRACTICAL MECHANICS October, 1951

The Wright aeroplane in flight-August 19oS. The Story of the Early Pioneers from Clement Ader and the Wright Brothers to the Pioneer -founders of the British Aircraft Industry in the First World War /F ever practical mechanics-without the By C. G. GREY flown acircuitin January on his biplane, help of scientists or learned professors or and on October 31st Bleriot on his mono- bookmen-brought about a revolution inpropeller of sorts.It covered 5o yards, quiteplane had flown 18milesacrosscountry. human life with their own hard hands andout of control and crashed.He tried again AlsoalittleBrazilianmillionaire, named heads they did so when they built aeroplanesin 1897 on October 14th, near Versailles, andSantos Dumont, who had done the first hop and made them fly.Yet so few know wheretravelled 300 yards, mostly off the ground,in Europe in 1906, in a queer thing like a they diditor when or how. A year orbefore he crashed; he then gave up trying tobox -kite with a tail in front (really an eleva- two ago I was shocked when a very senior fly. But he invented the name " avion,"tor), was flyinginatiny monoplane of officer of the R.A.F., whose memory of flyingfor all flying machines, anditisstillthenormal shape. goes back to 1912, as a boy at school, toldofficial word in France. All these things were built of wood with The Wright Brothersspars and struts and ribs and longitudinal Meanwhile,inthemembers, bolted and screwed together, braced U.S.A., two practicalwith wirestensionedby turnbuckles, and mechanics, namedcovered with fabric-very much the work of WilburandOrvillepractical mechanics. And, believe it or not, Wright, who owned athe fabric covering was made taut by coating bicycleshop,builta it with ordinary bill -stickers'paste, which glider on the experi-shrank the fabric and stiffened asit dried. ences of Lilienthal andNaturally, if caught in the rain it all washed Chanute. Later onout, and when quite dry it worked off as a theybuilt a fcur-powder.Not until 1913 did somebody dis- cylinderwater-cooledcover the use of celluloid varnish from which engine for it. On this,was derived Cellon and Titanine and other launched from arail" dopes " based on cellulose.From that the byaprimitivecata-plastic industry arose. pult, in which a cord ran overapulley at the top of a woodenWorld's First Aero Show pylon and was pulled The great revolution in the air (and in the byafallingweight,world's transport) began in 1909, after the Orville Wright madeworld's first aero show had been held in Paris the first authenticaround Christmastime, 1908. I was there, and wrote what I believe was the first aerc- The Voisin biplane of 19o8 -09. flight,ofabout 11 seconds. Actually itshow report in an English technical paper- me that only the officer commanding at thewas more of a catapulted, engine -assisted hopThe Autocar. Only one aeroplane in the Hendon Aerodrome knew that there had beenof about 4o yards.At a later dateit flewshow had ever flown. any flying there before the 1914 war, and300 yards or so, before coming down.And The great boost to flying was given by that none of the other officers had heard ofthere is credible evidence that on Septemberthe coming of the Gnome engine, a seven - the great R.A.F. Displays at Hendon between20th,1904, one of them flewa completecylinderair-cooledaffair,inwhichthe 1920 and 1937, when they ended. circuit onit. Not until 1908 Leonardo da Vinci could the Wrights, or Centuries ago men talked of flying.Leon- anybodyelse,claim ardodaVincidesignedplausibleflying that they really were machines in A.D. 15oo. Before A.D. 1800able to fly-that is, to balloons, both hydrogen and hot air, had Itcen take off and land used by the French Revolutionary armies, when they wished. and parachutes were dropped from them inEven then the failure exhibitions, but that was not flying.In 1804of their engine, or the Sir George Cayley, an English country gen-strength of a gust of tleman, built an aeroplane and a rotary enginewind decided fcr for it (driven by gunpowder, like a revolver), them when they but it only ran along the ground and brokewished to land ;and the leg ofits " pilot," Sir George's coach-where they landed was man.But that again was not flying. morebyluckthan Men first flew when the German, Lilienthal, judgment. But by in Germany, and the Frenchman, Chanute, in the end of1908 the Canada, made experiments with gliders in the VoisinBrothersand 189os.But they had no engines. So theHenryFarmanand first authentic instance of a man being lifted Louis Bleriot and off the ground, as against gliding down a hill,CaptainFerber were was that of Clement Ader, on October 9th,flying in France quite 189o,atArmainvilliers,inFrance. His seriouslyforamile machine was called " The Bat," and lookedor soatatime.In Pierre Ferrier, with a passenger, on a Maurice Farman like one, and it had a steam engine and a fact, Farman had " longhorn" biplane at Hendon. October, 1951 NEWNES PRACTICAL MECHANICS 11 He deservedlybe- Press when his home-made monoplane col- came a popular hero,lapsed with a broken back when he sat in and the Press of theit to be photographed. worldtoldus,ina Blackpool opened on October 18th with blindingglimpseoftheblessingof the Aero Club, notyet the obvious, that weRoyal.There were halfa dozen British werenolongeranmachines which did not fly, and of the hired island - whichw a sFrenchaviatorsonlyFarman,Latham, brought hometous Rougier and Leblancflew. A. V. Roe's byGermanaircrafttriplane,coveredwithvarnishedpaper, some five or six yearsappeared, but did not fly. It was called later. Bulldog,becauseit was financed by his Then on top of that,brother, Humphrey Roe, who owned a fac- in August, 1909, thetory which made "Bulldog " braces-hence Frenchheld the the jest, when Avros did fly, that they were world's first flyingkept up by " Bulldog " braces. meeting at Reims At both meetings the rain poured and the A 13It'riot inonoplane,of the early Type XI kind, hut with a Gnome wind roared. and there was little flying- (w h i c h the Frenchwhat could one expect in October ?Hence rotary engine. spell without an Astound-the story of a fussy official hurrying along crankshaftstoodstillandthecylinders " h."and they should know). the front ofapatient crowd, which had whirled round it. Petrol was fed through ingthings were done.Farman flew112 stood in the wet for six hours with nothing thecrankshaftintothecrankcase,frontmilesnon-stopin 3 hrs. 5 mins.,andhappening, who was hooked by a Lancashire which, along with large doses of castor oil,Latham, on hisbeautifulAntoinette, flewmanandasked:" Eh,lad,when'st' it was fed to the cylinders.(The smell of961, miles.The distance was governed byinterval ? " burnt castoroilcausesviolentattacksofthe non-stop ability of the engine rather than nostalgia in elderly gentlemen of 5oo 6oby petrol capacity or thepatience of the years of age.)The whole system was brutal, pilot.Generally the engine packed up.In-Moore-Brabazon but itworked, and we used to say that acidentally,theAntoinette'sengine wasa But on October 3oth, at Shellness, on the Gnome would make a tea-tray fly.Some of 52 -cylinderVee,withcopperelectro-de-Isleof Sheppey, Mr.J.T.C. Moore- the things thatit forced to fly were far less positedwaterjackets,directinjectionofBrabazon. now Lord Brabazon of Tara, won aerodynamic than tea-trays. petrol and steam cooling by aluminium pipesthe Daily Mail £1.000 prize for flying the By the beginning of1909,S.F. Codyalong the sides of the fuselage (or body). first mile in a circuit on a British aeroplane (now dead) and A. V. Roe (now Sir Alliott The Gordon -Ben- Verdon Roe, and very much alive)werenett Cup was won by disputing who was firstoff the ground inGlennCurtiss,who this country.The Short Brothers were be-took 15 mins. 5o secs. ginning to build an aeroplane underneath thetocover121miles, archesatBattersea, by the Dogs' Home,and heputupthe and in another arch were Howard Wrightworld'sspeedrecord (brother of Warwick, the famous motorist,bydoinga lapof and no relation to the Wrights. U.S.A.) andabout six milesat W. 0. Manning. nearly 55 m. p. h. Latham wont h e Height Prize with Glenn Curtiss 5ooft. I remember In the U.S.A.. Glenn Curtiss, the rival of a journalist asking the Wright Brothers and the greatest of all Curtisswhetherget- U.S. pioneers, was flying successfully andtinguptor,000ft. dodging the patents on aeroplane controlswas possible.Curtiss which the Wrights claimed.In Austria. Igosaid," Getting up to Etrich had built a queer, bird -shaped mono-t,000ft. isdead plane, which was later taken up by Rumpler easy... ."There the inGermany,andbecametheBumpierhe stopped and Taube, or Dove, so well known to our Armysmiled his slow smile. in the 1914-18 war, and naturally called theHe andIwere firm Henry Farynan ,flying at Issy-les-Moulineaux,Paris, in 5908. " Tawb." friends thereafter. The first real jolt to our insular self-suffi- with aBritish engine-a Wright type built ciency came on July 15th, 1909, when LouisFlying Meetings by Short Brothers, with a 6o-h.p., six -cylin- Bleriot, by an immense combination of pluck After that,things happened. Blackpoolder, vertical, water-cooled Green engine. and luck, flew across the Straits of Doverand Doncaster both decided to have flying George Holt Thomas-whose money had on a monoplane, with a three -cylinder, 35meetings a few weeks later, and Paris hadbeen made in the old Graphic-brought the h.p.engine,from Calais and landed ina itsfirstin September.Doncaster stolea French aviator, Paulhan. over with a Far- heap on the topofthecliffnear DovermarchonBlackpool. andopened onman biplane and arrangedfor him to fly Castle.Also he landed a prize of £i,000October15thwithseven or eighthiredfrom a cleared space in the middle of the offered by Lord Northcliffe's Daily Mail forFrenchaviators,andS.F.Cody andBrooklands motor track on October 29th and the first flight across the Channel. a Captain Windham, who gave joy tothe3oth.That gave Londoners their first sight of flying. Claude Grahame -White About this time Lord Northcliffe offered a prize of £to,000 for the first flight from London to Manchester (or the other way). On April 23rd,1910,awell-known car - driver named Claude Grahame -White, who had learned to fly at Pau, in the South of France, started on a Farman biplane from Park Royal. Meantime,GeorgeHolt Thomas had entered his French friend, Paulhan, for the contest. Looking for a starting -place for him he found a field near Hendon where a Mr. Everettand hispartner, Edgcumbe* were trying to persuade an aeroplane of their own design tofly. (To be continued)

* Now Lord Mount-Edgcumbe.The electrical firm of Everett, Edgcumbe & Co. Ltd., is still where it was Cody's biplane, of an car!), typ.'. then, in Coll ndale Works, The Hyde. 12 NEWNES PRACTICAL MECHANICS October, 1951 Facts About Geneva Steel A Brief Account of a Remarkable U.S. Steel Plant THIS modern steel plant is situated at By THE MARQUIS OF DONEGALL because three essentials of steel making were Geneva, Utah, about 4o miles from there-ironore,coalandlimestone-all Salt Lake City.Perhaps one of the available in great quantities in the surround- most remarkable things about this steel plant When I was there they were in the middle ofing Utah mountains.There was also water. is that it is situated in the middle of farm-a half -billion dollar construction programme. Thus, Geneva, covering 1,50o acres, became., ing country with a most impressive back-New facilities were in the course of installationthelargestcompletesteelmillwestof ground of mountains.Itproduces morefor the production of hot -rolled coils. These Chicago. than a million tons of steel per year and,coils will be utilised in the manufacture of Undoubtedly, Geneva is one of the most_ in order to do so,it has to allow the manysheets and tinplate.There will be a new cold -reduction mill which is modernsteelplantsintheworld.Fort farmers who are employed in the plant to to beestab-instance,oneofitsfeaturesisahuge have leave of absence to do their harvesting. lishednearSanFranciscoandanotherreversibleelectric motor which drives the similar sheet mill will be erected in the Losrolls in the slab mill.It is in fact the largest United States Steel paid the GovernmentAngeles district. 47,000,000dollarsfortheGenevaSteel These will, in fact, be theof its kind ever built by the General Electric plant. This was, of course, not United Statesfirst mills of this type on the Pacific coast.Company, and I was told that it cost over Steel'sfirstincursion intothe west coast. s,000,000 dollars.There are four batteries The west coast had always wanted to produceWartime Activities of coke -ovens, three blast furnaces and nine its ownsteel,andthisenormous outlay During the war, the critical need of theopen-hearth furnacestogivethe Geneva from the east was the largest investment ofAllies, as we all know, was keeping openplantanannualpotentialcapacityof the east in the potentialities of the west sincethe vital life -line of shipping from America.1,500,000 tons of pig -iron and 1,283,400 the opening up of the first transcontinentalThe Americans respondedtothis by thetons of steel ingots. railroad. inauguration of a programme which resulted From February, 1944, to October 12th, 1945: It was early in 1930 that it occurred toin the building of the largest Navy in theGeneva produced 676,447 tons of plates and U.S. Steel that the west hadsteelpossi-world, and the biggest merchant fleet that ever144,280 tons of structural shapes and shell - bilities,ifitwere manufactured on the sailed. The largestproportionofthesesteel billets.At the end of the war there Pacificcoast,andtheypurchasedthemerchant vesselswasconstructedinthe wasa certain amount of doubt about the propertiesand businessoftheColumbiawestern shipyards, and the means by whichsuccessful operations of the mill in peace- SteelCorporation. This continued to bethis was accomplished isthestory of thetime, in view ofitscolossalsize and the the only steel operating enterprise ontheGeneva Steel plant. character ofitsfacilities ;also because of west coast up to the second world war.In The United States Government asked U.S.the distance from the planttothe most 1946 the War Assets Administration askedSteel to construct and operate an enormousimportant consuming markets inthewest. for competitive bids for the purchase of thenew s:eel plant at Geneva, Utah, 40 milesHowever, there is no doubt that the decision Government -owned steelplantatGeneva,from Salt Lake City.This site was chosen totake what certainly was a chance has opened upa newindustrialera on the Pacific coast. Apart from all this, Geneva, as steel mills go, is very good-looking.It is not covered with dust, nor has rust yet attacked it-it isnot evenblack. Just behind the mill there is an artificial lake which is nearly as large as the entire plant of most of the Pitts- burgh and Pennsylvanian mills.In other words, there is plenty of room to expand as opposed tothe plantsofindustrialcities surrounded by houses and covering them with dust and smoke. Self-contained Plant Of course,ittook a war to doit,and there are some good things that even wars produce.For centuriespeople have been dreaming about the ideal steel plant with its coke plant, blast and open-hearth furnaces, slabbing, blooming, plate,strip and struc- turalmills. Then, in1941,the Govern- ment, with the lavishness that it only has in

,General view of the Geneva Steel Plant, Utah. Utah, and U.S. Steel submitted a bid which was accepted.This plant had been a war- time facilitylargely dedicated tothe production of plates and structural shapes for theuseinthe building ofships on the Pacific coastin connection with the U.S. Governmentemergencyshipbuildingpro- gramme.In fact, U.S. Steel had built and operated the plant for the U.S. Government during the war as a war effort. They tdok over Geneva on June19th, 1946, and it has been operated by U.S. Steel since then.As a result various new industries have sprung up in the west and will probably continue to do so when additional steel products become available for western The Geneva plant's1,roo-tonblast furnaces;the 50,022 -kilowatt pow2r plant d industries. switch house. October, 19 51 NEWNES PRACTICAL MECHANICS 13 time of war, combined all the latest dreamsThere was a certain amount of opposition Franciscoand Los Angeles withthe of engineers for many generations into oneat first from the Mormons and, of course,requisites for enormous building programmes, project and told U.S. Steel to build Genevanothing in Utah can possibly work withoutsuch as a new bridge in San Francisco.The -without a fee. theirsupport. Atfirsttheywereverysheet and tinplate market is really the basis Even so,no one could reallysay thatsuspicious of having a vast industry put downofGeneva'spotentialprosperity,butit Genevaisapicturesqueadditiontotheon their farming land-and not too exten-cannot rely on that alone and will have to beautiful scenery of Utah, but it may provesive farming landatthat,but they havegearitselfto the requirements of building to be a big economic asset.That dependschanged their attitude. in every field of architectural art. onanumber ofthings.Itdepends on The big question at present is:" Where is The chief competition at the momentis gettingtherawmaterialsandthesteelthis huge plant going to find an outlet forbetweenKaiser, who bought the Fontana economically, and also on whether Genevaits products ? " plant after the war at about 20 per cent. cansellthesteelthatitproduces.The It is true that the west in general is usingabove, proportionately, what U.S. Steel paid ready facilities of Utah have almost removedsome 25 per cent. more steel thanitdidfor Geneva.Kaiser charged high prices and the first doubt, but the second may last forbefore the war, but that is not enough, theyhoped to pay off thecapitalcosts of his aconsiderable time-thatistosay,untiltold me, to keep Geneva going ata profit.plant, but there isa buyers' market now in more and more new industries have comeThere are various States of the west whichsteelin California, and also inthe rest of into being to use the steel that Geneva pro-are not very much help as far as consumingthe United States.Kaiser promptly had to duces. Possibly that question will not besteelisconcerned, for instance, Colorado,reduce his plate by to dollars a ton and cut answered for 20 years. Arizona and Wyoming.The logical answerhis other prices by as much as 39 dollars. One factor that will probably help is thatto my mind would be San Francisco andThe fact of the matter is that Geneva sells the Pacific coast has for many years hadLosAngeles ;atanyrateCaliforniais the cheapest plate available on the west coast rather a complex about steel.It has alwaysundoubtedly the biggest potential customer. andthatitwillprobably,withevery wanted to produce its own steel rather than Thereisalsothe problem that Genevaincreasing adaptation to the needs of the big fetCh it the whole way from the rival east. isnot yetfully equippedtoprovide Sancities of the west coast, win out in the end. MakinAanElectric Heater An Inexpensive Appliance for Home Use By T. LAWLEY AN electricconvectionheaterof 375,of the leg nearest 43o, 500, 75o orr,000 watts ratingt h e connecting - can be made quite easily for not moreblock housing and than 5s. by following the simple instructionsbend the legs given below. around it to form a The 375, 43o or 500 -watt heater if installedlooptotake and inacupboard orbuilt-in wardrobe willclampthe3 -core convert it into a very useful clothes airer orsupply cable. Se- drier. cureeach pair ,'of uprights by a fur- Construction ther 4 B.A. screw Cut out the body as shown in Fig. r fromand nuts (see thepiece of 28 S.W.G. perforatedzinc.Fig. 2). Make a cut at each corner, marked F, for the Cutout the connecting -block housing.Fold up at 45former from a Fig .2.-The heater with the element partly withdrawn. deg. along AA and BB and down at 90 deg.pieceof3/16in. along CC, DD and EE. hard asbestos sheet and drill as shown instretch each spiral to 34in. by pulling at each For the legs cut out and drill four stripsFig. 4. For the 375 -watt element two spirals,end only.This will ensure an even spacing of r8 to 20 S.W.G. aluminium, as in Fig. 3a,each of 75o watts are required.For the 500 -of the turns of the spiral.Wind the first and bend as inFig. 3b.Pair the legs off,watt element two spirals, each of r,000 watts,spiral clockwise through the?,in. A holes forming a Y and locate each pair sin. fromare required, and for the 43o -watt element one(see Fig. 4).Anchor the ends byin. 4 B.A., either end of the body by drilling 4 B.A.spiral of 750 watts and one of r,000 wattscheese -headscrews, nuts and washers at A clearance holes in the flange of the body toare needed. To wind any of the above elementsand C.Similarly wind the second spiral correspondwiththeholesP(Fig.3a) through the B holes and anchor to B and C. and fix within. 4 B.A. screws (see Fig. 2). Only one spiral of the appropriate rating is Drill 6 B.A. clearance holes in the sides of the TDo5 requiredforthe750 -wattorr,000 -watt body to mate with hole Q (Fig. 3a) ill the legs Drill element. After stretching the spiral evenly to and fix with 3 16in. 6 B.A. screws.Insert 34in. and startingat A, thread clockwise the shaft of a }in. drill between the uprights through holes A B,,, A B,, A, B,,, A, C' then back through B, A,,, B A B,, A B,. .4 E 8 Anchor the ends at A and B.It is important that each free end of a heater spiral be firmly 277 fixed between a pair of washers. To fix the 4"- Cut We connecting block reverse one of the brass Herr: Here inserts so that the slotted screw of one is on the opposite face to the other.Locate the block below holes P and Q (Fig. 4) and connect one insert to A and the other to B with a 41i.n. and length respectively of /2 16 or 18 S.W.G. bare copper wire (or Nichrome if available) by threading through holes P 83* 8 or Q. The connecting block should now be located firmly against the bottom edge of the former Drill a 6 B.A. clearance hole on each side of the housing for the connecting block, to coincide with the centre hole of the block 3 I when the former is assembled inside the body 3/8_ (d) 8 (see Fig. 2).Assemble and locate the former A /=.4 and block in place with a ;in. 6 B.A. screw, nut and washer at each end. To enable the Fig.1.-Dimensions of perforated metal forFig. 3.-Details of the aluminium stripformains supply leads to be fixed to the ter- forming the main body. making the legs. minal block without the need to remove the 14 NEWNES .PRACTICAL MECHANICS October, 1951 former or block, drill holes in the perforatedbelowthesurfaceof zinc large enough to take a small screwdriverthe block and are tight. blade and opposite the lower slotted screwsSlacken off the 6 B.A. of the block. There will be one on each face.screw fixing the terminal blockandinsertthe Making the Ends guard (Fig. 5c) between Stand the assembly on its end, place thethe block and its hous- 5in. x. tzin. piece of zinc left over on top, andingbelowthefixing cut out toshape, leavinga ?,in.borderscrewwiththeopen along each end. Fold each border down overendnexttotheleg. the outside of the frame at 90 deg.RepeatTighten up the 6 B.A. for the other end (see Figs. 5a and 5b). Tofixing screw, and also fix each end to the frame adjust the end untilthe4B.A.screwtoa one of theperforationscoincides with aclamp the cable firmly perforation in the body and insert in each sidebetween the uprights of a 3/16in. 8 B.A. cheek -head screw previouslytheleg. Connect the tapered at its end. Round off the corners bygreen leadof the ca- tapping lightly with a hammer. ble to thisscrew by a The protective guard is cut out as indicatedfurthernutandtwo Cut slots to coincide in Fig. 5c. washers. with 684 fixingscrew Connecting to Mains Earth Connection eyV c Use 5 -amp. 3 -core rubber -covered cable. Undernocircum- Fig. 5.-End covers and detail of guard for connecting block. Pass the cable through the loop in the legstances must the heater (see Fig. 2). Connect the red lead to the insertbe used without an earth connection (greena dangerous electric shock will be felt by connected to terminal B and the blue leadlead) from the frame to the earth of theanyone handling the heater frame when con- to the other insert (Fig. 4). Make certain thatmains power supply.If one does not existnected to the supply if an element should no bare lead shows outside the connectingthe author strongly advises that an earth bebreak and fall, touching the frame.If a block, that the screws in the inserts are wellmade to the nearest water pipe.Failing this,stronger assembly is required the width of the former could be increased by Sin.at 12' 4 its lowest edge to the right of the connecting - 3' 3. 3" block position and this fixed between the 443" flanges of the body. By inserting the former between the other two corners of the body and re -wiring to the connecting block the heater could then be fixed. to a wall. LIST OF MATERIALS REQUIRED Description Dimensions No. off Perforatedzincsheet28 S.W.G 1 zin. x I8in. I Aluminium t8 or zo S.W.G. 6in. x tin. 4 White two-way connecting Approx. block (plastic) 2in. x Ain. x jin. I Nickel -chrome heating 750 watts As re - spirals r,000 watts quired 3 '16in. hard asbestos sheet tzin. x gin. I Bare copper wire 16 or 18 S.W.G. tzin. I Assorted B.A. screws, nuts,8B.A. x 3/16in. 8 Holes A,B and C No27 Drill Holes P and Q No -03 Drill.411 others ,k1 Drill The lines joining washers (all round head6B.A. x siisin. 4 the holes show the pathtorthe spirals used in making the 375, 430 and 500 Watt Heaters or cheese head) 6B.A. x iin. i 4B.A. x }in. 5 Fig. 4.-Marking out details forthe asbestos former. 4B.A.x lin. 4

Europe's Largest Steel Mill THE most impressive contribution to the reconstruction of British industry has taken place in South Wales, where the Steel Company of Wales has undertaken a vast £6o,000,000 reconstruction project which will completely modernise the sheet steel and tinplate industries in the south of the Princi- pality. The steel side of the project has been carried out at Margam, near Port Talbot, but equally important work has been carried out at Trostre, near Llanelly. The Margam project has consisted of enlarging and modern- ising theexisting Margam Steelworks by reconstructing the coke ovens, blast furnaces, and coal and ore handling plant. The blast furnaces are the most up-to-date in the country. The old blast furnaces were reconstructed to produce enough pig -iron to feed the old works at Margam and Port Talbot, as well as the new Abbey Works which are adjacent.These works were recently in- augurated by Mr. Hugh Gairskell, Chancellor of the Exchequer. The Margam Steelworks arc now the largest in Europe. Our illustration shows the slabbing mill, where the steel ingots are roiled into slabs. October, 19 51 NEWNES PRACTICAL MECHANICS 15 Submarine Escape Apparatus Two Suggested Devices for Solving the Problem of Preventing Loss of Lifein Foundered Submarines ByJ. WORDSWORTH 1 Air Cylinder ALTHOUGH I have it on the authority" Breathing Buoy " of ProfessorJ.B. S. Haldane, and There are two ways by which the problem the professor is one most qualified, tocan be eased:(1) by the storing in the sub- knoW, that gradual suffocation resulting frommarine of oxygen in cylinders to replenish the exhaustion of oxygen in air is painless,that lost by breathing, and a mixture of soda I am appalled that more has not been doneand lime to take excess carbon dioxide.This to prevent loss of life in submarine disasters.is a temporary measure:(2) by the use of When a submarine founders, the " Davis "a " breathing buoy," typified in Figs. I and2. apparatus isthe one chance of escape forThe apparatus consists of an air cylinder, the men inside, and when they come up at sealedagainstleakage,and a lengthof as in Spring Spring night-time, theydid theTruculent,rubber tubing.The whole fits snugly into Chamber with 90 /b. theirchancesofbeingpicked upbefore a pit beneath the deck and is protected from compression succumbingto exposureinthe water areabove by a grating in two halves.There only fair. may be two, three or more buoys to a sub- The alternative is to wait inside the sub-marine, so that the men will have access to marine until daylight, by which time the airone or more, whichever compartments may Pit may have deteriorated to such an extent thathave been flooded. the use of oxygen in an escape apparatus, When thesubmarine sinks,therelease after breathing air deficient in oxygen and withahigh carbon -dioxidecontent,will cause vomiting, with consequent loss of life Air Cylinder (Hermetically Sealed) by drowning. Cylinder has an upsurge of approx. 200 lbs. Water seals Taper seating

Caps are forced out by air pressure on surfacing. Surface ships may, if necessary, couple an air pump to one of these tubes

Pins prevent buoy turning with Spring Chamber

Twin wire stays to ensure air line Twin rubber Enlarged view showing Caps in tops of has "slack 'at top pip,ng(3/6 bores) Breathing Tubes at top of buoy to withstand an external pressure Enlarged detail at top Section A-.4' of 80 lbs per 0' of Spring Chamber / Buoy in at JO fathoms. 'release position) Aluminium orating - approx. we;ght is 40 los (In halves) Fig. 3.-Details of buoy ejection mechanism. Deck mechanism (Fig. 3) is operated and the buoy, shot out ofitspit,risestothesurface, throwing off thegrating inits component halves as it does so.Caps fitted to the ends of the breathing tubes in the top of the buoy are ejected by connecting bottles of compressed airto the lower ends of the tubes inthe submarine.Pumps are thenfitted and stale air is forced out of the submarine and fresh air pumped in. Surfaceships, when they arrive, may, if necessary, couple Twin wire stays to an air -line to one of the tubes. ensure air line has Ofcourse,circumstancesmightprove "Slack"at bottom much more difficultthan this.The submarine may be submerged at such a depth thatthe buoy stopsrising some distance belowthesurface. When thecapsare blown, water, instead of air, will enter the submarine, but should more enter than would normally fillthe pipes,it may be shut off altogether by closing the stop cocks.In this event, it would be imperative to have oxygen cylindersandsoda -limetouseas an alternative. Stoo Cocks This " buoy " should at least keep trapped When buoy surfaces, open cocks, drain any water men alive until help arrives. in pipes and couple to compressed air bottles until There is one important qualification.For Levers Interior the air pressure in the pipes expels the caps at the buoy to operate successfully, the com- operating of the top. When this has been done use pump for partments in which the men are trapped must buoy reease Submarine forcing stale air out and drawing fresh air in. be watertight.As the bulkheads are tested Fig. i.-The breathing buoy in positioninaFig.2.-Showing thebreathing buoyafterto7olbs. per sq.in.,Ipresume thiswill pit in the submarine. surfacing. be so. 16 NEWNES PRACTICALMECHANICS October, 1951

Escape Lift submarine willmost Buoy at surface probablybetiltedin Another idea of mine, an escape lift (see Short chains with rings can be attached -- Fig. 4), is based on the McCann rescue bell,twoplanesatleast.to buoy for men to cling to until rescued which was used successfullyby theHence the convex land- Americans to rescue men from their sub-ing surface. The lift, marine S gual us . its undersideshaped The McCannbellislowered froma like an inverted saucer, surface ship to a facing on the submarine,drops on to the landing and is guided to its objective by an operatorsurface and itsweight tiltsit.There should Guide inside. The rescue chamber shown inthe wires illustrationis guided by wires held taut bybe just sufficient "slack" Sea water, let into a buoy of substantial lifting power. inthe guide wiresto outer chamber allow it to settle into its after surfacing, The buoy, which fits around the lift,is original position. takes lift down Door opens released first.It rises to the surface paying again slowly outwards out guide wires which pass through the lift Chamber " A," now fullofwaterunder to two revolving drums inside the submarine. Escape lift The drums are locked when the buoy sur-pressure, is drained by Inner capable of faces (ie., when the drums stop turning) toa valve.The pressure chamber lifting two ensure there being no excess " slack " in thedrops andthewater men per trip wires. pressure outside the lift Sea escape forces it immovably Plan of buoy valve Two men now enter the inner chamber ofdown on to its seating le tilt the lift, and the two watertight doors, one Chamber it" / not again. The submarine Sheet metal top of buoy covers (maximum) in the lift, one in the submarine, are closeddoor is opened and thepit, jettisonedpriorto escape. Door opens and latched. Compressed air is then admitted water in theouter inwards Seating face to chamber " A " (the space between the twochamberofthe lift (Lift has. a doors)untilthepressurerisesabovethedrained. The lift is now ...., rubber skirt) external water pressure, when the lift, risingreadyforitssecond ,.. 1 from its seating, ascends to the surface.Theascent. door at the top is opened, the men climb out The success of such a ....., and drop into the sea. The surface buoylift is, of course, a mat- has a number of trailing rings to which theyter of conjecture.The can cling until rescued. effect of surface conditions may be such as to These drums Flooding the Outer Chamber Water escape-- Compressed air must be locked , render it impracticable, connection connection when buoy surfaces, To return to the lift.The closing of thebutIfeelit may be to ensure there is no top door operates a valve which quickly floodsworth while making excess "slackin guide wires, the outer chamber.The valve closes auto- some experiments alongFig. 4.-Details of a submarine escapelift.Right-hand diagram matically after a fixed period while the liftthe linesIhave indi- shows the liftin operation. is still comparatively near the surface.Thecated. outer chamber is of such a size that the lift One advantage this lift enjoys over otherpressure. The pressure is " atmospheric " descends slowly when it is flooded. methods of escape (including the " Davis "all the time ;consequently they do not get The liftisguided toitsfacing by theapparatus)is that at no stage are the men" bends," nor do they have to go into a com- wires, but now comes a complication. The rescuedsubjectedtoarapid decrease inpression chamber when they surface.

except for repetition work, whilst clamps tend to take so much heat and prolong the operation. Silver Solders The right flux, except for Easyflow solder, isborax. Although the oldsilversmiths Notes on the Composition of the Alloys and the Technique still prefer to grind a wetted lump on to a piece of slate,Iusually buy the powder of Silver Soldering By H. C. PIGGIN form and mix up small quantities of paste as required.For Easyflow solder, the special THE useofsilver -alloysolders,oncespecificindustrialpurposes,coveringafluoride -borax preparation sold as Easyflow confined to work in precious metals,temperature range of from 6to degrees Centi-flux is, without doubt, the best.Ordinary is now so universalin engineeringgrade to 83o degrees Centigrade. borax does not become active at a sufficiently practice as to warrant the attention of the Obviously in amateur work itis unlikelylow temperature. amateurcraftsman. Silversoldershavethat such properties as electrical conductivity, The action of the flux is, as with lead solders, many advantages over the usual zinc -coppertensilestrength,etc.,will have to be soto clean the work initially, and to prevent spelters which by far outweigh the slightclosely regarded, and a range of (at the most)further oxidation of both work and solder extra cost. four different alloys is all that will ever beunder heat. They are obtainable over a wide range ofrequired.Of the four shown in the table, I The flux is best applied as a smooth paste melting -pointswhichenables,bycarefulhave found Easyflow to satisfactorily coverand brushed well into and over the joint. control of temperature during use, the fabrica-all light -engineering jobs, and I have had toOne end of the solder strip itself should also tion of two- or even three -heat joins of quiteresort to a harder solder only on one or twobe coated. complicated structure. In the joining ofsilvenvarejobs where" whiteness " is copper and brasspartsordinaryspeltersrequired. Source of Heat would cause loss of efficiency by annealing the Silver solders may be obtained in several To fulfil rule No. 3, any clean flame of work at the very high temperatures requiredforms-sheet, wire, strip, powder, etc.Prob-sufficient temperature willsuffice. Small to " run " them.Silver solders " run " atably wire about20s.w.g., or }in. -wide strip,work may be heated by an ordinary Bunsen, only a few degrees above their comparativelyis most economical. or a mouth blowpipe, on a charcoal block, low melting -points, and become very fluid, The practice of silversoldering followsbut larger work will need a blow -torch, and quicklypenetratingquitecloseclearancesclosely that of ordinary brazing, but is, ofshould be well -packed with small pieces of with the minimum of void.Excess soldercourse, quicker. asbestos brick (cokeisa good substitute) and flux can be quickly and easily removed, to conserve the heat.The envelope of the so that, over-all, an important saving of timeSimple Rules flame at the point where it just becomes ragged and fuel can be effected. The following simple rules that apply to-well in front of the air-cone-gives the best Again, in joining dissimilar metals such asallhot -joiningofmetals,whetherwithheat. copper to steel, internal stresses are set upsoft or hard solders, should be borne in At the commencement of the operation, owing to expansion differences between themind :- the flame should be large and soft, and should two metals, but the extreme ductility of silver i.-A clean, well -fitting joint. be applied all over the work, being kept slowly solders makes them freely available for the 2.-The right flux. moving soastoprevent excessivelocal most complicated work of this nature. 3.-The right heat in the right place. heating. Larger components of the join With regard to the joint,itis generallyshould be given more heat than smaller ones, Temperature Ranges advisable to wire together any loose parts,and in the case of dissimilar metals, the more There are on the market over a dozenusing a soft iron -wire for preference. Solder-rapid conductor (e.g., copper in the case of a differentsilversolders,eachalloyedforing jigs are ideal but not always practicable (Continued on page 21) October, 1951 NEWNES PRACTICAL MECHANICS 17 B.R. New Tank Locomotive A BriefDescriptionofthe Chief Constructional Features OFthe six standard types of locomotives to be built this year two will be tank engines, the larger having the 2-6-4 wheel arrangement and powerclassifica- tion 4, and the smaller one the 2-6-4 wheel arrangement and power classification 3. The erection of the first Class 4 2-6-4 T locomotive has now been completedatthe Southern Region's Brighton works andis numbered 80cao. A total of 54 of these locomotives is included in the 1951 locomotive building programme, 44 of which are to be built by the Southern.Region at Brighton and to by the The new B.R. standard 2-6-4 mixed traffic tank locomotive No. Boom. London Midland Region at Derby.The manufacture of the details of the locomotives beingbuiltbytheSouthern Regionis 5ft. 3M, at the firebox end.The smokeboxwith manganese steellinerson the wear- divided between the works of that Region,tubeplateisofthe drumheadtype,gin.ing faces. - viz., Eastleigh, Ashford and Brighton. thick.There are 21 large flue tubes 5)§in. The boileriscarriedinthe frames by They have been designed and built underdia. outside, No. 7 S.W.G. thick and 157rigid attachment between the smokebox and the direction of Mr. R. A. Riddles, C.B.E.,small tubes Igin. dia. outside and 12 S.W.G.the saddle, and bya downward extension MemberforMechanicalandElectricalthick. The length between tubeplates isat each back corner of the firebox foundation Engineering, Railway Executive. The parent 12f t.3in. ring resting on shoes supported by a frame office for the design of this class is Brighton, The Belpaire firebox has outside dimen-cross stretcher, to permit longitudinal expan- whilst certain sections have been designed atsions at the bottom of 8ft. 6in. in length and sion. Swindon, Derby and Doncaster.The work4ft. olin. in width.The grate area is 26.7 The engineisfittedwith plain bearing of designing the new locomotive has beensq. ft.The inner firebox is of copper, theaxleboxes to all wheels. The coupled wheel carried out in the Brighton drawing officewrapper plate being 9/16in. thick and the axleboxesaresteelcastings, with pressed - concurrently with the design of the Classtubeplate tin. thick. The outer steel wrapperinwhite -metalledhorseshoebrasses,and 4 4-6-0 locomotive.These two types are ofplate is 9/16in. thick. sliding underkeeps of ample oil capacity with similar size and operating capabilities from The regulator is located in the dome andpad lubricationsuppliedbyoilfroma the point of view of power output, the tankis of the vertical grid type with an operatingmechanical lubricator.Guide wearing faces enginebeingintendedforshort -distanceshaft placedtransversely across theboilerareprovidedwith manganesesteelliners working, such as suburban and cross-coun-and mounted in a stuffing box on the secondweldedtotheaxleboxand lubricatedby try passenger trains, and the shorter distancebarrel ring.An external rod is employedgrease. freight workings, and will have almost uni-for the connection to the regulator handle in The coupled wheelspringsareofthe -:mal availability over main and secondarythe cab. laminatedtypewithcarbonsteelplates. lines throughout Great Britain. Underhung spring brackets with solid ten- Many of the details of the two Class 4Smokebox sion links tottered at top and bottom ends types are interchangeable, whilst various fea- The cylindrical smokebox is sup-andrubber damping padsareprovided, tures of the design, including nearly all theported by a fabricated saddle, and has theweight adjustment being made byfitting fittings, are common with those of the otherself-cleaning arrangement which consists ofcotters of suitable depths. British Railways' standard types. plates and awire mesh grid arranged to Boiler Design prevent accumulation of ash and the emis-Cylinders and Valve Gear The boileris of the same general designsion of large particles of unburnt fuel. The The twocylinders,18in.diameter by asthe L.M. Region Class 4 2-6-4tank,blast pipe has a plain circular cap 41in. dia.28in.stroke,are ofcastiron and placed except that the staying has been redesignedwhich also contains the four Cardew-typeoutsidetheframes. Piston valves,loin. to accommodate the higher boiler pressure,blower nozzles. diameter, are provided, operated by which has been increased from 200 to 2251b. Walschaerts' valve gear, giving a maximum per sq. in.The shell is of ordinary qualityFrames and Axleboxes travelin75percent.fullforward gear steel plate and the barrel is made of two The enginehasIgin.-thicksteelplateof 6 37/64in. withasteam lap ofrlin. rings, the second of which is tapered.The fran-iesbraced by horizontalandverticaland a lead of *in. The box -type piston head front barrel ring is rolled from 9/16in.-thickstretchers, the majority of which are fabri-has two rings 'with a bronze spring -loaded plate and the second ring of lin., the out-cated. The axlebox guides are steel castingsslipper on the underside to minimise the pis- side diameter being 4ft. 9in. at the front andriveted to the frame plates and are providedton head and cylinder barrel wear. The cross- 225 Les /so IN

4.-4ft 6- 3' 15'14" 36.10" TOTALWHEELBASE 44- 9COVER BUFFERS. Side and front elevations of the new locomotive, giving some of the leading dimensions. 18 NEWNES PRACTICAL MECHANICS October, 1951 head is guided by the two -bar type of slide -Bogie Cab bars with upper and lower bars. The bogie employs laminated springs for The cab, although dimensioned to suit the Lubrication of the cylinders and pistoncompensating beams and side bolsters.Side - smaller of the B.R. loading gauges, follows valvesisby atomised oilsupplied from aplay control is effected by means of doublethe approved layoutforallthestandard mechanicallubricator.The valvegearis helical springs. The wheels are 3ft. diameter.locomotives.Allthedrivingcontrolsare mainly lubricated by grease and plain bear- For the pony truck helical bearing springsgrouped for easy access and operationin ing joints areused, except for the returnare employed, with two nestsofsprings,the left-hand driving position, the vacuum crank rod big end, which is equipped with aeach nestconsisting of twosprings,one brake,blowerandsandingvalvesbeing self -aligning ball bearing.Screw reversinginternal to the other, arranged on either sidemounted on a pedestal, which also serves as gear of the conventional type is fitted, but forof each axlebox.The load is transmitted toa firehole screen, to the right of the driver. convenience of operation the cab handwheelthe axlebox by means of a yoke and shoe.Seats are provided for both driver and fire- is arranged with a bevel gear drive at 45 Side -playcontrol is effectedbydouble man. degrees to the axis of the reversing screw.helical springs, and helical springs are also Steam -operated cylinder cocks are provided.employed for the side movement retarding Two live -steaminjectorsarefitted on gear fitted fore and aft of the truck centrethe right side of the engine, under the cab, Wheels on the axlecentreline. The wheelsare withsteamandwatercontrolsgrouped The coupled wheels are 5ft. 8in. diameter,3ft. in diameter. within easy reach of the fireman. and the tyres have the lip fastening adopted forallB.R. Standard locomotives. A lipBrake Gear on either side of the tyre ensures its security Steam brakes are provided and may beTanks and Bunker to the wheel centre,thelip on the inneroperated by means of a separate steam brake side being sufficiently shallow to allow thevalve or inconjunction with the vacuum The tanks and bunker are of welded con- tyre when expanded to pass over the wheelbrake. The coupled wheels only are braked,struction throughout. Each tank has curved rim. 40 per cent, of the reciprocating massesby means of a single block on each wheel. sides and a pressed U-shaped bottom, form- are balanced, the weights in the wheels being ing a structure of considerable rigidity, and Water Pick-up is supported at the forward end on the out- built up with steel plates to form pockets side for the insertion of lead. Thisisprovided for both forward and slidebar bracket and atthe rear end Steam sanding is provided to the leadingbackward running on engines operating inon a frame bracket. and driving coupled wheels for the forwardthe London Midland Region only, but pro- The tanks have a water capacity of 2,000 direction and to the driving wheels also forvisionis made for the fitting of the geargallons and the bunker a coal capacity of reverse running. on all engines if required. 34 tons. A Simple Hygrometer

An Inexpensive Appliance for Home Use ByJ. E. C. STRINGER

MANY common materials are hygro-upon releasing the finger pressure, paraffinmore paraffin.This operationisrepeated scopic, i.e., they take up water fromis drawn up intothe capsule.The tubeuntil all airis expelled and the capsule is the atmosphere.For example, silkand capsule are now held upright and thecompletely filled, the paraffinlevel coming and wool fibres take up alittlemoisture,capsule squeezed again to expel more air,about halfway up the glass tube. cotton fibres rather more ;paper commonlyfollowed by inverting and again drawing in holds about 8 to 13 per cent. of its weight Mounting in water.These materials tend to expand Fig. 2 shows a suitable baseboard.Two in length as the moisture content increases wood " necks " are fitted and the glass tube and shrink asitis lessened.Human hair, held in place with leather straps and No.4 freedfromgrease,hasbeenusedfor wood -screws ;the capsule hangs free.To the construction of hygrometers. Seaside guard the capsule from damage, a piece of holidaymakersinVictorian days were in perforated zinc should be fitted as shown. the habit of taking home seaweed to be A small pledget of cotton wool should be used as a sort of " weather glass," because inserted in the open end of the glass tube seaweed,dryandhardinfineweather, Glass Tube to prevent entry of atmospheric dirt and to becomes soft and supple tothe feel when l4 `x is Bore stop evaporation of the paraffin. wet weather is expected.Another material Calibration that is hygroscopic is glue, and the following notes refer to a hygrometer making use of A paper scale may be attachedtothe baseboard with drawing -pins. this fact. Wood Baseboard The most convenient and accurate method Details of Construction Approx. /6"x 2. ofcalibrationistohang theinstrument The plastic capsules in which lighter -fuel alongside a wet -and -dry bulb hygrometer in issoldare made ofaglue -likematerial a gardening friend's greenhouse ;reference which varies in hardness from quite soft in tothetablessupplied for usewith such dampweather to nearlyrock -hardin instruments will give the percentage relative extremelydryweather.Thechangein humidity from day to day and these values hardnessis accompanied by a considerable may be pencilled on the scale.Calibration dimensional change, the material shrinking marks should be made for dry, normal and when dry.Consequently, a capsule of this humid conditions. materialwill have alarger volume when A new scale may then be made from damp than when dry, the change in volume white ivorine or similarmaterial, utilising being considerable. the originalscale markings. This greatly An empty capsule is fitted to a glass tube Lighter enhancesthe appearance ofthe complete about t4in. long by r/t6in. bore.This is Fuel hygrometer. conveniently managed by leaving the capsule Capsule If the constructor wishes, the paraffin may overnight in a damp place, such as a cellar, be tinted with an oil -soluble dye.Manufac- which makes the material quite pliable ;the turing chemists can usually supply a small end oftheglasstubeisthen warmed quantity at a reasonable charge. and inserted into the neck of the capsule, the warmth melting the glue slightly so asto FOURTH EDITION. cement the capsule to the tube.The joint is then allowed to cool and harden. (See 2 Wood "Necks' REFRESHER COURSE Fig. r.) 2 Leather Straps IN Filling the Hygrometer Perforated Zinc When the joint has become firm, the open MATHEMATICS end of the tube is placed under the surfaceFig.L-Detail of Fig. 2.-Front view By F. J. CAMM of some paraffin oilin a tin lid and thethe glasstube and and plan of the corn - 8/6, by post 9/- capsule squeezedtodriveout some air ; capsule. pleted hygrometer. October, 19 51 NEWNES PRACTICAL MECHANICS 19 Light PunchinMachine Constructional Detailsof a Handy Tool for the Workbench from short ends of cast steel or other suitable THE machine described here isa great ByR. G. ILSTON advantage in the home workshop or material and, providing that a sectional area garagewherelightmetalworkis on to the punch holder shaft, the two partsequal to that of 5/ t6in. diameter is not ex- carried out.As will be seen by reference tothen being inserted into the body ;the springceeded, punches and dies of shapes other Figs.t and 2, its construction is simple yetseating in the I tin. bore.The back bearingthan circularwill give satisfactory results, strong and itis capable of punching holesis fixed to the top by two 7/16in. B.S.F. set -while small bending sets for light sections up to 5'16in. diameter in 18 gauge M.S.bolts tin. long, and the handle and distancecan also be made and used satisfactorily on Machining limits are 1 .005in. and the finishpieces are fitted and held in position by athis machine. should be as smooth as is possible. Handle HT Distance Pieces Pivot Back Construction Bolt Beef -mg A body of B.M.S.isfirst machined to Screw size, i.e., 4in. x 3in. x tin. and a throat Qin. Long wide by 'kin. deep is milled in it, after which the bores for the punch holder and the die Fixing are turned (Fig. 3). Bolt Following the above operations the fixing Punch bolt holes for the back bearing are drilled Holder fry and tapped 7/16in. B.S.F. in the top, and Return the in.Whit.socketscrewhole is Spring drilled and tapped in the centre of the front, Tension jin. down from the bottom jaw face. Spring Two feet are made from tin. x tin. x kin. Front Bolv 4,; es.W. Bearing M.S. angle, with two holes in each for bench Screw fixing,afterwhich thefrontbearingof -rei Long 2in. xin. M.S. plate and the back bearing of !kin. x I lin. x kin. angle, tin. long, are Punch Holder cut and drilled. Socket Punch Screws Handle and Punch Holder Die A handleiscut fromt2in.length of sin. x kin. M.S. flat (Fig. 3), and the pivot Feet hole and the kin. Whit. hole for the spring fixing screw are drilled and tapped, following which two distance pieces are turned from tin.diameter B.M.S., A, 9 '16in. long, and B, 13/I6in. long, both having a bore of 7/I6in. rrnnt Elevation Side Elevation diameter. Figs.! and 2.-Front and side elevations of the completed punching machine. The punch holder (Fig. 4) is turned from diameter B.M.S. and the tin. Whit.high tensile 7/16in. B.S.F. bolt and nut 2fin. socket screw hole is drilled and tapped. long. Dia. One end of a tension spring kin. long x Assembling 5/I6in. outside diameter of 16 gauge wire is fitted to the handle by a fin. Whit. round 114 Inassemblingthemachinethefronthead screw, tin. long. the other end being bearing and the feet are welded in positionfixed to the body in the required position by /Pao and any surplus weld is cleaned off. another kin. Whit. screw. Next a compression spring ;in. free length Punch 14- xyin.inside diameterconsistingoffive Punches and Dies Holder ,04 turns of 16 gauge wire is obtained and slid The punches and dies (Fig. 5) are made Punch

A!' I kst -p.7rt/-1 r za Rad /2Red 7/6Die. 16 Dia. Die Bore L I Fig. 4.-Punch-holder and die. -4-2 I-.

Bore , WORKSHOP CALCULATIONS TABLES AND FORMULA Plan of Body 2" H Lb I Ninth Edition Front Bearing off by F. J. CAMM Bore Back Bearing Section Through Body Toff A handbook dealing with methods- of calculation, solution to workshop problems, and the 12 3' rules and formula necessary in various workshop processes.It contains all the information Rao. a mechanic normally requires. <4?.,1--) of From allbooksellers,6/-net, by post 6/6 from the publisher, Handle1 off GEORGE NEWNES, LTD. (Book Dept.), Feet 2 off Tower Rouse, Southampton Street, W.C.a Fig. 3.-Details of the body, bearings and handle. 20 NEWNES PRACTICAL MECHANICS October, 1951 Hardening Plaster Castings Notes on the Various Methods Used

THIS is not an article on how to cast in By C.V. THOMPSON direct with the plaster during the casting,. plaster.There are plenty of books there is the possibility that it will crack in on the subject that can be obtained in the drying. any public library, but a few remarks con-when a black speck only the size of a dot on A very good thing to harden plaster with cerning plasterin general isnecessary in aface a quarter of an inch from ear tois a clear cellulose, but it must be a really, order to point out its advantages and dis-nose shows up badly, and has to be dug outclear one such as Ercalene (Canning and advantages. and filled in, which is not an easy task. Co.).Here again several immersions, up to There aremany kindsofplaster(or When one tries to give the plaster strengthfour, are necessary.Although much dearer gypsum, as itis correctly called), and theyby adding something during casting, it mustthan glueitiswaterproof and very hard all have differences. Colour, density andnot be forgotten that anything added is proneand tough at all times. setting time are the main differences, butto make it shrink, and anything that shrinks they are all alike in one respect.They aremust lose detail and distort.The additionShellac Varnish soft and extremely porous.I shall confineof alum increases speed tremendously as to A good white shellac varnish is splendid. myself to those suitableforcastingbe almost unmanageable. Less immersions are necessary, and on com- ornaments, figures, etc. The reason plaster of Paris gives such apletion the objectis harder than the other There is no really hard plaster.Some are good impression is because it dries out ontwo, but more brittle. certainly harder than others, but they aresetting and becomes a mass of tiny holes Immersions in anything of an oily nature all very chalkish.There has been a rock- hardens only slightly and makes the object like plaster in ancient Egyptian days (it can semi -transparent.Immersions in skim milk still be seen on the walls of the tombs), but will harden a fair amount and give a marb- IthinkI can say without fear of contra- lish appearance. This can be mixed direct, but diction that how it was made, or of what great care must be taken to make sure that materials, is not known to -day.True there there is no trace of butterfat in the milk. are certain kinds of Nile mud thatwill Iwas talking recently to an official on harden very much indeed, but whether it the technicalside of a firm that makes a would harden in the English atmosphere as casting plastic.I showed him a small pen- it does in the dry hot air of Egypt is very dant of an Indian's head and shoulders in doubtful. plaster of Paris.Itis only an inch and a I have tried for many years to get a plaster quarterlong,butallthefrondsofthe that would set hard, but in spite of many feathers show quite clearly.He said that hundreds of mixes, I have dismally failed. he didn't think such detail possible in plaster There have been several liquid marbles ofParis. (Ithadbeenhardenedwith (Marblex, Marblene and Marbleite, to men- Ercalene.) Then Ishowed him aplastic tion three of them).They were going to casting from the same mould and he could revolutionise the plaster casting trade, but see how the detail had blurred in the shrink- to -day they are out of existence.Why ?I ing when compared with the other. have tried most of them, and they just did In immersion always remember that itis not come up to expectations. Removing a cast front a one-piece mould. better to immerse many times in a thin liquid Any mixes of plaster and cement are sus- The cast is plaster, the mould is" Vinamold" rather than try to cut out immersions by pect.If one tries to mix a plaster, with a HMC.774. making the liquid thicker.If you do you setting time of ten minutes, with a cement (By courtesy of Vinyl Products, Ltd.) will probably find cracks come where the with asetting time of fiveto 20 days, liquid has settled thicker in some places than theoretically one should get something harderwhere the water was, but occupies the same others. than plaster and softer than cement.But space.The only satisfactory way to harden it doesn't work out like that.To slow ait, therefore, is to fill those holes with someUsing Catalin plaster and quicken cement simply spoilsthing tough and hard.Little difference is If shrinkages don't matter, Catalin- has a both.They must harden in their own timemade by packing plaster (that is, putting invery good urea resin that mixes freely with and, anyway, cement mixed so that it flowsas much plaster as the water will take). The water. Itisnot dear if bought in fairly is not hard atall. fact is that the material itself is soft.Withlarge quantities (281b. upwards) and with it The hardest plaster I know is Stonecastcement this is different, and the more thatone can obtain whatever degree of hardness This is very strong, asit (Dohm Co.). can be packed in the harder it will be.Any is required, even sufficient to blunt filesin contains metallic dust. It has a reddishof the quick -setting cements now obtainabletrimming. colour and is rather heavy, but itis verywill mix with a slow plaster, such as Belpite This is mixed during casting, but beware fine,andwillgivea wonderfully sharpNo. 3 (Gypsum Mines Co.), and give it aof bubbles. impression, especially when used in Castogel it They come in the mix very reasonably hardsurface, but is not soeasily and unless careistaken moulds (Dohm Co.).Their white castis hard inside. the object perhaps a trifle harder than the usual plaster is spoilt by pin holes. Of course,itis not worth the trouble or of Paris, but not much. Hardening Solution expense to harden rough things like the dogs The next hardest I would say is Stone - First on the list of hardening materials is hard(Dental Manufacturing Co.).This is soldatamarket for 2/6 apair. Such glue or gelatine, which are both the same,things are best broken up anyway.But if nothing like so hard as Stonecast, but it isexcept oneispurer than the other.Pre- much harder than plaster of Paris. one does try to cast something worth while, Both aresuming the object to be hardened is ready,then hardening it should be worth while too. about/- a lb.There is not much to chooseimmerse it in a warm solution of glue water between the other kinds of plaster. It is very annoying to do a really nice job (i ounce to the pint) till all bubbling ceases.and then to knock off a nose or a finger in Take it out and letit dry in warmish airhandling it. Plaster of Paris (75 deg.F.).When dry repeat, and keep That isthe position in plaster, with aonrepeatingtillnobubblesappear onMiniature Casting natural casting hardness.A very popularimmersion. This maytakeuptosix Miniature casting, such as I do nowadays, idea isthat plaster of Paris, mixed with aimmersions.Remember on every immersionhas a fascination all its own, but hardening saturatedsolutionofalum,bakedandwater goes in with the glue and when itsuch thingsisvery necessary.They are ground, then mixed with water,sets rockevaporates it leaves holes.These holes getmuch too frail otherwise.If colour doesn't hard.It just doesn't. smaller and less every time.When finallymatter, adding Stonecast to a proportion of The main reason why plaster of Paris (ordone the cast may not be unbreakable, but25 to 5o per cent, of the mix is a great help any other superfine plaster such as made byit will be very hard and strong indeed. and comes cheaper. Gypsum Mines Co.) has held its own for The snag inthisisliabilityto damp. Finally,don'tbedeceivedbysurface hundreds of years, is that it is still the best.Immersion in formalin cures this, but I havehardness, itis possible to get a very hard For work with fine detail it cannot be beaten.found this not to be permanent.Of coursesurface shell with cement, plaster and glue It can be controlledeasily and ischeap.it can be painted, but that fills in the creviceswater, but underneath it is very soft even to Its only faults are liability to breakage andand ratherspoilsthedetail. Varnishisthe consistency of ordinary dry mud.And thelittleblackspecks. Theseare notbetter, but usually has adarkening effect.any of the water celluloses are very tricky. noticed much except inminiature workIn case anyone thinks of mixing the glueBaking will harden, but makes brittle. October, 1951 NEWNESS PRACTICAL MECHANICS 21 Fitments for Pipe Smokers Two Simple Devices for Providing Added Pleasure for the Regular Smoker

S areader,sittingin an easy chair, By " HANDYMAN " ting, asat B.-Itisnot essential that the after my day's work is done, and as holesshouldbedrilled ; theycanbe a draughtsman, bending over a draw- punched from the inside with a round steel ing board,Ihave found thatin many aone knows that the products of combustionspike on the end grain of a piece of soft- pair of trousers or a waistcoat I have burnedare water and carbon. If the pipe bowlwood, the burr on the outside being then littleholes and from many a drawingI is deep and is filled with tobacco that por-filed away. have had to quickly brush red-hot particlestion of the tobacco at the bottom will become One of these caps is placed in the bottom saturated as the result of the combustion atof the pipe bowl with the flange upwards the top.To some extent the accumulationas in the sectional view of the pipe at C. By of moisture depends upon the water contentthe use of these caps-I keep one in each inthetobaccoitselfandthiscannot beof my pipes-every bit of tobacco put into avoided any more thancantheproduct it of combustion. the bowl can be smoked and none of To get over the trouble I tried many thingsbecomes moist. fittedintothe bottom ofthe pipe bowl ;Cleaning littlefireclay buttons, blotting paper rolled The caps need to be taken out from time b into flattened balls and cinders out of the totime,accordingtothefrequencyof firegrate.Of these thelast was thebest,smoking, threaded on the end ofapiece and the blotting paper useless.Iused theof wire and held ina tiny blue flame of cinders for some time but they quickly becamea gas ring to burn off the accumulated car- clogged and were alot of trouble to findbon. At the same time the nicotine tar can of the correct size or to cut and shape tobe cleaned out of the bottom of the bowl Fig. I.-Details of the pipe shield. fit the bowl, and then I thought that an airand the stem with cotton wool.If the caps of tobacco.Even when such particlesare nothottheysoilthedrawing by being crushed under the tee -square or set -square.

Pipe Shield ThesethingsIputupwithuntilit occurred to me, some time ago, that they could be prevented by a most simple fitment to the pipe. From the thin vacuum seal tinplate of a tobaccotin,in some cases, and from the tin lids of pots of vacuum-packed jam-the kind on which youaretoldto" pierce with a pin to open "-I cut, with scissors, semi -circlesofsize and shapeasatA,Fig. 2.-A hinged pipe shield. Fig. 3.-Details of a perforated plug fora pipe bawl. in Fig.r.These were rolled with a cylindrical object, such as a pencil or fountain pen,tosuchacurvature,B,aswouldspace might get over the trouble and this Iare left in too long they will become locked enable them to spring into the bowl of thefound was the case. in place by the carbon lining the bowl above itthe pipe isfirst To provide this air space I used the tin - pipe, as at C. To use caps from small size tins of denture fixativethe cap ;this must be scraped away and filled with tobacco, the shield inserted and the cap can then be lifted for burning off, the match or lighter applied.Or, of course,powder (A,inFig.3)anddrilledseven if preferred the shield can be put in afterholes in them with a number 42 drill, reduc-with a wire hook shaped as D in Fig.3.I lighting up.I have found, when drawing,ing the, depth of the knurled flange by cut -keep such a hook for the purpose. thatitisbesttotilttheshield backa littletowardsthestern.In anycase,it effectually prevents any half -burned tobacco SILVER SOLDERS bubbling of the flux is finished.Allow one or ash from falling out of 'the pipe. (Continued from page 16) snippet about every lin. along the joint. Possibly a more convenient fitting could Comparative Table of Silver Solder Alloys be permanently attached toapipe of thecopper -iron joint)willrequire more heat. At first the flux will bubble as it is dried off, pattern which has theusual barrel -shaped Approximate Melting bowl ;this I havenot yet made but intendbut this will soon cease, and the flux will melt Solder point'. Remarks asto to fit it to one of my pipes.It is of thickerinto a glassy liquid under which the work compositiondeg. use tin, sheet brass or other metal, cut to some-will appear clean.Assuming wire or strip what the same shape but long enough tosolder is being used, the ready -fluxed end Easyflow ..Silver to, 63o Only Easyflow embrace half of the circumference of the out-should now be touched on the work.The Copper5, flux. side of the bowl. In it are soldered two smallflame should be shortened slightly and brought Zinc x pins which fit into little holes drilled in theto bear on the joint itself, being moved slowly Easy.. ..Silver a, 723 White for hall- sides of thepipe, near thetop.Such aalong the whole of the seam. The solder should Brass marked silver shield can be folded back towards the stem,melt easilyinto thejoint,being attracted articles. as at D, Fig. 2, for carrying in the pockettowards the hottest part, following the flame Medium ..Silver 3, 778 First in two - and for filling with tobacco, and then swungeven totheextentof running " uphill " Brass heat joint with over to the position E, when smoking.If'slightly. Any lumps should be smoothed Easyflow. the shieldisoftinit may be black lac-over using a fluxed iron -wire tickler, and, Hard Silver 4, too Used irk when the joint is filled-allowing for shrinkage Brass enamelled quered and if of brass can be oxidised brown. iewell cry on cooling-the flame should be removed. work :three - Perforated Plug heatfirst. Another little " gadget," which is of moreFlux Residue Spelter for Copper s. 890 a fitment to 4 recent date than the shield, is Flux residue may be removed bystiff comparison Zinc go into the bottom of the pipe bowl.Likebrushing in hot water, or if obstinate, in a most othersmokersIhadalwaysbeen bothered with wet tobacco-which has beenmild acid pickle. OUR COMPANION JOURNALS called " the dottle "-and which, in these days Occasionally, usually with beginners to the 1 of high tobacco prices,isa wasteful item.technique, the silver solder is applied to the Practical Wireless, 1/- Every Month The popularideathatthismoist,un-work not by strip but in the form of small Practical Television, 1/- Every Month smokable, plug is due to a " wet " smoker is,snippets about the size of a pin -head. These in most cases, fallacious. The moisture rarelyshould be fluxed and applied to the work Practical Engineering, 6d. Every Friday

comes from the mouth of the smoker. Every -by means of tweezers as soon as the initial -V J. I NM:Vs, AI .7. S.,,,SWAN.`eCo Z. CORNI.S. 1 I 22 NEWNES PRACTICAL MECHANICS October, 1951 A Passenger-haulinc Constructional Details of a 3in.-gauge Locomotiv(

to say nothing of the materials used for ain the firebox.With something of this sort solid foundation for the railway. the old Smithies' type water -tube boiler could I have no particular liking for the o -6-obe adopted, but it would be an expensive busi- type, but I do think that as a locomotive itness nowadays to run on methylated spirit, can be as handsome a machine as any expressand there are many objections to its use, not passenger type,ifitis artistically designed,least of which is the unpleasant smell. There- with some polished metal work and above all fore, althoughitinvolves much more time painted in an attractive colour picked outand labour in the making, the ordinary loco- and fine -lined as some of the railway com-motive type boiler burning solid fuelis by panies'goods engines usedtobe finishedfar the best and cheapest, besides which I before the grouping in 1923. From the accompanying drawings it will be seen thatI have, so far asispossible, simplified everything and have, except in a few cases, cut out castings, thus eliminating the need for making foundry patterns and core boxes.Instead of castings, many parts, notably the cylinders with their valve chests,

2 4, 5, are built up from tubing and sheet metal. Then againI have adopted whatisun- Fig. 2.-Front elevation of the locomotive. doubtedly the most simple and at the same time a most accurate valve gear, viz., Hack - worth's. This was invented by John, son IN designing this engine for the model -of the famous Timothy Hackworth, in the railway reader of PRACTICAL MECHANICS, year 1859. This gear has been used very I have kept certain outstanding featuresmuch more in marine engines than in locomo- in mind ;Iset out to design an engine oftives, because in a marine engine the crank- the most simple scale prototype, involving,shaft does not move in relation to the die - for its scale and size, the minimum amountblock guides, whereas ina locomotive the of labour and time in construction. Anaxle-which is the equivalent of the crank- engine which shall be capable of hauling-shaft-is constantly moving asthe engine again for its scale and size-the maximumrides upon its springs ;and so,a factor is passenger load.So I cut out all superfluous DELVER), TO L © FEED TO pure introduced which has the effect of varying CHEC, VALVE wheels and axles and other useless complica-the periods of opening and closing the steam tions-useless in so far as a working modeland exhaust ports by the slide valves. isconcerned-and adopted that " maid of Fig. 3.-Rear elevation, showing boiler fittings. all work " type:the o -6-o wheel arrange- In order to overcome this defect in the gear ment. This makes., possible small coupledin our model, I have arranged for the driving wheels which, of course, results in a maxi-axle to be in a fixed position, that is to say,know of no more interesting job in model mum tractive effort and draw -bar pull. the axle boxes will not rise and fall in thework than the flanging and riveting up of The scale of the model is three-quarters offrames, and there are no springs. This willsuch a boiler. an inch to one foot, so the gauge of track isnot matter, because the other two axles are the standard three -and -a -half inches; a widthsprung inthe usual way, and so any in-The External Design between rails upon which one can safely ride equalitiesin the track cannot cause derail- The general appearance of the engine when without overturning.Locomotives canbe, ment. finished may be seen from the three elevation and have been, made to half -inch scale and The boiler cannot, for an engine of this drawings. Fig.Iisaside view showing even for the tiin. gauge, capable of pullingsize, very well be simplified except by usingonly the outside work. This applies to the an adult person, but itisa somewhat pre-some form of liquid fuel such as vapourising fron:-end elevation of Fig.2also. From carious job balancing oneself on such a track,petrol or burning methylated spirit in wicksthese drawings dotted lines of internal part:,

rFl

6%. 4%1' 22 OVERFRAMES SCALE- 1 S, 2, INCHES Fig. i.-Side elevation of the o -6-o type, 3D.n.-gauge locomotive. October, 19 51 NEWNES PRACTICAL MECHANICS 23 Model Locomotive OvER and Tender ByE. W. TWINING

have been omitted in order to avoid confusionwhere the incoming water is broken up by and to give only what will be seen when look-perforated trays and so distributed over a ing at the model.The footplate endis large area.Apart from practical considera- shown in Fig. 3, but reference to this willtions thereis the fact that the valveboxes be made later when the boiler fittings arewould have to be specially designed and made given attention. because the ball valves must lift vertically On Figs. r and 2 scales are drawn ; thesefrom a horizontal seat.To provide a water- are appended to avoid the necessity of figur-way or port, from above the valve, down into ing dimensions on the elevation views. Somethe boiler, means a complicated bit of drilling

:GALE i INCHES + avER PLATES 2' Sx -VIININER CENTRES SW -- ,1" VALVE CENTRES 64' - - GAUGE Fig. 5.-Cross-section through cylinders, smokebox, boiler and driving axle.

the other boilerfittings,be bought from

Messrs. Bassett-Lowke Ltd. The only point worth mentioning in connection with these is that they will require internally screwed VSTRGRE collars, ,tapped out for the check valves to be screwed and soldered into the boiler barrel. The Internal Arrangement A longitudinal section of theengineis K!: given inFig. 4, whilst Fig. 5 shows on I----OVER FLANGES 29' the lefta half -section across through the Fig. 6.-Details of cylinder, valve chest and piston valve. smokebox and one cylinder and, on the right, a cross-section through the driving axle, the boiler barrel and flue tubes. of the measurements will have to be taken byand the whole thing would be so large, with From these drawings it will be seen that scale with dividers, since they are not shownthe covering case,asto be out of correctthe only parts which are made from castings on the general arrangement or sectional draw-proportion to the engine. Then again theare:the axle -boxes, the foundation ring of ings. water feed is to be by an axle -driven pump,the firebox, the firehole ring, the dome casing, I anticipate that some readers would preferor partly so, which means that the wholethe pump eccentric sheave, the chimney, the to have the check valves for the water feed onof the time the engine is travelling a smallsmokebox front boiler ring and the smoke - the top of the boiler instead of at the sidesstream of cold water would be falling uponbox front with door. in the positions shown. But for practicalthe steampipe and tending to condense the Allofthesecastingsarein gunmetal. purposes there would be no advantage what-steam which is passing through it. There is one which will have to be in ever in putting them on the top. The case The check valves shown in Figs. t and 2iron, namely, the firebars and, of course, the is altogether different from full-size practiceare standard fittings which can, like most ofsix wheels, also in cast iron. Cast parts

z- st" 6."2. Tigre

2 /HI

,EEC TO PUMP R 1-15122 tc.Xit25' 3V4" 4-- 55/9. 55/e 61'6. 91 41 61 i91 SI 'I 0, 9. I I°, SCALE 0, INCH ES. Fig. 4.-Longitudinal section of the locomotive showing the regulator valve and boiler feed pump. 24 NEWNES PRACTICAL MECHANICS October, 1951 which are not shown in these drawings willwith ordinary flatvalves, less friction andis shown between the portsa vee-shaped be the two pistons, the piston rod stuffing -loss of power in moving the valves ; no cast-piece of strip brass ; the object of this is to boxes on the back cylinder covers, the glandsingrequired for the steam chest and noput spring pressure on the port tubes and for same, and the crossheads. stuffing -box,glandorvalvespindlearewedge them in place whilst they are being There are one or two parts mentionedneeded, the valve rod-or radius rod-beingsoldered.Since the area of the port tubes above which are not bound to be cast.Forcoupled direct to the back end of the valve.at their ends is so small soft soldering will instance, the dome casing can be made from In the making of these cylinders the firststand up to the steam pressure they have to two pieces in copper, using a piece of tubingthing to do is to select lengths of two sizescarry.This argument applies alsotothe fortheverticalportion,annealingit andoftubing which should be very carefullyblock on the valve chest to which the steam - beating out toshape, and forthetopa callipered for truth and uniformity of dia-pipe flangeisscrewed as well asto the piece of plate, dished upwards and edgesmeter and circular form.Part off two piecessaddled exhaust pipes.As will be seen from flanged downwards to meet the tube, theof the larger, which should have an insidethe cross-section in Fig. 6, the exhaust pipes two being silver -soldered together.If, how-diameter of skin., each 21in. long and twohavetheirends pluggedoutsideofthe ever,the makerofthe model prefers apieces of the smaller kin.inside diametersaddles. polished brass dome it will have to be cast.(if possible slightly bare kin.).These latter Referring to the ports diagram the .pieces The chimney must be a casting and thewill be 3,1in. long.Cut all the port openingsmarked f, f, are the front ports and b, b, the pattern must have prints at top and bottomas shown in Fig.6. Next, from 3/32in.-back ports ;also that the ends A, A, A, A, for a simple round core.Obviously, if it isthick sheet brass, cut the end cheeks andwillbe saddled on tothecylinders and preferred, the petticoat pipe can be cast inpiercethesewithcircularopeningsatB, B, B, Br on the valve chests. one piece with the chimney, but this would I27/32in. centres to make a tight fit over involve the making of a corebox since thethe steam chest and cylinder tubes.See thatLapping the Cylinders bore of the petticoat is a taper with a bell -the axial lines of the two tubes are parallel shaped bottom. and that there is no twist. Whenallsolderingisdoneoneach The smokebox front with the door all cast The plates andtubes should now becylinderandchest,and notbefore,the inonepiecesimplifiesthispartofthesoldered, and the question arises how is thiscylinder bores may be checked up for truth, making of the engine.The flange is turnedto be done-by silver solder or soft solder ?but I think that even if they appear to be so that it is a push -in fit in the smokebox.Obviously silver solder makes the strongesttrue it will be best to lap them*out.To do This arrangement provides abigger open-job, but it requires a much higher tempera-this get a piece of lead piping a little larger ing for gaining access to the interior of theture, and is a blow -pipe or blow -lamp job.inoutside diameter than the bore ofthe smokebox.The hinge straps will be addedIn order that the silver solder shall flow, thecylinder and about 5in. long ;mount this in wood on the pattern so itis only neces-whole job must be brought to a bright red inthe lathe and turnit down dead true sary to drill the casting for the long hingeheat, and it would be necessary to pin, clampandparallelthroughoutitslengthtoa pin and the handles to obtain a front whichor by wire binding to secure nearly all thediameter which will just, and only just, pass looks like full size practice. parts together and solder at one operation.through the cylinder.Put a film of oilin

Constructional Details AA The work of construction may very well These Fig. 7.-Method of be begun by cutting out the frames. marking out the cop- are made from 3/32in. steel plate. 22in. long per tubing for form- by213/I6in. deep. The cross -stretchers and outside motion plates will be of the ing the steam ports. same thickness and material.Stretchers will B B measure 2 13/16in. across, which will result in a width outside of the frames of 3M. To receive the axle -boxes slots are cut kin.Actually the brackets by which the cylindersthe cylinder and oil the surface of the lap, are secured to the engine frames call for assprinkle on the leadalittle of the finest wide,thoseforthedrivingboxes being 5/16in. deep from the bottom edge, whilststrong an attachment to the cylinder tubesflouremery. Put the lapintothe the leading and trailing boxes will have slotsas possible, and what I recommend is this: cylinder and slide it backwards and forwards 7/i6in. deep.The difference is due tothat the cylinder cheeks or flanges be made,with asemi -rotary motion, withdrawingit asI have already said, a tight fit on thefrom time to time untilitis seen that the thedrivingboxeshaving no movement,ends of the tubes, and that the brackets, bentwhole of the inside of the cylinder has been whereas the other two pairs will slide verti-as shown in the cross-section on the right circular. cally.No horns are provided ;the chan- ground truly Now do the other nels in the axle -boxes will be cut to make ahand side of Fig.6,be made a tightfitcylinder:wipe them both out, clean the lap good fit on the edges of the slotted frames.between the flanges, then silver -solder theseand finish the polishing of the two bores parts only together.All other smaller pieceswith metal polish on the lap. Further, the axle -boxes are without keeps,can very well be soft soldered, using a small that is to say, they are solid and must there-blowpipe or even a large copper soldering Now get another piece of pipe,alittle forebe passed over the axles before the longer than thefirst, and with an outside wheels are forced on. Itwill be pearsbit for the purpose.After the silver solder-diameter of just over kin.This will be the before they need renewing.The sheave ofing it will be necessary to clean up brightlap for the valve chests.Unless the walls the pump eccentric must also he made andall parts which have to take the soft solderof this pipe are of heavy gauge it would be put on the axle between the boxes beforeand also tin the surfaces first. advisable to knock a hardwood core into it the wheels are assembled. When putting the The steam ports are made by flattening asin order to avoid the risk of bending. Turn second wheel on each axle care must beuniformly aspossiblea length of copperit parallel in the lathe and lap out the two taken to get the cranks all dead at righttubing of lin. outside diameter, that istovalve chests, taking special care to get the angles on opposite sides of the engine andsay, about 13/32in. diameter inside.Theboresoftheseperfect and withagood with the same crank leading.It does notflattening must be such that theflatsareinternal surface. matter which crank ;it may be either the3/32in.apartinside. About6in.will Not untilthevalvechestsare lapped right or the left,so long asallthree areactually be required for the four ports, butshould the piston valves be made.These alike. something over and above this will be neededare fully detailed at the top of Fig. 6.They With regard tothecrank pinsitwillfor holding the tube at the ends whilst bend-must beturnedtrulycylindrical,sothe make for greater accuracy if the marking offing, so I should flatten about 9in. or Join., ormounting in the lathe, and the lathe itself, for drilling of the wheels is done with squareevent tin.In order to prevent closing upmust be checked up to ensure that they are and scribing block on a surface plate afterat the bends it will be advisable to fill thenotcomingoutintheslightestdegree the wheels are on the axles. tube after flattening with molten lead, or, ifconical. Try this out with a micrometer. it is available, one of the low -melting -pointTurn out the three channels or recesses for The Cylinders white metals such as 'Rose's, Newton's orsteam and exhaust passages and, lastly, the Wood's,allofwhich fuseator belowfour piston surfaces. These are the most notable items in the 212deg. These should make a engine, and the whole or nearly the whole Now, around a bar held in the vice, or insomewhat tight fit in the bore of the chests of each cylinder is built up of brass tubingany other suitable manner, bend the tubeand should be eased by lapping, preferably andsheetbrass,with copper tubing for totheshape,anglesandmeasurementswith metal polish, until they slide slowly, steam ports. shown in the diagram, Fig. 7.Then, withina film of oil, with a perfect fit:they The details and measurements are clearlya fine saw, cut off each port at the pointswill then be stearntight. shown in Fig. 6.From this it will be seenindicated ; melt out the filling metal and file When all lapping is done thoroughly wash that piston valves have been adopted. Thesethe ends to saddle on to the cylinder andout the whole assembly of each cylinder with are machined from hard -drawn brass rodvalve chest, taking care that the filed ends petrolorparaffinmakingsurethatno and are lapped into the tubular steam chest.cover correctly the slits cut for port open-emery powder is left in the ports, or other The advantages accruing from this schemeings in the chest and cylinder. passages or cavities. are: larger ports than would be possible In the longitudinal section, Fig. 6, there (To be continued) October, 1951 NEWNES PRACTICAL MECHANICS 25 StudiesinElectricity and Magnetism Applying Kirchoff's Laws IN a previous article, examples were given (Continued from page 35o, August issue) of resistances, ABCD. There is no source of of load resistance and voltage problems, e.m.f. inside this closed piece of network.In and we may now state Kirchoff's twonegative, like the potential -differences acrossfact, the potential -differences add up to zero. Laws with a clearer understanding. the resistances (which suggests more clearly We have 6v. drop across each resistance, These are :- that p.-d.s are of the nature of " back e.m.f.s "but with + and - signs, A to D, and B to C, (r) The algebraic sum of any number ofopposing the applied e.m.f.) :- as indicated.The case may be compared currents at a circuit junction is zero. 6v- 2V. - 6x -4x= o, or, lox4, x-o.4A.with two cellsin parallel, with like poles And, Consider next Fig. 2c.Our two resist- joined together :in the series circuit between (2) The sum of the potential -differences(orancesareinparallelgiving a combinedthe cells, their e.m.f.s are in mutual opposition voltages -dropped) around a circuit is equal toparallel -resistance of :- and thus add up to zero, although across the the e.m.f. of the source. X 4-24-2.4 R ohms. parallelcombination we havethee.m.f. The secondLaw statestheimportant +4 ro6 of one cell. truth which was emphasised inthefirst Total current supplied, I = 6v. /2.4 2.5A. Providing no additional cell or battery, article-thatthee.m.f.ofa" source " Current in 6 ohms =0.4 of 2.5 = LoA.or other source of e.m.f.isinserted,the (battery, generator, etc.) is wholly lost in the 33, 4 33 =o.6 of 2.5 = 1.5A.algebraic sum of potential -differencesin any various resistances forming a circuit. closed mesh of resistances is always zero. Thus, if in Fig. rIli, R2, and R, denote 2.5A. respectively the resistances of the generator, Consequently, using x and y to represent the connecting cables, and of the load, the How would you apply Kirchoff's Laws ?branch currents, we can write our current, I, is the same in every part of thisSee if you can get the answers out beforeequations :- circuit, whilst in each resistance we have areading further.Start by denoting current For the closed mesh ABCD, 6x + 4yo (?) " drop" of I125,IR,, and IR:, volts-thedirections,thenwriteappropriatevoltage .. . .(Eq. r). drop, or p.d., across the load being usually byequations. Then we may form a second equation by far the greatest. equating the p. -d. across either resistance to the Therefore,ifEis the totale.m.f. battery e.m.f., for example, taking the 6 -ohm: - generated :- 6x=6, or x= rA. Substituting in Eq. (1), gives IR, + Ill,+IR,---E (I) or, 6 +4y=0 E-IR,--IR,-IR,=0 (2) 4y=-6 Eq. (2) suggests that the potential -differences y= -6/4= -1.5A.(?) acrossresistancesmust beconsideredof Something wrong, surely ? yisnot a opposite sign totheapplied e.m.f.,and,as currentinthenegativedirection-inthe previously suggested, there is more to this oppositedirectionto the one indicated- than a mere algebraic rule or convention. which wouldmakethebatterycurrent In certain A.C. circuits having earthed pointsFig. 1.-Kirchoff's Second Law : the algebraic(x-y)=(rr.5)= -o.5A., or11 -amp inthe (or, in radio, points at " cathode potential "),sum of all the voltages in a circuit (including thereverse direction round the battery circuit! we actually get an alternating voltage ofe.m. f. of the source) is zero. The and - signs Itshows how careful we must bein opposite phase relative to some other referenceacross each resistance represent the difference ofinterpretingsigns.We have our current - voltage. potential across each. conventions correct, but can you spotthe That isso because we tap our output mistake ?I made a mistake in typing the voltage off some point where the sign is that If you adopt straightforward conventionssign in Eq. (r) !I decided to leave it so, as a of the potential -difference across a resistancethe thing is very easy.Thus, in Fig. 3a :typical instance of what comes of using a (relative to our earthed point), and hence welet x and y be the parallel branch currents insingle wrong sign.Itis the algebraic sum have a phase -reversal with respect to thethe directions shown-the positive directionof the voltages in the closed mesh that is zero, portion of thetotale.m.f. appliedtotheof the applied e.m.f.Then totalcurrenthence Eq. (r) should be :- resistance. from the battery = I = (x +y). 6x- 4y =o Eq.(r) Rewritten. The phase -reversal in such casesisno Considering the battery and the 6 -ohm Of course, it matters not which term we mere matter of algebraic signs.It can beresistance :- make negative-the algebraic sum isequally demonstrated,forexample,ina valve 6v.- 6x= o,or, 6x=6, x=6/6= r.oA. zero if we write : amplifier that the output voltage(with a Next, the battery andthe4 -ohm 4Y - 6x = 0 Eq.(r) load consisting of a pure resistance) will, ifresistance :- With x= IA, either gives y =1.5A. fed back, oppose the original voltage to be 6v. -4x= o, 4x = 6, x = 6/4 r .5A. amplified-give whatistermed " negative Pitfalls with "Signs" feedback." In consequence, the nett Total current, (x + y) = 2.5A. Again, suppose we used a wrong current amplification may be greatly reduced. direction. Suppose y was reversed-shown So you see, Eq. (2) can have a very real flowingagainstthebattery e.m.f.,asin physical significance.However, when writtenDealing with a Closed Mesh Fig. 3c. in the form of Eq. (r), where all signs are There are other ways, not sostraight- Then, at junction p, y is towards and x positive, it says, purely and simply, that theforward, but exemplifying useful principles.away from the junction, when it appears we e.m.f. applied must be numericallyequal Let us denote the current from the batteryshould write (y-x) for the supply current. to the sum total of all the " voltage -drops "by x, Fig. 3b using y, say, for the currentWorkingoutonthisassumptiongives in a circuit.Eq. (2) then follows. in the 4 -ohm resistance.Current x flowsx= rA, y = -1.5A that is, y is opposite to the towards, and y away from, the junction p,wrong direction assumed. Need for Clear Thinking sothat the current in the 6 -ohm may be So the answers for x and y come out Some clear thinking is thus essentialinwritten(x -y) or (y-x), if we used thecorrect. But we must be careful about reading writing a Kirchoff's voltage equation for areverse convention of currents flowing awayour signs if we next proceed to find the battery network. from a junction as " positive." current, using (y -x), forgetting that y was It may be written in the form of Eq. (1) Now, in the wrong direction !Thus, if we keep to or (2).To avoid mistakes it may be best to Lly = 6, y=I.5A. start from first principles by applying Eq. (2) 6(x-y)=6, x-y-- r, E- 6v to all cases, doing transpositions afterwards. x=r+r.5 E -6v -.1 E- 6v. Consider thesimplecircuitsshown in =2.5A. Fig. z.In (a), we have E =6v., R,=4 ohms, Finally, current in the and R2=6 ohms.Straightforward Ohm's 6 -ohm= (x -y) Law gives the current as o.6A.But denoting (2.5- r.5)=- LOA. x a-21! it by x, and applying Kirchoff, we have :- Not, perhaps, quite as 6 - 6x -4x =o, or, rox = 6, x = 6/ro =0.6A.straightforwardasusing Rt In (b), we have an extra 2v. cell connectedx and y for the branch the opposite way round to the others.Itscurrents,but almostas 4 ohms 6 ohms 4f1 e.m.f. opposes, or acts, asa back e.m.f. toeasy. (a) ( b) the 6v., giving a resultant e.m.f.= 6v. - 2v. = Making use of either (c) 4v.Hence, I ---o.4A., using Ohm's Law. current -conventions, con- Fig. 2.-Applying Kirchoff's Laws to simple series and parallel Using Eq. (2), we must treat the 2v. assider next the closed mesh circuits which can be worked by ordinary Ohm's Law. 26 NEWNES PRACTICAL MECHANICS October, 1951 the signsas they stand, (y - x) = (1.5 -as applied to a Wheatstone Bridge network Alternatively, you couldconsider mesh .o) - -2.5A, which goes to suggest theof resistances, as in Fig. 4. BCD, or even not consider any " mesh " at current supplied by the battery is also the This may be regarded as equivalent to twoall, but write a third equation for the circuit wrong way. potential -dividers (Fig. -4b). If the p.d.'sABDC : Actually, as seen, y is " positive," the sameacross R, and R, = the p.-d.s across R, and 4x - toz + 5(yz) = 6v. as x ;both flow in the direction of theR the potential -differencebetween points 4x+ 5y -15z - 6. ...Alternative (Eq. 3) e.m.f.In other words, x and y are reallyB and D will be zero, and a galvanometer Here again, a negative sign must be used for currents flowing away from junction p. Hence,across these points will give no deflection.the p. -d.across R, because the (supposed) in reckoning the total current, if x is of +-The bridge is then said to be balanced, anddirection of z is opposite to x, and to (y -z). sign, so is y.The total is (x +y) = 2.5A. this is the condition requiredformeasur- The answers are: x = o 624A.; y= o . 58A.; Alternatively,- (x + y) signifiesnora ing an unknown resistance. and z = -o.o4A., i.e., with the resistance reverse current round the battery circuit but In Fig. 4b we have omitted the " diagonal "values given, z is a current from B to D, the a current opposite to the (assumed) wrong resistance R.The circuit is then a simplereverse direction to the one assumed. direction of y. Or again, keeping x positive,one of two parallel branches having in each If at first you cannot get your answers to we can write :total current = (x - y) = a-two resistancesinseries.The potential -agree, go over all signs carefully ;it is so easy (-f.5) = + 1.5 = 2.5A. difference between B and D may be calculated It is seen that various meanings-electricalby considering the voltage dropped acrossto make mistakes in solving three or more and " algebraic "-may be assigned to theR, and R and estimating if the differenceequations. word " negative." These few hintswillacts from B to D, or D to B. indicate some basic confusions which arise. But, except at the exact balance -point, theMore on Magnetic Circuits addition of the diagonal In a previous articleIfinished with a 6v 6v complicates mattersreference to M.M.F. A current -carrying coil enormously, so much sosetsupamagneto -motiveforcegiven that the network cannotapproximately by 1.25 (ampere -turns) beanalysedby Ohm'sthen, that M.M.F. axiallengthof an Law, orordinaryprin-isolated coil (or the total " mean length " of a ciplesofresistancesincomplete iron,air path, if provided) gives us series -parallel. another quantity, the magnetising force (H). The M.M.F. is the equivalent of a "magnetic p 4D Generally, we want to 3 potential -difference " between the ends of a vv\M know the currents inallsolenoid-or along some complete magnetic (a) (b) (e) the resistances, par-path. ticularlyinR, and the Itisappreciated that concepts such as Fig. 3.-Some possible " conventions" in applyi Kirchoff's Lawspotential -difference across":magnetic potential -difference " are not easy to the parallel network of Fig.2C. points BD. For simplicity, we suppose the battery isto picture, whilst there are some things in Can we formulate general rules ? an accumulator of negligible internal resistance,magnetic theory which take a great deal of e.m.f. = 6v.I am not going to work theexplaining :forexample,thefictionthat Watch Negative Signs 4.z Lines "-approximately 121 Lines !- problem in full, but show how to write theemanate from a " unit pole "-if such a thing Let us go back to fundamentals. Kirchoff equations with due regard to signs. Consider junction p with the currents as could be realised. Let x and y be the currents in AB and AD, What isinterestingisthat these fictions shown in 3a. and 3b.Exactly why did wein the directions shown.Then the batteryworkfairlywell incalculationsofelec- write :supply current =(x + y) ?(Fig. 3a). current = (xy).Next, considering junctiontromagnets and machines.Meanwhile, we Obviously because that is so!Obviously,B, let z be the current in R, from D to B asmay think of M.M.F. simply as a magnetic the total current is the sum of the parallelindicated.This direction may toforce-the total magnetic force-set up by branch currents.But let us not presume uponbe wrong in the final solution, as indicated bythe coil. this bit of electrical sagacity.Let us sticka " negative " answer for z. The magnetising force (H) = the M.M.F. to the algebra. Never mind about that.At B we have :per unit length of magnetic path. In fact, it is Currents x and y both flow away from p,x and z flowing towards B, therefore theshown that H is the same as the field intensity, and should thus be written -x and -y, oncurrent in BC must be written (x +z). expressed in lines per sq. centimetre, in air or the convention that currents towards p are to Similarly, at junction D :y flows towardsother non-magnetic material.For an isolated be of + signs.Therefore, the battery currentand z away from D, so that the current incoil having " air " or non-magnetic core, it is = -x -y = -(x --y) ;or isit not ? resistance CD is (y -z). We have altogethernecessary to add :field intensity at the centre Would this negative sign imply a currentthree unknowns, x, y, and z, which requiresof the solenoid, because lines of force diverge flowing the wrong way round the batterythe solution of three simultaneous equations.outwards towards the ends, as in Fig.5a. circuit?Clearly not.The Kirchoff equa-Let us proceed to write the voltage equations.When a complete iron path is provided as in tion is : For the arm ABC we have : Fig. 5b, the M.M.F. has to be divided by the (x +y) -x-y = o, 4x -4 6(xz) = 6v. total mean length of path (1) to find H. or (x + y) - (x + y) = o. or fox +6z = 6 (Eq. r) When iron is introduced, both the total This implies nothing more than that Also, for ADC : flux, and the " intensity " (lines per sq. cm.), (x + y) = (xy). Sy+5(y-z) = 6v. become much increased. The sum of the branch currents = the toy -5z 6 (Eq. 2) supply current. For our third equation let us take the meshPermeability So (xy) is correct for the supply current ABD.Remembering that for every closed H lines per sq. cm. " in air " become B lines even though x and y flow away from p.Withmesh of resistances the voltage acting in theper sq. cm. in the iron, where B may be many the equation written as above, i.e., equatedclosed-circuit = o, we must write : thousands of times H, and is termed the to zero, the signs of the branch currents must 4x- toz -5y = o. be negative to make the algebraic sum zero. (Eq. 3)flux -density in the core. The rest is fairly straightforward algebra. The molecular theory of magnetismis Thus, if we decide to show y negative as inBut why the minus signs Fig. 3c, we must keep to these fundamentals. forthepotential -differ- The supply current is simply (x -y), instead ofences across R and across (x +y), i.e., i-(-1.5)'= f -{-f.5,as in theAD ? above example. Well, observe that we On the basis of currents flowing towardsare treating the p.d. across (and away fromjunctionp),we have :AB as of " positive " sign. Rt P2 (x - y) flowing towards p ( +sign) ; y flowingThe current -direction as- A C towards p( + sign) ;x flowing away fromsumed for R is the opposite p ( -sign).Hence: way round the mesh to the (x - y)y - x = o, currentshowninAB, which is clearly true. whilst y (in AD) is also Of course, all difficulties may be avoidedthis opposite way round. by not choosing wrong current directions.Therefore, the sum of the But matters are not always as straightforward(negative) p.d.'s across AD in more complicated circuits, whilst one of theand R must be equal and purposes of these articles is to touch upon opposite tothe positive (a) (b) points of doubt. across AB-if the algebraic sum is to be zero, or : Fig. 4.-A "Wheatstone Network," which cannot be solved by The Wheatstone Net 4x -(toz + 5y) = o, or, Ohm's Law, or series parallel circuits. See if you can find x, y, and As an example of a fairly complicated net- 4x - toz - 5y0, z by solving the equations explained in the article. The current in R work, let us briefly outline the Kirchoff rulesas above. is assumed to be in the direction indicated (z). October, 1951 NEWNES PRACTICAL MECHANICS 27 probably the true explanation. Iron andbe used. We want a simple formula, of thethe molecules aligned as described above), /4 steelpossessalarge amount of inherentform, falls off to a value not much better than the magnetism ; each separate molecule isitself Current - e.m.f. permeability of air, which is 5.0. a minute magnet having N.S. poles.But in Resistance, the unmagnetised state, the molecules in aor, TotalMagnetic Flux, Procedure in Magnetic Designs mass of iron are in disorganised, " higgledy- M.M.F. Then different grades of iron and steel, or piggledy " formation. N Total " Magnetic Resistance."oftenthe same grade subjecttoslightly When a magnetising force H is applied, N isthen conceived of as a thing thatdifferent compositions, heat treatment, etc., the molecules are aligned in one definite flows " in the iron circuit, somewhat in thevary enormously in their magnetic properties. direction-all the n -poles pointing one way,same sense as a current flows in copper wires. We shall not study magnetisation curves hence the mass as a whole becomes a strongWe do not speak of " Magnetic Resistance,"now, butitwill befairlyapparent that magnet with N. andS.polesappearing calculations on magnetic circuits can never be at the ends. as exact as when applying Ohm's Law or The theory is well borne out by many facts. Kirchoff's Laws to networks of resistances. The relative case with which soft iron can Moreover, close exactitude is seldom required. be magnetised compared with the hard steels, At best, we can only make rough estimates having closely packed molecules ; the magnetic of the ampere -turns required to produce a retentivity of the hard steels, once magnetised ; givenflux,or of the pull "of electro- the fact that a bar or horseshoe magnet can (a) magnets, and so forth. be demagnetised by heating to a red tempera- In laboratory investigations much greater ture-as is well known, molecules are in a accuracies are possible, whilst in every case state of rapid vibration when the temperature (b) reliance has to be placed upon B -H curves is raised. which have been plotted in the test laboratory t. crass -section for given specimens of the iron and steel to Thus, whatever may be said for the latest la cms (ASQcm.) be employed. theories of magnetism, it is pretty certain the =Length The general procedureisto design an molecular theory is a good enough explanation of air gap electromagnet to work at a given flux density of how " H " gives rise to a greatly augmented B. This is chosen from a study of a B -H curve flux -density " B." (c ) of the sample, and may be in the region of But in developing the theory which com-Fig.5.-Simple " Magnetic Circuits" :(a)8,000 or io,000 lines per sq. cm. The value paredmagneticwithelectriccircuitsa isolated coil;(b) completely" closed" ironof H which will give this density is read at different concept was introduced.Iron andpath; (c) part iron, and part air -gap paths ofthe same time off the curve. steel were regarded as " good conductors " of 1, and lcnzs. Then, B/H = p, which means we are going magnetic lines, compared with air and other to " work " our electromagnet at about this non-magnetic materials. permeability. The total cross-section (and however, but of the Reluctance of an irontherefore the size of core) will have to be large The number of times B is greater than Hcircuit. enough to give us the desired total flux (N), (or the ratio B/H) was looked upon as a The electrical resistance of a wire of lengthwhilst keeping the density (B) already decided figure of merit denoting " magnetic conduc- I cms., and cross-section A sq. cm., is givenupon :ifB = so,000,andwe require tivity," or, to give its precise name, permeabilityby :- N = soo,000 lines, our iron section must be (p). Thus, if for a givenironspecimen I K N/B = so sq. cms. /4 = 400, then, if a coil sets up, say,20lines R = A, per sq. cm. " in air " (= H), the flux -densitywhere K = the electricalresistivity(specificCalculating Ampere -turns (B) in the iron will be H x 400 =20 X 400resistance) of a unit piece :the reciprocal of Knowing H, it is a simple matter to cal- = 8,000 lines per sq. cm. electrical conductivity. culatetheampere -turns on the coil. But p is of the nature of conductivity, and soH = M.M.F./Length of MagneticCircuit "Reluctance" must be written in the denominator of our= 1.25. A.T.//. Or, A.T. = HI +1 . 25 Permeability is a " specific " quantity : likeequivalent magnetic expression :- = 0.8 HI.If / = s cm. of core path, A.T. conductivity-and other " -ivities " or Magnetic Reluctance, R =/ = o. 8H = ampere -turns per cm. of length " -ilities "-it represents the magnetic con- of magnetic circuit. ductance of a " unit piece " of material-where I and A have the meanings assigned This is somewhat simpler than calculating s cm. long, and s sq. cm. cross section. in Fig. 5b. the Reluctance, but amounts to precisely the In a magnetic circuit such as Fig. 5b, what Unfortunately, magnetic permeability is bysame thing.Where there is an air -gap as in we require is a term analogous to " Resistance"no means as constant as electrical conductivity.Fig. 5c many more A.T. will be necessary of an electric circuit, where conductors ofIt varies all the time with the magnetic statebecause the permeability of this part is t.o. various lengths and cross-sectional areas mayof a core, and as saturation is approached (all (To be concluded)

thermostat again comes into operation, and cuts the current to the heater. Any source Temperature ControlDevice ofelectrical heat may be used withthis device, provided the current is not too heavy A Simple Thermostat for Use in a Greenhouse By G .W. B. STUARTforthe " cut-out " winding.Referring to the diagram, we have a thermostat A with THE thermostat described in the follow- a toa Ez bimetalstrip B attached terminal ing notes has operated successfully C A C, free to move between adjustable contacts inagreenhouse for thepast two D and E. years, without requiring any maintenance, or A " cut-out " K isconnectedtothe attention, other thansetting ofthetem- XR, thermostatA,soilheatingcable G and perature regulator. A bimetal strip 4in. long, the mains supply. attached to a terminal at one end, the other being free to move between two adjustable Operation contacts, operates a " cut-out," connected to L The cycle of operation is as follows :- the mains supply line, and soil -heating cable 41 V Thetemperaturefalls,bimetalstripB bends making contactatD, which com- of 15o watts. pletes circuit H, L, F, through " cut-out " Thermostats ofthebimetalstriptype, winding P, and M, which is connected to unlessfittedwitharapidcircuit making the soil -heating ,cable.The current flowing and breaking device, will " arc " badly and through P will hold armature L on to con- burn the contacts.For this reason a " cut- tact H until the temperature rises, then the out " was connected in the circuit. bimetal strip bends on to contact E, when The soil -heating cable does not by itself P isshorted out of circuit, releasing arma- raise the air temperature in the greenhouse ture L, thus breaking the mains supply to to any appreciable extent,but warms the the heating cable. The temperature ai which soil when the air temperature falls to a pre- the thermostat can be set is regulated by ten- determined level. sion screw R, and the difference between the During the day,ifand when, the sun " cut -in " and " cut-out " temperatures, by shinesand theairtemperaturerises,the Circuit diagram for a simple thermostat. the adjustable contacts D and E. 28 NEWNES PRACTICAL MECHANICS October, 1951

Model Making in Zurich : Scale Model Foden Wagon By "MOTILUS" lUrODEL ship enthusiastswill be in-detail is shown on the decks ; the rigging iswhich Mr. Buhlimann specialises.Mostly in terested in this month's photograph oftoo light for a fishing vessel of this type, andgauge 0 scale, these models carry all the de- V , a model British sailing trawler, madethe planking is incorrect, as the outside layertail of a steam locomotive of their day in by Mr. P. W. Kirby, of Benoni, Transvaal,of planking on the hull should be " foreappearance, but they are operated on the South Africa. This model, the Three Brothersand aft " and not diagonal. electric, two -rail system. of Rye, has an oak keel, with birch planking (t mm. thick) on mahogany ribs, and was built from plans that Mr. Kirby bought from a well-knOwn models firm in London in 1949. He entered the model in the Rand Easter Show last Easter and was awarded a medal. In making theaward,the judges also passed a few criticisms on the model, which

Fig. 2.-Gauge 0 model of an American steam locomotive of about 1865, from the collection of Mr. H. Buhlimann, of Zurich. Mr. Kirby has In looking again at these old-time steam since started buildingmodels I wondered whether the Swiss be- anothership model ;come tired of their up-to-date, simple, elec- this time it is to be atriclocomotivesandtrains,andifthis Thames sailing barge,accountsfortheirfondnessformaking the Lady Daphne.models of early period steam locomotives, With his previous ex-into which they cram as much external de-

perience to draw on,tail as they possibly can with accuracy. . Iam confident Mr. One of theillustrations(Fig.2) shows Kirby will produce a" Seminole," gauge 0 model of a 4-4-o type first-classmodel this (Continued on page 3o) time. Zurich Model Rail - Fig. 1.-A model British sailing trawler built byMr. P. W. Kirby, of way Club Benoni, Transvaal, awarded a medal at the RandEaster Show this year. In the spring of this yearIagainvisited Mr. Kirby has candidly included in a lettermembers of the Zurich Swiss Model Rail- to me.I note them here simply as a matterway Club.Among them I was pleased to of interest, as I consider the model to beinclude Mr. Buhlimann, of Zurich, to whose very good in other respects ;it shows verymodelsIreferredin" The Worldof careful workmanship and is typical of theModels " in November, 1949.Since then I prototype in character, which is an importanthave been able to obtain photographs of two matter in ship modelling. modelsthat aretypical oftherange of The judges' criticisms were that not enoughAmericanold-timesteam, locomotivesin

Fig. 4.-A close-upviewofthe forward Fig. 3.-Gauge 0 model of an American steam locomotive as used on the Baltimore and Ohio portion of the model steam Foden wagon built Railroad about 188o :also from the collection of Mr. Buhlimann, of Zurich. by Mr. G. Waint,s, of Innisfail, New Queensland. October, W51 NEWNES PRACTICAL MECHANICS 29 pressure but the " mean effective pressure," which is the mean value of the pressure takenovercompressionandexpansion strokes.The mean effective pressure in any cylinder cannot easily be found as it requires special apparatus, but for the average type of motor -car engine a value of between 90 to tzolb. per sq. in. would be a fair estimate -the higher value corresponding with the higher compression ratios. It is also necessary to note that in using this formula the pressure must be given in Soapless Detergents for pounds per square foot, the dimensions " L " Window Cleaning and " A " in feet and square feet and " N " SIR,-We were interested to the number of firing stroke per min., which see, in your current issue, is, of course, the same as I (r.p.m. of engine) correspondence regarding the X number ofcylindersforfour-stroke use of a soapiest detergent engines.Unless the mean effective pressure fcrwindowcleaning,and can be correctly ascertained the value of the thank you for the reference to " Teepol " Mr. Wilson must use his discretionini.h.p.calculated inthis manner would, I X.We must, however, point out that thisthe length of soakage time allowed.Thefear,be very inaccurate.-D. C. BOSTON prcduct, whichis now known simply asobject is for the solution to soak right into(Robertsbridge). " Teepol," is not generally available to thethe wood. A dry stump will require less public. tire_ than a green one.-T. H. ROBINSONPhoto -electric Exposure Meter So far as the domestic market is concerned,(Potters Bar). SIR,-Maywethankyourcontributor, our policy istosell to the repackers, whoDrilling at Right Angles to Surface W. L. Peacock, for the mention of our market our product either as bought from name as the supplier of selenium photo -cells us, or made up totheir own formulation SIR,-Working single-handed in a garageinhisarticleentitled" A Photo -electric withothermaterials,underproprietary Ioften experience difficulty in boringExposure Meter." We have had numerous names. holes with my sin. capacity electric drill atenquiries and are happy to be able to supply In fact, any of the better-known liquid all the standard size selenium cells, but un- soapless detergents, such asQuix," " Laun-. fortunately we are unable to supply the type dene," D. " Lather," etc., can be safely meter mentioned or the too ohm resistor. recommended for window cleaning.-SHELL Two % Dia. In addition to photo -cells, we market two CHEMICALS LIMITED (Strand, W.C.2.). circular spirit photo -electricexposure meter construction levels as kits, one a reflected light model, the other advertisedin Practical an incident light model.-G. R. PRODUCTS Preparing Hydrogen Gas Mechanics (Bristol). SIR,-I hardly think the chemical equa- August 195/ tion given by Mr. Hollis in your August "Making an Electric Blanket" issue (page 353) can be correct.Should it SIR,-Regardingthearticleentitledas not be :- above, by Mr. E. E. Cheetham, and zNa0H-I-2A1 -4- 2K,o=zNaAlo,-1-- 3H, ? subsequent correspondence, may I point out that transformer secondary windings must be Ifitisaquestion ofinflating one of the 4ft. diameter ex-R.A.F. balloons I calcu- earthed. late theoretically that one filling would require This is a requirement of the Electricity talb.aluminium, Supply Regulations, 1937.These Regula- theinteraction of about Flat board with tions cover the supply of electricity by the 211b. caustic soda and x pint of water. The hole to pivot undertakers (now the B.E.A.) to consumers. heat liberated by the reaction of these quan- true bar Under- these Regulations itis necessary to tities would besufficienttoboil about 8 e; True bar while lining up earth one side of a low voltage alternating gallons of water.-W. HALL (Dublin). current system, Regulation No. 4. A similar point is covered by Regulation Author's Note.-I apologise for the slip toot(c) of the I.E.E. Wiring Regulations, made in my letter.I agree with the information supplied by W. Hall providing that the 12th Edition. -17. J. BURRIDGE (Brighton). pressure inside the balloon isatmospheric. Black Etching Acid I should like to add that the hydrogen inside SIR,-Having read the reply to L. G., of theballoon wouldliftabout43ounces Leeds, in the August issue of PRACTICAL altogether.-R. Hows (Rotherham). Using spirit levels for ensuring alignment whenMECHANICS on the above subject, I would drilling at right angles. like to pass on to other readers the follow- Destroying Tree Stumps right angles to the job. I obtained twoing information:Neither hydrochloric nor Mr. R. A. Wilson's querygin. dia. circular spirit levels, one to be usedsulphuric acids, nor any combination of them, SIR,-Regardingin theAugustissueof PRACTICALfor vertical operation and one for horizontal.will give a satisfactory black etch on polished MECHANICS, in which he asks for adviceA flat seat is filed on the end of the casingcast iron or steel.The etchants used in the destructionoftreestumps ;theand to ensure it being at right angles to thetrade are far more complex in nature.If on the your correspondent willwriteto Messrs. following method may be of interest to himspindle a fin. bar is gripped in the chuck.Eyre & Baxter (Stamperaft), Ltd., 55, Brown andotherreadersfacedwiththesameThe end of the bar is steadied in a hole Street,Sheffield,t,they will be ableto problem. pre -bored in a flat board and the bar truedsupply their " Rapidblack " which will give Each stump, cut down to ground level,up, using a square.When the seatisatverysatisfactoryetchings should have a series of Sin. or tin, diameterright angles to the spindle the spirit level is witharubber held in position by two short 6 B.A. screws.stamp on polished cast iron or steel.Inci- vertical holesatSin. centresdrilled into dentally, the firm mentioned specialiseinall the cut face for a depth of not less thanSimilarly, another level was fixed on top oftypes of marking and supply the bulk of the gin.These holes should be filledwith athe handle to ensure alignment when boringrazor, saw and bright goods trades with saturatedsolution of potassium nitrate orhorizontally. Of course, thislevelonlyrubber stamps and suitable etching acids for chlorate and should be topped up every daytrues up the spindle for vertical misalignmentany type of job.-N. SLATER (Sheffield). for a fortnight.After this, they should be.and not horizontal. A plain rectangular type allowed to dry out thoroughly.Protectionof level would do equally as well in this from rain should be provided during theposition.-R. HURDITCH (Bridge -of -Allan). whole of this process. DEARS AND GEAR -CUTTING Thestumpsshouldthenbeignited,Calculating the I.H.P. of an I.C. Engine paraffin being used tostart thefire.The reference to the reader's query Edited by F. j. Camm. flames will soon die down, but smouldering SIR,-WithintheAugustissueof PRACTICAL will continue over a long period, oxygen beingMECHANICS concerning the pressure exerted Price 6s. from all Booksellers or 6s. 6d. by provided by the potassium salt, and even-on the cylinder head of an internal-corn- post from George Newnes,Ltd. (Book tually the stumps will be reduced to ashes bustion engine, in using the formulaPlan Dept.), Tower House,Southampton Street, toa depth of about ain. below ground 33,oao- London, W.C.2. level. the symbol P dcno:es not the maximum 30 NEWNES PRACTICAL MECHANICS October, 1951

A Review of the Latest Appliances, Tools and Accessories

Glazemaster Drills ofa million people, and the seasonal and FOR drilling holes in glass of all kinds,holiday homes for possibly twice this number.the latest features in caravan design, but his John M. Perkins and Smith, Ltd., of Two of the principal reasons for the in-caravan should give him many more years London Road Works, Braunston, near Rugby,creasing popularity of this new way of lifeof satisfactory service. are marketing two types of tungsten carbideare the revolutionary improvements that have Copies of the handbook can be obtained tipped Glazemaster drills. Type " A "is taken place in caravan design and contruc-from Berkeley Coachwork, Ltd., 175, Great intended for the handyman and householder,tion, and the ever-increasing service offeredPortland Street, London, W.I. and is the ideal drill for windows, mirrors,to caravan owners by leading manufacturers. bottles,plateglassshelves,and blackor ThelatestinstancewhichhasbeenNew Electric Fence Battery coloured vitrolite. A NEW battery produced specificallyfor The drill can be used powering most makes and types of with hand brace, electric fence has just been introduced by breast drill, portable Chloride Batteries Ltd., of Clifton Junction, electricdrill,orin near Manchester. adrillingmachine. Designatedthe Exide 3-DTG/NT, thin Type " B "drillis battery comprises threez -voltcells assem- madespeciallyfor bled as a 6 -volt unit in a light metal carrier. the tradesman and is Thecellplatesareofthewell-known a super drill for the " mass " type which are eminently suitable production of a great for duties where long discharges at low rates number of holesin are required. When not in use, a freshen- allkindsofglass Two examples o.1 Ciazemaster drills. ing charge once every six months isquite and vitrolite. With sufficient to keep the battery ina healthy this tool holes can be drilled right throughbrought to our noticeis the publication bycondition. without reversing the glass, and with prac-Messrs. Berkeley Coachwork Limited ofa Great care has been taken with the in- tically no flaking underneath. The cuttingwell -producedillustratedloose-leafhand-ternal contruction to secure a long trouble - edges can be resharpened several times, givingbook designedtotellthe owner ofthefree working life.Intercell connectors are a long overall life.The drill is suitable forMessenger(thecompany'smostpopularburned tothe platepillars, thus ensuring use in power drills of all types.Both drillstouring model caravan) everything that heperfect and permanent connections, while the are obtainable in various sizes from fin. toneedstoknow regardingitsmechanicalpillars themselves form an integral part of -din.Further particulars, including instruc-maintenance. This objectively written hand-the cell lids. No acid creepage can take place tions concerning drilling speeds and the usebook for the layman, for which no chargeas a result of their working loose, therefore, oflubricants,arecontainedinabookletis made, cont.,;ns many helpful hints for theand theriskofcorrosionisconsequently which is obtainable from the above address." old timers," and is a mine of informationminimised. The non -interchangeableter- for the novice who is inclined to take mechan-minals are of different shapes and colours Caravan Service icalmaintenance forgranteduntilsome-to avoid any confusion.The specification THE caravan industry has now won forthing goes wrong. is as follows:voltage, 6 ;capacity, 12A11 itselfrecognitionas animportant Ifall the, advice-the" do's "and(too -hr.rate), 7 Ah (so -hr. rate) ;charge national social asset. To -day it provides com-" don'ts "-inthishandbookarefaith-rate, amp.Dimensions,33/I6in. W x fortable mobile homes for an all -the -year-fully followed, the Messenger owner will not9 i/16in. L x 5 15/16 H. Weight (includ- round caravan population of nearly a quarteronly succeed in benefiting to the full froming acid), Irlb.

locomotive chassis by Mr. W. Whiteley, andfollowed into third place by Mr. H. Gavins won the Founder's Shield offered by thewho exhibited a 3ft. 6in. lathe. chairman for the best exhibit, and afirst- The Aircraft Stand was very busy, and the classdiplomaintherailway and steamexhibits here were varied.Mr. V. Smith section. won afirst-class diploma with a Ladybird Keighley and District Model Engineering A tugboat engine by Mr. Willmore camefree flight aircraft. Mr. H. Brownless came Society second, followed by Mr. Greenwood's xiin.second with a solid scale Sunderland flying THE above Society held a Festival Exhibi-scale free lance traction engine. boat, and Mr. A. Brownless, junior, third tion in Keighley between the 7th and Dominating the Steam Stand was a sin.with a 6oin. glider of his own design. t4th July, 1951.It was sponsored by thegauge L.M.S. 5XP Locomotive entered by The Marine Stand was unique in the fact Keighley Borough Council, inconjunctionMr. W. E. Wood. This was jacked up andthat all the members had commenced their with local craftsmen, and from the outsetworking under compressed air. Like manymodels since the formation of the Society proved to be a huge success. other models this was under construction,justover a yearago.-H. BROWNLE S S Over 5o models were on show, all of them,and was unfinished. (chairman), 159, Redcliffe Street, Keighley, withoneexception,being madebythe The winners in the Workshop EquipmentYorks. membersofthe Society,the one ex- World of Models ception being a model (Continued from page 28) over 5o years old of American steam locomotive of about 1865, theoriginal engine and Fig. 3 shows the "Rapid," as used on installed in the works the Baltimore and Ohio Railroad about 1880. of Messrs. Dean, Smith and Grace, Scale Model Foden Wagon Ltd.,thef amous In the September -October issue of PRAC- lathe manufacturers, TICAL MECHANICS for 195o I wrote about a of Keighley. This model steam Foden wagon built by Mr. G. model and others were Waines, of Innisfail, New Queensland. This workingundercom- year I again heard from Mr. Waines, and he pressed air. sent me a photograph (reproduced in Fig. 4) Mr. Douglas showing a close-up view of the front portion Miller, M.B.E., presi- Air. W. Whiteley's prizewinningo -6-o model loco chassis of this model.In this picture can be seen dent of the Brighouse some of the good detail model work on Society,andMr. Harry Byram-intheClass were first Mr. G. Batty with a reallywhich I commented when I described the absence of Dr. Fletcher, of Colne-judged fineset of lathe accessories.The secretarybuilding of the steam wagon.By the time the exhibits. oftheSociety, Mr. Allan Hornby, camethis appears in print Mr. Waines will have The best exhibit as judged was an Austensecondwithaprecisiondrillmadetipadded -reversing gear to complete this work- Waltonsin.gauge2Fdockyardtankfrom asetofPotts'castings. He wasing model. October, 1951 NEWNES PRACTICAL MECHANICS 31

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1.37 32 NEWNES PRACTICAL MECHANICS October, 1951 Every one a Bargain! GALPIN'S HYDRAULIC PUMPS.High pressure Electrical Stores HAND BENCH DRILLING MACHINES for Bakelite press, etc., (in. inlet and outlet, 408, HIGH STREET, LEWISHAM, splineshaft2in.long,flangemounting, S.E.13 WITH ADJUSTABLE AUTO- weight 5 lbs.451-, carriage 21- extra, Tel.: Lee Green 0309. Nr. Lewisham Hospital. MOTOR PUMPS.12 volt D.C. Stuart, MATIC FEED AND 0 -bin. CHUCK. 120 g.p.h., 66.10.0.230 volt Stuart. 100 EarlyClosingDayThursday. g.p.h., 66.10.0 ; foot valve and strainer 251, Terms :Cash With Order.No C.O.D.All MOTOR BLOERS, 24 volt D.C., for goods sent on 7 days approval against cash. valve cooling or- conversion to hair dryers. 211-, post 21, 12 volt C.A.V., 21,in. inlet, EX RADAR MAINS TRANSFORMERS Height Chuck to base lain. outlet, 551-, post 24.32 volt D.C., 230 volts input 50 cycles I phase, output Sin. inlet, 4iin. outlet, 116h.p. motor, 450015500 volts approx. 30 mlamps 6.3 20in. Min. .0 £4. 230 volt A.C. Cub, h.p.motor, volts 2 amps, 4 volts11 amps, 2 volts 2 3in. inlet, 3in. outlet, 67.10.0, carr, 716. amps, these transformers are new immersed Max. 9in. LIGHTING PLANTS. Briggs & Stratton, in oil, can be taken out of the oil and used 350 watts 12118 volts D.C. with Switchboard as television transformers, giving output and fuel tank, 630.Lyon Norman, 550 of 10 mlamps, overall size of transformers watt 12118 volts D.C., mag. ig. with Slbd. separately 5iin. x x 4in. and 3in. x 3in. and tank, £35, surplus stock reconditioned x 21in., price 6311010 each, carriage paid. Column dia. and offered as new, tested on load.Other EX RADAR TYPE 101R.F. UNITS Depth of feed sizes in stock, write for list. (NEW) containing 6 valves,including I in. TRANSFORMERS formodelrailways. grounded grid triode F.H.P. 24 volt Univer- 21 in, etc., 1051230 volts input, 12 volts 3 amps. sal motor, numerous resistances and con- output, double wound, 211-, post 116. densers, etc., 351- each, carriage 316. HEATER ELEMENTS, 24 volts 75 watts, MAINS TRANSFORMERS (NEW) for soil warming, etc., 116 ea.Ten can be suitable for spot welding, input 2001250 used in series off 240 volt mains. Special volts, in steps of 10 volts, output suitably Weight price for quantity orders.' tapped for a combination of either 2141618110 0-iin. 3 jaw RECTIFIERS, A wave Selenium, 500 volts or 12 volts 50170 amps, 874 each, carriage 17 lbs. 40 m.a., 716.20 volts I amps., 151-. 716. self -centring CONDENSERS. 250 volt Paper I plus EX -NAVAL ROTARY CONVERTERS, (7.7 kg.) I rnfd. and 2 mfd., 716 don.Hermetically Input110 volts D.C. output 230volts chuck. sealed.8 mfd. 400 volt, 4 mfd. 1,000 volts, A.C. 50 cycles I phase 800 watts capable of 2 mfd. 2.500 volts ;send for special list. 50 eer cent. overload, as new, crated weight 21,.; cwt. price £251010 each carriage forward, TELEPHONE CONSTRUCTOR'S D.C. PARTS, ex G.P.O., forwall mounting, anotherex -navaltype 110 volts comprising bracket mike in bakelite. case, input, output 230 volts A.C. 50 cycles I areof heavy and . accurateconstruction. phase 250 watts capable of 50 per cent. over- These machine tools Magneto Bell, transformer, condenser. The precision ground spindleisfitted with an automatic and Switchbook and Contacts, connection load, weight 100 lbs., price £1011010 each, strip in carriage forward. adjustable feed control, andballthrust.Castings are of finest pol. wood box Bin. x 6in. x 3in.. MAINS TRANSFORMERS(NEW), hand magneto Generator and single input 2001250 volts in steps of10 volts grey iron.All machines are guaranteed. G.P.O. Receiver, 351- per pair, carr. 51-. output 350101350volts 300 miamps6.3 CRYSTAL SETS.The LesdixFestival volts 8 amps twice, 4 volts 4 amps, 5 volts Model in black bakelite case, tuning coil, 4 amps 651- each, carriage 316, ditto, 450101 PRICE 451- carriage216. variable tuning condenser, diode everset 450 volts 250 mlamps 6.3volts 8 amps detector and headphones, 301-, post 116. twice 4 volts 4 amps, 5 volts 4 amps 651 - Morse Keys, Buzzers, Magnets, Vibrators, each carriage 316, another input as above, We take this opportunity of thanking the many customers who have been kind enough Thermostats, Microphones, Relays, output, 500101500 volts 250 mlamps 6.3 to write expressing their appreciation of the quality and value of these mazhines. Switches, Motors,Dynamos,etc.,etc. volts 8 amps twice 6.3 volts 4 amps, 4 volts Send us your enquiries. 4 'amps, 5 volts 4 amps, 701- carriage 316. Another, wound to (electronic) specifica- From the manufacturers : Please include postage formailorders, tions, 350101350 volts 250 mlamps 4 volts QUEENSROAD. ELECTRADIX RADIOS 8 amps, 4 volts 4 amps 6.3 volts 8 amps. ELLIOTT MACHINE CO. TWICKENHAM 01216.3volts2 amps, 6316 each, carriage 214, Queenstown Road, London, S.W.8 paid, another input as above output 5001 T lephone: MACoulay 2159 3501013501500 volts 250 mlamps 6.3volts 6 amps 01216.3 volts 2 amps, 01415 volts 4 amps twice, 6716 each, carriage 316. PRE -PAYMENTII- SLOT METERS 2001250 volts A.C. 50 cycles I phase set at BANKRUPT BARGAIN 3d. per unit, 601. each, carriage 51-.Ditto for D.C. mains, 451- each, carriage 5/-(all BUY NOW. -Stocks 20 amp load). SWITCHBOARD METERS.4in. scale moving coil (D.C. only), 0 to 14 amps., 1716 may not lasttill each,post116. MAINS TRANSFORMERS (NEW). In- winter put 200/250 volts in steps of 10 volts, outputs, 350101350 volts180 mlamps 4 volts 4 amps 5 volts 3 amps, 6.3 volts 4 amps A.C. MAINS MIDGET RECD 3916 each, post 116, another350101350 volts180 mlamps 6.3 volts 8 amps, 01415 RADIO RECEIVER volts 4 amps, 3916 each, post116, another Why not build a few an -mains receivers 150wile. 4 volts 4 amps this Autumn, and you will find them ready makes ideal 500101500 volts sellers among your friends and relations, CT., 6.3 volts 4 amps, C.T., 5 volts 3 amps, or maybe they will solve your Christmas 4216 each, post1;6,another 425101425 Present problem. volts160 mlamps 6.3volts 4 amps, C.T. We can offer all the parts and cabinets, ' mock-ups' twice 5 volts 3 amps, 4216 each, post116. complete with all the mechanical and ELECTRIC LIGHT QUARTERLY decorations' de tails, chassis, tuning scale, TYPE CHECK METERS, all for 2001250 knobs, back, etc.The one illustrated isthe" ELPREQ OCCASIONAL 4 ": volts, A.C. 50 cycles I phase, 5 amp load, this costs less than £6 to make and it 1716 each, post 116,10 amp 211- each, post really is a nice -looking job that plays ' Plasticine' is unique ; for 116, 20 amp load, 251- each, post 116. well.Constructional data and detailed SLIDER VARIABLE RESISTANCES, price list. 118.Cabinet in walnut, green prototypesand or ivory with knobs.Printed dial and " mock-ups " 14 ohms. I to 4 amps., 1216 each postII - 101- each, baokplate, pointer, metal chassis com- Another 0.4 ohms, 25 amps., pletely drilled, fibre back, and construc- there is nomore practical post 116. tional data, 31'6. plus 2.6 post, MAINS TRANSFORMERS(NEW), THE "LECTROSS" TOWEL AND 2001250 volts input, in steps of 10 volts, CLOTHES AIR EH. modelling material and none so 6,12, 24, volts 6 amps., 3716 The " Viewmaster " is a television set Will warm your room as it speedily dries outputs, 0, which any average man can construct your clothes. It is ideal for flats, hotels, each, post 116. Another as above but 10-12 mainly because the data has been so care- bedrooms. nurseries and for airing dainty widelyused. ' Plasticine 'is amps, 4816 each, post 116, another as above fully worked out, and even possible faults underwear, baby linen, bathing costumes, but 25130 amps, 70/- each, carriage316, have been anticipated and fully dealt etc.Size 3ft. wide by 3ft. high by Sin. long lasting, hygienic and avail- another input as above, output 0/18130136 with.Why not see this data and judge deep. Chrome -plated rails and enamelled volts, 6 amps. 4216 each, post 116. it for yourself ? We are quite willing to base. Quite portable, operates for A.C. COILS supply it on approval.Simply send 51-. or D.C. mains.Consumption only 750 able in16 attractive colours. FIRST GRADE MOVING whichamountless postagewill be watts. Absolutely safe, even for children. METERS (SWITCH -BOARD), 6i r'. scale returned to you if you don't think you Guaranteed for6 months -spares will 0 to 10 volts 251- each, post 116, 0 to 75 can make the set and return the data always be available. Made to be sold at volts 2716 each, post116, 0 to 200 volts, within 7 days. Please state whether Lon- £12.12.0 but our price only £5.19.6 plus 2716 each, post 116. don, Birmingham or Holme Moss, 7 6 carr. AUTO WOUND VOLTAGE Allparts, evencabinetsavailable. Statemainsvoltagewhen ordering. CHANGER TRANSFORMERS, tapped H.P. terms if required. 0111012001230 volts350 watts, 4816 each post 116, as above but 500 watts 6216 each, 2 -VOLT ACCUMULATOR carriage 316, as above 200 wafts, 351- each, KLAXONS Suitableforradioormodel Non -electric. Sim- HARBUTT'S PLASTICINE LTD post 116. ply pull strap to driving, houselighting, etc. DU -COIN VARIABLE TARIFF II-,Id. Heavymass -type plates -Pre- Bathampton Bath Somerset SLOT METERS 2001250 volts A.C. 50 give very loud signal. Intended for charged -only needs filling. New cycles I phase, 5 amp load tariff can be unused -size 7in.x 2in. x 2in. d.to113d. per unit, data 1 2 small naval craft varied from PO but suitable 15/-, valueforonly sheet supplied, 451- each, carriage 316. for lex W.D., works signals, etc. Post and ins. 113. ROTARY CONVERTERS, ex Early Closing -Wed., Ruislip: Sat., City. Post orders to Ruislip.5/9 L 24 volts D.C. input, 50 volts, 50 cycles, 1 phase at 450 watts output, £611010 each, 152-153, FLEET STREET, E.C.4. 716. Stepup transformer,5P 42-46, WINDMILL HILL, RUISLIP carriage to 230 volts, 450 watts, £311010 extra. E. P. E. LTD MANOR, MIDDX. (1) October, 1951 NEWNES PRACTICAL MECHANICS 33 If the paint, when dry, tends to peel off, stir into it Luminous Paint on Fabrics a few more drops of castor oil in order to render the T WISH to decorate a fancy dress with luminouspaint film more flexible.It is sometimes an advantage Apaint.Can you please suggest an effectivein this connection to brush a little of the clear cellulose method of applying it to the costume withoutvarnish on to the fabric before the paint is applied. QUERIESam4 it peeling off ?As I want it for use in amateurThis underlayer will penetrate the fabric more com- theatrical work I would like to know if there ispletely than will the paint itself and it will act as a any method by which the paint could be per-" key " to fasten the paint layer down to the fabric. manently fixed, to prevent it coming off when the costume is being used and packed. ENQUIRIES The costume will probably be made of blackout Chemical Fly Exterminator material. -Eileen Moody (Maidenhead). WOULD you please supply me with the formula of the chemicals used in an electrically NX7E suggest that you obtain from Messrs. Derbyheatedflyexterminator.Iunderstandthat & Co.,Ltd.,MillmarshLane,Brimsdown,when the heater is switched on evaporation of the A stamped, addressedenvelope,three penny Middlesex, luminous powders of varying kinds, thesechemicals takes place and the resulting vapour stamps, and the query coupon from the current materials being non -radio -active.It is possible thatproves deadly to all insects. -H. Thomas (Bickley). issue, which appears on page 8 (THE CYCLIST), this firm may supply actual paints.If so, you can use must be enclosed with every letter containing a such a material direct.If you can obtain only the THE material to which you refer is sold under the query.Every query and drawing which is sent luminous powder, make this up into a paint by in- trade -name of " Gammexane."Itisbenzene must bear the name and address of the reader. corporating it into a clear cellulose varnish or lacquer,hexachloride, and ishighly toxic to insects.It is Send your queries to the Editor, PRACTICAL such as you will be able to obtain from any large paintvolatile, so that when it is spread on a heated surface, MECHANICS, Geo. Newnes, Ltd., Tower House, store. it goes off into the air.You cannot possibly hope to Southampton Street,Strand,London,W.C.2. You can obtain a clear cellulose lacquer of this type make this material for yourself.There is no " formula " from Messrs. Wm. Canning & Co., Ltd., Great Hampton for it.You will have to make inquiries at I.C.I., Ltd., Street, Birmingham, price about 7s. 6d. per pint, orLondon, S.W.I. you can make a simple type of clear lacquer yourself Another volatile mixture is one of naphthalene (meth by dissolving clear scrap celluloid in a mixture ofballs) and para-dichlorbenzene, in about equal pro- Testing Vacuum in Sealed Envelopes equal parts of amyl acetate and acetone, and by adding portions.This is not anything like as toxic to insects a few drops of castor oil to each half-pint of the lacqueras is " Garnmexane."Yet it is a useful mixture for T WOULD appreciateyouradviceonthein order to make its film more flexible. keeping away moths and gnats. following problem. I.C.I., Ltd., produce their" Gamrnexane "in a special I wish to test for vacuum envelopes made of form whereby a charge of it can be ignited.Clouds Foil Pliofilm after they have been filled with of vapour are then generated, thus rendering every one ounce of vegetable material. Readers are asked to note that we have I have successfully extracted the air from these surface in the room completely toxic to all forms of envelopes and sealed them off, but require some discontinued our electrical query service. insect life. means whereby I can test the packets to ensure Replies that appear in these pages from that the contents are virtually in a vacuum until time to time are old ones and are pub- Compressorless Refrigerators required for use. lished as being of general interest.Will CAN you give me an explanation of how a Com- Can you suggest any means I can employ to pressorless refrigerator works ?I under- apply a quick test to these containers ?-H. E. readers requiring information on other stand that, in some way, it makes use of Dalton's Newport (Edinburgh). subjects please be as brief as possible law of partialpressures. -G. E. Williamson, with their enquiries. (Bickley). NIVE assume that the degree of vacuum within the sealed metal envelopes will not be of a very IT is hardly practicable for us to give you a detailed high order, which means, therefore, that the envelopes account of the working of a modern compressorless will still contain a certain amount of residual air. Always remember that when the luminous paintrefrigerator, since this would involve our wiiting at We assume, further, that the vacuum -testing methodwhich has been brushed on to the fabric dries, it willleast half a dozen pages and drawing several diagrams. desired must be one that will not involve penetrationstiffen the area considerably.Usually, such paintsThe working method is as complex as it is ingenious of the envelope and consequent destruction of theare only required for edgings, so that the unavoidablebut you will find it all carefully described in a volume degree of vacuum within it. stiffening is seldom of any consequence. by H.P.Manley entitled RefrigerationService This being the case, we suggest that the sealed Costumes painted in the above manner must beManual," whirls is published by Messrs. F. J. Drake & and evacuated envelopes should be placed in a glass exposed to sunlight periodically in order to renew theCo., Ltd., Chicago, U.S.A. This book may be obtained container of suitable construction in which a fairlyactivity of the luminescent paint.Aminute or two'sfrom any good foreign bookseller, such as Messrs. Ed. high degree of vacuum may be established by means exposure is quite sufficient.If sunlight is not available, Bryce, Ltd., 54, Lothian Street, Edinburgh, or Messrs. of a rotary or a mercury high -vacuum pump. Theany strong artificial light can be used, but the directH. K. Lewis & Co., Ltd., r36, Gower Street, London, evacuated envelope will now be situated within arays of the sun have the greatest re -activating power. vacuum which is of a higher order than that existing Donoruse anyof theexpensiveradio -active Refrigerators of the compressorless type contain within it.Consequently, the residual gas particlesluminous paints.They are net safe for costume workammonia solution and hydrogen.The refrigerator is within the envelope will cause the latter to swell or tosuch as you describe. operated by its heating element which werms up the expand in some measure, the exact amount of swelling ammonia solution and drives off the ammcnia as a depending on the amount of vacuum within the gas. This gas is condensed and then allowed to re - envelope and the amount outside the envelope. An evaporate. The re -evaporated ammonia (gas) is re- envelope which had been subjected to this test would absorbed in water, which, not being near the heating not in any way be destroyed and its internal vacuum THE P.M. BLUEPRINT SERVICE element, is maintained relatively cold. This absotbing and contentswould remainintact.Foraccurate water, in reality, takes the place of the mechanical measurement it might be possible to cement a light I2FT. ALL -WOOD CANOE.New Series, No. I. pump, because it maintains a state of relatively low needle to the outer sides of the metal envelope and to 3s. 6d.* pressure whilst the cold -producing initial evaporation secure the envelope in some fixed position so that the 10 -WATT MOTOR.New Series. No.2. 3s. 6d.* of the ammonia is proceeding.The hydrogen obeys swelling of the envelope would cause the needle to COMPRESSED -AIR MODEL AERO ENGINE. Dalton's Lawof PartialPressures, and helps to maintain travel across a fixed scale. NewSeries.No. 3.Ss.* a pressure equilibrium in the system.It also assists The whole arrangement will, naturally, have to be AIR RESERVOIR FOR COMPRESSED -AIR the circulation of the ammonia from the evaporator to determined in detail by dint of experiment, but, with AERO ENGINE. New Series.No. 3a.Is. the absorber of the machine. care in the construction of the instrument, we see no Such is a very brief explanation of this system of reason why the notion should not work sufficiently " SPORTS "PEDAL CAR. New Series. No.4.5s.* refrigeration which forms the basis of the " Electrolux " well to enable you to derive reliable indications from it. F. J. CAMM'S FLASH STEAM PLANT.New refrigerating and other systems.If you will prccure a Series.No. 5.Ss.* copy of the above -mentioned volume or consult it at SYNCHRONOUS ELECTRIC CLOCK.New a library, you will find therein a complete elucidation Cleaning an Electric Cooker Series.No. 6.Es.* of the subject in both its theoretical and its practical T HAVE an electric cooker in my pre-fab, and ELECTRIC DOOR -CHIME.No.7. 3s. 6d.* aspects. J.the casing is made of aluminium or one of ASTRONOMICAL TELESCOPE.New Series. its alloys.Could you please tell me how to clean No. 8 (2 sheets).7s.. Interior Decorating the burned grease from the inside of the oven, CANVAS CANOE.New Series. No. 9.3s. 6d." I AM shortly moving to a larger house, which as caustic soda preparations are not to be used Ishallattempt tocompletely redecorate on aluminium ? DIASCOPE.New Series. No.10. 3s. 6d.* myself, and would like your advice on the follow- How can I clean the aluminium grill reflector EPISCOPE.New Series.No.I I. 3s. 6d.5 ing points. that has been immersed in a weak soda solution PANTOGRAPH. New Series. No. 12.Is. 6d.' (a) I want to use one bedroom as a nursery, and turned black ?-R. Greenwood (Corby). COMPRESSED -AIR PAINT SPRAYING and would like to finish the walls so that they are PLANT. New Series.No. 13. 7s.6d.. really washable.Could Iuse enamel for the mETALLICaluminium is soluble in hot solutions walls and if so, what preparations must I make ? of caustic soda with the formation of sodium f20 CAR The walls are at present papered. aluminate.Despite this fact, a cleaning preparation (Designed byF.J. CAMM) (2) I require a similar washable, gloss finish in containing caustic soda may be applied momentarily Its. 6d. per set of four sheets.* the scullery, which is of distempered brick and to an aluminium surface, always provided that it is MASTER BATTERY CLOCK wooden ceiling.This room is half -tiled with well washed off afterwards. Blueprints (2 sheets),3s. Id. whiteglazedbricks, to that Irequire a white Ordinary washing soda (sodium carbonate) does not Art board dial for above clock, Is.* paint or finish. attack aluminium or its alloys in this way.You would, OUTBOARD SPEEDBOAT (3) The bath is not panelled, and I wish to do therefore, be safe in using any such solution to remove 10s. 6d. per set of three sheets. the dirt and grease from your cooker.You could also this myself.Can you tell me where I could get use ammonia for the same purpose. SUPER -DURATION BIPLANE thin plastic sheets of a suitable size for this Another solution for the above purpose is made by Full-size blueprint, 2s. purpose ?-R. A. Horne (Birmingham). dissolving one part each of sodium metasilicate and THE 1-c.c. TWO-STROKE PETROL ENGINE (\ First of all, strip the paper from the walls of the trisodium phosphate in about five parts of water, and Complete set,7s. 6d. i) future nursery.This is a tedious task, but it is stirring into this solution a quantity of soft soap or STREAMLINED, WAKEFIELD necessary if you desire a good foundation for the paint. of soap jelly.This solution will attack hard, greasy MONOPLANE - 3s. 6d. Give the stripped walls a light washing down.Allow surface grime, but will not injure the aluminium metal. LIGHTWEIGHT MODEL MONOPLANE them to dry out.Then brush them over with a It is probable that your blackened aluminium plate Full-size blueprint, 3s.6d. solution made by dissolving six parts of glue in 94 parts is composed of a certain alloy, since the pure aluminium of hot water, and use this solution hot.It will act as would not react in this manner. The only way to P.M. TRAILER CARAVAN size for the walls. clean it is by immersion in weak hydrochloric acid for Complete set,10s. 6d.. You will now be ready to apply the paint.There a minute or two.For this purpose, dilute one part P.M. BATTERYSLAVE CLOCK --2s.5 are two methods of doing this :- of strong hydrochloric acid with three parts of water. (a) Use a flat paint as an undercoating, and a gloss The acid will, of course, attack the aluminium, but it The above blueprints are obtainable, post free, or enamel paint as the final layer. will first act by removing the blackness,"so that the acid from Messrs. George Newnes, Ltd., Tower Moire, (b) Use a single coat of one of the new " scrubbable " may then rapidly be rinsed away from the article. Southampton Street, Strand, W.C.2. paints.For this purpose, we recommend " Murac," Apart from this method, we can only recommend which is manufactured by Messrs. John Hall & Sons, some abrasive method, such as the use of a scouring An * denotes constructional details are available, free, Ltd., 4, Cadogan Road, Hengrove, Knowle, Bristol 4, powder, followed up with an ordinary metal polish, with theblueprints. and from which firm you can obtain literature and or a paste of fine silica flour and light oil. addresses of your local retail suppliers.This paint 34 NEWNES PRACTICAL MECHANICS October, 1951 gives a matt finish.It can be had in delicate pastel of light which will pass through it, and the higher shades, and it can literally be scrubbed.It is ratherDissolving White Shellac will be the brilliancy of the image as seen through the expensive, costing about its. per quart, but, on aT HAVE about rlb. of white shellac and I cannotinstrument-other factors, of course, being equal. well -sized surface, its initial cost is lowered by its get it to dissolve in methylated spirits ;it Thus, a binocular instrument having object glasses excellent covering -power. remains suspended in the spirit no matter how Iof, say, 3z mm. diameter, will give a more brilliant (2) For your scullery, we recommend a thoroughlyshake it up.-S. Harper (Wednesbury). image than one having object glasses of 26 mm., when good scrubbing of the walls, so as to remove as much should be perfectlysolublein these objective glasses are used under the same condi- of the distemper as possible.Follow this up with twoWHITEmethylated shellac spirit, and if you find that the materialtions.In other words, the 32 mm. instrument can sizings (as above described).Then apply a coat of awill not dissolve in it, the inference is that it is notbe said to havea greater light -transmitting power flat white paint.Over this, use a two -coat finish ofwhite shellac, or that it is very highly adulterated. than the 26 mm. instrument. white gloss paint. Perhaps, however, your method of effecting the solu- p We are not so sure that you have done well to decidetion is not correct. The white shellac should be placed " Bee Wine" on aglossy finish for your scullery walls.Glossy surfaces tend to condense steam and to give rise to ain a bottle and sufficient methylated spirit added toT SHALL be glad if you will give me any informa- cover it to a depth of about an inch. The bottle is tion regarding bee wine. stream of water on the wall, whereas a semi -matt orthen allowed to remain undisturbed overnight-or, This had a vogue about the 192os and was a matt surface " holds " the condensed steam betterbetter still, for an entire 24 hours. After this time, themade from some substance placed in a jar of water in the form of an invisible film which evaporates muchshellac should be in a partially dissolved, gelatinous and fed daily with sugar, the resultant liquid more readily than a stream or rivulet of water.You state. The bottle is now put into a pan of cold water.becoming a palatable, and, possibly, alcoholic might, we think, with advantage use a matt finish onThe cork is removed from the bottle, and the water" wine." The substance mentioned, in combina- your scullery walls.For this you can use two coatsin the pan is slowly raised to the boiling -point, the bottletion with the sugar, apparently caused some form of a flat white oil paint, or two coats of " Murac "being shaken from time to time. The shellac should nowof fermentation. Particles of the substance used (white) as recommended above. dissolve completely in the hot methylated spirit.Ifto move up and down in the water and also increase (3) You will be able to obtain plastic sheets fromthe solution sets to a jelly on cooling, heat it up again,in bulk. Messrs. R. Denny, 15. Netherwood Road, London,and add more methylated spirit until you have a solution What is this substance, and can the resulting W. 14.Such material, however, is apt to be expensive. of the desired consistency. liquid be classed as a wine ?-J. C. Cox (Hythe). On the other hand, we would not advise you to use an ordinary hard board ina bathroom, since, by MHE species of mould which is utilised in the making absorption of moisture, this material is apt to buckleBi-metal Flasher A of bee wine is usually known as the ginger -beer and warp.In our opinion, plywood would suit the plant.It is a white, yeast -like substance which, in a job admirably, provided, naturally, that it were suitably T REQUIRE a circuit diagram for a unit to give suitablemedium, continually reproduces itself by an intermittent flash on a lighting circuit. painted and finished.You could also consider theI want to use it with Xmas tree lights so that theybudding. We do not know where you can get it from use of plaster -board.This would require to be wellflash at intervals.The time interval does notat the present time, but possibly a good herbalist might painted in order to reduce its absorptive qualities.Itmatter.I believe there is a circuit which usesbe able to procure some for you. would not buckle, but it is brittle, and would notcondensers and this is the type of circuit I would The procedure for making the bee wine is as follows: stand up well to mechanical knocks, blows and other Dissolve stoz. sugar and 40z. treacle (not syrup) in prefer.The mains are A.C.-J.. Hanna (Shire - 112 pints of water.Place the liquid in a glass jar and shocks. moor). put a few small pieces of the ginger -beer plant in the liquid.Each day add about a teaspoonful of sugar. Staining and Polishing a. This addition willset up a brisk fermentation so that Wood Block Floor Contact scg..16LompS on the following day a portion of the fermented l liquid Heating element can be filtered off and drunk as the " wine." The T HAVE recently bought a new house fitted 9 LI ginger beer plant itself quickly grows, and portions with wood block floors. The wood is in its of it can be used to set up new batches of liquid natural state and shall be glad if you can tell Bi-metalstrip in other jars.The plant requires a moderate room me how I can make them have that dark temperature in which to grow. and polished appearance which you see in so S Metal having lower co -efficient Ordinary yeast can be used in this manner to many large buildings.-E. Jones (Bristol). Supply of expansion give an alcoholic liquid,but the liquid derived QCRUB the wood block floors with soap and from the above -named fermentissuperior in " water to remove all dirt, grease, etc.Then, flavour. after the blocks have dried out thoroughly, brush In our opinion,it would be difficult -to cla-sify the them over with a mixture of equal parts of boiled linseed Connections for a bi-metal flasher. beverage as a true " wine," but it is certainly an alcoholic oil and white spirit, to which a little drop black or umber liquor,since it may easily contain up to to or 12 per cent. alcohol. has been added. Let the blocks again dry thoroughly, then AA TIMING circuitemploying condensers would be polish them with floor polish in the ordinary way. unnecessarilycomplicated forthecontrolof This will give a good floor which should last 2o years Xmas tree lights.We suggest that a simple bi-metalRemoving Condy's Fluid Stains without restaining.Umber has a dark brown colour, flasher would meet your requirements.For this you Front a Bath and you may think it preferable to a true black, evenneed a bi-metal strip, which consists of two metals if the latter is only used in small amount. Please notehaving different coefficients of expansion which areT HAVE a porcelain enamelled bath which is that the above -mentioned colours are not soluble injoined together throughout their length.This strip is badly stainedwithCandy's fluid.I have the oil. They are absorbed by the wood, along with encircled by a heating element, consisting of a coil ofbeen unable to remove the stains. On the advice oil.Be careful not to add too great a proportion ofresistance wire and the connections are as shown in theof a chemist I tried a solution of ioz. oxalic acid colour to the oil, otherwise it will brush off from thediagram. in t pint water and with very hard rubbing it was surface. When current flows through the lamps the heaterpossible to remove the stain but, unfortunately, Before polishing with floor polish, you can brush overwarms the bi-metal strip, the metals expand and thethe glaze of the enamel also came away. I the oiled floor a solution of one part of shellac in twostrip curls so that contact is broken at the screw, pro-should be gratefulifyou could suggest any parts of methylated spirit.This will give the floor anvided the strip has been mounted the right way up. means by which the stain may be removed without additionatgloss although, by some people, this gloss isWhen the current is cut off the strip cools, contractsaffecting the enamel.-J. F. C. Newitt (Wolver- objected to.We ourselves find that a well -polishedand makes contact again. Enclosure of the element andhampton). floor, stained on the above lines, is quite satisfactory,strip will increase the length of the " off " periods.OXALIC solution will not remove a Condy's fluid provided that the colour is not overdone. Like all floors, The size of element required will depend upon the stain satisfactorily, besides which itis a very of course, it must be treated with wax polish from timelamp current.The Midland Electric Manufacturingpoisonous substance to work with. to time. Co., Ltd., of Reddings Lane, Tysely, Birmingham, x r, You will find the following method quick and effective An alternative treatment is to make use of an anilinemake a bi-metal strip and overload element rated atand entirely harmless. Provide yourself with the two dye. Obtain from your nearest paint shop, a quantity of0.3 to 0.4 amps and also one rated at o.6 to 0.8 amps.,following solutions : a suitable wood stain, which must be spirit soluble. which could no doubt be adapted for your purpose. (1) Acetic acid, t part; water, 4 parts. Dissolve this in methylated spirit-about x part of stain (z) Sodium sulphite,t part;water, 3-4 parts. in ro-r5 parts of spirit.Brush the resulting solution Have two soft rags, one saturated with solution a, thinly over the cleaned and degreased wood surface.Magnification of a Telescope the other with solution 2.Rub the first rag over a Then polish up with normal floor polish. rAN you inform me if there is any method stained area of the bath, and then the other rag immedia- Either of the above treatments is effective, but the-+of calculating the magnification of a tele-tely afterwards so that the bath surface is successively first method gives a more .durable stain which seems scope without removing the lenses ? wetted with each solution. The Condy's fluid stain to have more` body " in it, and which, also, is quite Also, what is meant by the light transmittingwill rapidly vanish, after which the bath should be unfadable in sunlight.Aniline stain, for the mostpower of binoculars ?-A. Kirton (Normanton). well rinsed out. part, will not resist the action of strong sunlight. If the stain has penetrated below the surface enamel THE amount by which a given telescopemagnifies of the bath it may be very difficult to eradicate.In depends on the focal length (or " focus ") of thethis case, apply the solution hot and with a brush. Dyeing a Carpet objective or front lens, and the focal length of the eye-Apply them liberally. By repeated treatment in this WILL you please let me knowhow to make apiece lens, and is equal to the ratio of these two quanti-' manner you will get rid of the stains without any actual dye, red or blue, for a carpet of 12 sq. yds. ? ties. Hence, if you know the focal lengths of the objective and eyepiece of your telescope, you will be able to abrasion of the bath enamel. It is now a medium green colour.-A. J. Gould,work out the magnifying power of the instrument Do not use oxalic acid, which is useless for the (Billingshurst). without removing the lenses. purpose, quite unnecessary, and severely poisonous. TT is not practicable to dye a carpet by home methods The magnifying power of a telescopeisusually Aof brushing the dye solution on to the carpet.Forexpressed in " diameters."Thus, if a small telescope A CORRECTION this reason, we do not advise you to make the attempt.is said to have a magnifying power of 16 diameters, Carpets dyed in the above manner are never satisfactory. this means that the diameter of any object seen throughTN the circuit diagram for a small generating plant, They are always patchy and the applied dye comes offthe telescope looks t 6 times as large as it appears without A published on page 358 of the August issue, the very badly indeed. Time and money are wasted and the the telescope, which is practically equivalent to sayinglead from the regulating resistance is shown wrongly last state of the carpet is worse than the first. For anythat the object viewed through the telescope appearsconnected. It should, of course, be connected as shown type of dyeing, the entire fabric must be immersedonly one sixteenth as far away as it actually is. in the diagram below, so that the shunt windings and bodily in the dye solution, heated gradually to near Sometimes the magnifying power is assumed to beresistance are across the two dynamo brushes. boiling point, and then thoroughly well rinsed.Eventhe number of times that the area of an object seems Shunt Field Windings this orthodox process is liable to shrink the carpet. to be increased.And because areas are proportional Regulating Double However, if you wish to go on with the job, the carpetto the squares of lines, the magnifying power of a Resistance Pole must first of all be washed and rendered clean and grease - " t6 diameters magnification " might be termed a Switch free. After this, brush it over with a solution of I part" power of 256." of tannic acid in about 16 parts of water. Let this dry in. When light passes through a telescope or a telescope - Then apply the dye solution by means of a brush. The prism system (as in the case of binoculars of the pris- tannic acid, having been absorbed by the fibres of thematic type), some of the light is always lost by absorp- carpet, will combine with the dye (or with some of it)tion and by reflection at surfaces.Hence, strictly and will thus " hold " it.Finally, the carpet must bespeaking, the light transmitting power of a telescopic swilled down with COLD water several times and theninstrument is the ratio between the amount of light 7b allowed to dry slowly. which enters the instrument and the amount which Lighting To make the dye solution, dissolvetpart of anyultimately emerges through it at the eyepiece end. Cn-cults aniline dye in 6 parts of water.The dye solution In the case of binoculars, the term is usually employed should be used hot. more loosely in reference to the diameters of the You cannot dye a green carpet red, for the reason objective glasses.It will at once be realised that the Voltmeter Fuse that the imposition of red on green will tend to givelarger the diameter of an object lens (or " front " lens) the fabric a grey -black appearance. of a telescopic instrument, the greater will be the amount Circuit diagram for a small generating plant. October, 1951 NEWNES PRACTICAL MECHANICS 35 TAKE UP HIGHSTONE UTILITIES Crystal Sets. MORE POWER TOOLS Our latest Model is a real radio PELMAN ISM receiver,which is fitted with a FOR YOUR WORKSHOP permanent crys- For All Times tal detector.WhY not have a set in your own room? and Circumstances 1016, post 6d. De LuxeReceiver has stood the in polished oak cabinet, 18/6, pELMANISMtest of time. During the last post 1/-. half -century, in peace and war, in SparePermanentDetectors, 21-each. When ordered separately, 2/6.With clips times of prosperity and of depres- -and screws. 2/10, post 3d.headphones, sion, it has helped and encouraged brand new. S. G. Brown, G.E.C., etc., 15'-, men and women in all the affairs 23/-, and super -sensitive, 30/- a pair, post 8d. New Headphones, 10/-, a pair.Balanced of life.Now in these times of armature type (very sensitive), 12/6 a pair. strenuousendeavourtwofacts Both post 8d.New Single Earpieces, 3/6. Bal. armature type, 4/6; ex-R.A.F. stand out against a background of earpiece, 2/-, post 4d.Headphones, in good order. 5/6 (better quality. 716).all evidence-the increasing number post 8d.Headphones with moving coil of men and women who want to mike, 15/..Similar phones with throat mikes, 12/6, post 8d. Headphone -Cords, make a success of life, enrolling 1/3 a pair, post 3d. Replacement Bands, for the Pelman Course ; 1/3.post 4d. Wire Bands,6d. the con- (All Headphones listed are suitable for tinued supportof serving and use with our Crystal Sets.) ex -ServicemembersofH.M. Bell Transformers. These guaranteed Forces. transformerswork This increasing demand proves from any A.C. Mains, giving3,5. the creative and re -creative value or -6 volts output at I amp., operate bulb, of Pelmanism. Minds under stress buzzer or bell.Will and strain are sorely in need of supply light in bedroom or larder,etc. PRICE 8B, post 8d. BELLS for use with restfulrecreation and soothing either the above or batteries, 6/6, post 6e1. stimulus. Pelmanism gives all this " Big Ben " Chimes.Housed in Cream Plastic Case.Easily connected to give and more.It is the way to clear Two -Note Chime from Front Door, and thinking and calm but determined Single Note from Rear. Operates from 6-9 voltBatteriesorTransformer (shown action underallcircumstances. £9 above), 19'3, post 10d. You cannot be harassed by anxie- -POLISHER burn- Ex-R.A.F. 2 -valve (2 -volt) Microphone SANDER polishing, Amplifiers as used in 'plane inter -coin., ties,fears and worries,or feel 5 INCH sanding, cleaning tool for old paint, in self-contained metal case: can be used helpless, mute and fearful in times all-round rust and to make up a deaf -aid outfit. intercommuni- The ideal removing available. cation system, or with crystal set: complete of sudden emergency when drilling, of accessories with valves and fitting instructions. 20/-. ishing, Full range post 1/8. Useful wooden box with partitions imbued and buoyed up by the metal etc. to hold amplifier, 2/- extra.Ditto, less friendlypersonalguidanceof up wood, valves, 10/-.One -valve amplifier, complete Pelmanism. TaketheCourse with valve. 10/6, post 1/-. Hand Allerophones, with switch in handle to -day and possessthoseself- caonidl,le7a6d,, post4/-. Similar instrument, moving reliant attributes permanently Sparking Plug Neon Testers with vest- enjoyed by over 750,000 grateful YES...more 'HANDY -UTILITY' pocket clip, 313, and with gauge, 3/6, post 3d. Pelmanists. S.B.C. Neon Indicator Lamps, for use on low-pricedelectrictools! mains, showing " live " side of switches, etc., 3'6. post 4d. Soldering Reduced fees for serving and ex -Service More power to speed your Irons. Our members of His Majesty's Forces newstream- (Apply for Services Enrolment Form) work . . more scope for lined Iron is fitted with your craftsmanship! Take a Curved Pencil Bit.200/250 v. 50 watts, 10/-, post 6d.Standard Iron with adjustable A True Philosophy bit, 200 250 v. 60 watts. 11/-, post ed. Heavy look at the Sander -Polisher Duty Iron, 150 watts. 14/-, post fhl. All parts Pelmanism is a true philosophy 1/2 INCH DRILL Ell .7.6 replaceable and fully guaranteed.Small forordinarysensible -the quickest, easiest way Soldering Irons, for use on gas, 1/4, post of living Capacity in steel, I" (up to 3' 4d. Resin -cored solder for easy soldering people who wish to make the best in sheet metals, using a HOLE of sanding wood or metal, 6d. packets, or 1lb. reels, 6/-, postage extra, of themselves atalltimes and SAW); in hardwood, Bench Mierophoues.-Just thethingforim- Stand available for assembly wax polishing, buffing, wire promptu concerts, room -to -room communi- under all circumstances. as Drill Press. cation, etc.Bakelite table model, 6/9: The general effect of the train- Suspension type,8'6. Post 6d.Mike wheelbrushing,grinding! Buttons (carbon), 21-.Muting Coil, 4/6: ing isto induce an attitude of Transformers, 5!-.All post 4d. each. mind and apersonalefficiency Takes twist drills, too, up to Rotary Transformers, 24 v. input; Output 1,230 v...2 amp. in case with suppressors. favourable to the happy manage- 1/4 inch. And look at the big etc., easily converted to run as a high voltage motor, 25/-, carr. 3/6.Also 12 v' ment of life. input: Output 6 v., 5 amp.,: 150 v., 10 mA..: Remember-Everything you do is new drill !Both tools are as and 300 v., 20/240 mA., 22/6, carriage 3113,

preceded by your attitude of mind. morse-Keys.-Standard-size keys wired to superbly built as the original work Buzzer or Lamp, 3i-, post ed. Slightly simple smaller keys, 2/6, post 4d.BUZZERS, The Pelman Course is 1/4 inch 'Handy Utility' Drill 3/3, or heavy duty. 4/6, post 5d. and interesting, and takes up very 1/4 INCH DRILL L6.10.0 Terminals, brass, 2BA, mounted on strip, little time ;you can enrol on the -- and the same magnificent 6(1. pair..0005 Airspaced Variable Con- Still the most popular of its densers, 2/6, post 4d..00003 twin gang with mostconvenientterms. The kind. Capacity in steel, )1", in value. trimmers, 2/6, post 4d.24 -volt, 15 mim,. Courseisfullydescribedina hardwood Full range of 11.E.S. Bulbs for model railways,etc., 1/- each, 10/- doz., post 4d. Wander Plugs, book entitled" TheScienceof accessories available for grind- Brass, 1/6 doz.. post 4d.Fuses. -1 amp., ing,wirewheelbrushing. 1 lin., packet of 10, 2/6, post 3d. Also 150 mA. Success," which will be sent you, Polishing,etc. Horizontal and 250 mA.. same price.Hydrometers, gratis and post free, on application Stand: Bench Stand for Standard Type, 6/, post 6(1. assembly as DrillPITSS. Bargain Parcels of really useful equip- to :- ment, containing Switches, Meters, Con- densers, Resistances, Phones,etc..tot, PELNIAN INSTITUTE, or double assortment. 17/6: treble,25/-. r: (Established over 50 scare) All carriage paid.This country only. Field Intercommunication Sets, complete 130, Norfolk Mansions, with ringing hand generator, bell, signal lamp, morse key, relay, in strong metal WigmoreStreet,London,W.1. ilANM111 case with circuit diagram, 25/- each, carr. TOOLS 2/6: 47/6 pair, carr. 3/8.Ex-G.P.O. Tele- ""POST THIS FREE COUPON TO -DAY phone Twin Bells, with box, 5/-, post 9d. PRODUCTS OF Telephone hand generator, with handle, 7/6, To the Pelman Institute. 'HANDYthe fulAl sricantgces:; post 1/6; Bell, 3/6, post 6d. -UT 130, Norfolk Mansions, Wigmore THE H.U. DIVISION OF tootkits, Meters.10 v., 2 lin.Rectifier(ACC.),in acc wooden carrying case,14/6;15v.,2/in Street, London, W.1. BLACK & DECKER LTD. IL"'t°cils m'c., 9/6; 150 v., 2in., Mc., 10/-; 3,500 v. and benchstands. 3; in., min., 20/-; 6,000 v., 31in., Mc., 57/6 " The Science of Success," please 151600 v., 21n., Mc., double reading,9/- 100 Ma., 2in., Mc., 7/6; 3.5 amp., Sin., T.C. Name 5/-; 4 amp., 2/in., T.C., in case with switch 7'6.All meters post extra. Address Money refunded if not completely satisfied, OBTAINABLE FROM YOUR LOCAL TOOL SHOP, ELECTRICAL HIGHSTONE UTILITIES -- 58, NewWanstead,London,E.11. DEALER, IRONMONGER OR STORE Letters only. New Illustrated List sent on request with Callers welcoerel. 11d. stamp and S.A.E. 36 NEWNES PRACTICAL MECHANICS October, 1951

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All letters should be addressed to theEditor, "THE CYCLIST," George Newnes, Ltd., Tower House, Southampton Street, Strand, London, W.C.2. Phone :Temple Bar4363 VOL. XX OCTOBER, 1951 No. 353 Telegrams : Newnes, Rand, London Comments of the Month

UNDER 2 HOURS FORso! By F.J. C. CORUSCATING CORONERS IN 1947 George Fleming did 5o miles in WE have on more than one occasion found under two hours on two occasions, and it necessary to criticise that archaic and at that time it was considered by sometouring and the health benefits which are toout-of-date institution-the coroner's court. that he had put the record on the shelf for abe derived from regular cycling exercise.ItThe coroner seems to rule by divine right, and considerable number of years; that, in fact,has no news value, whereas speed events have. instead of confininghisattentiontothe his performance would be like some of thoseWould that it were possible to evolve somecomparatively simple one of ascertaining the put up by Harry Green.Since that timenon -racing event which couldattractthecause of death, or the owner of treasure trove, four other time-trialists have beaten Flem-same amount of editorial space in the news-he will deliver an exordium on the accident ing's figures. papers as the Tour of Britain. When the Tourwhich is a mere expression of opinion. Quite Walter Fowler was the first to beat twoof Britain race was discussed with us by aoften the remarks areirrelevant. Thus, hourswithanout -and -homerideofrepresentative of the newspaper, he informedamongst our press cuttings the other day came hr. 59 mins. 34 secs. Seven days later, G. K.us that opposition to it had been fomentedthe remarks of a coroner who had held an Bentley beat Fleming's i hr. 59 mins. 14 secs.behind the scenes, but we were able to reassureinquest on a cyclist.These are his remarks : with a record of 1 hr. 58 mins. 29 secs., andhim on the matter and to point out the reasons" Very often motor -cyclistsand motorists Fowler lowered his time to s hr. 59 mins.for such opposition. remember that they are in peril of killing 27 secs.D. J. Keeler returned a time of themselves, but a lot of cyclists do not realise hr. 59 mins. 5o secs.The following week The whinings of the N.C.U. and thethat with very little effort on their part they L. V. Willmott did a " 50 " in s hr. 59 mins.R.T.T.C. were ignored. The recent maliciouscankillthemselves by falling from their 7 secs. and highly defamatory bulletin issued by thebicycles as this man -did." R.T.T.C.is,we understand,nottogo Of course, the time is approaching when theunchallenged ! The cyclist concerned had looked round record cannot be beaten. What the ultimate whilst riding to see if his rear light was work- time will be for " out -and -home 50 " it -will When this journal was published weekly iting, had fallen from his machine, fractured his be difficult to say.Certainly the times canachieved and maintained the largest circulationskull and died. only be improved by seconds.What willof any cycling journal in the world, and this The remarks are so irrelevant and meaning- happen when the record is considered to bewas due to its policy of catering for the soless that we wonder why they were uttered at unbeatable ? Will a different set of records bemillions rather than the soo,000. We dealtall.Everyone that is driving a car or riding a created ?Or will riders still attempt to beatwith sport, but we did not allow it to pre- ponderate in our pages. motor -cycle or bicycle exercises a proper care what is unbeatable ? forhis ownsafety,orshoulddo,self- preservation being the first law of nature. THE BATH ROAD too This particular accident was one of those odd affairs which happen very rarely indeed. We THIS well-known event, one of the high- do not believe that the cyclist concerned was lights of the cycling calendar, proved to not exercising proper care. be less well organised this year than in others. The marshalling at the finishing point was On a number of occasions we have written ineffective and careless, with the result that to the Lord Chancellor criticising the conduct spectators obstructed theriders. Officials of some of these coroner's courts, and in some guilty of negligence should be made to answer cases coroners have been told to confine their before a properly constituted tribunal, and be comments to facts.There is not a cyclist in penalised if found guilty.It is a matter of the land, and never has been, who has not great importance to the riders and to the good fallen from his machine at some time or name of the sport that courses should be kept another, either in the novitiate stage or when clear, thus enabling the riders to sprint to the the roads have been particularly slippery. finish.But most important of all the course Some, indeed, have been brought off by means should be kept clear to avoid accidents. Many of steel studs intended to mark a safety zone of those present were severe critics of massed - for others, or by means of tramlines. It cannot start racing. We have yet to witness, either at be said in these cases that cyclistsfail to the start or at the finish of a massed -start race, exercise proper care. the scene at the finish of the Bath Road this year.The conditions were highly dangerous and do harm to the organisers. BATH ROAD SMITH MEMORIAL too ? We prefer to see a massed start than a WHEN the late Bath Road Smith died, the massed finish ! original Bath Road too Cup came into our possession, and it was left to us to decide PUBLICITY FOR CYCLING what event would be worthy of it. We have THE recent Tour of Great Britain sponsored given the matter a great amount of considera- by a prominent morning newspaper tion and have come to the conclusion that the brought considerable publicity to cycle -racing. cup would serve as a Challenge Cup for a Bath We must remember, however, that cycles were Road Smith Memorial too.It was at too not primarily created so that riders could test miles that Smith won the cup outright, pre- their endurance against distance or the clock. vious holders being Edmund Dangerfield and Out of to million cyclists only about scso,000 L.S.OMPTON. S. F. Edge.If any clubs are interested in this at most are interested in racing.Much less R.R.Ey suggestion we ask them to get into touch with than that are interested in track racing, as is . us.The cup is a large one weighing over 8o shown by gate figures at recent Herne Hill One of Englards moSt interest.noi ozs. and itbears, of course, the names and ckurrheS. Unkque for its two charlt the times of those who had won it. events. Herne Hill has, indeed, turned out to one above another and its gallery be a bad investment for the N.C.U. Containing the noted balustrade. Failing any interest in club circles,itis Newspapers, unfortunately, cannot devote One of the oldestpieces ofNOf man proposed to melt it down and to make another the same space to the pleasures of cycle woodwork in Lnqlancl. trophy from it. THE CYCLIST October, 1951 Wheel Location MANY cyclists find that they have to tion. A isthe cone, the end of which, B, depend fo: the correct location of theHow to -EnsureTrue Centringis slotted to take a thin spanner. This makes wheel rim in the front or back forks the end of such a shape that in some positions on pulling the wheel true with the framefor Accurate Wheel Alignment it would almost fit into the slot in the forks. and then tightening it in the forks by means In any case it would pull in and distort the To avoid malalignment in the forks, theforks when tight- rider has to hold the wheel true in the forksening up the while he tightens the hub axle or spindlewheel. Therefore, nuts and often the very tightening of thesea washer C causes the spindle torise up or down inshould always be the slot. To prevent this trouble the methodfitted of sufficient 8 j offixing shown inFig.3,a and b,is width, shown in IF/ adopted by some ofthe more particular Fig.5,atB, so makers. thattheend of The slotis formed in the fork ends asthe cone presses %0 usual just wide enough to admit the hubonthewasher and the pressure is distri-1111111101i butedoverthe width of the fork end, and its outer A C. \ face shouldbe Figs. i and 2.-(Left) The end of a front ,fork proud of the faceFig. 4.-A section through blade with the usual slot.(Right) Showing of the fork end sothe hubcone,axle,the how easy itis for the threads on the axle A washers and nut. to imbed themselves in the surface B. thatthenut E, Fig. 4,cannot bed down on the fork, but only the washer of the axle nuts.This means that should D. The amount the washer projects is shown these nuts slacken at all the wheel is imme- at F, and it should fit neatly into the recess diately put out of position and the tyre may in the fork side. touch front or back forks or backstays. With such an arrangement, the wheel, once This trouble seems to occur more often with correctly set at the factory, can always be the front wheel. centred and cannot get out of centre at the Most forks are now slottedsothat the wheel can be conveniently dropped out with-Fig. 3.-The method adopted by some makersfork ends. out removing the nuts, and this slotting hasto prevent the spindle from rising up and down An Arrangement for Wing Nuts had the effect of making the wheel position- in the slot. Where a quick -release thrust nut is used, ing alittle more uncertain. somecyclistswillgrudgethelittletime Fig.t shows the end of a front fork bladespindle, and, at the outside surface of the fork a recess X shown at a and b, Fig. 3,necessary to clear the washers (D, Fig. 4) out with the usual slot.It will be seen that the oftheirrecessesbeforethe hub canbe axle A rests up against the top of the slot andis bored out.The centre of this correspondsdropped out of the forks.In such cases, the since the axle is threaded, the weight of thewith the centre of the top curve of the slot,washers may be omitted and the body of rider rests on the edges of the threads, which the wing nut may be turned to a diameter indent themselves into the metal of the forks; to fit exactly the recess in the fork ends for the section of which is formed of three strips 3/16in.This arrangement provides a quick of soft steel brazed together-the " trapped " drop -out,andyetprovidesaccuratecen- (flattened) fork side tubes and a strip liner tralising of the hub spindle.Itisshown to make up a little width for strength. This in Fig. 6 where the end of the wing nut shows how easy itis for the threads on the A at B is seen to be a parallel fitin the axle A to imbed themselves in the edges of recess in the fork end. the layers of In the case of the back fork ends where three thick- chain adjusters are used, and the arrange- nesses of ment is not of the drop -out kind, the chain softsteel adjusters have flats and a central projecting and brass, at part which fitsin the forkslots. Thisis thesurface shown in Fig. 8, where A is the projecting B, if the nuts piece which fitstheslot. Itis shown in do not hold side viewat B, Fig.8.The axle passes the axle very through in the hole A and does not touch tight. the fork -end slots. Malalign-Figs. 5 and 6.-(Left) Showing the end of the cone pressing onthwasher, and thus dis- Where a quick drop -out is used at the rear, ment tributing the pressure over the width of thethe chain adjusters are not used, but even If thisfork.(Right)Details of a quick drop -out.there the threads of the axle need not rest occurs, one against the inside edges of the slots and the end of the (Continued on page 3) axle may bebut the circumference is wider than the slot. higher u pIn Fig. 3, a is a side view, and b a sectional the slot thanview, the recess X is of a diameter greater theother,than the width of the slot Y, but the top and the rimof the slot Y is concentric with the recess, so ofthethata washer on the axle will locate the wheel willaxle close up to the top of the slot, but the approachweight oftherider and machine;instead theside ofof being taken by the tip of the slot in the the fork nearfork end, is taken by the washer, which has thecrown.more than half a circumference support in A matter ofthe recess X in which it fits, and which also /i6in. at theprevents theaxle from coming down the axle could slot. makeas Fig. 7.-The wing nut with much as 'Ain. Distortion an extension the full width of out of centre Fig. 4 shows the end of the hub cone,Fig. 8.-Chain adjusterswith flats and a the slot. at the crown. theaxle, the washers and the nuts in sec-central projecting part which fits in the fork slots. October, 1951 THE CYCLIST 3 Why Spokes Break FA I ThereareSeveralReasons Why Spokes Break, and Theyare Rarely Due to Negligence on the Part of the Rider face.It is therefore necessary that the shape of the spoke should be such as to conform to the shape of the inside of the hole in the hub flange ; and also that the direction of pull on the spoke-the direction of strainFigs. 5 and 6.-A section and erd view of a hub -should be such as to have no effect in the using straight spokes. direction of bending the spoke. If, since Figs. t and 2.-(Left) An incorrect hole in thethis strain comes on and goes off once fortaken by one side of the head at A.This flange. (Right) A spoke placed in a wronglyevery rotation of the wheel, there is any bendconcentrates the strainat the most brittle shaped hole. which is unsupported, the metal is subjectedpart of the head and the spoke breaks as to a very slight backward and forward bend-shown in Fig. 4, which is an enlarged view AGOOD deal of attention has lately beening many times a minute. And those whoof an actual spoke taken from a cycle wheel drawn to spoke breakages, which forhave broken a wire by the process of bendingwhich suffered with continual breaking of many years were almost unknown, andbackwards and forwards, when a wire -cutter spokes. was not available, will know how this rapidly oldriders are puzzled about the epidemic Weakness of the Bent Spoke of these troubles, which has lately assumedresults in fracture-disruption of the mole- rather serious proportions. cules. Earlier designers were conscious ofthe weakness ofthebentspokedesign, and There are many conditions which lead toThe Shape of the Hole numerousarrangementsweredevisedto such breakages. Actual damage in riding Additional to this alternate bending there can be ruled out of the question-the break- overcome the defect of the bend by using is the fact that the shape of the hole in thestraight spokes in a tangent wheel. One ages are too frequent to be accounted for byhub flange is often incorrect.The hole is extraneous violence.They must arise either design is shown in Figs. 5 and 6 in section from some defect in wheel building, some " flared "eachside and end view of the hub. strain which should not be there, some defect toapproximate,in A parallel stud, A, is a tight fit in a hole in the shape of the spoke head or the hole section, a curve, butin the hub flange whose axis is parallel with in the flange, or some defect in the actual toooftenthetoolthe axis of the wheel spindle.This stud is used leaves a knifedrilled each end and countersunk to take the manufacture of the spoke. Some are inclined edge inthe tothe opinion that spoke defects are the holespoke and its head.The two holes in the againstwhichthestud were at such an angle to each other as principal if not the actual cause in a very wholepullofthe largenumber-perhapsthemajority-of required by the layout of the wheel, and the spoke comes.Thesespokes were direct from the stud to the rim. cases. t w o defects arcThere could be no bending strain on such Heading and Bending Process shown' inFigs. r a spoke, but the wheel was more expensive In the case of a cycle spoke, considerable and 2. to make and the hub was heavier. A some- work has to be done on the metal in the In Fig. t we havewhat similar arrangement was used on the heading and bending of the end. This work the spoke head bent" New Rapid," a popular machine made by is done cold, and the effect of upsetting the to a biggercurvetheSt.George's Engineering Co.-a firm metal to form the head (and to a lesser extent thanthatofthewhich made a determined attempt to popu- the bending of the metal toa right-angle section of the hole inlarise long cranks and high gears-a vogue curve)isto harden it ,and make it brittle; the hub.Our illus-at that time, which did not last. and since it is here that the strain comes, the tration is d r a w n result may often be fracture. oversize to make Those who have had trouble with certain t hi s clear. The WHEEL LOCATION (generally cheap) makes of spokes, have gotFigs. 3 a d 4.-(Left)weight of the rider (Continued lion page z) over the difficulty by annealing the head andA spoke u'th too long aand, in the case ofcorrect method is shown at Fig. 7, where the the bend by heating to a blood -red heat andcurve. (Above) A spoketherear wheel, thewing nut has an extension which is the full allowing to cool in the forge ashes. Butwith the head brokenpull of the drive (inwidth of theslot, but does not project as thiscannot be done when the spokes are away. thecaseofspokes far inside as the width of the metal of the polishedandplated,withoutthealmost in onedirection), fork end. certain danger of spoiling the plating. and the retarding strain of the hub brake This locates the wing nut correctly in the Iftheheading and bending processis in the case of spokes in the other direction, slotandtheaxleislocatedbybeing . carried out on a spoke which is toughenedhas a tendency to straighten out the curvescrewed in the wing nut. Thus a fair sur- or hard -drawn metal, the likelihood of theat A, whichisunsupported here by theface is in contact with the edge of the slot, metal becoming brittleisgreat, and some-flange. and not a threaded surface. Withdrawing times methods of manufacture, which are In Fig. 2 is shown a spoke more or lessthe wing nut by the amount of the projec- necessary to produce a tough metal, have thecorrectasto bend, but placedina holetion lets the axle free in the slot_with plenty effect of then making itso tough thatitwhich has been wrongly shaped. of roomfor movement. Butitisnot crystallisesunderfurtherworking(the The two ends of the hole have been flarednecessaryto unscrew the wing nut so far crystallisation being the direct result of thewith a tool which leaves a knife edge, assince the wing and projection will slide down further " working "). The metal then be-shown at A and A, and the spokeis sub- the quick -release slot. comes, in workshop slang, " short." Thejected to the same straintending to close The wing nut has an extension A of a dia- molecules of the metal have become so dis-the bend and, in addition, to what is almostmeter equal to the width B of the slot. This arrangedthatthemolecular attractionis a point contact at A and A, which concen-extension isa little less in length than the reduced, and the metal placed under a tensiletrates the strain.Here we have the alternatethickness of the back fork end C and so, stress.What was a fibrous arrangement ofbending and releasing strain accompanied bywhen tightened up,itdoes not come far the molecules, giving great adhesion of the acontact which almost ensures the spokeenough to touch the washer D (if oneis particles under tension (or pull), becomes abreaking at A. fitted) or the end of the cone E, where an crystalline one.It is attended by a slight inside washer is not fitted. hardening of the metal, but softening by heat-Head Sideways This arrangement allows of a very quick ing will bring it back nearly toits original Some spokes are correct as to curve, butdetachment with nothing to watch but that formation. the head is sideways.The head should actthe wing nuts are screwed back far enough asananchorageandshouldbed downto loosen the tension on the nut and cone. Tendency to Break closely in the flared end of the hole.Fig. 3It has no loose parts to get crosswise when The tendency to break is accentuated whenshows a spoke with the curve too long.Thefitting the wheel up in the fork ends again. the strains are concentrated at definite pointssection of the hole is correct, but the headIn this type of fitting the wing nut has a instead of being distributed over a fair sur- issideways and the pull of the spokeis swivel washer F carrying the projection A. 4 THE CYCLIST October, 1951

rules required two time -keepers to be present, and naturally there was only one. Around the Wheelworld I was told that the cost of hiring another time -keeper was '5os., so for this paltry sum a man was deprived of the honour rightly due By ICARUS him.The promoters lost money on the event, and did not feelinclinedtorisk National Committee RejectsB.L.R.C. when the event was eventually held only 2,000another 5os. spectators turned up.This, of course, was I think I can say, without fear of contra- rAFULL meeting of the National Committeevery disappointing for the promoters, thediction, that if such a thing asthis had on Cycling has unanimously rejected anKentish Wheelers. happened in any other sport there would application from the British League of Racing have been a first-class row.As it was, it Cycliststoberepresentedonit.This It was known by allinterestedpartiespassed unnoticed.You see,cyclists expect decision, in my view, is a right one, for how(including the N.C.U. and the promoters)this sort of thing in their sport ;they have could the National Committee representingthat, barring accidents, the race was a foregonegrown used toit, having had over half a the R:T.T.C., the N.C.U., the C.T.C., andconclusion for Jerry Waters of the Southcentury of N.C.U. misrule to look back on. the manufacturers who haveconsistently,London Road Club.Waters already had Is it not time that some of the people who jointly and severally denounced massed -starttwo wins to his credit :no one had, up tillare taking so much out of the cycling game racing acknowledge that those denouncementsthen, ever won the " paced 5o " three timesstarted ploughing alittleof itback ?If things are so bad that they feel they cannot afford it, perhaps someone could take the hat round at the next meeting and raise enough to ensure that such a mistake never occurs again. As I have said- before, the N.C.U.'s style of racing is dying expensively and beyond its means.Just managing, in fact, to keep its head below water ! "Edwardian Flashback" ONpage 72 of the July issue appeared a paragraph under the above title.Mr. J. R. Millburn, of Aylesbury, has sent me the accompanying picture.The design of the bicycle appears to have changed so slightly in the past 5o years that, but for its single front tyre brake and sit -up -and -beg handlebars, it would not look out of place on the road to -day. Although in general principles the bicycle is the same to -day as it ever was, because its fundamental units consist of a frame, two wheels, handlebars and saddle, and pedals, chain -wheel, chain, and rear -wheel sprocket, Dave Bedwell winning the 1951 " North Wolverhampton Road Race" from Jowett and it has certainly undergone considerable and Clark. Cook, who finished fourth, is screened by gowett, and the fifth rider is Alec Taylor. continuous improvement indetaildesign. -- It is a lighter machine, its wheels and tyres were unjustified, as they undoubtedly would dorunning and there had been many gallantare livelier, braking systems make C.T.C. if they permitted the League to be representedattempts, including Freddie Frost and Ernie" Dangerous Hill " notices look silly (in fact, Mills, to name only two. they belong to the period of the photo- on the committee ? graph !), gears, lighting systems and bearings I am surprised that the League was so All these factors added up, plus the factare vastly different now to what they were ill-advised as to make the, application, whenthat Waters might beat the record as well asthen.Itisalways nostalgic, howeverto they must have known what the result wouldbreaking the " hoodoo," which seemed tolook back on the past and say that things be.13y their action they have thus given thehang over the event, added spice to the race.are not now what they were then.They committee a further opportunity of obliquely Well, as we know now, Waters led the waynever were ! attacking massed -start racing. home and also broke the record, but, of course, he was not credited with it because the N.C.U.Tricycles Objects of Derision? The Tour ofBritain ICHORTLED when I read in the Sunday ONCEagain cycling has hit the headlines, Times recently the following :" It must thistime with the Tour of Britain be ridicule that prevents anyone nowadays 14 days cycle race sponsored by the Daily from riding atricycle."There are many Express and organised by the British League adherents to the three-wheeler, and they will of Racing Cyclists.The race took place tell you that it has a fascination not possessed from Sunday, August19th,toSaturday, by the single track vehicle.They also forget September ist, and it included teams from to tell you of its considerable disadvantages. FranceIreland,Scotland, England, with It is, undoubtedly, heavier, it has three tracks regional teams representing London North, instead of one, thus making the ride less London South, Yorkshire and Northern. comfortable, generally it requires a lower gear, The race was run without untoward incident, and, in fact, it is harder work.I know that and this will be a further source of annoyance those who race on them have put up times to critics of this form of racing. which do not greatly differ from those done on the two -wheeler.The factisthat the Cheap and Nasty ? tricycle was originally introduced for those recent meeting witha number of who could not learn to ride a bicycle, and AT pressmena notconnectedwiththe particularly for elderly gents to whom riding technical press, the subject of cycling cropped a two -wheeler would look less dignified than up.One of the journalists associated with riding,a tricycle. a prominent morning newspaper contended To -day, riding a tricycle, except for racing, that the outlook of cyclists generally was a is chiefly done by elderly gents.There are poverty-stricken one, and healsoargued those who think that itis easier to ride a that the sport would never attain national bicycle than atricycle.Iinvite them to recognition,in the sense thatfootball or have a shot at it ! cricket have done, until this cheap outlook is replaced by ideas on a much more generous "Angling"for Beginners" scale. QPRATTS, LTD., havejust published an As an example of this- cheap and nasty interesting little booklet entitled outlook,letus -taketherecent N.C.U. "Angling for Beginners."It costs Is. and 5omilesTandem PacedChampionship. should be of interest to all those cyclists who The advertised meeting was rained off, and Edwardian Flashback combine angling with wheeling. October, 19 51 THE CYCLIST 5 IMPORTANT NOTICE to Owners of MOTORISED BICYCLES! You've got the EXTRA MOTIVE POWER NOW you need the EXTRA BRAKING POWER w=j7IN of GOLDEN WINGS FEATURES INCLUDE frame of Reynolds531tubing Cantilevers",..) (Ladies' model with 531 tubing has Maes dropped MOST POWERFUL and SMOOTH ACTING bar); Dunlop Sprite tyres; caliper brakes; attractive CYCLE BRAKES in the WORLD finish in blue or Windsor Red with silver panels. Available on easy terms. Go and see your dealer and insist on a B.S.A.

CANTILEVERS have been given special tests on bicycles fitted with many of the leading Motor Units, and as a result they are being strongly recommended for PRICES : their complete EFFICIENCY and RELIABILITY.Your life depends upon your GENT'S MODELS brakes, and the addition of a motor unit to your bicycle makes it vital that you COUPON To B.S.A Cycles Ltd., 12 Armoury Rd., Birmingham 11 are equipped with the best brakes obtainable.CANTILEVERS will give you from kr3 .r7. 6 complete CONFIDENCE in ANY EMERGENCY.Fixed rigidly on the forks or (Plus .0 .4 . 9 tax) stays, they are always positive in action, smooth and powerful, grip well in the Please send me at once the B.S.A. Cycle Catalogue. wet, and give long service.Special models available for useonWestwood rims. LADIES' MODELS from £13 .o .o Fitted with our Locking Lever, they make the ideal SAFEGUARD against petty NAME thieving.Twelve month guarantee with all new brakes. (plus . o . 8 tax) SAFETY FIRST! Second Thoughts are Too Late! ITS TIME YOU 11411 ADDRESS THE RESILION CO. LTD. 200, LIVERPOOL ROAD, LONDON, N.1 7471 S 4 SIGNPOSTS IN CYCLING HISTORY

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Ori June Loth, 1842, after knocking over a child in Glasgow, '40 was clumsy and heavy, and it never became popular. Kirkpatrick MacMillan became the first bicyclist to be But its rear wheel drive-produced by a system of cranks prosecuted and fined.But itis not because of his un- and swinging levers -and, to a lesser extent, its plunger brake fortunate mishap that MacMillan's name is famous in have since shown the machine to be many years ahead of its cycling history.It is because he was almost certainly the time. Indeed, when pedals next appeared they were arranged first man to fit pedals to a bicycle.The wood and iron to drive the front wheel, and this method was practically machine made by this Dumfriesshire blacksmith in 1839 or universal until the advent of the modern chain drive. ISSUED BY DUNLOP-MAKERSOF THE FIRST PNEUMATIC BICYCLE TIRE 114,319 THE CYCLIST October, 1951

CLIWESDA LE THE "FLUXITE QUINS" Bargains/in Ex -Service Radio and Electronic Equipment AT WORK HAND GENERATOR COOLANT PUMP10 WATT MK II. by Packard, U.S.A. Designed for WS.48 and " If you'll pass the rope to me A turbine type, pump directly WS.18,drivenbytwo driven from semi -ball point handles, complete with I'll tie the punt tothis tree, splinedsocket(bymotor,notoperator's seat. Speed Then a spot of FLUXITE supplied), clockwise rotation, should be 50-70 r.p.m. with safety valve, sludge vent, etc. Smoothed outputs 162 v. Will put our stove right, Diam. of turbine, 6in., diam. of 60 ma. 3.1 v. 3 A. and 12 v And then for a nice cup o' pump chamber, 8)in., depth 2in. Generator dim.: x InletandOutletdiarn., 11.. in. x 6.1in., weight. 13lb. Overall dim., I x 7IxI 3in. Leg wlseat dim.:33 x CLYDESDALE'S PRICE ONLY 49/6 CARRIAGE PAID 6 x 2 weight 51 lb. For all SOLDERING work-you need FLUXITE-the paste flux Legs (2) dim.: 25 x ;in. -with which even dirty metals are soldered and " tinned." For ELECTRONIC IGNITION CLYDESDALE'S the jointing of lead-without solder ; and the "running " of white TESTER PRICE ONLY E2.5.0. Type V.E.D. Patt. 563562, CARRIAGE PAID metal bearings-without " tinning " the bearing.It is suitable made by English Electric. for ALL METALS-excepting ALUMINIUM-and can be used A Cathode Ray tester em- PUMP DESSICAT OR with safety on ELECTRICAL and other sensitive apparatus. ploying an entirely new tech- ADM.PATT. 12128 niqueinignitiontestingof internal combustion engines. FOR TELESCOPES With IFluxite joints can be " wiped " Enablestheelectricalper- AND BINOCULARS successfully that are impossible formance of the entire igni- Hand operated with tion system to be observed on spare gel cell and conn. by atm other method the screen of the Cathode ray tubes. Stroke cap 480 Used for over 40 years in Government works and by leading tubewhilethe engineis ccs. fitted humidity engineers and manufacturers. running. Will operate from gauge, reads 10-100 per cent., Of all Ironmongers-in tins, 6,12 and 24 volts D.C. or vacuum gauge 0130in.In wood from 11. upwards. 230 v. A.C.Built into a black transit case,19) x 12 x 9in. crackle case, with hinged front CLYDESDALE'S PRICE ONLY .TO CYCLISTS! For stronger wheels that and. carryinghandle,dim. : E5.10.0 CARRIAGE PAID will remain round and true, here's a time - 151 x 8) x III in. tested tip.Tie the spokes where they cross CLYDESDALE'S FEATHER! NG PUMP PRICE ONLY £35 U1402 with fine wire AND SOLDER.It's simple- CARRIAGE PAID Cat. No. H. 531. with FLUXITE-but IMPORTANT. ENGINE DRIVEN GEN-Driven by 24 v. D.C. mo- ERATOR TYPE A 5CI562tor type C280I, through ALL MECHANICSWILL HAVENa 2.1reduction gear, fluid THE"FLUXITE" InOriginal Wooden Boxes.moved by two 12 tooth Output 12 volt500watt. GUN puts - FLUX- wheels. Safety valve Clockwiserotation, 4hole ITE where you fixing.Size overall, 10in. L., xfitted. Overall di men- want it by a simple Sin.diam. Spindlein. L. x sions124 x 6x6in. Pumping rate : lubricatingoil 2 pressure. drain.Weight 24)lb.nett.gals. per min. approx. Air pressure :40 lb. per sq.in. Price 2/6 or filled FLUXITE CLYDESDALE'S Oil pressure : over 100 lb.per sq.in. Inlet 3/6. PRICE ONLY £3 0 0outlet)in. IT SIMPLIFIES ALL SOLDERING CARRIAGE PAID CLYDESDALE'S PRICE ONLY £2.10.0 CARRIAGE PAID IVrilefor Book onthe ART OF SOFT SOLDERING and forLeafletson direst front :- CASE -HARDENING STEEL and TEMPERING TOOLS withFLUXITE. LBARSIGDgE STREET Also on WIPED JOINTS.- Pricl 1)d. Each. LTD.I FLUXITE LTD., Dept. P.M., Bermondsey Street,S.E.I Phone:CLYDESDALli' South 2706-9 Branches In Scotland, England andNotthern Ireland.

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ez&- roads means mud uptotheorganisation.Such a rally is, of course, an rims in places, making the go-expensive business, and the folk who find ing hard. Our longest day wasthe needful coin will have the last word on 42 miles, and on several occa-the matter ;yetIfeelthatthe causeis sions we made a two-day stopworthy of the cost.It may be a compro- atplacestotravelround themise will be made that a combined rally of - -4..)tie great Keep regular tourist routes, using ourthis nature can be successfully held every CA 2is BROOKE. bicycles instead of motor -coachthree years, thus bringing into its enthusi- and boat.Everywhere we wereasms the younger folk who are beginning CAUL E welcomed, and once, when I wasto discover thedelight and adventure of How to Do It St,e+eltA frorK a ceinew ots cycling. tAowalls busily buying provender, afat oserlookutqka- RECENTLY, with my Ciat6s.te 5k Castdates oldpriestwithajollysmile daughter as companion, from klorntan days and was warned my daughter she must A Compact Repair Outfit IrodenearlyGoomiles the Wace occonflnemen+ takecareofthe" old man " round,overandliterally of Nader I . and not allow him to ride the URRY'S remarks inTHE CYCLIST, MR.April, 5951,criticising theusual throughthemountainsof hills ! Such, yousee,isthe S.W. Ireland. We left this country for cork,average thought of the average ancient whocyclists' repair outfit gave me cause to ponder. and it was a lovely morning when we arrived.holds the idea this cycling game is only forI think he is correct in his assertion that a screw -topped tinisthe mostsatisfactory We packed a few spare clothes, a primusthevigorousyoungster.Timeaftertimecontainer for solution; it has always been my stove and picnic outfit and, with the addi-we met similar suggestions atthe hotels ;practice to carry one. tion of a little food, were fairly loaded.I it was marvellous I could do the riding and Surelyit would be easy for the manu- will not detail our route beyond saying theenjoy it!It's nothing of the tort ;it's justfacturers to supply us with a properly designed intention was to crossas many passes asgetting and keeping cycling fit, and lovingrepair outfit.Itis my idea that something possible,findthelittlelanestoremoteits freedom. on the lines of the appended illustration would places, and really see Ireland from the in- be a convenience as 1 suppose every cyclist side, as it were. And this we did over roughA Great Success has experienced the exasperation of trying to mountain roads wriggling among thehills ICAME home just in time to attend theclean a tube with a piece of worn-out glass and only occasionally descending to the val- Festival of Cycling Rally at the Dunloppaper (probably damp).Hence, acleaner leys, hard highways, leading toand fromSports Ground on June 23rd and 24th.Atmade by moulding glass particles into the the main holiday resorts.So few touristslong last the cycling organisations and theplastic cap should afford a permanent and either cycling or motoring risk the bad roadstrade have pooled enthusiasm and resourceseffective cleaning device that would not be running over thehills, and thatisapityto run a show worthy of the game and itsaffected by dampness. The container could for the loveliness to which they lead is, incause.For years I have dreamt of such abe made in two chambers, one holding a large many cases,far more delightful than thehappening,andonthedatenameditsupply of solution and the other the usual advertised tourist routes, and no one canoccurred and satisfied everyone concerned.clutter of patches, valve tubing and talcum, possibly know Ireland unless they penetrate,Probably no bigger concourse of cyclists andetc.The solution container to have a per- take the rough-and mostly that-with thebicycles has ever been seen, and certainlyforated dispenser. smooth, and carry food for the day, forno greater enthusiasmfor thesport and Made of plastic with a screwed cap at each stopping places are frequently thirty milespastime displayed.It was a revelation toend, it should provide a convenient, light and apart ; hence the reason for the picnic things.numerous makers and retailers and a satis-unspillable outfit which could probably be Taken in this way, Ireland is the best cyc-factionto some 30,000cyclists, many ofproduced at least as cheaply as the conven- ling touring area I know.There were dayswhom came from 200 miles away,rodetionaltin box.-G.HOOD(Kingsbury). when we saw only a couple of cars. through the night and were greeted on the ground with a substantial breakfast provided ABRASIVE LARGE SUPPLY Easy, This Way by the industry.Some idea of the number MOULDED OF SOLUTION OUR troubleswereonebrokenbrakeof all-night riders can be measured by the IN PLACE cable-not remarkable on a fourteen -fact that over 6,000 breakfasts were served. FOR years -old bicycle-and one puncture, a draw-It was the wedding feast of the sport and CLEANING ing pin, head deep, right in the centre ofpastime, and the industry, for never before the tread of my rear tyre, picked up in anhave the varying interests been so joyfully area where one would not expect to find amixed. And the whole show was a real drawing pin even doing its usual job.NotBritish Festival magnificently staged by the very serious incidents, both of which wereorganisers, and as greatly appreciated by the easilyrepairable. Duringthetour wesupporters. No finer venue could have been climbed nearly 12,000ft. over various passeschosen, for the Dunlop Sports Ground makes and took our bicycles up crossings we wereexcellentsetting, not merelyasan open told it was impossible to make.The valuespace, but because of the great company's of this tour from the cycling point of viewclose association with cycling, forit should isthe fact that afit man of 72, and hisnot be forgotten that John Boyd Dunlop'sMr. G. Hood's suggestion for a repair outfit. 8 THE CYCLIST October, 19 51

Maps and Guide Books WHO can resist the fascination of a map CYCLORAMA H. .. or a good guide book ? Ifever I find myself in a town with time to spare, invented the bicycle ?(I gatherI find my way to the best -looking bookshop that not many knew the correctorstationersand browseinthecorner answer to this one! Few haddevoted to maps. Ordnance maps, handy heard, apparently, of old Kirk-pocket maps, guide -books which tell one all patrick Macmillan, the Scottishabout the towns and villages, of England . . . blacksmith.) Who wasJameshow good they are!And I am glad to see Starley . . . and where is there athat the famous " Dunlop Guide " has been monument to his memory ?Whorepublished for thefirsttime since before wasWilliam Hume, and whythe war. This is a grand volume, and apart ishe famous in the annalsoffrom the complete gazetteer there isa fine cycling ? I can well believe thatsection devoted to the care of tyres. And this " quiz " was a great success,tyres do need a little care !One might not and I commend the idea to thosealways think so from the casual way in which clubsecretaries who like, whenmany riderstreatthem, but a reasonable the winter months are upon us,amount of intelligent care will result in longer to stage a little " get together " formileageandbetterservice. Whilst, the their members, and are seeking" Dunlop Guide " is published primarily for for new ideas of entertainment.the motorist,itis an excellent volume for Cyclingand cycleshaveanthe cyclist'sbookshelf, and I am gladto absorbing background and history,have the new " Festival " edition. andtherealenthusiast always likes to learn. Gipsy Cavalcade Lure of October IT was on the fringe of the common where I met them . . . a gipsy family, with the TLOVE this pleasant month oftraditionalgaily -paintedvan,thepiebald October, when the morning airhorses,thelurcher dogs,thetawny -faced iscrisp, when thetrees of thechildren, and allthe trappings of Romany woods and coppices are turningland. Ichatted. withthem abouttheir from green to russet brown, whentravels and discovered that they had come the lordly pheasant fliesout of toStaffordshireby wayofGloucester- the plantation, and all the worldshire, Worcestershire and Warwickshire. I is mellow, and the orchards fullsmoked strong tobacco withone, Reuben of fruit. King Winter is lurk-Smith, admired his earrings and his great ing round the corner, but on thesesilver ring ;I drank tea from a tin mug, and Fine half-timber work -on pleasant October days the sun is wasintroducedtoLydia,Risinaand the frontage of Cs old still warm to the bark, the coun-Belinda . . . all fine looking girls with the Cheshire inn . tryside isstill colourful and fulldark skins and black hair of their race.I of charm . . . and no fogs haVewatched the expert preparations for their stay blot Ancient Repton yet come stealing over the meadows to on the common, and saw the pegs and mats out the landscape and blur the beauty ofwhich they would, next day, peddle around EVERYONE knows of Repton's famous thescene. Not too latefor mushroomsthe villages.A flash of the picturesque, a school, but fewer know of the ancientin the big field by the church ; not too latecameo of wanderlust, a hark -back to an older and historic St. Wystan's church. I wasfor the Michaelmas daisies inthe gardenEngland! These wanderers are folk apart, privileged recently to accompany a party ofborder to maketheircontribution toandnotatallwilltheyunleashtheir cyclists to Repton, and the good vicar con-the pageantry of the autumn scene ;and atongues; butI have always found that a ducted us over thebeautiful and age-oldgrand time in which to sally forth with gunsilver coin and a pipe of tobacco will unlock church and into the thousand -year -old crypt.and dog and secure a rabbit to augment thethe door, and to me, these nomadic people, Here in the stillness history speaks from therations!I'm making the most of this monthwhose origins are obscure and ways mysteri- stones, and it was quite thrilling to hear fromand touring the pleasant villages which dot ous;arealways %fascinating. Dusk was the lipsof the vicar the story of Reptonthis countryside.Most are rich in old innspurpling the scene when I rode away from through the ages-the burying of Mercian . . . and it is traditionalthat ale is best whenthatlittle wayside encampment, where the kings in the crypt, the pilgrimages of thebrewed in October or March! women crooned ancientlullabiestotheir devouttotheshrines ;thestoryofSt. babies and the men smoked their pipes under St. Wystan, Guthlac andSt. Chad ;the the canopy of a darkening sky. . . . transfer ofthe Bishopric from Repton toAn Artist Awheel Lichfield.And, after our tour of the church, Slogans we saw a little of the famous school, watched MOSTardent riders like to read cycling a cricket match on the pleasant playing -fields, notes in newspapers ... and I always IAM fortunate that in my village there are and wandered throughthisancient placerejoice when I finda paper which runs a two cyclists (of the same mature age as which has been a seat of learning and cul-regular " cycling feature." Such a one ismyself !) who like to " potter around " and ture for a thousand years. Not far awaythe Burton Observer-a weekly paper I readexplore the countryside. We foregather to is a make our plans at an inn which has existed ... busy bustling Derby, with its factoriesregularly. " Wheelman " not only and foundries. Cycling brings many joys,delightful writer, but a keen observer of thesince 175o or thereabouts . . . and our topics but to me, none so good as these runs outcountryside, and heis an artist of merit. of discussion range from politics to poultry - to ancient places where England's chequeredHis little sketches of inns and cottages andfarming, from radio to runner -beans, from story goes back over the centuries, and lich-wayside curiosities are delightful, and as, ofcabbages to cricket. But the other day we course, his riding is in my own area, I amtalked of advertisingslogansinthecycle ened walls and pillars speak of men and trade and voted that three of the best ever happenings of the past. . . . familiar with most of the places he portrays so charmingly in his notes. Cycling deservescoined were, " Made like a gun "; "Rudge more space in our_ newspapers than it gets it... don't trudge it " ; and "It's time you A Cycling " Quiz" . . but I know ofthe difficulties of editorshad a B.S.A."As an old advertising man AN energetic clubsecretary I know has inthesepaper -shortagedays. Isalute I found the conversation quite fascinating, recently staged, and staged very suc-" Wheelman," whoever he may be, and hopeand for our "next session " I'm taking along cessfully, a " cycling quiz." The membersthat he will long continue his pilgrimages someoldcycle catalogueswhichIhave of the club foregathered in the clubroom, andaround the villages and hamlets, and sketchtreasured over the years . . .and I have over pipes and drinks had an interestingtheir features. For myself, I am keepingno doubt that from their pages we shall find " quiz " . . . asking and answering questionsall his sketches in that ancient album whichother slogans and the sales storiesabout all of which had to relate to some phase ofis full of notes and pictures, and records of" makes " which may now have disappeared cycling, or be about cycles. Who actuallycycling days. from the cycling scene. Published about the 30th of each month by GEORGE NEWNES, LIMITED, Tower House, "Practical Mechanics" Advice Bureau COUPON Southampton Street, Strand, London, W.C.2, and Printed in England by W. Speaight & Sons, This coupon is available until October 31st, 1951, and must be Ltd., Exmoor Street, London, W.10. Sole Agents for Australia and New Zealand-Gordon & attached to all letters containing queries, together with 3 penny Gotch (A/sia), Ltd.Sole Agents for South Africa-Central News Agency, Ltd. Subscription stamps.A stamped, addressed enrelope must also be enclosed. Rate (including postage): For one year, Inland and Abroad 14s. (Canada 13s.).Registered at Practical Mechanics. October, 1951. the G.P.O. for transmission by Canadian Magazine Post. G. E. O. DUKE & CO. (Model List) TELESCOPES, TYPE MK. AA.111.- NO MAN CAN KNOW TOO This isof the twin type, built on a solid GERMANIUM base. Lenses over 2in. dia., uses prisms. Has fittings for night use and strong CRYSTAL DIODES MUCH OF HIS PRODUCT light. Packed in its own transit case, LATEST, SMALLEST, £7/10/0 each, plus carriage. SUPREME CRYSTAL DETECTOR The Ultra Lens is a revealing eye of six actual RADIO VALVES. -3/9: EA50,LP2, Fortheclose diametrical magnifications, which- brings SP61, SP41, 955, 954, and at only 5/9 : Midget Size, 51I6in. x 31I6in. scrutiny of out points of strength or weakness, and 6138, KT8, U15. U19, VP2, 6E7, VT501, Wire Ends for Easy Fixing. every conceiv- 8D2, AL60, DET19, 7C5, 706, 757, 7117. enables themostminute measure - The rest, 6/9 :ILNS, ILD5. 22013, 6K7, 416 each, postage 21d. ableobject, menu tobe gaugedaccurately. 6K6, 6SL7, 6C5, 210VPT, MVS, PenB, ,Wiring instructions for a cheap, simple, metals Actual Whether you areengaged Pen22A, 9D2, 12SK7, VP133, IlL133DD, but high quaky Crystal Set included. fabrcs,itools, re 63,- in manufacturing, buy - Pen383, EF50, VR99A, 6.15. All subject Technical Details and Selected Types fibres, it- /5/8. ing orselling,it to being unsold. The following at only minerals, is half PurchaSe Tax rate :EL33, CL33, available. f7, an ally of 6V6.6Q7, AZ31,5Z4,--FW4/500, SP4 SILICON CRYSTAL VALVE precious real value. (5 pin). stones, paint, print, manu- No instru- A FEW HUNDRED ONLY :NEW 316 each, postage 2jd. scripts, biological and botanical ment you can .1124 RECEIVER CHASSIS.-Con- Fixing Brackets 3d. Extra. specimens, cutting edges, fractured buy will more tabling 30 fixed condensers, 36 resistors, 24 trimmers (ceramic), 3 I.Fs., 3 tuning surfaces, raw materials, powders, granules, quickly justify coils, 5 Yaxley 8 -way switches. v/con- COPPER INSTRUMENT WIRE and innumerable other purposes, the ULTRA and pay for itself. trol, v/caps, 2 transformers, O.P. and ENAMELLED, TINNED, LITZ. LENS is invaluable, and presents in many instances , Full particulars I.V.If made to work, set covers Tele- COTTON AND SILK COVERED: hitherto unsuspected data which can be used to advantage. on request. vision, Police, F.M.. etc. Less valves, Most gauges available. 9/6, plus 1/6 postage. TYPE 25/1196 SUPERHET RECEI- B.A. SCREWS, NUTS, WASHERS, THE ULTRA LENS COMPANY, VER.-Newpurchase makes it possible soldering tags, eyelets and rivets. to again offer a limited number of these 75, Finsbury Court, Finsbury Pavement, London, E,C.2. bargains.NOTE PRICE,12/6 only EBONITE AND BAKELITE PANELS, each. With free drawings. These con- TUFNOL ROD, PAXOLIN TYPE COIL vert easily to A.C. Universal or Battery FORMERS AND TUBES. All -wave Receivers. 465 LFs., 4 tuning ALL DIAMETERS. condensers. 32 resistors, trans., switches, v/controls, v/holders, and all ..atest Radio Publications. the usual parts less valves. SEND STAMP FOR LISTS. BEDSIDE RADIO KIT.-Inbakelite MAKE MONEY-makingcasts ! b cabinet.4 -valve T.R,F. Universal or CRYSTAL SET A.C, for only £5/12/6. or ivory cabinet, 6/-extra. Assembled,35/-extra, ICORPORATING THE SILICON Cabinet. x bin. x Gin. Post, 2/6. CRYSTAL VALVE BATHING POOL IN YOUR withV I NAIMOLI) . , GARDEN.-Idealfor kiddies paddling. Adjustable Iron Cored Coil. ?,...- These-ex-W.D. dinghies easily deflated when not in use. Price,.55/-, plus carr. RECEPTION GUARANTEED THE ORIGINAL FLEXIBLE MOULD AERIALS. -2/9. 31/Oft. on winch, Polished wood cabinet, 151-, post 9d. ex-W.D., new. A REAL CRYSTAL SET NOT A TOY. 1 EX -MILITARY BOATS.-13ft. New. For pleasure or prOfit and withoutpre- All accessories packed in two shoulder any --packs. Inflatable. 6 guineas; plus carr. POST RADIO SUPPLIES vious experience you can mass produce PANNIER BAGS.-Rubberisedbags, 33 Bourne Gardens, London, E.4 object from a chessman to a largestatue 14in. x 101in. x 51in. Require only fixing with " Vinamold."Itiseasy towork, clips, 7/6, postage 1/6. gives excellent results, and canbe used COMFORTABLE SEATS.-Coveredin hide or moquette, 341n. x 161n. x 4in., over and over again. thick, 22/6, plus cars. Complete double " Vinamold " has been used withcomplete success for years by leading seats, same size (back 191n. high), 45/-, industries, including all the big filmstudios. Trade enquiries are invited. plus, ears. ideal for cars, caravans, utilitieg,etc. Money backguarantee. Cashwith A SPARE -TIME HOBBYWITH BIG POSSIBILITIES order please, or C.O.D. Stamps ONLY Write for full details and instructions for Lists. to :- 219, ILFORD LANE, ILFQH13, ESSEX. Ilford 0295. VINYL PRODUCTS LIMITED, (Dept.P.M.1)Butter Hill, Carshalton Mail Orders :621,ROMFORD ROAD, MANOR PARK, E.12.Grangewood 6677 TELEPHONE INTERCOM SETS BOOKS: Consists of two combined telephones " Working Model Railways " ... THE FINEST which are also microphones, connected- " Electric Model Railways " ...... 3/6 25ft.flexgivingeffectivetwo-way " Make Your Own G.O. Motor " ...3'6 FSPARKS speaking communication, no batteries, CLIP speech energised.Tested up to 300ft. RAILWAY PARTS: 00 0 Extra flex, 5d. yard.Price 8/6 Post 7d. Diecast StatiOn Figures, sets...2/9 3/4 DATA SHEETS at/key/0U Many other bargains. Send S.A.E. Water Cranes - ...... 2/84/6 for list.Trade enquiries invited. Ex-R.A.F. 16 S.W.*Boxes ...5/8 5/6 Offer theSafest, theSimplest and the L. C. NORTHALL, 20v. Bulbs for Hornby... -- 1/2/ Finest means for Constructing Tested 16, HollyRd., Quinton, B'ham, 32 Assorted Lots. W.R.,S.R. *L.M.R., and Guaranteed Designs Secondto L. ROBINSON & CO., (GILLINGHAM)LTD., Retail :416, High St., Smethwick N.E.R.. Loco. and Train 'Postcards None. Phone : WOO 3166 per I doz. 1/9 mdon Chanters GILLINGHAM. KENT. PHONE 5282 MODEL BOATS: LATEST RELEASE JetcraftPower Boats,Min.long, THE "MIDDY." A 2-valver of outstanding %FEELEY AIR PISTOLS Performance on M/L waves.All -dry bat- ADANA PRINTING MACHINES Marvellously Usually 8/6. Now 3/6. teries. Very compact and simple. Tested Print in the odd hours with an accurate for R Postage extra. " 00 " or " 0 " Parts List 3d. in Dorset under stringent conditions (15ft. Adana-still the most absorbing target prat- ' TYLDESLEY & HOLBROOK (M.E.T.A.), aerial 5ft. above earth). L.S. results on of crafts. No. l 11/8 109, DEANSGATE, MANCHESTER, 3. Ship -to -Shorestations,both" Third" Machine14.10.0 wavebands, " Light "ditto.Regional No. 2 HIS Machine No licence required to stations plus Continental.The ideal set £9 . 15 . 0. Wil 1 purchasefor useon for bedside, etc., as a stand-by (be ready ,tuckly pay for itself. enclosed premises. for power cuts), caravans, yachts, camps, REFILL YOUR etc., etc. Full-size Data Sheet, with instruc- Send for illustrated Senior. Mark I tions, etc., for this model, 3/-, plus stamp foldertoDept. P.M.47 Junior. Webley Air Rifle ADANA (Printing Machines) Ltd.,TwiCken- OWN BALL PEN Order nowand get cracking. ham, or call 8, Grays Inn Rd., London, W.C.1. Write for List.WEBLEY & SCOTT, LTD., VISCOID REFILL KIT 106, Weaman Street,Birmingham,Eng. Post Free 3/8inc. tax REMEMBER SPARKS fora SQUARE AND DRIVES IT A HOME -BUILTRADIOGRAM DEAL HOMEINTO THAT You can save half the cost by building My tested designs range from a Crystal Set &IPA SCREW your radiogram at home. Send 5d. now Complete with Tool and Illustrated to 9 -valve Quality Radiogram. Send stamp 011ICK,EASY,/1 LIME MIRACLE! AWKWARD SPOT/ for our latest Catalogue giving full Filling Instructions. for list. details of elec. Gram. Motors (incl. CONTAINS SUFFICIENT INK latest 3 -speed type), Pickups, Chassis, FOR IS LARGE REFILLS . COMPONENTS SUPPLIED. Speakers (including latest high-fidelity Available in Blue, Red and Green. models) and Cabinets. Also high-fidelity Grips smallest grub screw or large wood Audio Amplifiers, Tuners, Baas Reflex Trade Enquiries Invited, screw - firmly.instantly - drivesit Cabinet Kits, ete., etc. Table R/G Cabi- VISCOID INKS (P.M.) quickly home ISaves time and labour I nets in figured walnut,57/6,carr. 3/6. 6,Sherlock Mews,Baker St., 1 ORMOND SPARKS (M) POST A/ MAILEXSUPPLYCO. (P), '70 NORTHERN RADIO SERVICES, London, W.I. PAID 'rf "PoyntersRd., Duns table, Beds. 16, Kings College Rd., London, N.W.3 48A, HIGH ST., MANAGE. DORSET SAW BENCH COMPONENTS Mains Transformers Standardised Spindles,Flanges and MERCHANT NAVYand Air Radio. UPRIGHT - DROP TARGET BLOWPIPES Bearings for Sawbenches or Grinding Here is an opportunity to train as THROUGH and Drilling Assemblies. Spindles Radio Officer.The big liners are - s ,..- - *-''' PL .US1RA E_ I 43 t .* S lin. to llin. from4/6. Ball Bearing open to you, but you mustqualify T Types Only, Plummer Blocks from lin., 15/-. Com- fortheP.M.G., Certificate. Day, Guaranteed. " Radiocerts "postal No. 1:250-0-250v.. 80 plete Assemblies for Saws, 4in. to 241n.; .Eveningand InA., 0-4-6.3v., 5 amp. The " Target "FINE Circular Saws from 4in., 8/-.All sizes courses. S.A.E. for Prospectus from 04-5v., 2 amp. No. 2: FLAMEGas Blowpipe supplied.Combined sawing, grinding WirelessOfficer, THE WIRELESS Same, but 350v. Both (self -blowing) is ideal for and drilling machines, 97/3. SCHOOL, 21, Manor Gardens, Holloway, . all those small and deli- Send 7d.for fully illustrated catalogue. London, N.7: (Estd. 30 yrs.). (Phone : 16/-, post II-for 1 to 3. cate soldering and brazing ARC 3694). Students deferred from HILLFIELDS RADIO, BEVERLEY PRODUCTS, 41111111111to Jobs essential to model mak- 22,Oakwood Avenue,Leeds,8. Military Service. 8, ing. Fine intense flame easily hBlutah. aCmoveRnotryad, melts small copper rivets. Sold- ering and small brazing lobs done TheSUPER in no time.PRICE2s. 90. each. Price The ' Adept ' Bench POST FREE. RATCHET & REVOLUTION £8 Se. 03. ADEPT' LATHE Carr. Extra. Hand Shaper 1li0. centres, 6in, The " Target " FIERCE FLAME Cs, Length of stroke 01 ,wiiiii_---,..--,, -between Blowpipe (self -blowing). For solderifig COUNTERS ram, 311ns. ii centres. and brazing LARGER jobs. Ask- for No. 2B. 11. Stia,Per,-6Bn. The " Adept" Gives a fierce, roaring 4 -inch teafIet No. 1817 stroke price25.4.0d. 21In.4 -Jaw flame.Guaranteed to melt Pries£16Os. Od. independent in. copper tube. PRICE Speed. up SO Postage and Packing,Is. 9f. (U.K.) withfull instructions), 6,000 LII.M. et A ele your dealer. Chuck. Reversible Jaws, 85/, ,fiGoodRange s. 6d. each. POST FREE. 8.& F. CARTER ' Manufactured by of Accessories is available. RetailersEnquiries Welcomed Machine TARGET MFG. CO., & Co., Ltd., Bolton 5 Vice Ki. F. W. 'PORTASS, Membersof13.E.S.T.E.C.Organisation. ADEPT WORKS, SELLERS STREET, SHEFFIELD, 8 Wollaston,Wellinghorough (Dept. P.M.) 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Welding-Aerodynamics--Electrical Engineering-The FREE GUIDE explains : Television-Electric Wiring-D i e s e I Engineering- Openings, prospects,salaries,etc.,in Draughts- -Generation and Supply-Works Management- manship, Inspection, and opportunities in all other Metallurgy - Refrigeration - Planning - Estimating. branches of Engineering and Building. Rate-fixing-Time and Motion Study-Aero Inspec- How to obtain money -making technical qualifications tion-Automobile Engineering-Sheet-metal Work- through special RAPID FULLY -GUARANTEED Engineering Draughtsmanship-Aero Draughtsman- COURSES. ship-Jig and Tool Draughtsmanship-Press Tool and Die Draughtsmanship-Structural or RIF ConcreteWrite now for your Draughtsmanship-Sanitary Engineering. copy of thisremarkable GENERAL publication. A.M.I.Mech.E., A.M.I.M.I., Gen.Cert.ofEduc.,-CollegeofPreceptors-A.M.Brit.I.R.E., A.M.I.P.E., A.C.C.S.-A.C.I.S.-Aircraft Apprentice. 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