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AA'ke- ,144-eA.A- Assiol ENGINEERING WORKSHOP PRACTICE Recent developments in engineering workshop prac- tice have been so rapid that it has been found neces- sary to produce a new and revised edition. This new edition deals with the underlying principles, crafts- manship, machines, tools, measuring processes and machining methods of today, and it will prove indis- pensable to the engineer, draughtsman, mechanic, apprentice and engineering studentIts scope extends by using from simple hand tools and machines to the latest elaborate machines and methods employed for mass - AZOL ina production purposes. SOME OF THE SUBJECTS Files,Chisels, Scrapers, Shears, Punches, Burnishers, Hand Screw -cuttingTools,Spanners,Vices,VariousMeasuring methods. Verniers, Micrometers, Gauges, Optical Devices, Fluted and TwistDrills,Grinding Angles,DrillingData, TANK Small and Large Drilling Machines, Electric Drills, Practical Your camera need not be idle during the Lathework inallitsbranches. Machining of Metals and coming months. There are plenty of good Synthetic Materials. subjects "ready to hand", simply demand- Tungsten -carbide and Diamond Tools. SpecialOffer ing to be taken. You can be confident that Lapping,Honing,Cleaning,Polishingand Rust -protection 1/7 P.O. Iohnsons will send you a goodnegativeswillresultifyouuse ofvariousmetals. GrindingOperationsandMachines, For a Johnsons Tanks and Chemicals. Free book- trial setof Chemicals, including :1 -oz. Milling Operations, Cutters and Machines.Planing, Shaping, bottle of AZOL, to develop eight spools let telling all about Home Photography will Slotting and Broaching Operations. Special Machines for 21 x 31 ;4 -oz tin ACID -FIXING, making readily be sent on application to Dept. 41 30-60 oz.solution ;onepacket M. -Q. Johnsons Adjustable Tank takes five Production Purposes.Plate and Bar Machines. Gears and DEVELOPER, enoughfor 36 gaslight popular film sizes ... 17/6 GearcuttingMethods. Templates,JigsandFixtures. prints.Address Dept. 41. Time and Temperature Calculator 1/6 OverhaulingandAdjustingMachines,MillwrightWork. JOHNSON &SONS, ManufacturingChemists, LIMITED. HENDON, N.W.4. Welding,BrazingandSolderingMetals. Forging Work. Sheet Metal- Work.Foundry Work.Patternmaking Practice. PressWork. EngineeringSteeland other Metals;their Properties,Testing, Hardening, Tempering and Annealing THE " FLUXITE QUINS" AT WORK Engineers' Drawings. Workshop Calculations,Data, Hints and Recipes.British and Foreign Screw -thread Tables. Young 00 in the dead of THE ILLUSTRATIONS the night The hookislavishlyillustrated so thatthe explanations Heard noises below-lit are rendered very clear with examples taken up from actual a light. works practicein many instances.There are 24full -page "Hands up! " cried she, plates and 1194 line and photographic illustrations in the text. Cried 01 "Not me! ENGINEERING POCKET BOOK It's a bust-double up! In order to make the work even more comprehensive we -get FLUXITE!!" have brought out a pocket book, which is supplied free to all purchasers.It contains many useful tables of Screw Threads, Tapers, Angles, Drill Speeds and Sizes, etc. See that FLUXITE is always ay you --inhe house-garage-workshop - wherever speedy soldering is reeded. Used for 30 years in Government works and by leading engineers and manufacturers. Of ironmongers --in tins, 4d., 8d., 1 4 and 2'8. Ask to see the FLUXITE SMALL SPACE SOLDERING SET A FREE BOOKLET -complete but substantial-complete with full instructions, 8 7.Write for Free Book on the ART OF " SOFT " SOLDERING and ask for Leaflet en To the Caxton Publishing Co., Ltd., CASE -HARDENING STEEL and TEMPERING TOOLS with FLUXITE. 119 Clun House, Surrey Street, TO CYCLISTS !Your wheels will NOT keep round and true unless thespoked London, W.C.2. are tied with Sue wire at the crossings and SOLDERED.This makes a mud stronger wheel.It's simple-with FLUXITE-but IMPORTANT THE FLUXITE GUN is always Pleasesend me,free ofcharge,IllustratedBooklet ready to put Fluxite on the sol- describing "Engineering Workshop Practice." dering job instantly.A little pressure places the right quan- tity on the right spot and one Name charging lasts for ages.Price Send this form in unsealed envelope (1d. stamp),or a postcard. 1/6, or filled 2/6. FLUXITE Ltd., Dept. P.M., Bermondsey Street,S.E.I Address ALL MECHANICS MUHA.VEN

FLUXITE G.29 IT SIMPLIFIES ALL SOLDERING 242 NEWNES PRACTICAL MECHANICS April, 1941 E THIS IMPORTANT GUIDE TO SUCCESSFUL ENGINEERING CAREERS After months of intensive effort and research weare pleased toannouncethattheneweditionofourhandbook, "ENGINEERING OPPORTUNITIES," isnow out of the publishers' hands and ready for free distri- bution. Containing 208 pages of practical guidance, this book is, beyond argument, the finest and most complete handbook on Suc--R.A.F.- cessful Engineering Careers ever compiled. It is a book that should be on the bookshelf of every person interested in engineering PILOTS whatever his age, position or experience. OBSERVERS, The Handbook contains, among other intensely interestingmatter,detailsofB.Sc., A.M.I.E.E., ETC. A.M.I.Mech.E., A.M.I.E.E., A.M.I.A.E., A.M.I.W.T., A.M.I.R.E., A.M.I.P.E., CIVIL SERVICE, and other Special rapid Home - important Engineering Examinations:outlines courses study courses in the in all branches of CIVIL, MECHANICAL, ELEC- essential branches TRICAL, AUTOMOBILE, RADIO, TELEVISION, AERONAUTICAL and PRODUCTION of Mathematics. For ENGINEERING, DRAUGHTSMANSHIP, TRAC- fulldetailsofthis ING, GOVERNMENT EMPLOYMENT,BUILDING scheme apply or (the great after -war career),R.A.F. MATHS.,etc., and ex- write:- plains the unique advantages of our Employment Department. B.I.E.T. (Dept. M410)

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A Sunderland Flying Boat on Patrol Work. Aircraft Recognition Suggestions for Home Study, by R. A. Saville-Sneath. LONG RANGE MARINE AIRCRAFT4. THEqualification" long-range " is the German Air Arm has atleastthreelarger; secondly, they have two or more deliberatelychosenin order towell-knownlong-rangemonoplanefloat -engines, and, thirdly, they are all monoplane limit our immediate study to a con-plane types in regular service.These arefloat -seaplanes. venient andeasilyassimilablenumber.the twin -engine float seaplanes Heinkel 115, The Fokker T.8.W. is the only twin -engine Aircraft operating with the Fleet Air Armthe Blohm & Voss Ha:140, and the four -monoplane seaplane included in the list of andR.A.F.CoastalCommandmightengine float -seaplane Ha.139. friendly types which might conceivably be reasonably claiM the description" marine Italy has the Cant. Z506B, a three -engineconfused with, say, the Heinkel 115.The aircraft " by virtue of their employmentmonoplanefloat -planeof modern typeillustrations of these seaplanes should be on coastal reconnaissance and similar duties.possessing a range of about 3,000 miles. carefully compared. The Fokker is smaller but many of these, such as the familiar These may quite easily be distinguishedthan the Heinkel, and there is little real Anson and Hudson are definitely landplanes. from the friendly 'plares already mentioned.resemblance if the nose, fuselage and tail The spotter who wishes to study theIn the firstplace, they are considerablyunit are examined.The seaplanes of this smaller fry of marine aircraft will find ample type which are now co-operating with the scope for industry, since their name is legion. Coastal Command escaped when the Nazis " Small fry " is used here in no disparaging overran Holland.. sense, but simply with reference to the dimensions of the various types and their Long-range Marine Aircraft radius of action.Used in this sense, the If Mercury, the float -seaplane component termnecessarilyincludessuchnotable of theexperimental Short -Mayo trans- performers as the Fairey Swordfish, victor atlantic composite aircraft is excluded, all of Taranto and Sardinia.Itcertainly Britishlong-rangemarineaircraftare would be no consolation to the humiliated flying boats, easily distinguishable from other Duce to learn that the battle strength of the structural types by the deep, boat -like hull. Italian Navy had been reduced to half by The principalserviceflyingboats are : " small fry ." of the Fleet Air Arm. Monoplanes : Sunderland, Lerwick. Interesting as these types are, we must leave them for later study, although the following list of the principal friendly and hostile ship and shore -based aircraft may be useful in the meantime :- British. -Albacoee, Fulmar, Nimrod, Osprey, Roc, Seafox, Sea Gladiator, Sea Lion, Seal, Shark, Skua, Swordfish.Dutch (servingwithR.A.F.).-FokkerT.8.w. U.S.A. (serving with R.A.F.).-Bermuda ( Brewster 138), Martlet (Grumman F4F). German.-Arado 95, Arado 196, Heinkel 59, 60, 114, Junkers 52'W. I (titian .-111cridionaliRo43,Re44, Cant. Z501. Ocean-going Types The majority of marine aircraft designed to cruise independently with a range of 1,000 miles or more. are built as flying boats, with a seaworthy hull.To most of us this The Walrus amphibian, showing the folding wings andl landing wheels in position. seems but natural and even essential, but An underside view is shown in the inset. April, 1941 NEWNES PRACTICAL MECHANICS 245 of the hull, and the marked unequal span are most helpful. Two Bristol Pegasus air-cooled radial The London I engines of 960 h.p. give the London service flying - atop speed of 155 m.p.h., a cruising speed boat. of 137 m.p.h., and a range exceeding 1,700 miles. Supermarine Stranraer Designed by the Supermarine-Vickers Company, which developed the famous Spitfire, the Stranraer is obviously produced Biplanes :London, Singapore, Stranraer, It is much more likely to be confused withto meet the same general specification as Walrus. At least two American -built mono-the Sunderland, particularly if seen in sidethe Saro London, and has a very similar plane flying boats are in production for theelevation.From this point of view, theperformance.Like the London, itis a R.A.F.-the Consolidated PBY-5, and thenumber of engines may not be clearly dis-biplane of unequal span, with twin fins and Consolidated 31. tinguishable. On the other hand, the hull,rudders. The span of the Stranraer is about The three Dorniers, Do.18, 24 and 26, andwhich is noticeably deeper forward, the gun -five feet greater, and the inequality of span the Blohm & Voss Ha.138 are, so far as isturret amidships, and the angular fin andis much less marked than in the London. known at present, the principal types ofrudder, with nearly square -cuttip,areThe interplane struttingissimpler, and flying boat operating with the Luftwaffe. useful distinguishing points.Note also thethere is no appreciable difference between These twelve designs form a convenient" bite " below the rudder, where the tail gunthe chord of the upper and lower planes. group for study. Each possesses distinctiveturret is mounted. The sweepback of the wings, which can and characteristic features which are briefly The Lerwick is fitted with two 1,375 h.p.be observed from many points of view, most outlined in the following notes. Bristol Hercules radial air-cooled engines,easily distinguishes the Stranraer from the Long -Range Marine Aircraft-Flying Boatsbut performance figures have not beenLondon.Itisuseful to remember the Short Sunderland released. initial letter " S," for Stranraer, " S " for The Sunderland,thefirstmonoplaneSaro London sweepback, and " S " for simple strutting. flying -boat to go into regular service with The Saro London biplane flying -boat, anFrom the side, the tail unit is most distinc- the R.A.F., is developed from the Shortearlier product of the same company, hastive.The rudders of the London overhang Empire flying -boats, which in 1937 made abeen a familiar sight round our coast forthe elevator, resembling the stern of a number of experimental flights preparatory to the opening of a regular transatlantic service. The 915 h.p. Bristol Pegasus radial air- cooled engines provide a maximum speed of Left. The Saro 210 m.p.h.. and a cruising speed of 178 Lerwick 'twin-engined m.p.h. The normalcruisingrangeof long range marine 1,780 miles can be increased to nearly aircraft.Span 80ft. 3,000 miles. 10 in. Length 63 ft. A high -wing monoplane, with single fin 71- in. and rudder, the four radial engines mounted on the leading edge of the wings provide the principal recognition feature, since the only similar R.A.F. type, the Saro Lerwick, has twin engines. German flying-boats-as explained in theRight.The Heinkel following notes-are of radically different 115 reconnaissance design.The four-engined Consolidated 29,torpedo bomber. which may be ordered for the R.A.F., has aSpan 73 ft.Length distinctive twin tail. 56 ft. 8 in. The Sunderland's power -operated gun - turrets in nose and tail indicate that the assitx6\i11,000io business of this British flying -boat is by no means civil.They easily distinguish itseveralyears. WhilsttheLondonisVenetian gondola.The Stranraer rudders, from the " C " and " G " versions of Empireunlikely to be mistaken for either theon the contrary, are cut off short of the flying -boats.The fixed, braced wing -tipGerman or American monoplane flying -stern. floats supply a minor recognition point. boats, itis frequently confused with the The two Bristol Pegasus radial engines Saro Lerwick Supermarine Stranraer. give a maximum speed of 165 m.p.h., a Built by Saunders -Roe, Ltd., the Saro The wings are of unequal span, the in-cruising speed of 105 m.p.h., and a range of Lerwick is the only twin -engine monoplaneequality being much more marked in the1,000 miles. flying -boat of British design in service withLondon than in the Stranraer.The chord the R.A.F. At least two other twin -engineof the lower wing is also noticeably smallerSupermarine Walrus types,theAmerican -builtConsolidatedthan that of the upper wing.The wings The Walrus, a product of the same com- PBY5, or R.A.F. " Catalina," and the Con-have neither taper nor sweepback.Thispany, has many easily recognisable features. solidated 31, will be making transatlanticabsenceof sweepbackinthe LondonFurther, being designed chiefly for Fleet deliveryflightsto augment ourforcesprovides the easiest means of distinguishingspotting,its cruising speed is low, about during the coming months. between the two ships, the wings of the95 m.p.h., and the observer has ample time From the spotter's point of view, theStranraer having marked sweepback. to notice its salient points as it ambles Lerwick has little in common with either of In the head-on view, the more complexleisurely across the horizon. these types, or with German designs. arrangement of interplane struts, the shape A biplane of equal span, its wings are untapered, but have pronounced sweepback. They are cut away at the trailing edge to giveclearance for the pusher airscrew, driven by a single Pegasus radial air-cooled engine. The location of this single engine between the main planes generally distinguishes this flying -boat from other types.In plan view it is not unlike the Stranraer, but the two engines of the latter can be clearly seen from this point of view, whilst the centrally - placed single engine of the Walrus is hidden by the hull.If the observer has a clear view of the underside, the wells of the retracted The R.A.F. twin-engined reconnaissance flying-boat-Catalina.In general outline this is landing -wheels may benoted,forthe similar to the Dornier D.O. 18 (see next page). Walrus is the only amphibian flying -boat 246 NEWNES PRACTICAL MECHANICS April, 1941 in service with the R.A.F. This flying -boat has also given many years' valuable service in the Royal Australian Air Force, where it is known as the Seagull. The Blohm Voss Short Singapore and This well-known biylane flying -boat is anHA. 1 4 0 earlier product of Short Brothers. The typelong-range is now rendered rather obsolete by theseaplane. greatly improved performance of the same company'smonoplaneflying-boats-the Empire types-and the Sunderland. The Singapore is exceptional in the R.A.F." Jumo " diesel engines provide a maximum There may be a slight possibility of con. in having four engines arranged in twospeed of 161 m.p.h., a cruising speed offusion between the Dornier 18 and this tandem pairs, driving two pusher and two140 m.p.h., and a range exceeding 3,000American -builtflying -boat, but the twin tractor airscrews.The four liquid -cooledmiles. radial engines of the Catalina, mounted in Kestrel engines, each pair having a large the orthodox manner, are usually distin- boiler -like radiator mounted on top, readilyDornier 24 guishable from the tandem diesels of the distinguish this craft from any other.The The Dornier 24 monoplane flying -boat is aDornier 18. tail unit is equally unusual, three fins anddistinctdeparturefromeitherofthe Further, the Catalina has neither sponsons rudders being mounted above thelargepreceding types.It has three radial air-nor fixed wing floats.The observer will braced tail -plane. cooled engines mounted along the leading edge of its parasol wing.The long slendernotice that the extreme tips of the wings The maximum speed is 145 m.p.h., the are thicker than the centre -section.These cruising speed 123 m.p.h., and the rangehull, whilst similar to that of the Dornier 18thick wing -tipsareactuallyretractable about 800 miles. --having sponsons instead of wing floats- terminates in twin tins and rudders. wing -tip floats. Dor vier 26 The power unit consists of either Pratt Fitted with three 880 h.p. B.M.W. radialand Whitney " Twin Wasp "or Wright It is appropriate to study the Dornier 26engines, the maximum speed is 195 m.p.h.," Cyclone " radial air-cooled engines. With the latter, the maximum speed is 206 m.p.h., and the normal cruising range about 4,000 miles. The first of this type to be delivered experimentally to Great Britain-in 1939- flew direct from California to Felixstowe, over 5,700 miles with only one refuelling stop, at Botwood, Newfoundland. Consolidated 31 This very advanced type is also under- stood to be in production for the R.A.F. It is characterised by an extremely thin wing of high aspect ratio, a deep, relatively The Stranraer twin-engined seaplane. short hull, twin fins and rudders of, large This is,a biplane of unequal span, and size,and retractable wing floats.The has twin fins and rudders. Inset : power -plant, consisting of two 2,200 h.p. Underside view. Wright " Duplex Cyclone " radial engines, is reported to provide a cruising range of after the Singapore, since it has the same 10,000miles. A top speed around 265 feature of four engines arranged in two m.p.h. is claimed. tandem pairs, driving two pusher and two The Blohm & Voss Companyhas tractor airscrews. followed unconventional lines in developing The Dornier 26 is, however, one of a long seaplanes such as the Ha.139 and 140 as lineof high -wing monoplane flying -boats long-range ocean-going aircraft. The descending from the giant Do X, with its Ha.138 isequally unconventional, being twelve engines arranged in six tandem pairs, almost a compromise between a flying -boat through the Super Wal, the\Val,the and a float -seaplane.This unusual craft Dornier 18, and the Dornier 24. is a high -wing monoplane, fitted with three The slender hull terminates in a single finthe cruising speed 160 m.p.h., and the rangeJunkers diesel engines, one of which is and rudder, and the wings are remarkableslightly over 2,000 miles. mounted above the centre -section, and the for their sharp upward inclination from theR.A.F. Catalina (Consolidated PBY-5) others centred on the leading edge. The hull hulltothe engine nacelles-a form of In view of the similarity of its hull lines,is cut short just aft of the trailing edge. dihedralgenerallydescribedas"gull -itisappropriate toconsiderhere theTwin fins and rudders are mounted at the wing."In contrast to the fixed floats ofAmerican -built Catalina, a type known inextremities of narrow booms which appear British types, the Dornier 26 has retractablethe U.S. Navy as PBY-5 and developedto be extensions of the engine nacelles. wing floats. from the Consolidated Civil Model 28. TheThese also support the tail -plane.Fixed Thefour600-h.p.Junkers" Jumo "slender lines of this monoplane flying -boatwing -floats arefitted. The power -plant diesel engines give the Dornier 26 a topare in marked contrast with the deep, shortgives a top speed of 171 m.p.h., a cruising speed of 208 m.p.h., a cruising speed ofhullsofthelatestBritishtypes,thespeed of 146 m.p.h., and a maximum range 193 m.p.h., and a maximum range ofSunderland and the Lerwick. of about 1,500 miles. 5,600 miles. Dornier 18 The Dornier 18, also a high -wing mono- plane with single fin and rudder, may almost be described as a simpler version of the Dornier 26, having one instead of two tandem pairs of engines, driving a pusher, and a tractor airscrew. Whilst the Dornier 18 lacks the distinc- tive gull wing of the later type it has another recognitionpointof equalvalue-stub wings, or sponsons, built on to the hull, instead of the usual fixed or retractable wing -tip floats. The hull of the Dornier 18 is particularly long and slender.But for the tandem engines and stub wings, it might easily be confused with the R.A.F. Catalina (Con - The Dornier D.0.18, a high -wing monoplane, with single fin and rudder.It has one so lidatedPBY-5), ItstwoJunkers tandem pair of engines, driving a pusher, and a tractor airscrew. April, 1941 NEWNES PRACTICAL MECHANICS 247

Lifeboat roadless tractor, with carriage and lifeboat, travelling over sand. MECHANICAL METHODS OF Launching Lifeboats A Description of the Method of Launching a Lifeboat by Tractor-A Paper Read Before the Recent Annual General Meeting of the Institution of Mechanical Engineers, by Lt. -ColonelP. H. Johnson, C.B.E.,D.S.O., M.l.Mech.E. THE Royal National Lifeboat Institu- tion was founded in 1824, and its 12.--0. DIA. WHEEL rescue work has beencarriedon 6--0 DIA. WHEEL Fie. 2 without a break for the past 116 years. 64-0'01A. WHEEL WHEEL There are at the present time 170 life - 3=0 DIA. b ats available for service at various points WHEEL round the coast of these islands, and of these 143 are motor lifeboats. A total of 128 can be moored afloat in harbours or are Vto, r r housed in suitable buildings from which .e , they can rapidly be launched down slipways ( 1-0'DIA. WHEEL directintodeep andprotectedwater. 2-0" DIA. WHEEL 6:-CrDIA. WHEEL There remain many hundreds of miles of e-CrOiA. WHEEL coastline where such methods are not Fig. 1 2=0 DIA WHEEL practicable. In these circumstancesit 11-0'01A. WHEEL becomes necessary for a proportion of the I6-0.CPA. WHEEL lifeboats, forty-two in all, to be launched 11-o DIA. WHEEL t-e from an open beach, the boat itself often WHEEL being housed some distance away from where any launch can be made, especially at low tide. The ability to choose between a number of practicable launching places, Fig. 3 according to the position of the wreck and weather or tide conditions, may be very valuable. To travel a comparatively short Figs.1 to 3.Effect of width and diameter of smooth steel wheels on rolling distance along a beach may save many resist antes. miles of travel by water in the face of a gale and heavy sea.Strategic launching points can be chosen, which may have the effect of saving vital time. Beach Conditions - To make the picture clear, it is necessary to describe in some detail the beach con- ditions in which the launch has to take place.The beaches themselves vary from firm wet sand to deep layers of clean shingle composed of smooth and rounded pebbles with nothing to bind them to- gether ;" the latter type forms one of the most difficult surfaces to deal with. Up to the point when the shingle approximates to coarse sand, the smaller the pebbles, the more easily do they flewbeneath the Fig. 5.Lifeboat carriage in use, showing Tipping's plates on wheels. application of weight to the surface and 248 NEWNES PRACTICAL MECHANICS April,1941 thus the more difficult are the conditions for transport. Small wet and clean shingle approximates in behaviour to a fluid rather than to a solid.Sandy beaches may be complicated by dunes of dry wind-blown sandwhichalsopresentconsiderable difficulty. Some beaches which may stretch for miles at low tide and are almost level, abound in treacherous mud pockets which have their origin in adjacent river estuaries. An instance of this is the beach at Hoylake, in Cheshire.In other cases the sand may be so waterlogged as to become what is commonly known as quicksand. Of shingle beachesitispossible that Dungeness is the worst example. Even to walk over some parts of it is so difficult that the local inhabitants have developed the practice of shuffling over the surface on a primitive sort of snow shoes locally known as " back -stays."The pressure put upon the ground by a man of average weight standing on one foot, and . assuming no sinkage and thus no support from the instep,is about 10 lb. per sq. in. The Fig. 4.Girdle for lifeboat wheels (Tipping's plates). " back -stays " have an area approximately five times that of the human foot and thustyredwheels when operating over softexperienced. The rolling resistance may be reduce the pressure to about 2 lb. per sq. in.surfaces. such that to effect forward movement a pull In the circumstances referred to, it willRolling Resistance of Smooth Steel-Tyredequal to or even greater than the total be appreciated that very special equipmentWheels weight of the vehicle is necessary.The iscalled for if a modern motor lifeboat Over a good hard road surface the rollingpower required for haulage is, of course, which, complete with its carriage, weighsresistance of steel-tyred wheels can be aswasted in the creation of ruts in the ground approximately 11 tons, is to be hauled overlow as 30 lb. per ton weight of vehicle.surface, and a common misconception is the beach without difficulty.The firstOver a loose sandy beach this can rise tothat the difficulty of high rolling resistances mechanicalrequirement,therefore,for200 or 300 lb. per ton, and even more.Inover soft surfaces can be cured by an beach launching of the lifeboat is that itsvery soft patches, even with wheels of theincrease in wheel width thus offering a weight shall be made movable withoutlargest practicable diameter, sinking to a,larger surface of support. undue rolling resistance or sinkage over thedepth involving immobility-within practi- While in certain cases a moderate increase urfaces described. cal limits of motive power-can readily bein width can have beneficial resultsin minimising theliabilitytosinkage, yet increase in width alone is no answer to rolling resistance.If a steel-tyred wheel 4 inches wide sinks into a soft surface to a depth of 2 inches the cross-sectional, area of the rut created will be 8 sq. in.If by doubling the wheel width the sinkage is halved, then the cross-sectional area is not reduced, being still 8 sq. in.As the cross- Fig.7. Double interlock sectional area of the rutcreatedisa for girder track. reasonably accurate measure of the rolling resistance,littleif any benefit has been obtained by doubling the width. Great advantage arises, however, from an increase in wheel diameter, as is indicated by Figs. 1 to 3. To illustrate the point, Fig. 1 shows wheels 3 feet, 6 feet, and 12 feet diameter respectively, so proportioned in width that they sink to an equal depth of 4 inches in soft soil when equally weighted.It will be Fig.8. Girder track seen from the rut sections that the 3 -foot assembled without hinge wheel has to be rather more than double pins. the width of the 12 -foot wheel, and this is a fairly accurate measure of their respective The Mounting of the Lifeboat and Carriage The carriage which carries the boat, and from which also the boat is launched into the sea, was developed nearly a century ago and was originally equipped with steel- tyred wheels.Even to this day there, are carriages in use with such wheels, and where the boats are of light weight, say 3f-4 tons, and the beach conditions are favourable, no great difficulty is experienced.In con- ditions specially favourable, boats up to 6 tons in weight have been and are even Fig. 6.Locked girder track. The now transported on carriages equipped with track forms, in effect, a wheel of plain steel-tyred wheels. The weight of the very large diameter. boat is concentrated over the rear axle, the turntable and forecarriage being used for steering and stabilising purposes.As the weight of the boats tended to increase, especially when engine power was sub- stitutedforsailsandoars,itbecame increasingly difficult to launch from any but the firmest of wet sand, owing to the high rolling resistance offered by the wheels. It may be appropriate here to deal with some aspects of the rolling resistance of steel - April, 1941 NEWNES PRACTICAL MECHANICS 249 rolling resistances.The same three wheelsObviously, the area of support given by theconsisting of a series of flat plates linked are shown in Fig. 2, but in this case theyground to a wheel standing on a soft surfacetogether (see Figs. 4 and 5).These girdles are all 6 inches wide. With equal loading,is equally distributed on either side of theweretheinventionofLt. -Commander the 3 -foot wheel creates a rut more thanvertical centre line of the wheel, whereas asGartside-Tipping, R.N., who was appointed three times the depth of that created bysoon as it moves forward the rut left behindDistrict Inspector in the Royal National the 12 -foot wheel. provides no support to the rear of the verti-Lifeboat Service in 1879, in which capacity Actually, the figures given above arecal centre line and in consequence the areahe served until 1892.While these " Tipping rathermorefavourabletothesmall - of support for the wheel and its load isplates" (as they were termed) reduced to diameter wheel than would be realised inhalved, involving additional sinkage untilsomeextentthedifficultiespreviously practice.One factor which the figures dothe requisite area is obtained.It by noexperienced and made itpossible to use not reveal is the " angle of attack " illus-meansfollows,therefore,because somecertain beaches which would otherwise, have trated by Fig. 3.This shows that, givenparticular type and size of wheel will sup-been quite impracticable, they were not equal depth of sinkage, the 12 -foot wheel isport a given load on the surface or withoutwholly satisfactory.It will be clear from in effect being called upon to climb aundue sinkage when stationary, that it willFigs. 4 and 5 that only when the wheel is gradient of 1 in 51, the 6 -foot wheel ado so when moving. in the centre of one of the plates is the gradient of 1 in 4, and the 3 -foot wheel a weight truly distributed over the ground gradient of 1 in 3. A factor which has notTipping's Plates. surface. With the weight concentrated on been taken into account in the foregoing, Towards theendofthenineteenththe joint between the plates, sinkage and as it does not affect the comparisonbetweencentury an attempt was made to overcomeundue rolling resistance is inevitable, though the figures, is the essential difference be-the difficulties with wheels over the softernot so great as in the case of the ungirdled - tween a wheel which is standing still on atypes of beach by fitting the rear wheelswheels. softsurface and one which is moving.carrying the weight of the boat with girdles (To be continued) Two Useful Lathe Tools Constructional Details of Two Tools for Screw Cutting and Light Turning

THE tools shown in the accompanying The slot forming the cutting face can bebe drilled by holding the stock in a vice at sketches will be found very useful insawn and filed after turning.The line ofthe required angle, mounting the vice on their different applications.Figs. 1the face cuts the centre axis of the tool andthe drilling machine table and drilling down to 4, inclusive, show details of a formerintersects the lathe axis. right through the stock. tool which has the advantage that the Thecircularcotterishardened and grinding of it does not in any way affecttempered by heating to a full red colour, Slottingthe Holder its contour.As shown, it is suitable forand quenching in cold salt water. It is then screw -cutting a V -type thread, such aspolished bright on its formed edges, and to The hole for the clamping bolt can then Whitworth, or any standard angle thread.draw the temper it is threaded on to a barbe drilled so that its edge contacts with The tool itself is a disc mounted on a east -of red-hot iron or steel and left there tillthe edge of the hole for the cutter. A slot steel shank. The side view shows the cutting edge which is formed by slatting out a gap in the disc. Pin arance The disc is turned from a piece of cast - Cutting steel bar, or can be drilled out of plate Edge Ali L HT A cast steel, and chucked and turned to the shape shown.It is held to the shank by 17 AV' A ik" the slotted head screw.This screw has a 1111011104 taper head which fits a taper in the central 1, NM hole in the tool.The taper is 90 degrees, inclusive, or 45 degrees each side. The tool \\M also has a female taper in the central hole Cutter to fit the taper on the screw and a male entre tom\ taper on the other side to fit a female taper Line Side in the shank.Fig 2,a sectional view, shows this fitting. Side Section and Plan Views of Cutter Clamping Screw The screwisfittedwith a left-hand thread which should be finer than Whit- worth, and there should be clearance, as Figs. 1 to 4.Details of a disc tool for screw -cutting. shown, so that the tool cannot bed up Figs. 5 and 6.A simple tool -holder and cutter for light turning. against the flat face of the shank, but is held wedged in the taper hole in the latter. The end of the male taper on the tooltheperiphery assumes a golden strawis now sawn right down the tool at the should also not extend to the bottom ofcolout when itis immediately quenchedsame angle as the cutter hole, and bisecting the taper hole in the shank, the objectagain in cold salt water. The bolt and nutit and extending, as shown, about a quarter being to pull the tool up, by the screw andcan be case-hardened with " Kasenit " toinch below it. A 1 -inch case-hardened bolt lock -nut tightly in the taper which willensure a long -working life. with a thin flat head, and a hardened give it full support against the pressure of hexagon nut is then fitted in the transverse cutting. hole and is used to clamp the cutter firmly The reason for the left-hand thread onFor Light Turning the bolt or screw isto ensure that the In Figs. 5 and 6 is shoWn a simple toolin the hole. in. This tool holder can be used either right tendency to turn the tool will be resisted,holder which takes a small cutter of or left-handed as the work requires, and and the tool tightened by reason of theround cast or silver steel stock. the cutter clamping bolt and nut can be threaddirectionbeingsuchthatthe The holder is made from square cast - tendency is to tighten it.A small pin,steel bar of a size to suit the lathe slidefitted with the nut on either surface. The driven in a i in. hole in the bolt, engagesrest tool holder. cutters can be ground also to any angle with a slot in the hole in the cotter, and It is sawn at an angle of 45 degrees atsuitable for the job in hand. prevents the tool turning on the bolt. Fig. 3the top, leaving a face through which is Cutters should be hardened dead hard, is a sectional view showing the cutting face,drilled ain. hole to take the cutter. Theand the temper then drawn to a golden and Fig. 4 is a side view. hole is square with this face, and can bestamber colour, and qubnched. 250 NEWNES PRACTICAL MECHANICS April, 1941

and, of course, the progress and out- come of any operations in which it may engage . Internal Communications These are the communications within a fleet between the Admiral commanding it and the units which he commands and be- Communications, (2) Internal Communica-tween those units.They are required at all tions. times for the transmission of information External Communications and orders within the Fleet. In harbour they These, as their name implies, are theare required for little else, as a rule, but communications between a fleet, regardedwhen the Fleet is at sea they are required as a unit, and the outside world. A fleet,for a multitude of other purposes, such as whether in harbour or at sea, has need of amanoeuvring, fire -control, torpedo -control constant supply of " intelligence," that isand, of course, for reporting the enemy. to say, of information regarding the enemy,Means of Communication WHEN thinking of naval warfare,of navigational information (a matter of The means used for naval communication there isa natural tendency tovery great importance in time of war, moreare no less varied than the purposes for thinkprimarilyin termsof strategy and tactics, of the manoeuvres of fleets and ships, and of the handling of the various weapons , with which they fight. Naval Communications The factor of communications is seldom given a thought.But it is of primary and By Commander Edgar P, Young, R.N. fundamentalimportanceinany naval operations. The Various Means Used for the Transmission of Orders Navalcommunications may becon- sidered under two headings :-(1) External Within the Fleet, and from Ship to Shore especially in con-which they arc required.Some are useful nection with mine-for only a limited number of purposes, or fieldslaidcon-in certain circumstances, while others may stantlybythebe used for a variety of purposes and in a enemy and by itsvariety of circumstances, their selection Hoisting a flag signalown minelayers),being determined by those circumstances. on board ship. Noteof meteorological They may be discussed, for convenience, the various signallinginformationunder the following four headings :- flags in the lockers.(which may have (1) Land -line Telegraphy and Telephony. an important (2) Visual Signalling. bearing on its op- (3) Sound Signalling. erations, especi- (4) Wireless Telegraphy and Telephony. ally in connection with aircraft), ofLand -Line Telegraphy and Telephony orders and instruc- This means of communication, which tionsfromthecovers also overseas cables,requires no Admiralty, and ofexplanation, even to the layman reader. It news of a generalcan, for obvious reasons, be used only by a character for theFleet or by ships in harbour, and as a rule information of itsonly for external communications, though personnel. It mustthe ordinary telephone can sometimes be also be abletousedforinternalcommunication. Its communicatetogreatest advantage, perhaps, isits com- thosewho areparative immunity from interception by interested or res-the enemy and the secrecy which is thereby ponsible any " in-secured. elligence which it Messages passed by this means may be may acquire,either in plain language or in code, though meteorologicalthe use of code for telephonic messages data (withoutpresents certain inconveniences and diffi- which accurateculties. weather forecastsVisual Signalling cannot be made), " Visual Signalling " is a term used to its day-to-day re-coverall forms of signalling which are quirements of anperceived by theeye. Such forms of urgentcharactersignalling may, in certain circumstances, be April, 1941 NEWNES PRACTICAL MECHANICS 251 used for external communications, but are tated him before hauling down the signal normally used forpurposes of internal first, and then the negativeflag. After communication only.They may be used that, he may, if he so wishes, rehoist the with equal facility in harbour, where they signal in its amended form. are used for the handling of most messages, The negative flag may be used also, and at sea. superior to a signal, to give it a negative Visual signals may be transmitted by any significance(e.g.,superiortoasignal of the following means :- meaning " Fire a salute," to indicate " Do (a) Flags. not fire a salute), or, in conjunction with (b) Semaphore. distinguishing signals inferior to a signal, (c) Morse Flag. to denote that the signal is not addressed to (d) Flashing. the ships or units denoted by those dis- The first three of these can be used only tinguishing signals. by day, but the fourth may be used either Flag signallingisprobably the most by day or by night.Messages passed by rapid means of communication when orders any of these means may be either in plain or simple reports, for which suitable short language or in code, but the use of sema- groups are provided in the naval code phore for passing messages in code is in- books, are to be conveyed, though wireless convenient and unreliable, and the use of now provides a means which is scarcely, if plain language when signalling by flags is at all, less rapid. It has the great advantage undesirable,forreasons whichwillbe over wireless telegraphy, however, that the explained. use of the latter betrays one's presence, and perhaps even one's exact position, to the (a) Signalling by Flags enemy. Flag -signalling is conducted by means of Signalling by Semaphore. flags and pendants, hoisted by halliards at Semaphore is used extensively, both at the masts and yards.The flags used for sea and in harbour, for the conveyance in naval signalling may be one of three shapes. plain language of messages which cannot The pendants used for naval signalling being conveniently be coded, on account either long and narrow. of their nature or of their length. For purposes of naval signalling there It is both Sending a signal by means of a flashing lamp. rapid and, generally speaking, unsusceptible areusedtwenty-sixAlphabeticalflags to interception by the enemy. (representing the letters of our alphabet), repeating the signal keep it flying at the dip The signs used in the Navy are the same tenNumeralflags (representing the as those in use elsewhere, and they may be numbers 1 to0,inclusive),twenty-sixuntil the most distant ship has hoisted her answering pendant close up, and then hoisttransmitted either by a mechanical sema- Special flags (each with a name and designa- phore or by hand flags.Any ship wishing tion), ten numbered Pendants (numberedit close up in sequence from out-in, to showto pass a message by semaphore hoists a from 1 to 0, inclusive), and fourteen Specialthe originator that it has been read and understood by all to whom it is addressed,flag which denotes her intention, inferior, Pendants (each with a name and designa- ifnecessary,todistinguishingsignals tion). the more distant of whom he may be unable For details of these, see " Signal Cardto see. Either immediately, or shortly afterindicating those with whom she wishes to this procedure has been completed, thecommunicate. The ships addressed hoist an 1937 " (B.R.232), which can be obtained answering pendant at the yard -arm, close up from H.M. Stationery signal is hauled down by the originator, aswhen they are ready to receive, and while These flags and/or pendants are hoistedis. also the repeated signal or answeringthey can satisfactorily read the message, either singly or in series, each single flag orpendant by the ships to which it is addressed.' If the signal is one ordering the per-and atthe dipif,for any reason, they pendant or series transmitting an order, cannot read it. making an enquiry or conveying informa-formance of some evolution or manoeuvre, tion, according to the code book which isit is carried into execution as soon as it isSignalling by Morse Flag in use. Several signals may be hoistedhauled down, subject to the instructions Signallingby Morseflag(" flag -wag- simultaneously, separated one from another,contained in the signal books regarding theging ")islittlepractised in the Navy, if on the same halliard, by a short length ofmethodof execution. Itispossible,because ships are provided with so many halliard called a " tack -line." When this ishowever, by hoisting the appropriate flagother,and more convenient, means of done, the sequence in which such signalssuperior to a signal, to indicate that itscommunication. are to be read is from starboard (right) toexecutionisop- port(left),as regards the halliards, andtional, or, by from toptobottom,asregardseachhoistingthe ap- halliard. propriatesignal In order to indicate to which ships orinferior toit, to units a flag signal is addressed, each shipindicate that it is and unit has a " distinguishing signal,"to be executed at composedof oneor twoflagsand/ora certain time or pendants.These distinguishing signals areon arrivalata hoisted superior to the signal or signalscertain position. addressed only to certain ships or units, It will be obvi- but they may be used also hoisted inferiorous, on considera- to a signal or signals, to denote such shipstion of the pre- or units in connection therewith. A signalceding paragraph, whichishoisted with no distinguishingthat, in the event signal superior to it is termed " a generalof the originator signal," and is addressed to all ships underwishing to cancel the command of the officer hoisting it or,or modify a signal in the case of a report, to any ships whichwhich has been may see it. hoisted, he must Flag signals are normally answered bynot just haul it the ship or ships to which they are addresseddown. What he by means of an answering pendant, which ismust doisto hoisted at the dip (or half -way up) as soonhoist the Negative as the signal is seen, and close up as soon asFlag in a position it has been read and understood. In certainsuperiortothe circumstances, as,for instance, when itsignal, which may would be difficult or impossible (on accountbe lowered at the of distance or of masking) for the ship mostdip if necessary to distant from the originator to read a signal,make thatpos- it is repeated by all the ships to whom it issible,andthen addressed, excepting the most distant one,waituntilthe whichusestheanswering pendantasship or ships ad- described above.'When this occurs, shipsdressed have imi- Signalling by semaphore. 252 NEWNES PRACTICAL MECHANICS April, 1941 It is sometimes used, however, by navaltelegraphy on several frequencies (or wave- on reconnaissance or enemy -observa- landing parties for communication withlengths) for both these purposes. tion duty or spotting the fall -of -shot. their ship or with units of the Army. For reasons of secrecy it would be un- The usual Morse codeisused,anddesirable to describe in any detail the typesWireless Telephony messages may be either in plain languageof instruments which are used, and how Wireless Telephony has replaced Wireless or in code. provision is made for the elimination ofTelegraphy for use for some of the purposes mutual interference between them. Signalling byFlashing It ismentioned above, more especially for com- For purposes of passing messages in thepermissible, however, to remark that inmunication with and between fast-moving Morse code, it is obviously far quicker toevery modern warship the fullest possibleunits such as aircraft, E -boats and, to a use some flashing device, rather than theprovision is made, within the limits of spacelesser extent, destroyers.It has done so flag, described above, which in any case,available, for long-range and short-rangealso wherecircumstances renderdirect cannot be used at night. It is not surprising,communication by wireless. conversation between principals desirable therefore, that such flashing devices are used very extensively in the Navy. For signalling by day, since itis im- practicable to use a heliograph on board a ship, use is made of signalling projectors of varioussizesand, moreespeciallyfor signallingwithaircraft,whose bearing changes very rapidly,the Aldis Lamp. The former, when used for this purpose, are fitted with a shutter which can be opened and closed rapidly by means of a handle operated by hand, while the latterTransmittinga consists of a bright source of light (battery -message in Morse fed) contained in a small, portable barrel code. fitted with a pistol -grip and a sight, the beam of which is directed along the line of sight (to make a flash) by the movement of a mirror -reflector, operated by a trigger. Any of these means can, and in fact are, used also for signalling by night, but suffer from disadvantages, firstly, that they are directional," and can, therefore, not be used for signalling to several ships at once, and, secondly, that they are very con- spicuous. Thelatterdisadvantage,of course, is prohibitive of their use for night signalling in time of war, except at bases The number of lines of radio -communica-for purposes of greater speed and flexibility. and in waters where there is no possibilitytion which are required by any ship is It suffers, however, from disadvantages of the presence of enemy warships or aircraft.dependent, of course, on the functions whichof a technical nature-such as, for instance, For non -directional signalling, that is toit may be called upon to perform and onthe greater risk of mistakes being made, its say, for signalling to several ships at once,the degree in which it is required to co-greater interference with communication on at night, an all-round light, at the mastheadoperate tactically with consorts, or withother wireless lines, and its lack of secrecy- or at the yard -arm, is used. Such a light isaircraftand/orsubmarines. Itmustwhich render its more extended use im- fed from the ship's mains, and is keyedevidently be greater on board a flagshipprobable. from one or other of the bridges. The pro-than on board a private ship. Some idea of Owing to the fact that the transmission cedure used is very similar to that usedthe number of lines which may be requiredof a wireless message by a ship, even if low when signalling by flags, a general call or amay be gathered when itis stated thatpower is used or if a high frequency is distinguishing signal being used by thewireless communication is used :- employed, enables the enemy's direction - transmitting ship, according to whether the Externally.For the transmission andfinding stations and enemy ships fitted with signal is addressed to all ships in sight, orreception by ships of- direction finders to fix the position of that only to certain ships, and is answered by (1) Meteorological Reports. ship, the use of wireless is subject to severe those addressed with an answering sign. (2) Navigational Information and Warn-restriction in time of war. Where circum- .Just as in flag -signalling, also, the signal is ings. stances render it possible, or desirable, that not only answered, butisrepeated,if (3) Intelligence of a strategical character.a ship should " break wireless silence," it circumstances render that necessary, by all (4) Requests for, and the issue of, ordersmay nevertheless be undesirable that other ships lying between the originator and the from the Admiralty. ships should do likewise in answering the most distant of the addressees. Internally. For the transmission and re-message transmitted. In such circum- Such all-round signalling is, for obviousception by ships of- stances the message may either be broadcast reasons, not practised where secrecyis (5) Enemy Reports and other Intelligencetwice over for purposes of securing its desired, but is substituted by directional of a tactical character. correct reception, or be transmitted to, and signalling with a screened lamp (portable (6) Operational Orders. repeated back by, some shore wireless and battery -fed), which can be shaded as (7) Manoeuvring Signals. station or some other ship which can afford necessary to reduce its range.Any signal (8) Fire -control Signals. to betray its position, with the intention passed by this means which is addressed to (9) Torpedo -control Signals. that it shall be intercepted by those to more than one ship must be made to each (10) Signals to and from aircraft engagedwhom it is directed. ship separately, and must, in many circum- stances, be relayed from ship to ship. Sound Signalling Sound -signalling, by means of a syren or TechnicalBooksService hooter,isused only when fog or lowIN response to an urgent need which hasvidual titles will be gladly supplied from visibilityrenderitimpossible tocom- Ilately become evident, the National Bookthe address given. Itis proposed to municate by visual means and when the useCouncil, 3 Henrietta Street, W.C.2, havecirculate future issues of Supplementary of wireless is, for some reason, consideredcompiled a portfolio of information con-Lists, four or six times a year, and the undesirable. cerning recent technical books from leadingN.B.C.willbe pleased toreceive any The Morse code is used, and the procedurepublishers,This portfolio provides a freesuggestions with regard to these lists.One for passing signals is similar to that usedservice to British Industry, and should helpof these useful portfolios should be in the when signalling by flashing. towards a greater and a speedier output.hands of all users of technical books. Wireless Telegraphy A great deal of care has been put into the Another serviceof the N.B.C.is an Wireless telegraphy is used extensively incompilation of the lists of selective andEnquiries Bureau, for the use of which the Navy, both for external and for internalauthoritative books, and the portfolio willthereis no charge to members of the communications.The increased accuracyprove handy for reference.An order slipNational Book CounciLThe full privileges of the tuning of wireless transmitters, andis included so that any books mentioned inof membership can be had for half a guinea, the increased selectivity of wirelessre-the lists can conveniently be ordered fromand further particulars may be obtained ceiverspermit oftheuseof wirelessa bookseller.Fuller particulars of indi-from the Secretary. April, 1941 NEWNES PRACTICAL MECHANICS 2.53 Loud speaking Telephone Radiator Type Loudspeaker having an output of Twenty Watts. MANY high -quality sound producingthe lower frequencies. In addition, themove in unison. This effect can be overcome systems have been constructed ineffective mass of the diaphragm must beby using a diaphragm in which all parts do recentyearswithvariousloud-small enough to radiate the higher fre-not move in unison when operated at speaker elements designed to cover a widequencies efficiently.Even with very thinhigher frequencies, and such a diaphragm frequency range.For the most part these will radiate uniformly at all frequencies if systems have utilised multiple devices in properly designed. The problem, then, which two or more loud speaker units have becomes one of determining the proper been used in combination, each component diaphragm material, and shape, to provide unit reproducing only a part of the frequency thedesired high -frequency performance, spectrum.Other systems have been con- and at the same time to permit free piston structedinwhich asingle loudspeaker vibration at low frequencies where large plays the double role of reproducing lower amplitudes must be provided for. frequencies through a horn connected to Thin metallic diaphragms offered the one side of the diaphragm, and higher most favourablepropertiesforsuch a frequencies directly from the opposite side. development as far as the desired effects In some cases, a rather wide frequency range are concerned, but the problem of forming has been produced, and very satisfactory a diaphragm of this type, which would duality has been obtained. permit the necessary amplitudes at low Several factors associated with sound frequencies, have the requiredhigh -fre- radiationandvibratingsystemshave quency performance, and be free from necessitated multiple systems forrepro- rattles and extraneous sounds, required ducing wide frequency ranges.The more considerableexperimentalwork. The important of these are the low -frequency development of such a device, however,was radiation requirements, which demand large finally successful in the Western Electric) 750A loudspeaker. amplitudeseven whenlargeradiating This instrument is a direct radiator with surfacesareused;theinertiaof the a formed metal diaphragm eight inches in vibrating system which results in a loss of diameter, and a driving coil four inches in efficiency at the higher frequencies; and diameter, which moves in a permanent the directivity of sound radiators at higher magnet field.The loudspeaker is intended frequencies, which is a' unction of the size for mounting in a closed cabinet of the of the radiator or diaphragm. proper design and capacity ; when furnished Multiple units generally involve com- so mounted, the combination is known as plications both in the mechanical structure, the 751A loudspeaker.Any cabinet of and in the associated circuits.These com- suitable design, however, may be used. plicationscan be overcome bycareful The new loud -speakingtelephone, and design, but the result is an instrument of its designer. Response -Frequency Characteristic relatively high cost. For some time a low- A representative response frequency char- cost speaker of high quality, small size, andmetal diaphragms, mass reaction is sufficientacteristic of the loudspeaker when thus moderate power capacity has been needed.to cause excessive loss in the high -frequencyhoused is shown by the solid curve in Fig. 3. Such instrument is required in broadcastrange if the diaphragm operates as a piston :The sound pressures measured on the axis are monitoringrooms,andinreproducingthat is, if all parts of the diaphragm surfacerelatively uniform from about 60 to 11,000 systems for small rooms. Direct Radiator Type Low cost and small size are most readily obtainableinadirect -radiatorloud- Fig. 2 (Right). The driving speaker ;thatis,one whose diaphragm coil vibrates in a narrow radiates sound directly into the air, and slot in the ring-shapad field which does not require a horn. To obtain magnet. the high -quality performance desired with a single loudspeaker of the direct -radiator type, the diaphragm must be small enough so that it will not be too directive at the Fig.1 (Below).The dia- higher frequencies.At the same time the phragm and magnet unit. diaphragm must be capable of operating at the large amplitudes required for radiating 254 NEWNES PRACTICAL MECHANICS April, 1941

35 cycles,a frequency range sufficientfor -J high -quality reproduction. The sound out-Fig.3. Response - 30 put is somewhat less uniform in the upper C.; Tr)if\.,...-, ,,..._, , i'tlir, ,..,, .. 1 '0,-J frequency character-t 25 .....,- as frequency range than for some horn -typeisticofthe 750A , is for i L , ,s1ii, I,' 1,,P, ,x speakers,butit adequate good loud -speaking tele-- 204 ,., If reproduction.For comparative purposes,phone in its cabinet V s 11 the response -frequency characteristic of the( full line) compared Z 15 II 1 u i best commercial cone -type dynamic speakerwith tthat of one of 0. I In which has come to our attention is shown in thebest commercial 10 r dotted line on the same drawing. Identicalinstruments(dotted 5 testing conditions were imposed in measuring line). 50 100 500 1000 5000 10,000 20,000 the two speakers. One feature of the '750A FREQUENCY IN CYCLES PER SECOND loudspeaker, the effect of which is indicated on the response curves, is application ofquality is observed within a thirty -degreeweight. When reproducing speech or music mechanical damping which reducestheangle, but satisfactory performance over aitis capable of handling the maximum low -frequencyresonancepeak so as towider angle is obtained for many purposes.undistortedoutputofatwenty -watt eliminate so-called " hang -over " effects. The diminution of high -frequency radiationamplifier at single -frequency rating. is not serious up to an angle of forty-five The 750A loudspeaker is not intended to An inherent limitation in a device of thisdegrees. In rectangular rooms of moderatereplace existing multiple -unit systems, but type, as compared with a more elaboratesize a single speaker usually suffices.Forrather to fill a long -felt need in situations combination of horn -type speakers, is thelargerrooms,or rooms of considerablewhere more elaborate devices are not re- inability to control the distribution of thewidth, two or more speakers may be re-quired or may be .prohibitive because of radiated sound.As previously indicated,quired for the best reproduction. cost or size.In locations where high sound the reproduction from a speaker of this typeTwenty Watts Output levels are not necessary, and where the is more and more deficient in the higher The efficiency of the new loudspeaker isangle of coverage is not too great, the frequency range as the observer movesequal to that of commercially availableinstrument will reproduce speech and music away from the ax:s of the speaker. The bestcone -dynamic speakers of the same size andwith remarkable fidelity.-Bell Laboratories

NEW SERIES MakingaSuccessof Your Photography By JQHN J. CURDS, A.R.P.S. (Continued from page 209, March issue) Some Interesting Facts concerning Sensitised Material and Chemicals. THE following is an interesting experi- Do not get the impression that it is onlyyou want.But there are limits, and a meat which anyone can do, and itpossible to do good photography if onereflex with a first-class lens and shutter will only cost the price of aspool;possesses a "high-class' camera; it has beenwill obviously offer more opportunities than get a friend to sitfor youwhileyouknow for a beginner with a cheap cameraa camera costing only one guinea, just as a exposefouroftheeight, thefirstatto score a " winner " and to take a bigRolls Royce is more capable than a ear six or ten feet,whichever is themoney prize, and for one with a 30 -guineacosting £150. first distance on the scale,the second at theapparatus to make a real mess of his first next distance, and the fourth at infinityefforts. Thereiswith photography, asHistorical Notes ' mark; the next four exposures should bewith almost any other hobby, a touch of To arrive at a really appreciative under- made on a building such as a church at" beginner's luck,- but the great thing is tostandingoftheveryhighqualityof varying distances. Take a very careipl noteknow everything you possibly can aboutour present - day films, papersand of the position of the main °Well eachyour own instrument, and make it do whatchemicals, it is necessary to delve into the exposure; in the case of the portraits you history of photography, and to follow step would naturally note the head, and this by step the work of our scientists and should be in the centre of the view -finder. chemists whose perseverance hasgiven Also be careful to hold the camera perfectly amateur photographers suchhigh-grade square; it must not be tilted, and finally material that it can almost be said to be be sure of the distances up to infinity. Your fool -proof. notes will help you on examining the nega- The word photography is derived from, tives to see what is wrong.It is quite or has the meaning of," sun writing or possible that every result will be perfect, drawing " ;just when it was first used can and you have got in the negative all that only be a matter of conjecture, as there are you saw in the finder, and that proves that no definite dates or records, but the early when you took a little extra care no mistakes Egyptians were well versed in the art of occurred.What really happens when you carrying sunlight by means of mirrors into behead the subject being photographed is dark chambers, and itisquite possible very often due to holding the camera their magicians knew the equivalent of the slightly tilted, or it may be that the finder camera obscura, a popular exhibit in the has had a knock, and is in consequence out last century. of its true position. A careful application Our earliest records of the actual use of of the pliers will put the trouble right. photography indicate that Thomas Wedg- wood, in about 1802, made use of a form of Comparisons " sun -drawing " in connection with designs Your experiment will have shown you for use on his pottery, and also that Sir some interesting comparisons.Put the Humphry Davy was keenly interested in prints from those eight exposures in a line, thisprocess. Early inthe nineteenth in their proper order, and note what a century, three men devoted a considerable difference there is in the size of each image. amount of their wealth, time and knowledge It will also have given you the opportunity to proving and perfecting what was known to test the markingsofyour distance scale, as the " silver " image;, two of these were and to make any necessary adjustments to A stack of bars of silver for turning into Frenchmen, Neipce-1765 to1833, and this and thus avoid having blurred images nitrate of silver.Each bar weighs about Daguerre-1787 to 1851; the third was an when taking close-ups. 1000 ozs. Englishman, named Fox -Talbot --1800 to April, 1941 NEWNES PRACTICAL MECHANICS 255

1877.These three names are indeliblymarket. This is not altogether a fault, forClassification of Films linked with the commencement of the prac-if their case could be thoroughly analysed, Films can be classified into two groups, tice of photography, and it is to them thatit would be found that they have beenmonochrome andcoloursensitive,the we owe the initial work on the permanencyrather careful to find out all they can, in aformer being largely superseded by the of the silver image. practical manner, any little characteristicslatter. Monochrome films Lave their advaA- of the film, such as the latitude that couldtages for certain work, but that is mostly Wet Collodion Process be allowed in exposure, or the developerindustrial or commercial work, and not, There follows in fairly quick successionwhich was most suitable for it; whether ittherefore, of much interest to amateurs. many names of Englishscientistsandgained density too quickly, and what sortthe ortho or panchromatic variety offers experimenterswho,seeingthegreatof gradation was possible.In this way heopportunities to those who revel in outdoor potentialities of the photographic image inwas able to obtain results which, to him,pictorial work such as landscapes, trees, silver, worked hard in their laboratories towere better than he might have obtainedstreet scenes, etc., where colour plays such turn the device into a commercial pro-from other brands. an important part in the general design, position, and in 1851 a Londoner named construction and effect of the scene, and Scott Archer, published a description of hisOverhauling and Testing which can only be correctly reproduced, in formula for the wet collodion process, and Here, then,is the lesson which shouldblack and white,if the medium used is it is interesting to note that, although thisappeal toall who desire to make theircapableofdifferentiatingbetweenthe processisstillpractised in our processphotography more successful ;there is aextremes of black and white and giving a engraving departments for the reproductionwide range of very excellent films, and youtrue rendering of half -tones, i.e., the steps of first-class illustrations for the press andcannot help selecting a good make, butbetween the extremes. This is exactly what magazines,ithas had but verylittlehaving made your choice, stick to it untilour photographic emulsion makers have alterationor improvement sinceitwasyou have mastered its capabilities, and yousucceeded in doing for us, and the pan- invented. will find that your work is improving.If, chromatic grades will be the right films for Wet -plate photography, however, becausefor some unknown reason, you are notyou to use for this class of work.Certain it was a cumbersome business, had only a limited following, but in the " seventies " there were definite moves being made for finding a method of making negatives in a simpler or more convenient manner, and the result was the appearance " of " dry " plates.These were manufactured by the firm of Ilford, Ltd., whose films, plates and papers areto -day known allover the A bowlofre - world; the Selo films, made by this firm, crystallised silver are very popular with amateurs. nitrate ready for supplying to sen- The " Silver Image " sitised material The word " silver " in connection with manufacturers. image has been mentioned, and calls for some explanation;the designwhichis found on a negative or photographic print is only made possible by the incorporation salt of silver in the emulsion that is coated on the glass,celluloid or paper; this salt is the sensitising agent, or, in other words, it makes the emulsion capable ofgetting entire satisfaction, you must firstsensitive dyes have been incorporated in recording the action of light.It is manu-examine your own method of working.the emulsions; also, filters can be used in factured as nitrate of silver, and it must beOverhaul the camera, test the dark -roomconnection with the exposures which can so of a remarkable degree of purity otherwiselamp;take the temperature of the de-control the power of the light reflected from it would create great difficultiesfor theveloper before using ;is the thermometerthe various colours in the landscape, or makers of films, and amateurs would notregistering accurately ?and so on. other subject being photographed, as to be able to do the first-class work which Here is an example. A friend bought angive each its true position in the scale of they are now able to do so easily. Althoughexpensive camera to take on an excursiongradation in the negative, and ultimately some tons of nitrate are produced weekly,to Switzerland, and was advised to use ain the print. each ounce of which has to contain 0.625certain make of film ;on receivinghis There is one important point that must of pure silver metal,yet the analyticalprints from a " D & P " chemist, he wasneverbeforgotten when panchromatic chemists who use it will not permit moredisgusted to find them spoiled through afilms are used for the first time; they are, than 0.0004 per cent. impurities.One ofnumber of spots of all shapes; he at onceas the name implies, sensftive to all colours, the accompanying illustrations shows barsblamed thefilmsandtheparty whotherefore, they will not stand the ruby light of silver, each about 1,000 ounces in weight,advocated their use.I asked to see hisof the darkroom, and must be processed in that has beenrefinedto999.9purity.negatives and his camera.It was onlythe dark. Further mention will be made of These bars are cut into small pieces and thenecessary to look at two of the negativesthis in the next article when dealing with metalis then granulated ready for dis-to read the whole story,for when thedeveloping. solvinginnitricacid, which purifiesit further and also reduces it to aostate forcamera was opened and shaken over aSpeed of Films crystallising and re -crystallising, as shownpiece of white paper, numerous tiny frag- Having decided to use a colour sensitive ments of dust, straw and wood fellout.fihn, the next question which arisesis, in the second illustration, in which con-There was nothing else wrong, the camera ditionitis sold to the film and paper should that film be a slow, fast or speedy manufacturers. Silver nitrateis manu-was good and so were the films. one? The answer rather depends on the factured by the 200 years old firm of type of camera inuse, and the class of Johnson & Sons, who have been supplying subjects that you are interested in.If you it for photographic purposes ever since the are using a camara with a fast lens, one very earliest days. THE LEADING WEEKLY with a large stop such as F4.5 or 5.6, you The reason why amateurs have such are probably specialising on fast-moving excellent material for their hobby is due FOR ENGINEERS objects, and require a speedy film, but with entirely to the skill of our British chemists, such stops, a medium -fast will serve most scientists and engineers;so much care is purposes ;if the camera works at F7.7 or given that itis almost impossible for an F8 as its largest stop, then the speedy film inferior batch to leave the factories, and PRACTICAL is advocated, especially if it is intended to this is a point winch we must remember use filters, but the fast films which are when anything goes wrong with our work; now obtainable will be found quite fast itis more likely to be due to something ENGINEERING enough for average work.There is no which we ourselves have slipped up on, special advantage to be gained in using rather than the chemicals, films or papers. slow films for general work. Most advanced amateurs have their own It has only been possible to mention very particular fancy as to which is the best 4d. every Thursday briefly certain features of our present-day film, and it takes a lot to conyince them films, but more will be said in subsequent that something better has come on to the articles. 256 NEWNES PRACTICAL MECHANICS April,1941

way willcutthrough theforest,thus Giant X -Raycheapening and speeding up transport. Machine

INSPECTIONI ofNew Copper -lead bearing certain largeANEW copper -lead bearingisbeing machinery partsr-% made by powder metallurgy.This will be speeded updifferent form of bearingconsists of a by aboutfortypowdered metal sintered to a steel sup- times now that theporting piece which acts as a strengthening world's largest in-of a comparatively thin layer of babbitt dustrial X-ray unitmetal.Triplex bearings of this type are has been com-said to withstand fatigue to a higher degree pleted at Schenec-than ordinary babbitt metal bearings. A tady according to. further bearing development is the copper engineersofthetellurium bearing, the metal of which it is General Electriccomposed being easily forged, hardened and CorporationThe giant there. machined. machine ratedat 1,000,000 volts, andAny -way -up -raft exceeding by MR. R.S.CHIPCHASE, managing 600,000 voltsthe director of the Tyne Dock Engineering largest previous in-Company, has invented a new type of life- dustrialunit, issaving raft. No matter how the raft, enters said to be capablethe water it is the right way up. Both sides of producinghave similar provision for the storage of energyequaltoequipment, water, provisions, sails, mast that of aboutand occupation.It is bullet proof and can £22,500,000 wortheven float a sinking ship if there is no time of radium.Itisto launch it.Mr. Chipchase who has given housed in -a specialthe patent to the Ministry of Shipping, building behindsays, " I want to make nothing out of it." walls 26 in.thick toprevent injury to workers from itsCorrosion resistance powerful rays. En- AN invaluable invention is the increasing gineers said that it of corrosion resistancein metals by wouldexpose aimpregnation with silicon. The silicon alloy

Men operating the new life-saving at sea.A description of this ingenious appliance is given elsewhere on this page. THE MONTH picturethroughfive Automatic Radio Control inches of steelin five Minutes, compared with ALTHOUGH radio control of aircraft hasthree and a half hoursOFSCIENCE been in use for a number of years, ataken by the 400,000 - completely new type of directional auto-volt machine. forming thecase has valuablephysical matic radio control was recently demon- Properties, and does not part from the core, strated in America before Army and Naval while it is virtually free from the tendency officials.Without any more help from theFzre Bomb Alarm to split or flake.The silicon impregnation pilot than the depressing of a couple ofFIRE-BOMB detectors that operate byis no more expensive than ordinary case- buttons the plane is able to fly in a straight means oflightaction on aphoto-carburising. Thousands of transport vehicle line from point to point.Years of experi-electric cell are among a number of devicesparts have been used to replace expensive mentation are behindthis new device,to fight incendiaries recommended by theally steel parts when treated in this way. which has been developed in Los AngelesInstitution of Electrical Engineers in a by the Harvey Machine Company.Thisreport to the Ministry of Home Security. new control consists of two radio receivers.The ignition of a fire bomb 300 feet from620 -Miles -an -hour Two radio stations are chosen on the pro-the cell, it is stated, will sound the alarm. AN American testpilot has probably posed line of flight and each receiving set flown at the greatest speed any man is tuned to one of these stations.The has ever travelled in an aeroplane. Testing signalsare mixedinthecontrolthatPlastic Planes an Airacobra fighter plane he reached a operates the automatic pilot so that the THE use of plastics in the manufacture ofheight of 27,000 ft. and then shot down in a plane is held in an absolute straight line, aeroplanes has been explored by officials5,000 ft. dive while a film camera photo- regardless of cross winds or other outsideof the Aircraft Production Branch of thegraphed the instruments of the plane. The conditions. To make this possible, the planeCanadian Department of Munitions andphotograph developed afterwards showed will often fly up -wind, or " crab," at anSupply. Mr. Ralph P. Bell, director-generalthe speed needle well past the 620 -miles -an - angle to the true course, but the body ofof the Aircraft Production Branch, recentlyhour mark. the plane exactlyfollows an imaginaryrevealed in a statement that if processes " white line " in the sky. now under study fulfil promises held out by their inventors, mass production of plasticBombarding Smoke fuselages, wings, tail plane assemblies and ACCORDING to the American Aluminium Fire Bomb Snuffer other aircraft components may result. N ews-Letter , a strange device which bom- MR. W. KELLETT, a Sheffield engineer, bards smoke with high -frequency sound has placed on the market a device for waves, thereby causing the smoke to " lie dealing with incendiary bombs, which hasAn Elephant Tramway down," is being developed by the United been granted a patent.Mr. Kellett states AN elephant -drawn tramway,possiblyStates Bureau of Mines.The idea is to that by mass production methods he couldr-% the only one of its kind in the world,attach one of these units to every chimney manufacture the device at a price whichis to be built at Port Blair, in the Andamanand stack, and prevent the smoke from would put it within the reach of the workingIslands.The Government of India, whogettingout and spreading around the man's pocket. The apparatus consists of aadminister the islands, have approved thecountryside.Inside a piece of hollow pipe steel conduit, through which runs a rodproject, which is intended to facilitate theis a large piece of aluminium which is con- attached to a pair of jaws shaped so thattransport of timber and other productsnected at one end to a loud speaker and they can pick up an incendiary bomb forwhich now reach Port Blair by a circuitousspecial radio set.The radio sets up a safe disposal in a bucket of sand or earth. route round the coast. The elephant tram -magnetic field which causes the aluminium April, 1941 NEWNES PRACTICAL MECHANICS 257

cylinder to vibrate, producing a powerfulrings, door latch parts, striker plates, andFireproofing Forests high frequency sound that, in turn, createsshifter shoes, having been made from them. high -frequency waves. These waves areRadiator grills are being formed from alloyr:ERINIAN chemists claim to have per- die castings possessing a zinc base. fected a process for making forests directedatthe smoke and causethe proof againstR.A.F. incendiaryleaves. particles in the smoke to coagulate into Woodenhouses,barracksandfactory large lumps of soot which fall out of the airNew Narrow Gauge Locomotive buildingswillalso be treated with the stream by gravity.Although still in the NEW design of oil-engined locomotivepreparation. experimental stage, it is claimed that theAhas recently been developed by the device has possibilities of doing much toHunslet Engine Co., for service in sugarDoze solves a Problem reduce air pollution by smoke, if it can beplantations.Itis of the 0-6-0 type for applied to large-scale service. ARESEARCH chemist of Cleveland, 2 ft. 6 in. gauge, with a wheelbase of 5 ft. 6 in. Ohio, dozed while experimenting in the allowing operation on a track with radiusmanufacture of red copper oxide, which is Niagara Falls New Bridge curves of 75 ft.The locomotive, which hasused extensively in ship paint to prevent a total weight of 10 tons 15 cwt., is driventhe growth of salt water parasites on the CPECIAL ceremonies were held at Niagaraby a four -cylinder Gardner oil engine ofsides of vessels.His furnace overheated, .)Falls recently relating to work on the102 b.h.p., designed to develop that powerand thereby provided the solution to the new Rainbow Bridge being built betweenat a speed of 1,200 revs. per minute.Theeconomical production of red copper oxide, the United States and Canada to replaceHunslet-type clutch is employed in con-previously manufactured by an expensive the structure destroyed by ice on Januaryjunction with the makers' constant meshelectrolytic method. 27th, 1938. Concrete and steel foundationsthree -speed gearbox.The tractive effort have already been completed on both sidesis 6,500 lb., with a maximum speed ofWell -Balanced Bridge of the river, and it is hoped that the new41 m.p.h. on this gear, the other gears giving IT is interesting to note that when the bridgewill be completed by August or 84-m.p.h. and 13i m.p.h.respectively. Kincardine Bridge over the Forth was September. It will cost £1,000,000 and willThis high tractive effort renders the loco-built, it was so nicely balanced that the be 1,440 ft. long. At the point where it ismotive well suited for long, steep gradients.huge 1,600 tons span can be moved into being built, which is a few hundred feet position by a power no greater than that downstream from the side of the old bridge,World's Largest Dam generated by a motor -cycle engine.This the cliffs are 1,230 ft. apart, and the road- ACCORDING to a recent report, 97,000is all the more wonderful when it is remem- way will tower 200 ft. above the mean level visitors a month arrive by bus, car andbered that the bridge is the longest road of the river. plane to view the wonders of the greatbridge in Britain, and the swing span one Boulder Dam. Recognised as being one ofof the largest in Europe. the world's greatest engineering feats, seven Magnesium Die Castings million tons of concrete were used for theSecret Aero Engine IN pursuit of increased lightness manyfoundations alone, and above this the dam T is reported that a Leicester syndicate sections of the transport vehicle industryrises to a height of 730 feet to hold back Ihas offered to the Minister for Aircraft are turning to magnesium die castings andthe billions of tons of water of the ColoradoProduction plans for a new aero engine, abandoning those of aluminium. Mag.river. details of which are a closely guarded secret. The invention is the work of a London inventor,whosename is well-known throughout the engineering world, and he claims that the engine is capable of a speed IN THE WORLD of more than 600 miles per hour in the air; has a fuel economy of at least 40 per cent. compared with engines now in use ;the cost of production is 50 per cent. of the cost of any existing aero engine ;has AND INVENTION perfect balance and no vibration, and is of nesium castings are both lighter and moreLarge Oil-engined Generator a very low weight. machinable than aluminium.They easilyfor N.S.W. take protective films and finishes; they U.S. "Stratoliners" for Britain are highly suitable from the standpoint ofTHE power station at Mullumbimby, ACCORDING to a recent report, British enlargedbythe air experts are considering buying five mechanical properties; and they represent N.S.W.,istobe thirty-three passenger " Stratoliners " from a considerable economy.Body finishinginstallation of a 310 -kW. Diesel-enginedthe Trans -Continental and Western Airways equipment, portable tools, and other pur-generating set. The present plant comprisesCompany.These four -motored high -flying poses represent typical employments. Brasstwo 140 -kW. water turbine sets, and amachines,itissaid, would be useful in die castings have also extended their use, 37 -kW. and a 230 -kW. oil-engined alter-ferryingpilots engagedinflying planes suchpartsas transmission synchronisernator. from Canada to England.

The King George V., the most powerful and fastest battleship.Main armament consists of ten 14 in. guns, sixteen 5.2 in. guns, and multiple pom-poms. 258 NEWNES PRACTICAL MECHANICS April, 1941 Useful Drilling Jigs Two Handy Fitments for Use inDrilling Round Bars NE of those simple jobs which re-the two surfaces of the V -groove have toset screw is tightened.This arrangement quire much more care and attentionbe filed dead flat down to these fine scribedhas the advantage that thedrillguide than at first seems necessary is thelines. comes close to the work whatever the drilling of a hole through a round bar, Now setting the block on its base-apexdiameter-within the adjustable range of shaft or spindle exactly square with andof the triangle D.C.E. upwards-we can laythe tool. exactly intersecting its axis. it on the table of the sensitive drill and To ensure the guide holes being in line A simple jig, which can be used for thisdrill i in. holes along the top at the positionswith the axis of the job, the jig is made up purpose and can also be made to suitshown in Fig. 3 on the line we have scribed.all but drilling the guide holes in the angle several sizes is shown in Figs. 1 and 2.ItThe axis of these holes will bisect the anglepiece.The position of the holes is deter- is a V -bar, which can be made of cast-iron,of the V -groove.We can open them out tomined as follows:-Lay the block on the cast from a wooden pattern. On its underthe size of drill we want, or we can opensurface plate on the face A, set the scriber edge it is grooved to an angle of 90 degrees,them to take bushes, as seen in the sectionalof the scribing block to the apex C of the and through itsheight are drilled andpart of Fig. 2. V -groove. Then, without moving anything, reamered differentsizedholestotake scribe the line for the holes along the top different sized drills. A Modified Jig of the angle piece. The axis of these holes bisect the angle Using the same methods to slotthe Another way is to hold a piece of round A.B. so that when the V -block is laid onV -groove, we can make the more elaboratestock in the V -groove,the stock being the spindle or shaft it acts as a guide to thejig shown in Figs. -5 and 6.Here theaccurately centred at each end and held drill.The holes may be bushed if desired.Vblock stands open. at the top, and anby the angle plate, B.Use the centre pops One bushed hole is shown in the sectionalangle plate B is screwed to the V -block, A,each end to set the scriber points of the part of the side view in Fig. 2.The bushalong one side.This angle plate is drilledscribing block, the V -block being down on the surface plate, resting on face A as 1 before. Then, all being in the same position, scribe the line on the top of the angle piece, B. Mark the centres of the guide holes on this line. Keep the round parallel stock in ,1 position and adjust the angle plate by the , back screw ao that it rests tightly on the stock.It will now be parallel with the 0 9 E base and we can then drill the guide holes which will then be square with the base when the base is laid on the table of the sensitive drill. It is well, when doing this drilling, to Figs. 1 to 3. Cross- Fig 4. (above). leave the round stock in the jig and drill section, side view, Method of marking through into it.Open out the holes as and plan of a simple out the V -bar. required for different drill sizes, or to take V -bar drilling fig. hardened bushes in exactly the same way as described in dealing with the simple jig shown in Figs. 1 to 4. is of cast steel and hardened.It may bein the top for guide bushes, the axis of the When drilling shafts or bars, the angle - almost dead hard, and is pressed in abushes being in dead vertical line passingpiece should always be lowered to rest on drilled hole.The top view .of the block isthrough the axis of the bar being held inthe bar.That will ensure the holes being shown in Fig. 3. the V -groove, and also in dead vertical linesquare with the axis of the bar being Shaping the V -Block with the apex of the angle in the block. drilled. The V -base will ensure them passing To make the jig, lay the block (the sides This angle piece, B, is slotted at the back,through the axis of the bar or tube. of which should be dead parallel with eachand lies against one side of the V -block. other, and the top and bottom also deadA set screw and washer hold it in place.Simple Jig for Small Work parallel) on the surface plate, and scribeThis arrangement allows it to be raised or In Fig. 7 is shown a simple drill jig for lines A.B. at each end exactly dividing thelowered for different diameters of bar orvarious small work.It is intended for any oblong and without moving the block ontube to be drilled. The set screw is loosened,drilling in the sensitive drill, and acts solely the plate.At the point C, at equal heightand the angle piece lowered to touch theas a steady for the drill.It is an iron bar at each end, scribe lines down to the basetop of the bar being drilled, and then thecranked as shown, with the surfaces A -B each side of line A.B. and each line at an and C -D parallel angle of 45 degrees to the line A.B. These with each other. lines are shown at C.D. and C.E. Without The base A.B. is moving the block on the surface plate, slotted to take a scribe lines on the bottom face and top face bolt and nut for from A and B on one end, to A.B. on the holding it to the other end.These lines are important and drill table. .The should be carefully scribed with a sharp height marked E scriber giving a fine line.Now saw down will suit the work line A.B. from B to C, using the longi- generally done. tudinal line from B to B on the bottom sur- The drill guide face as a guide and sawing no further than is a hardened the point C at each end, finishing the cut bush, F,with a with the saw dead flat in the cut. Shoulder which Next saw down lines D -C and E -C from rests against the the line on the base which have been Figs. 5 and o.Section and side view of a modified form of drilling jig. guide bar, as scribed from the surface plate from E at shown.Different one end to E at the other, and from D at busheswillbe one end to D at the other.These saw cuts made fordiffer- will, like the cut B 0, end in the point C at entsizeddrills, each end of the block. Fig.7. Section andallwill be File the 90 degrees V -groove thus sawn and plan of a the same di- out carefully to the scribed lines with a simple drilling jig ametersoutside hand smooth file. The saw cuts should just for small work. and will push in leave the lines along the bottom, and at NEWINIIMIMP the hole made in each end showing at the side of the cut, as the guide bar. April, 1941 NEWNES PRACTICAL MECHANICS 259 DieselRailTraction

A General Survey of the Progress madewith Diesel-engined Loco- motives during thepast decade.

Railbus and Railcoach As already stated, the railbus and rails coach are in successful operation in Britain, many of these giving extremely good results their seating capacity being usually ih the Fig. 1. region ' of sixtypassengers with suitable An A.E.C. space for luggage.Fig. 1shows one of Diesel-engined the A.E.C. single units in operation on the coach in operation Great Western Railway, andFig.2 a on the Great diagram of one of the " twin " cars fitted Western Railway with buffet and lavatories, and eminently suitable for long-distance runs. On various railway systems in the South American and Australian continents, cars are in regular ... ,-r".... , service, covering journeys of 200 to 300

I miles daily with ease, many of these pos- THE possibility of employing the dieseOther features call for comment also-as,sessing most of the refinements of a British engine in locomotives, railcars, andfor example, the absence of standby losseslong-distance express train.In India and otherrailpower unitstogreaterin the diesel-and these will be referred toCeylon, also, many of these vehicles are advantage than can ever be attained withlaterwhereappropriate. Beforecon-doing fine work on leading railways, and the steam engine has intrigued engineerssidering the foregoing essentials, however,have become a very attractive feature with for many years past, and as ten years havesome remarks will not be out of place onthe passengers for several reasons, not the now elapsed since a leading firm of loco-the various types of diesel units which inleast important being their ability to keep motive builders in Britain pioneered thisdifferent countries are seriously competingabreast of the severest operating schedules proposalandappliedtheirresourceswith the steam locomotive. with ease. seriously to this end, it may be opportune In South America and the U.S.A. the to survey the fieldo -day, and assess thePassenger Transport permanently -coupleddiesel power house future possibilities of this form of traction For passenger transport three types areand train with driving compartments at in the light of the work accomplished in theavailable for selection by those responsibleeach end are being used with increasing past decade. on the various railway systems-the single,success, and provide a means of high speed Whether thedieselvehiclewilleveror twin, railbus or railcoach (according totransport with luxurious comfort in the wholly displace the steam unit is an idlecapacity required); the heavier power housemost modern of designs.As these units speculation, although some have attemptedand permanently coupled train, which mayoperate over long distances, every con- to convince themselves, and others, thatcomprise one coach in addition to the powervenience is provided, and the traveller on such is not merely possible but actuallyunit, or any other number up to eight orsome ofthesetrainsisprovidedwith inevitable.As a matter of fact, it wouldeven twelve coaches;or the independentfacilities which compare very favourably seem at present that one is complementarylocomotive, capable of operating for pas-with those offered in the best hotels, and to the other-each having a definite fieldsenger or goods traffic with very slightat charges appreciably less when allowance wherein its operation is particularly success-changes.With thosethree typesitisis made for the included cost of transport. ful, and where the rivalis at a distinctdefinitely possible to produce a series ofForthissection,Fig. 3 illustrates disadvantage when in competition with theunits that can operate the entire traffic onthe type described, and shows a four -coach other.Examples that come to mind areany system, and although experience so fararticulated train set recently built by the those of the fast main line locomotive, andin this country does not extend beyond theEnglish Electric Co. for the Ceylon Govern- the local railcar.In this country no successrailbus and railcoach for passenger traffic,ment Railways. has yet been achieved with the diesel in theand the smaller -powered locomotive forHigh -Powered Diesel Locomotives realm of the first -named, while on the othershunting operations, all types appear to be The diesellocomotivefor high speed hand, it is a definite fact that the diesel -operatingsuccessfully in -otherfields,passenger transport has not so far achieved operated railcar has reached remarkablynotably in France, U.S.A., South America,the same degree of successful operation as successful results in actual service. and the Far East.By articulating thethe railcoachor power house,probably In considering the work done by eitheradjacent ends of two coaches in the Gresleyowing to thelargerproportions ofthe unit-steam or diesel-the essentialstomanner, considerable savings in first cost,enginepowerunitrequired,andthe receive prior consideration are power for operation, and final maintenancerelatively smaller experience which has so (1) Reliability in service. are obtainable for the longer trains andfar been obtained with these.This fact (2) Maximum availability. power houses, this practice being alreadycarries no reflection whatever on the pos- (3) Economical working. invogue oncertainsuburbanstraightsibilitiesofthesevehicleswhenthe (4) Ease of operation and maintenance. electric services, with very marked success.experience required with the larger engine

E L_

2. Elevation and plan of a " twin " car fitted for service on long distance runs. 260 NEWNES PRACTICAL MECHANICS April, 1941 units will have been gained, and from those already in operation in the U.S.A., France and elsewhere results are being obtained which fullyjustify the belief that the successful operation of the high-powered diesel locomotive can definitely be envisaged during the early post-war years. A recent example of this design is shown by Fig. 4, and affords an excellent idea of the lines which such a unit may follow. Although not yet the dependable unit necessary for passenger operation, the diesel locomotive cannot be so criticised when the field of shunting operations is under review. For this service smaller engines are re- quired, and owing to the fact that a large number of engine builders have very fine designs available, development in the diesel shunters has been most extensive, and the results quite remarkable. The power of the diesel engines available vary from 30 H.P. to 600 H.P., and the transmissions include mechanical, hydraulic and electrical, each of these having a fair measure of success to its credit.Practically all the shunters built by reputable locomotive builders are Fig. 3.An eight -coach (two four -coach units) " English Electric "Diesel- successful in their own spheres of operation, electric articulated train in service on the Ceylon Government Railways. and the final selection is largely influencedAvailability vastlydifferentundertaking,asexpert by consideration of engine design, trans- Maximum availability, referred to in thereaders can well appreciate. mission and general assembly features, asprevious paragraph, is an asset which is The economy in the working of the diesel well as cost.Figs.5 and 6 show twopeculiar to the diesel vehicle if well designedpower unit comprises several factors, and recent types that are to -day renderingand constructed, as users of these confirm.for 'purposes of comparison the main items valuable service on railway systems inIn the steam unit the boiler, engine andthat go to make up the bill in each case may Britain and Ceylon respectively. carriage are the main sections, and thesebe tabulated, thus :- correspond to the engine, transmission and Steam. Diesel. Of the four essentials stated in an earliercarriage on the diesel vehicle.The boiler Fuel. Fuel. paragraph, the chief is probably, thatofand the diesel engine would, therefore, be Water. Cooling Water. reliability in service, and judging from theco -related, and might logically be considered Lubricating Oil.Lubricating Oil. records kept by users at home and abroad,as the members likely to cause the highestThe fuel charges for the diesel are lower, this is amply proved in favour of the diesel.maintenance chargesin their respectivedue to the fact that Two factors which operate in its favour aremachines.Of thetwo,theboileris (1) the engineisonly runninginter- incontestable, viz.: definitely that which will have the highest mittently on this vehicle, whereas the (a) the absence of the steam boiler withcharge levied against it for maintenance, steam boiler is continuously eating its limitations and disability due tolargely due to the fact, already referred to, fuel,irrespectiveof whetherthe being continually under stress whileof its continuance under stress during the locomotive is actually in operation or the vehicle is in service, and entire service period of the locomotive, not, and (b) the fact that the number of diesel -while the diesel engine is operating for but (2) the fuel costs less per horse -power engine hours is well below the numbera fraction of the time.The newer type of developed than for the steam loco- of hours during which the locomotivevehicle is available for the entire twenty- motive. itselfis on duty, thus appreciablyfour hours of each day for at least six toTrue, the fuel required must be imported extending the useful life of the engine.six -and -a -half days out of most weeks inso far as British railways are concerned, the year, and can be operated, therefore, bybut so long as the export trade for coal can This feature, however, merges into that ofcrew relays without difficulty.But nobe maintained-and the present condition availability so greatly that possibly theC.M.E. would dream of running his steamis definitely abnormal and not one likely to clearest definition of the latter term is-locomotives in this manner except duringendure when war is over-it should be dependability at all times. This is certainlytimes of extreme necessity. A further goodpossible for the one more or less to balance the experience of most of those operatingpoint in favour of the diesel is the ease withthe other.Water consumption-and,there- carefully designed power units,andwillwhich the engine can be removed and afore costs-for the steam engine is naturally become increasingly so as time eliminatesreplace unit substituted, thus ensuring themuch higher than for the diesel, and the the various weaknesses in the vehicles nowlocomotive being almost constantly on duty.consumption of lubricating oil is higher on in, use. To change a steam locomotive boiler is athe former than on the latter, due to that

Fig. 4.Side and end elevation and plan of a high- powered Diesel locomotive. April, 1941 NEWNES PRACTICAL MECHANICS 261

Al ruling consideration-Electrical trans- mission. ----- Power Houses and Trains.-Any power- 441ii Electrical transmission. Locomotives, Shenting.-As for railcars k 1" above. Do. Main Line.-As the power of these will be well above 500 h.p., an electrical transmission would appear to be the best form, and this has been the line developed byallthe leadingcon- structors so far. No statistics have been given in this review of the position, as these notes are c--- , itil Fig. 5. A Diesel rather intended as a general survey of the shunting loco- lines along which considerable success has motive operating followed during the past decade. The trend .., ----e"-----or - on a British of events in the more progressive spheres of .Itl._ --41-txiki---ts.....--.---:,_-.n-W.-7.-.:114' . railway. railway operation would certainly suggest .xi : a greater use of diesel railcars and shunters ID" '21 . J'A- ____- " - (both heavy and light) in Britain in the futurewhenconditionsbecomemore lost on the road, and in the exhaust steam.driver will enter similar points on his dailynormal ;close -coupled and self-contained With suitable filters and cleaners, most ofreport sheet for shed attention. power houses and trains in the American the oil on the diesel engine can be used over continent, together with the double-begie again repeatedly, this being the actual dailyTransmission Methods type of diesel electric shunting locomotive. experience of many large operators. A point which has not hitherto been re-The future of the heavy express main line Single Man Working ferred to concerns the method of trans-diesel locomotive, whether for passenger or A further feature, the value of which hasmission.Assuming naturally that capitalgoods transport, lies with the designers and yet to be obtained by the big railways, liescost must have due consideration, probablybuildersof thedieselengine and the in the economy of single -man working, andthe following would constitute the mostelectrical transmission-when these can be where suitable accommodation is availabledesirablesolution,judging from recentproducedtogivethe same degreeof for handling the traffic at the stations,experience. successful and reliableserviceastheir issuing and collecting of tickets, handling Railcars.-Engine units up to 150 h.p.-smaller brethren are to -day rendering, the luggage, etc. no other vehicle can compare Mechanical transmission. big diesel locomotive will come into its own, with the diesel in this respect.If the and the continued use of the steam loco- objection be raised that a second man on Do. above 150 h.p.-Electrical trans-motive will then have greater cause for its the car is essential to stand in the breach mission. justificationthan would seem toexist should the driver collapse, this is countered Do. of any power, if expense is not theto -day. by the fact that where such happens-and it is an exceedingly rare event-the dead - man control takes complete charge and brings the vehicle to rest.Incidentally, have those who raise this objection ever considered what would happen on a road vehiclewhich hasnosuchautomatic device, but has the driver cabined in such

a manner that, when running, no conductor 11 can possibly take over the controls if the driver should collapse. Ease of operation and maintenance has only to be seen to be acknowledged, the former, especially on the railcar or smaller shunting locomotive, being often achieved by a beginner in a few days, while a steam locomotive driver must go through what is virtually a long apprenticeship to the job before being entrusted with the control of Fig. 6.A small a main line locomotive. Actually, the Dieselshunting driver of a diesel car or other vehicle can locomotive in ser- be trained in a maximum of three to six vice in Ceylon. months' ,not only to drive the car skilfully and efficiently but at the same time to do IIIMICIIII a multitude of smaller jobs which avoid .--maamiimanP3- laying it up for attention, where a steam less than the Spitfire-and the single Bristol Mercury engine of 840 h.p. gives it a top speed of around 255 m.p.h. "Gladiators"Vake History During the Norway campaign a squadron of Gladiators distinguished itself in an epic BRIT1SH, CanadianandAustralianits great asset, probably no aircraft has everfight against immense climatic difficulties fighter pilots have recently been gainingbeen designed more suited to the close andand overwhelming odds. Operating from an glory in encounters over the Western Desertintricate manoeuvres of air fighting. Someimprovised landing ground, 17 out of 18 with fighter and bomber aircraft of Italy'sof the most spectacular aerobatics andGladiators were lost in two days' continuous Regia Aeronautica.Among the aircraftbreath -taking formation flying seen at Hen-fighting ;but heavy losses were inflicted on they have used is the Gloster Gladiator, lastdon displays before the war were carriedthe enemy. of the long line of fighter biplanes adoptedout by Gladiators. And, as the first British Gladiators have since exacted their full by the R.A.F. fighter to mount more than two guns-fourrevenge,in combat against the Italian Names of Britishfighteraircraftarebeing the Gladiator's standard armament-invaders of Greece and Egypt, though often singularly apt." Hurricane " and " Spit-it was the first multi -gun fighter to go intofighting against superior numbers. In one fire " have caught the imagination of friendservice.Gladiators were also used for thefight in Egypt recently, six Gladiator pilots and foe, typifying as they do the great speedhigh -altitude" weatherflights "whichmet and routed 18 Fiat C.R.42 fighters; in and devastating fire-power of these modernwere a feature of pre-war days. another, four Australians, flying Gladiators, eight -gun monoplane types. But never was Technically,theGladiatormaybesmashed a formation of 17 C.RA2s ;whilst a combat aircraft more appropriately nameddescribedasasingle -seat,equal -spanthe exploits of " Lucky B " flight in clearing than the Gladiator, calling to mind thebiplane with metal structure fuselage andEgypt's air of the Italians have already fighter in the arena. Although speed is notwings. Wing span is about 32 feet -5 feetmade history. 262 NEWNES PRACTICAL MECHANICS April, 1941 OurusyInventors For Shavers By this article is a flexible sheet possessing a Dynamo " high degree of absorption of water and also safety razor is not extinct like therun overby a vehicle. Consequently, uponconsiderable strength, when moistened.It THEdodo ;but, as I write, it is annoyinglytheir release, they recover their normalshould not have the feeble character of wet rare. Therefore, any effective means ofuprightness. The resumption of the verticalblotting paper. renewing the cutting edge of existing bladesposition is assisted by incorporating with According to the newly proposed process, will be hailed with a chorus of welcome bythe sign one or more metallic springs. the paperistreated with an aqueous shavers of larger growth.An invention A patent for a sign of this description hassolution of a water-soluble cellulose ether. with this raison d'etre is the subject of anbeen applied for in this country.The in -This sheet will be especially acceptable to application which has recently been accepted travellers, who appreciate a virgin towel, by the British Patent Office. and do not care to share a communal This new appliance has a handle and one The information on this page is specially supplied to drying cloth. or more rotatable cylindrical sharpening " Practical Mechanics " by Messrs. Hughes & Young, Patent Agents, of 9 Warwick Court, High Holborn, elements.It is admitted by the inventor London, W.C.I, who will be pleased to send free to that a knife sharpener of this type is not a readers mentioning this paper a copy of their Attachtuent for aTin Hat new idea. He points out, however, that a handbook, " How to Patent an Invention." THE illustration on this page shows an previous apparatus of the kind has pos- attachment for a standard tin hat.It sessed an electric motor, whereas his device will be seen that a small container is attached is distinguished from its predecessor by notvention is a flexible sign -panel mouldedby the screw which is fitted in every tin with equallyflexiblesupporting pillars,hat. being power -driven.His chief aims haveeach having a coiled spring embedded in been to produce a blade sharpener of simpleit. The lower end of each pillar is adapted Inside the container is a small flat -type construction, and one that can' be carriedto receive an arrangement for attaching theelectric torch battery. By simply rotating in the pocket or will occupy little space inpillars to a solid foundation. thecontainer a smallamount, the battery is one's luggage.The sharpening element is made to make or break contact with the preferably made of glass, but it may be electric lamp bulb fitted in front. Encircling composed of other material such as car- the container is a celluloid band, parts of borundum. which are coloured purple and red, and a In these days when waste is deprecated, part isuncoloured. Moving this band, it is almost a sin to discard blades which white light, purple or red light can be are not worn out, and which may have shown. The appliance is very easy to their keenness constantly restored. manufacture and apply to all existing tin hats, and standard batteries and lamps Elbow She!'" would be used.Variations of the white, THE arm -restisa familiar objectin purple and red light can be used, and words railway carriages and other vehicles ; insteadof colourscould be employed. but, as a rule, it is rigid.An adjustable The inventor is Mr. J. Kingston, Reading. to repose one's arm has been Enquiries relating to the device should be devised for the travelling public. This addressed to Gascoignes (Reading), Ltd. arm -rest is intended to be fitted to the inside of a vehicle door. On to the window For the Home Fires ledge or the door may be placed a hook with a shank having a number of holes. N these days of scarcity of coal, any These holes enable one to fix an arm -rest I method of adding to the longevity of the in a position convenient to the driver or home fires will be welcomed with appro- passenger.And both the height and the priate warmth. As the briquette contributes angle may be regulated to support the to the durability of the fire, a new process elbow in the most comfortable attitude. of working up coal into blocks is worthy of consideration.Theprocessinquestion A lighting attachment for a standard dispenses with binders.It has been dis- Sowing Machine tin hat covered that a material particularly suitable AN improved apparatus forthesys- for moulding into briquettes without the tematic cultivation of thesoilhas The sign may be fitted with one or moreaid of binders can be produced by moisten- appeared at an appropriate time. This new.electric lamps, which are so made anding the coal before the fine comminution; acquisition for the agricultural home frontmounted as to be shielded from damagethat is to say, by increasing the water is a seed -distributing device.The sowerwhen the sign is struck or run over. content.After this treatment, the fuel is who broadcasts by hand the seed, some of This wayside cicerone, which gives waydried. which falls on stony ground, is a familiarso courteously, will add to the amenities of sight in devotional pictures.This methodtransport. Seat -Indicator for Cinemas of sowing may now be replaced by a mechanical sower arranged to be attachedTo X -Ray Tyres MILLIONS of people attend the cinema to a harrow or roller.It comprises a seed - with a hammer, is a time- at least once every week. Seating this box with delivery holes and chutes.TheTAPPINGhonoured method of testing the sound-enormous crowd is not achieved without seed is fed from the box to the chutes byness of the wheel of a' railway coach. Guiltydifficulty. The problem of the long, waiting means of feed -wheels.These are mountedmetal has a cracked voice.It is now pro-queue is still unsolved. on the box behind the delivery holes on aposed to examine pneumatic tyres by means It is interesting to note the characteristics shift coupled to a driving wheel runningof an X-ray inspection equipment.Thisof a recently introduced seat indicator for on the ground by the side of the harrow orpermits a scrutiny without the removal ofpicturetheatres. In the caseof this roller. the tyre. indicator, each seat has a switch which is This apparatus will ensure the rapid and Hitherto we have been accustomed toactuated when the seat is occupied.The even distribution of seed switches of all seats in a row are connected associate X-rays with an investigation ofin series and also in series with an electric the interior of the human body.By thelamp. And the switches and lamps of Signs Which Bend same method it will henceforth be possiblevarious rows are arranged in parallel in a I T is an irony of fate that signs which areto penetrate the inmost recesses of mountedcommon circuit. As a result, when all the erected to assist the motorist are some-tyres. seats in a row are occupied, the circuit' to times struck by the car of the driver whom the lamp of that row is completed. When they direct.If the sign be of unyieldingA Clean Sheet all the rows of a group are filled, the material, the result may be disastrous to THE paper towel is not a novelty. A re-current flowinginthe common circuit the inanimate guide. vised version of this handy sheet hasoperates another lamp or other indicator to In order to reduce the violence of anappeared. Presumably the idea of the newshow that the whole of the seats are in use. impact, there has been constructed fromtowel was conceived prior to the scarcityThismakesnecessarytheintimation, rubber, signs which bend when struck orof paper.The most effective material for" Standing room only. April, 1941 NEWNES PRACTICAL MECHANICS 263 Transformer uilding The Designand Construction of Small Static Transformers. By A. H. Avery, A.M.I.E.E. FEW of the smaller electrical appliancesand brushes at the opposite end. The fieldsdisadvantages, however, from the maker's within the scope of the amateur con-are excited by the input current whichpoint of view, when it comes to hand - structor offer a better return and surerdrivesthearmaturealsoasa motor.winding a large number of turns of wire, all results from his efforts than the transformer.Motion is represented by the curved arrow,of which have to be threaded through the Its design can be calculated and its workingand remains continuously in one direction.centre of the ring.This would take a long characteristics pre -determined within closeIn Fig. 2, which is a conventional diagram oftime, and inevitably lead ° to rather an limits,while the constructional work ita static transformer, all the parts-namely,untidy finished appearance as they could entails is of the very simplest. iron core, primary and secondary coils-arenot lie closely on a curvet} surface. Practical Technically speaking, the term " trans-stationary, and it is the magnetic flux thatconsiderations soon decided, therefore, that former " can be used to describe apparatus aplain straightcore was necessary to widely differing in principle and operation; accommodate the coils. Why not, therefore, thereareRotary Transformers,Static a plain straight core like that of the induc, Transformers, Voltage Transformers, Cur- tion or spark coil ?This form proved easy rentTransformers,etc.,withfurther enough to wind but resulted in unexpected variations in the way of auto -connections difficulties, the chief of which was excessive and independent -windings.It is correct to magnetic leakage owing to the great air -gap speakof Rotary transformers only for existingbetweenitstwo ends.Every directcurrentoperation,theirpurpose magnetic line generated in an iron core by being to transform direct currents from one reason of current flowing round an exciting voltage to another. Static transformers are coil has a complete circuit of its own. Fig. 3 those which deal entirely with alternating Fig. 1.Diagram of a rotary illustrates this.Current from the battery currentsorthetransformationof one transformer. flowing through a coil wound over the iron alternating voltage to another. Apparatus gives rise to a magnetic flux, one line of which changes the nature of the current which is indicated.All lines leave the coil itself,from direct to alternating, or vicemoves rapidly to and fro through themat one end and re-enter at the other.In versa,comes underthedescriptionofwith every reversal of current in the pri-completing their circuits they find an easy converters, and should not be confused withmary coil, the rate of motion responding topath through the iron, but a much more transformer 3. the frequency of the supply, usually 50difficult one where they emerge into air, the cycles per second, or 3,000 cycles per minute.result being to reduce greatly the number Rotary Transformer The flux speed is thus easily comparableof lines set up by a given excitation. The The rotary transformer, shown in diagramwith the rate of armature revolution in thesame magnetising power of the coil can be in Fig. 1, is used for stepping up or stepping used to far greater effectif the length down direct currents from one voltage to traversed through air can be shortened. another, and is a running appliance similar In other words, instead of an " open " in construction to a direct -current electric magnetic circuit a closed circuit should be motor but having two windings on its aimed at, so that the lines encounter the armature. One of these functions as a motor least possible resistance. Since the circular winding, the other as a generator winding, form of closed core is open to objections the latter being connected to a separate already pointed out the alternative is a core commutator and set of brushes. By this of rectangular shape, such as Fig. 4. Here means an output voltage differing from the the magnetic lines have an all -iron path and input volts can be obtained according to the the exciting coil lies on a straight limb, ratio existing betWeen the turns in the two making it easy to wind, so that two distinct armature windings. Machines such as these Fig. 2.Conventional diagram of a advantages have been secured. But still the naturally involve a considerable amount of static transformer. transformer would not be easy to wind if work and skill in fashioning the running the core were made in one piece, owing to parts ;also, they are subject to wear and the necessity of threading the wire through tear which is absent entirely from the staticD.C. type of transformer. If a static trans-the centre opening The idea of building or A.C. transformer. The latter is an abso-former were connected to a D.C. supplythe core in separate parts was the next step lutelystationarydevice;thereare nothere would be no motion of the flux afterforward, the result being a two-piece con- moving parts.But energy in some form the instant of switching on or off, hencestruction,as.Fig. 5. must be supplied to it as an input before anythere would be no reaction or transformer output is possible.If connected to a D.C.effect in the coils. circuit it will not function as a transformer Independent Coil Winding at all.What, then, is the form of energyGeneral Form This allows of the coils being wound inde- communicated to it when connected to an Confining attention particularly to thependently, insulated, and afterwards slipped A.C. circuit ? static transformer in this article, being theover the straight limb of the core, thus There is no visible motion with which wesimplest of almost all electrical devices toeffecting a great saving of time. Eventually are accustomed in the case of most electricalbuild, one can next consider what generalit was found possible to further reduce the and mechanical devices. The answer to thisform they take in practice.The simplecost of construction by building up the liesin the fact that although motion isdiagram in Fig. 2 represents a circular ring - unquestionably present it takes the invisibleshaped ironcore, the most symmetricalsides of the core from straight slips of steel form of a rapidly oscillating magnetic fluxshape that would naturally suggest itself,sheet, after the style of Fig. 6, since this in the molecules of the iron core, and theseand, in fact, the one adopted by earlyentails the least possible waste of material in their turn cause strong reactions in theexperimenters.It presents rather obviousand calls for no special tools or dies. stationary coppercoilssurrounding the core as the flux threads them first in one direction and then the other at a high rate of speed. In the rotary transformer it is the armature coils that move in a stationary magnetic field; in the static transformer it is the magnetic field or flux which moves through a system of stationary coils. The two ideas are expressed in Figs. 1 and 2. The D.C. rotary transformer in Fig. 1 shows two armature windings on one core, rotating together on one shaft, the motor commu- tator and brushes in connection with one Fig .3, 4 and 5.Diagrams indicating magnetic flux, and shape of transformer core. set of windings, the generator commutator 264 NEWNES PRACTICAL MECHANICS April, 1941

to zero condition again. The same thing happens with the second halt cycle of mag- netisation when current is reversed through the exciting coil. The results, if plotted out in the form of a complete curve, give a figure representing hysteresisloss in one complete cycle of magnetisation. The close- ness or open-ness of this F -shaped curve representsmagneticfrictionandisa measure of the suitability of the iron for its purpose. The smaller the area enclosed by Figs. 6, 7 and 8.Various types of transformer cores, and disposition of windings. the curve, the fewer watts will be wasted in ironlosses,and the higher theoverall These arethestages by which the Not only must the iron core be laminated, efficiency. " Core " type of transformer was arrived at,therefore, but the choice of material from a form still very popular and as efficient aswhich it is built is of importance. A definiteMaterial for Stampings any.There is another form preferred bymagnetising force produces a much greater Although "Stalloy' may be regarded as some, known as the " Shell " type, Fig. 8.response in some grades of iron or steel thana standard material for use in transformer In this it is the centre limb that receivesin others.Materials having a high " per-cores, a good deal of interest centres round the coils and the magnetic flux after thread-meability " are,therefore,essential, andsome of the newer alloys of nickel and ing them divides up right and left at theequally so is the ability of the iron to followaluminium with iron, such as " Permalloy," ends, returning by the yoke or outer shell.the rapid reversals of flux directions with as" Perminvar," " Mumetal," " Radiometal," Since the shell thus carries only half thelittlelag aspossible.Magnetic lag,oretc.Some of these have extraordinarily total flux, its sectional area can be reduced" hysteresis," means a loss of energy, andhigh permeability values at the lower mag- to half that of the centre limb. Stampingslowers the overall efficiency as well asnetising forces. Others possess an extremely for these cores are obtainable in two forms,increasing the core temperature.Fig. 12small hysteresis loss, a feature which is one a " TU " shape, the other an " EL "serves to illustrate both these points. Anhighly important from the designer's point combination, Figs. 9 and 10. alternating magnetising force applied toof view inconnection with radio work. The positioning of the two coils, primarythe corefirstinthedirection HHere the frequencies are much higher than and secondary, on any of the foregoingcauses a response in the iron indicated bythose met with in commercial transformers. cores, is a matter of some importance. In Their use in such work also permits of a the Shell type both coils naturally are striking reduction in weight and dimen- wound on the centre limb, and there is no sions. For instance, the drawing to scale choice of position, but in the Core type two in Fig. 13 shows the comparison between arrangements are possible. For the sake of the sizes of stampings for two radio trans- symmetry one would naturallyincline formers of similar output capacity, the large towards putting the primary on one limb one in ordinary silicon -steel and the other and the secondary on the opposite one, but in special nickel -iron alloy.Their relative there are objections to this course, not at weights are as 24 oz. to 0.64 oz. once apparent. If Fig. 7 is examined, where Figs. 9 and 10.Two formsof Permeability this method is illustrated, with the primary transformer stampings. A curious feature of some of these alloys and secondary coils separated on opposite is the way in which they are affected by the limbs, it will be clear that the magnetic lines presence of the element nickel in varying generated by coil P will have a tendency, proportions. The permeability of pure iron, when heavily loaded,to leak away as for instance, is gradually lowered by adding shown by the dotted lines, so that they do Eddy from 10 per cent. upwards of nickel until a not wholly thread the other limb of the core Currents point where the nickel content reaches but leak away on shorter circuits without 30 per cent., when the alloy becomes prac- threading the secondary coil S. Any loss tically non-magnetic. Further additions of so entailed upsets the true voltage ratio nickel, however, have the rather surprising between the two coils and the " regulation " result of again increasing the permeability of the transformer suffers accordingly. The until a mixture of 78 per cent. nickel with best practice, therefore, is to wind both the iron gives an alloy superior in magnetic primary and the secondary coils on one and Fig. 11. Showing the formation of " eddy qualities to almost any other known sub- the same limb ; this restricts magnetic leak- currents " in a solid iron core. stance. A small addition of copper, too, age effects to a minimum. With the same appears to further improve performance and object in view, the secondary coil should bethe curve a b. When the exciting currentstabilise the properties generally.Special wound next to the ironcore, with thedies down again to zero before reversing, thealloys like these, however, are expensive, primary coil encircling it. magnetisation does not fall to zero butand their utility lies more in the line of radio remains at some value c, a little higher thanwork where low magnetising forces, audio - Laminated Construction the point a where is started. This is due tofrequencies, and minimum possible dimen- In all alternating current devices, anda certain hardness or " retentivity " of thesions count largely. For general industrial transformers in particular, there is a reasoniron.A further magnetising current d,work, Stalloy, or silcon-steel alloy, prac- for using thin stampings instead of solidtherefore, becomes necessary in the oppositetically holds the field. bars or castings, as a laminated constructiondirection H - before the iron can be brought (To be continued) checks the formation of heavy cross currents in the substance of the core when it is sub- jected to an alternating magnetic flux. These, known as " eddy currents," would cause serious heat losses, and it would be impossible to keep the temperature of the whole transformer down to a reasonable Fig. 12 (Left). figure without this precaution.Currents Diagramrepre- such as these circulate in a direction at senting hysteresis right -angles to the flux in the core itself, loss. (see Fig. 11), and as they are generated at very low voltages a relatively small resist- Fig.13. (Right) ance in their path reduces them to a harm- Comparisonbe- less extent. When the stampings are suffi- tween the sizes of ciently thin, the natural scale or oxide on stampings for two their surfaces forms almost sufficient resist- radio trans- formers of equal ance by itself, but in practice it is usual to capacity. The give additional protection by coating one largeoneisof side of the stampings with very thin paper, silicon steel, and or spraying them with a special insulating the other of varnish. nickel -iron alloy. April, 1941 NEWNES PRACTICAL MECHANICS 265 Phosphors and Phosphorogens The New Types of Luminous Materials used in Modern Industrial and Scientific Work. IN the year 1602 a cobbler of Bologna, inLuminous Compounds proportion to the phosphor, after which the Italy,named Casciarolus,whoalso Considerablestrides have latelybeenlatter is very carefully heated for some hours dabbled in alchemy, prepared a strangemade in the commercial manufacture ofto a controlled temperature in order to kindof" earth "by heatingmineralluminous compounds,,both of the fluorescentinducethenecessarymicrostateof baryteswithcharcoal. The resultingand of the phosphorescent types. Suchcrystallisation.The greatest possible care material was luminous in the dark, and itcompounds are now generically termedisnecessaryinthis work of phosphor wassubsequentlygiventhenameof" phosphors." preparation. Almostabacteriological " Bolognian phosphorus," atitlewhich Regarding the nature of these phosphors,technique is required to keep contaminating clung to it for centuries and by which it isit has been shown that they all compriseimpurities at bay during the making of the sometimes known even at the present day. certain inorganic or mineral -like materialsphosphor. It is chiefly on this account that The Bolognian phosphorus, which con-in a micro -crystalline state. the amateur preparation of such phosphors sisted of impure barium sulphide, was the Phosphors usually comprise the sulphides,or luminescent materialsisnot usually first luminous substance to be preparedsilicates, phosphates, borates or tungstatessatisfactory. artificially.It had, however, no practicalof the metals zinc, cadmium, calcium and The firstcommercial application of a uses, for its luminescence was far too feeblemagnesium. Almost any of these corn -phosphor or luminescent material followed for the material to be utilised commercially. the discovery of the X-rays in 1895. X-rays At a later date other similar luminous werefirstdetected by theiractionin compounds were discovered, but it is only causing barium platinocyanide crystals to within the last decade or two that the fluoresce, and thereafter fluorescent screens scientific study and systematic manufacture containing barium or potassium platino- of luminous compounds have been taken cyanide (mainly the former) were employed up seriously. in hospital and industrial radiographic work. The true cause of the luminescence which Barium platinocyanide, however, for radio- some materials exhibit when exposed to graphic screen work has two attendant certain types of radiation is still unknown, disadvantages. In thefirst place,itis although several promising theories have extremely expensive, and, in the second been put forward to explain their action. place, it is apt to be converted into a brown It is not now proposed to discuss the inner modification by the action of the X-rays, causation of luminescence. Sufficeit to whichmodificationispracticallynon - state that luminous materials convert a fluorescent.Hence, barium pIatinocyanide portion of the radiation which impinges visual screens for X-ray work were con- upon them into visible light, whereas, with tinuallydecreasinginluminosityand ordinary, non -luminescing substances the efficiency. They remained in use, however, incident radiation absorbed by them is until about 1912, when visual X-ray screens converted merely into heat. containing powdered Willemite, a natural silicate of zinc, were introduced for metal- lurgical and industrial radiography and also Two Types of Luminescence for hospital work. Subsequently, artificially prepared Willemite was substituted for the Modern technical science distinguishes natural mineral. two types of luminescence, viz., fluor- Willemite (zinc silicate), whether natural escenceand " phosphorescence." or artificial, fluoresces a bright green.It A fluorescent substance (so-called because is far cheaper than the platinocyanides and the mineral fluorspar was one of the first more efficient. studied of luminescing materials)is one These flaskscontainliquid fluorescent which directly converts into visible light solutions.Above them is an ultra -violet Fluorescent Screens some of the radiation which it receives, the ray generated with filtering screen of After Willemite, cadmium tungstate was material thereby glowing or " fluorescing " Wood's glassto filter out any visible as long as the energising radiation, such as introduced for fluorescent screens. This ultra -violet rays, is allowed to act upon it. light. material glows with a bluish -white coloura- When, however,the tion under X-ray excitation.Moreover, it incidentradiationpounds can function as phosphors providedisextremely permanent and doesnot ceases, the fluorescence at once terminates.that they are in a fine, or, as it is termed, adecrease inluminosity under prolonged Fluorescent substancesare,therefore," microstate of crystallisation.If suchX-ray bombardment. radiation -convertors, converting thematerials are not in a crystalline condition, Then, for the same class of work, came short-wave radiation of ultra -violet light,they are useless as phosphors. zinc -cadmium sulphide which superseded cathode and X-rays into the longer wave- In addition to being in a state of microordinary cadmium tungstate, since it glows lengths of visible light. crystallisation, phosphors must be intern-with about four times the brightness of the Phosphorescent materials, on the otherally activated by the presence within themlatter under the same intensity of X-rays. hand, act as radiation accumulators. Theyof a minute trace of some foreign metallic Recent, developments in the making of luminesce under the influence of short-wavesubstance, which latteris now usuallyX-ray screens comprise the introduction of radiation, but their glow does not ceasetermed a "phosphorogen." screens carrying calcium tungstate, and when the incident radiation stops. On the also another type of screen bearing an active contrary, the phosphorent material con-Phosphor Preparation material of zinc sulphide which has been trives to glow for many hours after its Copper, silver and manganese compoundsspecially " doped " by the presence of a activating radiation has been stopped, thecan all act as very efficient phosphorogenssilver phosphorogen which imparts to it a substance functioning as a veritable storerinaidingthefulldevelopment of thebrilliantbluefluorescence under X-ray of light and subsequently releasingitsluminous properties of the phosphor. excitation. accumulated store of light energy in small In commercial practice, the phosphor is Modern research work in this direction is amounts over a period of several hours. manufactured on the laboratory scale, theconcentrating upon the problem of arti- All the ordinary commercial luminousgreatest possible care being taken to obtainficially preparing a phosphor which will paints belong to the category of " phos-it in the highest possible state of chemicalemit the maximum intensity of fluorescent phorescent "substances. They requirepurity, for if certain contaminating com-glow with the minimum intensity of X-ray periodical " activation " by being exposedpounds are present, even in the minutestaction,therebyenablinglower -powered. to a bright light, after which they emitdegree, the phosphor, fluorescent or phos-X-ray tubes to be employed and photo- light of a gradually decreasing intensityphorescent, will not function satisfactorily.graphic exposures to be lessened. For this until they are again reactivated by a fresh The selected phosphorogen or activatingpurpose,thesearchformore suitable exposure to the energising light source. trace -materialisthen addedin minutephosphors proceeds apace. 266 NEWNES PRACTICAL MECHANICS April, 1941

Cathode-ray Tube Screens inthe preparation of luminous paints. Nowadays, radium " self -luminous " The employment of phosphors in theThese compounds emit a blur phosphor-materials contain 0.2 milligrams of radium construction of cathode-ray tube screensescence which persistsfor a long time,bromide per one gram of phosphor.The for television, and other purposes, has givenalbeit its luminosity is but feeble. cost of such materials is approximately a very great impetus to the recently - Research on the effect of specially -devisedhalved,andtherateofdecreasein established phosphor manufacturing indus-phosphorogens on the luminosity of ordinaryluminosity is very much lessened, owing to try,although, of course,thewar hasphosphorescent materials may be expectedthe smaller radium content. temporarily called a halt to such activities.to " improve the breed " of these substances For a television cathode-ray tube, thevery considerably. fluorescent screen should ideallygive a Phosphorescent zinc sulphide is the mostSelf -Luminous Materials black and white image, since greenish andpopular of this class of phosphors at the In modern times the tendencyisto bluish coloured images arelesspleasingpresent time.It forms the basis of manymanufacture" self luminous "materials when viewed continuously. luminous paints and enamels, and since itfrom mesothorium salts instead of from There is no phosphor known at presentcan withstand the effects of heat, it can beradium bromide, and, in consequence, the which produces by itself a perfectly whitemade up into vitreous enamels withoutuse of radium paints is becoming obsolete. fluorescence.However, by combining twomuch detriment to its properties.It is in Mesothoriumself luminous " phosphors phosphors in the one screen, one giving anthis manner that many of the luminousare usually made to the standard of 0.2 orange and the other a blue fluorescence,buttons and other devices are manufactured.milligram of mesothorium salt to one gram a very good approach to a perfectly white In Germany, enamels prepared from thisof phosphor, which usuallyconsistsof fluorescence is obtainable.It is upon suchphosphor have for a few years been em-synthetic zinc sulphide. The mesothorium problems that much commercial researchployed for the making of air-raid shelterused for this purpose is freshly extracted work will be directed after the war, for thedirection notices. from its sources, since it has been shown cathode-ray tube is showing itself to be A novel use of such phosphors consists inthat the alpha -ray activity of mesothorium capable of many important applicationsincorporating them with plastic mouldingincreases during the first four and a half not only for television work, but also ,npowders of the synthetic resin type. Theseyears of its life. In practice, the luminosity other spheres of industry. Mercury Vapour Tubes Anotherapplicationofscientifically - prepared phosphors which will rise to the highest importance in the post-war period relates to the use of these materials in gas A modern zinc silicate discharge tubes of the mercury vapour phosphor photographed illuminating type. by its own glow under It is well known that, in addition to the visible light produced by these tubes, a ultra -violet activation. large proportion of invisibleultra -violet rays are also generated. These are usually wasted, since such gas discharge tubes are generally employed solely for visual illumin- ating purposes. Ithas, however, been proved possible to give an inside coating ofpowders are moulded in the ordinary mannerof mesothorium phosphors is quite constant aspecially -preparedphosphortotheseby hydraulic pressure, and an article of theover the first twelve or eighteen months of tubes so that the ultra -violet radiationbakelite type results, which is self -luminoustheir lives, after which it decreases very activates the phosphor, and ispartiallyafter exposure to light.Here, again, is agradually. converted by the latter into a visible andpost-war development which will take place For many important uses, these " self - highly -brilliant fluorescent glow. upon a considerable scale. luminous " paints of either the mesothorium Various types of phosphors have been or the radium type are vital.Yet it must used for the construction of such gas dis-Luminised Dials not be imagined, as many -are inclined to charge tubes, and the colouration of the The use of radio -active compounds in thedo, that these luminous paints are essentially illumination produced by any given tubepreparation of luminous paints is one whichpermanent in their luminosity. In all cases, depends upon the natural colour of thehas been known at least since the last war.as we have seen, there is eventually a slow glowing gas combined with the characteristicA very small amount of aradio -activedecrease in efficiency due to the deterioration hue of the fluorescing material. By varyingcompoundisintimately mixed with aof the phosphor. both the nature of the gas in the tube andsuitable phosphor and the resulting material The fact that all phosphors when com- that of the phosphor employed, it is possibleis utilised for the painting of numerals onbinedwithsuitablephosphorogenswill to obtain a wide range of brilliant colours,watch dials,for the tipping of compassfluorescevividly under the influence of some of which have actually been employedneedles, watch and clock hands, and otherinvisibleultra -violetrayshas rendered for advertising work. indicators. The paint or enamel so appliedmany of these new compounds of use for The light -giving efficiency of these tubesis more or less permanently luminous sincestage and advertising work. A certain type isvery satisfactory. For instance,athe ceaseless radiation (alpha rays) from theof glass, known as Wood's glass," con- mercury vapour tubeinternallycoatedradio -active compound acts in the same waytaining a small percentage of nickel,is with a zinc silicate phosphor activated withas short-wave ultra -violet or other radia-transparent totheinvisibleultra -violet a special type of phosphorogen (the naturetions. rays, but is almost opaque to all visible of which is secret) gives a brilliant greenish Many of these " luminised " dials find anlight rays. If, now, articles of stage scenery, light, the efficiency of which is of the orderapplication in the construction of navigationwritten advertising characters, or designs, of about 96-100 lumens per watt, whereasinstruments, both aeronautical and marine,and similar objects are given a thin varnish the efficiency of an ordinary gas -filled lampand they have been employed in the makingcoating of a suitable phosphor, they will operating on a similar voltage is only aboutof many varied types of sighting devices. shine brilliantly when activated by ultra- 10 lumens per watt. During the last war, radium bromide wasviolet radiation filtered through a piece of Mercury vapour lamps for street andemployed as the energising material of aWood's glass.And since ultra -violet light factory lighting are very deficient in redzinc sulphide phosphor.About 0.4 milli- isinvisible, such articles when excluded rays, which fact imparts to their character-gram of radium bromide was incorporatedfrom any visible illumination will appear to istic illumination a rather ghastly naturein one gram of luminous material. Experi-shine of their own accord in the dark. which is unpleasing to a large number ofence proved, however, that these " self - By varying the nature of the phosphors, individuals.If, however, a mercury vapourluminous " paints and enamels were not somulti -coloured effects of great vividness and tubeissurrounded with another tubefoolproof as they were at first consideredbeauty may readily be obtainedunder internallycoatedwith azinc -cadmiumto be. The bombardment of the particles ofultra -violet ray radiation. sulphidephosphor,thefluorescenceofthe phosphor by the alpha -rays of the Here, again, is another application of the which is orange, the red deficiency of theradium resulted in a progressive deteriora-properties of modern phosphors which will mercury's radiation is compensated, and ation of the former, so much so, that thesee further extension in the post-war period. very much more pleasing illumination isefficiency of the luminosity of such paintsIt may even be extended to industrial. obtained. fellto about a quarter of their originalusuages, for, in some circumstances, it is Luminous Paints during the first year of their life.Further-oftendesirabletohavecertainareas Ordinary phosphorescent materials of themore, by increasing the radium content ofilluminated by invisible radiation, and the " luminous paint' variety have not foundthe zinc sulphide phosphor (and, thereby,employment of a selected phosphor com- anything like the important applications ofthe resulting brilliancy of the luminescence)bined with filteredultra -violet radiation the fluorescent phosphors.Calcium andthe rate of decrease in luminosity of theprovides an admirable, and simple means of barium sulphides have been used for yearspreparation was greatly accelerated. effecting such requirements. 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FOR many years it has been the customposssed.He took a delight in visitingpointed to his evident passion for mechani- among writers on industrial history toneighbouringgrist -millsandinnotingcal pursuits, and his mother, being a shrewd look down upon the character andcarefully the action of their machinery.and sensible woman, encouraged him in his merits of James Brindley, England's firstThen, during the long, dreary nights of theactivities, believing that they would be the canal builder, because he was altogetherwintertime,hewould' makeminiaturemeans of his ultimately acquiring a com- uneducated, and almost illiterate. Through- petence in life. out his life he could hardly read anything save the most elementary of sentences, and Apprenticeship when he wrote his necessary accounts it In the village of Sutton, near Macclesfield, was only with the very greatest difficulty there lived one, Abraham Bennett, a mill- that he managed such a task. wright and a wheelwright. A millwright in Other individuals since Brindley's time those days= was an individual who not only have patronised the man's memory. They made, assembled and erected machinery, have regarded him with a certain amount of but who also functioned as a practical con- good humour, and have dubbed him as an sulting engineer, whose fame, if it existed eccentric person. The truth of the matter, at all,, would be known far and wide over however, is that James Brindley, entirely the surrounding districts. Millwrights were untutored and unlettered though he un- carpenters,mechanics and engineersall doubtedlywas,standsoutvividly,if, rolledintoone. Theirknowledgeof perhaps, somewhat picturesquely, in the mechanical matters, or perhaps it would be history of industrialism as a natural genius better to say their experience of such affairs whose circumstances during his mature had to be comprehensive and sound, so that years were fortunately such as enabled him they could tackle any mechanical job from to carry out his creative works with the the mending of a plough to the handling very minimum of opposition. and erection of a wind or a water mill, or It was James Brindley who engineered even one of the then new-fangled steam the first of the world's big canals, an enter- pumping engines. prise which was rapidly to result in the Brindley, having attainedthe age of covering of England (as well, also, in after seventeenyears,sought out millwright years, of other civilised countries) with a Bennett, and, at his mother's prompting, veritable network of artificial waterways. offered himself as apprentice to the village Brindley's first canal still exists in much mechanic. This was in the year 1733. the same condition as it did originally. Bennett was favourably impressed by the Running from Worsley to Manchester, a lad's enthusiasm for mechanical matters. distance of more than seven miles, this now He took him on trial for a few weeks, and historic waterway provides to this day a James Brindley. then bound him apprentice for seven years. convenient channel of commerce for many Of. Brindley's prowess with millwright lumbering chains of horse-drawn barges,models of the mills which he had visited,Bennett there is extant quite a wealth of which slowly and contentedly navigate itsemploying bitsof wood and scraps ofinformation.It would seem that, although gentle turns and windings. wrought iron for his purpose, and theseBrindley had within him the vital spark of models, rough as they were, worked well.creative genius, he was very slow to acquire Early Life Miniaturewater -wheels,operated by atheessentialdetailsof his millwright's neighbouring stream, windmills and othertraining. Abraham Bennett thought him The birth of Brindley was as obscure astypes of mechanisms came into being underthe stupidest and slowest of all the appren- his parentage. He first came into the worldBrindley's active hands during these for-tices who had ever passed through his in a small roadside cottage which stood inmative years of his.They all, of course,hands, and he made no secret of his opinion. alonely spot between the hamlets of Tunstead and Great Rocks, near Buxton, Derbyshire. The year of hisbirthis assumed to be 1716, but no records of the event appear in any of the local parish registers.The lonely and almost desolate cottage, in which the future canal builder made his entry into the world has, after remaining in a ruined condition for decades, long since entirely disappeared, leaving not even a stone to mark the unrecorded birth of one of England's mechanical geniuses. Brindley's father was a humble crofter who seems to have been fonder of dissipa- tions than he was of work. Consequently, his family was reduced almost to beggary, although, during his laterlife,Brindley senior became more industrious and ab- stemiousinhishabits,andprospered accordingly. Itwas fromhismother, a humble, industrious woman,thatyoung James Brindley acquired whatever little education and knowledge he possessed in his childhood days. James, however, being the eldest of the family, had to fend for himself very early on in his life's career, and from about the age of eight until he was seventeen, the lad worked as a farm boy. But during this time he showed clear signs of the very remarkable mechanical abilities which he The starting point of Brindley's original canal at Worsley, near Manchester. 270 NEWNES PRACTICAL MECHANICS April, 1941

thedirectionoftherenownedJosiah Wedgwood. Brindley did many mechanical jobs in the Potteries, and he became generally known as " The Schemer," in consequence of the many new notions whichhe put forward during the course of his work. Throughout his career, Brindley made a practice of making day-by-day entries in a number of notebooks, which were, in fact record books and ledgers of his growing business. These memoranda books of Brindley have, fortunately, been preserved, and they give us a clear insight into the essentially hard-working and honest char- acter of James Brindley, besides allowing us to gain an understanding of the technical methods adopted by him. Early on in his memoranda volumes we find a record of Brindley's fitting a water pump for " Arle Gower.'Now, this " Arle Gower," as Brindley calls him, happened to be. Earl Gower, an influential landowner of the Midlands, for whom Brindley, during the course of his career at Leek, performed many services.Earl Gower seems to have Even at the present day, Brindley's original " Bridgwater" canal from constituted the tide in Brindley's affairs Worsley to Manchester still serves as a busy lane for water -borne traffic. which ultimately led, if not to his fortune, at least to fame and a reasonable com- Nevertheless, Brindley was nothing if notjourneyman untilhe died. Then, afterpetence, for had not Earl Gower come into a determined " trier." He worked his waywinding up his accounts, he removed to thecontact with Brindley, itis possible that to manual skillinthe carpenters' andlittle town of Leek, in Staffordshire, thereposteritymightneverhavebeardof metalworkers' arts by dint of sheer per-to begin business for himself in an humbleEngland's pioneer canal builder. severance.Unlike the many journeymenway in the year 1742. About the time at which Brindley was with whom he worked, he was of sober and Leek was only a small market town inmaking a name for himself in the north industrious habits.But during the firstthose days, but industry in England wasMidlands, there was residing in his old Hall couple of years of his apprenticeship, herising, and the demand for competent mill-at Worsley, a picturesque rural hamlet to made so many blunders, ruined so manywrights,engineersandmechanicswasthe west of 'Manchester and verging on the tools, and was the cause of so much wastagerapidly outstripping the supply.At thatborders of the then notorious Chat Moss, of material, that his master was on theperiod,theaveragemillwrightworkedone Francis, Duke of Bridgewater.The point of turning him away from his service.independently of any factory orunder-Duke had had an unsettled career.In taking.His services would be called inparticular, he had been badly crossed in Turning Point in Career whenever necessary by a mill owner inlove, which event had converted him from Then, curiously, came a turning point inmuch the same manner as the present-dayone of Society'sshininglightsinto a Brindley's career.He seemed to acquirefarmer may call for the expert assistance ofmisogynist of retiring and decidedly curious practical skill with very great rapidity. Ina veterinary surgeon. dispositions. Indeed, as the years passed by, the autumn of 1735, for instance, a silk Francis, Duke of Bridgewater, became, in mill at Macclesfield had been very badlyAs a Master Man some of his habits, wildly eccentric. damaged by fire.Bennett was called upon Thus it was that when Brindley com- Despite the abovefact,the Duke of tooverhaul andre -erectthesalvagedmenced business at Leek it was not longBridgewater was a shrewd enough man. machinery, and, since labour was not toobefore he found himself prospering steadily.He owned collieries at Worsley, the coal easy to obtain at that period, he took with His first jobs consisted in the repairing offrom which had to be carried in carts or on himhis" bunglingapprentice,"Jameslocal corn and grist -mills, of assembling newthe backs of mules to the river Irwell, some Brindley. The latter acquitted himselfwater wheels, and in actually constructingdistance away,on whichriveritwas exceedingly well at his *allotted tasks, soa number of these appliances.Gradually,shipped into Manchester on barges. much so that the mill owner praised him,his fame extended to other districts and he The Duke of Bridgewater was nothing if and insisted that he should be sent to thebecame known as an expert and highlynotenthusiasticover anyideawhich mill on any future occasion requiring theskilled engineer, even in the busy Potteries,seized him. Now, one of the notions which services of a millwright. which were then rising to importance underrapidly became uppermost in his mind was No one was more surprised at this sudden acquisition of fame thanold Abraham Bennett. To his master's questionings as to how he had managed so well on the job, Brindley could only answer in all sincerity and truth, " it came natural -like" During the course of the next few jobs which Brindley was sent out to undertake. he made the discovery that there existed within him the power of diagnosing a mechanicalcomplaintwithverylittle trouble and,also,ofthinking out the appropriate remedy with equal "'facility. These things his associate apprentices and journeymen could not do. They were more interested in the customary allowance of free ale which was handed round in the local hostelry after the task was completed. As an apprentice, the former " bungling Brindley " was now beginning to gain quite a local reputation for himself. He designed and put into operation a new paper mill at Manchester, which triumph put him on almost equal terms with his master. Suffice it to say, that ever afterwards he lived with old Abraham Bennett on the greatest of The modern swing -bridge which carries Brindley's original canal across what good terms, and served him faithfully as a is now the Manchester Ship Canal. April, 1941 NEWNES PRACTICAL MECHANICS 271 &reasonidly certain Government Departmentsand thousands of Engineering firms from world-famedorganisations to the humblest repair shopsare now using INGENIOUS &PRACTICAL

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FIFTY-SIX YEARS OF CONTINUOUS SUCCESS To be filled in where you already have a special preference. SOUTH AFRICABRANCH E.G S.A.R.O. BOX 8417 JOHANNESBURG FOUNDED 1885 - - OVER 85,000 SUCCESSES April, 1941 NEWNES PRACTICAL MECHANICS 273 that of cutting a canal leading from theOff it went from Worsley across country in It is a curious fact that Brindley seldom Bridgewater mines at Worsley almost intoan almost direct line.Then its engineerpaid himself anything more than a mere the heart of commercial Manchester.Hetook it for two hundred yards across thelabourer's wage. He was " cheap," as the expounded the idea at great lengths to theRiver Irwell at Barton on a stone aqueductcanal owners remarked. They forgot, few friends and acquaintances which heor bridge which carried it some thirty-ninehowever, to observe the fact that Brindley, had, but allridiculeditas impossible.feet above the river below, and, from thence,despitehisilliteracyandhishumble There was just the Duke's land agent,. Johneventually it made its way to Manchester,mannerisms, was a genius, and that he was Gilbert, who thought that there might beno particular trouble being experienced inat that time performing work which no something in the notion, although Gilbertits cutting or engineering. other man living could do. himself could suggest no practical means of Brindley's secret of rendering his canal For Brindley, canal planning and engin- carrying it out. watertight, especially that portion of iteering lasted until the end of his life.For, Put the Duke had a relative, one Earlwhich was carried over the River Irwell,in this pm -railway era,canals offered a Gower (afterwards the Marquis of Stafford),was to puddle it well with clay. He formedcheap mode of transport of goods across the who, Gilbert had heard, had had somestrong embankments for the canal where itcountry from one town to another.Canal dealings with a man named Brindley, apassed throughflatcountry, making itprojectors waxed rich, speculation in canal working millwright, who was said to be aalmost impossible for the waterway to burstbuilding became rife, and some financial bit of a genius in his way. Upon Gilbert'sits banks.On an average, the canal costcrashes resulted. sugeAion, the Duke of Bridgewater com-the Duke about a thousand guineas per Brindley, however, had no interest in municated with Earl Gower, and the upshotmile to cut, and to this expense was addedsuch movements.To him, a canal was of it was that Brindley shortly afterwardsthe cost of its terminals at Manchester andpurely and. simply an engineering project travelled up to Worsley, aqd was receivedWorsley. But the canal was eminentlycontaining many various problems to be in person by the Duke himself. successful. Itbroughtfame bothtoovercome. It would appear that Francis, Duke of Bridgewater and humble, practical James r Brindley instantly took a mutual liking to each other. The Duke propounded his ideas at great length to the interested Brindley, He explained that if he could get his coals to Manchester at a cheap rate, not only he hims ilf, but the inhabitants of Manchester would benefit greatly. Brindley's First Canal Any ordinary individual would have been overawed by the magnitude of the pro- position,butapparentlyBrindleyjust treated it as another commission.At first he made what he spells in his memorandum book " an ochilor servey or a rieconitoring " (an ocular survey or a reconnoitring) of theA canal in mid air ! country between Worsley and Manchester.An end -onviewof Upon the results of this survey he drew upBrindley's canal as it is plans for the design of the Duke's canal. being swung across the Canal building had been attempted inManchester Ship Canal England previously, but very little successto permit sailing ships had been made of it.Brindley, however, to go by. saw no reason why it should not be possible to cut an artificial waterway between the Worsley coal pits, and seven miles -distant Manchester.The one snag in the project was the existence of the RiverIrwell flowing almost atrightanglestothe projected track of the canal.It had been proposed to make the canal level descend to that of the Irwell by means of a series of locks,but Brindley rejectedthisplan. Instead, he put forward the brilliant, and at that time almost wildly audacious plan of carrying the canal over the Irwell by means of a brick -built aqueduct supported on stone columns, thereby doing away with the necessity for locks and making it pos-Brindley and the Duke, and, perhaps moreHis Last Job sible for a 'barge to navigate the waterwayto the latter than to the former. It was in consequence of a long spell of high above a vessel sailing on the River The " Duke's folly," as the canal hadcanal surveying that Brindley met his Irwell below it. been dubbed when it wasfirstbegun,death which took place on 27th September, At first, the Duke of Bridgewater doubtedturned out to be a veritable wonder of its1772. He had been engaged in planning out the feasibility of Brindley's project.Heage.People flocked from far and near toa canal which was to be cut near his adopted called in several engineers, among whom issee it, and in particular to witness bargeshome town of Leek, Staffordshire.For a said to have been Smeaton, the lighthousebeing carried high above the River Irwelllong day he, had remained out in the rain builders and they all pronounced Brindley'sat Barton. without anything to eat or drink.He re- planasbeing absolutelyimpossibleof Needless to say, Brindley's canal projectsturned chilled and famished to the inn at attainment. did not stop;with the successful completionwhich he was staying. They put him into By his friends, the Duke was entreatedof the Bridgwater canal. He subsequentlya damp bed, and that was the last of not to throw away good money upon theextended this waterway and, under theBrindley.On the following day he just attempt to construct his canal, but, beingauspicesoftheDuke,undertookthemanaged to crawl to his home at Turnhurst, a man of adventure, he eventually con-cutting of canals in other districts as well. near Leek, where, after a short period of sented' to Brindley's engineering the project.Grand Trunk Canal illness, he expired. For years, the local folk at Worsley had At a later date, Brindley engineered the In the whole gamut of engineering history called the Duke " canal mad," because hemaking of the Grand Trunk canal whichthere is no other example of self -acquired had been unable to think or talk of any otherconnected the Mersey with the Trent, andexperience, and innate ability in the same subject.Now, when the rumours of hisboth these rivers with the Severn, thereforecategoryasthatpossessedby James projected attempt to carry one waterwayenabling inland water communication to beBrindley.Brindley was the true pioneer. across another began to be booted about,made between the ports of Liverpool, HullDevoted to his duties, courageous, efficient they called him a raving lunatic, and gaveand Bristol. Perhaps, indeed, this wasand even brilliant, he forged ahead even in him up as hopeless. James Brindley's biggest enterprise.Yetthe face of his handicap of lack of schooling. As soon as Brindley began his canal-or,he projected and engineered numerous otherNeedless to say, after his death, he had rather, the " Duke's Canal"-from Worsley,canals which, invariably were more to hismany imitators, but no equal,inthe its progress was watched with great interest.patrons' financial benefit than to his own. sphere of canal building. 274 NE JUNES PRACTICAL MECHANICS April,1941 "MOTILUS" PEEPS INTO An Interesting gauge tinplate in 1902, and caused quite a sensation.It was hailed at the time as a mostimportantnewmodel,areally creditable representation of the" Black Prince "L.& N.W.R. locomotive and tender,withslidevalvecylinders and reversing motion, whichisdeserving of greatpraiseas a genuine stepin the direction of more realistic model locos. than have often been supplied by pro- fessional model makers.One happy pur- chaser of a similar engine wrote:"The appearance is most realistic and it works splendidly.With only four burners going, and running light with tender only, it ran without astopforforty minutes and covered 3,000 yards. The way in which it keeps the steam up is surprising. The above was on a track with many curves and points ;on astraighttrackitwould probably do far better." Lateronthe" BlackPrince "was modelled in 2 -inch and in 11 -inch gauge, and the model here shown is one of the last A fine scale model of the " Sirius," the first steamship to cross the Atlantic, of the models before the locomotive dis- beating Brunet's " Great Western" by a few hours. appeared from the market.,t will be seen NE comes across weird model con-models, I suppose, that have been so famousthat this model has the standard type of traptions from time to time, andfrom a commercial point of view :as this inpiston valve cylinder, still in use, and the 0here are two views of a model, sentits various stages.A model of this well -cylindrioal boiler is heated by a vaporising me by a friend who is interested in oddities in model work. These illustrations show a very crude attempt on the part of some person or persons unknown, at modelling a locomotive. The present ownerisMr. Dunkley, an active member of the CoventryA modelofthe Society of Model Engineers, but although famous the model isin his possession he is not L. & N.W.R. " the perpetrator of the outrage."The " Black Prince" model was literally " dug up " on a new locomotive seen housing estate in that city, and when it recently in saw the light of day, clay was still clogging Bassett-Lowke's the wheels !The overall length is about repair shop. 18 inches, and the height to the top of the chimney 8 inches. The distinctive arrange- ment of the steam pipe from the dome to the oscillating cylinder is certainly an innova- tion. The regulator, too, you will notice isknown British locomotive was first placedspirit burner, whichhas long superseded high up in the dome, evidently to be certainonthe market by Bassett-Lowke Ltd.the wick type. the steamwas dry !Whetheritever(then W. J. Bassett-Lowke & Co.) in 2i in. Business as Usual worked or not, is a mystery, and I expect I was in the other day, which, it will remain so ! as we all know, has suffered very much from enemy action, and last time I was A Model Span Bridge thereI happened to take the snap repro- These are days of building in steel, and duced here, of Messrs. Bassett-Lowke's very when the war is over, no doubt the re- attractive window. Alas, this shop has now building of Britain willsee much steel been damaged by the attack on the opposite constructional work, as well as re-inforced side of the particular street, and the windows concrete.Here isafineexample,in are boarded up. But there is still a display miniature, of British steel work-a model of those famous models which fascinate of a 45 -metre span bridge,built inthis enthusiasts.For a week or two Mr. Cox, country and presented by Vickers Ltd. and Bassett-Lowko's energetic manageir, carried theMetropolitan-CammellCarriageand on business via the back door. But now the Wagon Co. Ltd. to the Tientsin Pukow windows areboarded up withdisplay Railway. The actual span was constructed " holes " in them, and it is almost " business by their subsidiary company, the Patent as usual."It takes more than the ferocity Shaft & Axletree Co. Ltd. The model was of the enemy to rob the British public of made for record purposes, contained all one of its favourite hobbies, or to make accurate detail, and is to a scale of 1 inch those who cater for them give up because to 1foot. Every nut, bolt and rivet is of difficulties, albeit some of them seem shown, and there are approximately 5,000 sometimes insurmountable. model rivets in the model. A Liner of the Future ! When the war is over-and when that An Interesting Model Locomotive will be no one knows-there is sure to be Looking into the repair shop of Messrs. renewed activity on the land, sea and in the Bassett-Lowke Ltd., when in Northampton air.No doubt, progress in the air is being recently, I was most interested to see a A scale model of a punch press, made advanced by the war, and the developments model of the old L. & N.W.R. 4-4-0 loco- in America for advertisement made in bombers and fighters will no doubt motive, " Black Prince."There are few purposes. be turned to good use in air transport. But April, 1941 NEWNES PRACTICAL MECHANICS 275 THE MODEL WORLD Description of (`yodels Ancient and Modern what of the sea ?Warships are not con-and smuts, and when nearing port two vertible to civilian use and shipbuilding,Collapsible funnels would come into action. except for cargo ships, has almost come toAs will be seen, the ship has beautiful lines, a standstill, not only in this but in otherand one wonders when the war is over countries. At the World's Fair in NewYork,whether experiments will be made in this

Two viewsof a weird model loco- motive " dug up " on a housing site at Coventry.

there was a model review of ships that havedirection,because designers aresatisfied made history, commencing with the Sirius,that finality in ship design and propulsion which was reputed to be the first steamshiphas by no means yet been reached. to cross the Atlantic, arriving a few hoursA Model Punch Press Bassett-Lowke's attractive shop window before Brunel's Great Western, on April 23rd, at as itappeared beforethe 1838. The Cunard -WhiteStarQueen This picture of a punch press comes from " blitz." Elizabeth, was our latest development inAmerica. The model was on a circular base ocean transport designed up to the out- break of the war, but designers were busy on further ideas in fast ocean transport, and here is a model of " the liner of the future," as visualiSed by Mr. A. C. Hardy, famous ship designer, and Monsieur P. de Malglaive, technical director of the French Line. In a recent paper to the Institute of Marine Engineers, Monsieur de Malglaive described what, in his opinion, would be the " Ship of the Future." He stated that the threat of trans -ocean air travel made it necessary to tackle shipbuilding from a new angle.The ship could never compete with the air liner in speed, but it could offer its passengers comfort, safety, cuisine, freedom, amusement and rest to a far greater degree. The ship of the future as visualised by the famous ship designer, A. C. Hardy, -and Monsieut P. de Malglaive of the well-known French line. Streamlining These things, therefore, must be exploitedand covered with a glass cover, which wasWAR DAMAGE -AND YOU to the full. As will be seen from the illustra-removed in order to take the photograph. tion, streamlining is an essential part of theAt the time when this model was built, DESPITE the Prime Minister's efforts to design, and the decks are glass -enclosed tohexagonal nuts were not a commercial pro- get rid of jargon in official publica- decrease wind resistance, as well as protectduction, and all of those used were made bytions, and replace it with straightforward passengers from the breath of the sea.hand, as indeed was nearly everything elseEnglish, the War Damage Act contains Indeed, itis possible that conditioned airon this realistic model, which is only aboutphraseology which is even puzzling lawyers. would be used throughout the ship except6 inches high.The makers, the ThextonIf they cannot make head or tail of some of in the outside cabins.The ship would beMfg. Co., of Minneapolis, have a window init, what chance has the ordinary individual ? electrically driven, the exhaust gases fromwhich they display productions to advertise The man in- the street is asking all sorts the motors being carried along the sun decktheir business, and this model was made forof questions about the new Act. To whom and out near the stern, to prevent fumesthis purpose. does he make contributions ? What happens if he does not agree with the value placed on his" damaged property-a thorny problem indeed !Can. heobtainan immediate advance on a damaged shop to start else- where ? These are a few of the vital problems affecting many thousands already-but to sift the answers from the mass of long- winded English in the Act is no easy task. For months, however, a barrister has been working through the Act, section by section, setting down in simple language exactly what the man in the street wants to know, and anticipating his questions and answering them.The result is the publica- tion on Friday, April 4, of War Damage Compensation, an invaluable book for all at the popular price of 1/-. Obtainable at newsagents, bookstalls and booksellers 1/-, or 1/2 by post from George A realistic model of a 45 -metre span bridge-scale 1 in. to 1 foot-as used Newnes, Ltd. (Book Dept.), Tower House, on the Tientsin Pukow railway in China. Southampton Street, London, W.C.2. 276 NEWNES PRACTICAL MECHANICS April, 1941

stops.Do this on each of the chosen subjects, and then when the film has been processed, pull it slowly through the projector by hand and decide which HOME MOVIES exposure gives the best results.Speed ratings deter- mined in this way have the advantage that they take into account individualprojection and processing conditions, and are to that extent preferable to the Notes by G. P. KENDALL, B.Sc. ratings issued by the makers, which must necessarily be averaged to suit some assumed set of conditions. in inches, or 20 feet 10 inches, in fact, which we shall NEWS AND COMMENTS probably decide to call 21 feet for practical purposes. Comparison of DIN and Scheiner That is not an operation to be done in the field, Is the DIN system of speed rating simply another form while preparing to make a shot.A good plan is to of the Scheiner degree scale ? Practical Tracking work out the H.F.D. for each stop marked on The No, there is a radical difference in the method of amateurs get an urge at times to try " track-diaphragm scale and write out the result on a piece measuring speeds on these systems. Scheiner is based MOSTing " shots, in which the camera runs up to or ,of stiff card which can be carried in the camera case. on a measurement of the smallest amount of light draws back from the subject, but few meet with much It is then only the work of a moment to refer to the needed to produce a just -perceptible image, whereas success. The reason is simple :a good tracking shottable, set the lens, and get busy. DIN works on the amount of light required to produce demands a certain amount of preparation, and unless a certain (small) standard strength of image. you are ready to give it the attention it needs you had better give up the idea. QUESTIONS ANSWERED Filters for Colour Contrast Better weather and light will soon be with us (we What is the rule for choosing a filter to make coloured hope I) and since much of our shooting is now done items in the view contrast with each other ? perforce in our own gardens, it may be worth whileUsing Variable Shutters The filter lightens objects of similar colour to its own, to think about tracking shots; the garden is just the darkens those of the colours it blocks.Thus, a red place for them. What isthe object of the variable -opening shutter lightens red and yellow tones, darkens blue ones ; The first requirement is something on wheels to on some very expensive cameras? I thought the aim yellow lightens reds and yellows and darkens blues, clamp the camera upon. A dinner wagon or a child's should be to get all the light possible through the shutter but to a lesser extent;a green lightens yellows and tricycle does ,quite well.Next in importance comes a ---not to cut it down ? really smooth track for your " camera truck " to run greens, darkens both reds and blues. along. Some stout planks are best, but a very carefully A shutter opening of something less than the full smoothed and rollpd section of lawn or path will serve.180 deg. or thereabouts which is standard can beDepth of Field Tables Do not be. too ambitious in your first attempts. usefulinvariousways.For example, a reduced Would it be very difficult to work out a depth of focus Let the tracking be over but a moderate distance, say, opening will prevent unduly blurred individual frames table for my I -inch fj2.5 leas ? 15 feet, moving in from a lens -to -subject distance of when filming a fast-moving object, and it solves the Not at all difficult (only simple arithmetic is in- 20 feet at the beginning to one of 5 feet at the finish problem which arises when a very fast film is used volved), but rather tedious.The result is well worth of the shot, and you are likely to make a success of it.under conditions of very brightlight.(This case the labour, however, a definite knowledge of depth of Next you need an assistant, carefully drilled to push should not arise,ofcourse, butis sometimes un-field conditions being often of great practical value. the" camera truck "alongslowly,steadilyand avoidable.)A more important use for the variable The formulae which follow are simple forms of the smoothly, and come gently to a halt at a spotapreviously shutterisinpermitting the operator to use some calculation, but give results of sufficient accuracy for marked.This leaves you free to handle the camera,particular lens aperture, which he desires for depth. normal purposes.The first step is to find the " Hyper - adjusting the focus as you go. of -fieldreasons.Suppose, for instance, that he is focal Distance," usually called the H.F.D., thus :- To make this latter operation simple and certain, making a semi -close-up and desires to have his back- H.F.D. mark two or three of the intermediate distances, soground right out of focus so that the subject shall sx .00 that as you come to each you can turn the distancestand out well ;his exposure meter may tell him that Here f is the foeal .ength of the lens in inches, and scale on the lens to the appropriate setting for thatat normal shutter opening the stop for correct ex-8 is the stop number.In the case in question f is one, range.In between these points you can leave the lens posure would be f/8 but from his depth -of -field tableshence ,11 is also one, and the little calculation becomes alone " depth of field " will cover the differences ifhe sees that this stop would give him an almost sharp very steeple indeed. the light is good enough for you to work at a fairly background.From the tables he decides that f/4 is Having found the H.F.D. for the particular stop at small stop, such as f[8.As you near the end of thethe stop he wants, so he sets the diaphragm to thatwhich it is desired to find the depth of field, we next track, you must gradually turn the lens scale to the andthen reduces-theshutter opening to the angle proceed to work out the near and far limits of definition mark for the final distance ;it is only over the last few which will give correct exposure at this stop.(This for a particular distance to which the focussing scale is feet that you need to do this, bemuse it is only here is given by another table.) set, thus :- that the range is becoming short enough to make the Near Limit= H.F.D. focus really critical. Finding a Speed Rating 11.1.1). +1.4 I have several hundred feet of a French film which has Far Limit = H.F.D. x Make Friends With " H.F.D." ! been in the country for nearly a year.What speed will H.F.D. - it need on my Weston meter ? MANY otherwise sound and sensible cinemato- In each case, " D " is the distance to which the lens graphers seem to have something approaching a Even If we knew the make of the film we could focussing scale is set.(411 distances must be put into horror of that really very useful quantity, the hyper -not answer this one, because in a year the film may inches for the calculation, and the final result con- focal distance of their lens.Now that is a pity, for have lost some speed, but it gives us an opportunity toverted into feet afterwards.) " 11.1.D." can be a very good friend if rightly applied, explain once more how a speed rating can be found by As will be seen, the H.F.D. must be worked out for and there is nothing alarming about it at all. the user for himself.Take the camera out on a sunny each stop in which we are interested, and the near and One of the main uses of the hyperfocal distance is inday and hunt up some good test subjects-scenes withfar limits calculated for a series of distances at each calculating the depth of field at a given stop and bri ht highlights and some shadow areas as well.On stop.Thus, the first step Is to find the H.F.D. for the focussing distance, but that is admittedly rather a each expose short lengths of film at progressive speedmaximum aperture of the lens, then work out the near laborious business which most of us shirk. settings on the metes.In the case under consideration, and far limits for focussing distances of, for example, A simpler and even more valuable application is in for example, these should be run off at meter settings3. 5. 10, 15, 20 and 30 feet.Next the operations are deciding how to set a focussing -mount lens for use as of 8, 12, 16 and 20 Weston, I.e., set the instrument to repeated for the next smaller stop, and so on until all fixed -focus objective.When the subject to be filmed each of these speeds in turn, find the exposures then the marked apertures (or just those in common use) is one which involves quick shooting at a variety of indicated,and shoot a toot of film at each of these have been dealt with. distances, with no time for measurement or careful estimation of range, that can be an extremely useful dodge. What one does in practice is to look up the H.F.D. for the stop in use and set the focussing scale to that distance.When that has been done, everything will be reasonably sharp from half the 11.1.D. up to infinity.Suppose, for instance, that for the stop in use the H.F.D. turns out to be 30 feet ;the operator then knows that if he sets his scale to 30 feet he can shoot anything which is more than 15 feet away with- out further adjustment. It is true that objects at a great distance will not, under these conditions, be quite so sharp as they would be if the lens were properly set to infinity, but the difference will be Very slight indeed. In any case, it is not likely that a subject at great range will present itself under conditions calling for the H.F.D. setting. If it does, well, it is simple enough to slip the lens collar round to the infinity mark, make the shot, then put it back to the H.F.D. before resuming operations at shorter ranges. This is how to find the hyperfocal distance.Take the focal length of the lens, in inches, and square it. (Multiply It by itself, that is.)Then multiply the lens aperture in use by .001 and divide the result into the squared focal length. The result is the H.F.D. in inches. If you prefer it as a formula, here it is : H.F. D. =f' sx. .001 "s," of course, is the stop number, while the figure .001is an arbitrary one chosen according to the stafidatd bf definition at which you are aiming.The figure given is a good all-round value. Perhaps an example will make the method clearer. Suppose we are using the 1 -inch lens which is standard on most 16-m.m. and many 9.5 m.m.'cameras.First, we " square " the focal length.That means multi- plying one by one, and, of course, the answer is still just one.Next; we decide the right stop for the job in hand is f[4.Multiplying 4 by .001, we get .004. Dividing this into 1 (the focal length squared), we find How they pick up the voice of a moving actor.Note the microphone boom being swung it goes 250 times.That is our hyperfocal distance near the player (Leslie Henson) as he mounts the stairs. April,1941 NEWNES PRACTICAL MECHANICS 277 THE USEFULNESS OF PELMANISM QUERIESGA,4 is useful in all the affairs of PELMANISMlife.Thatisitsoutstandingrecom- mendation to those who wish to make the best of themselves in their occupations, in \ENQUIRIES all their recreations, and in their social and cultural relations. Every line written in the Pelman Course isdirectlyapplicabletosomeaspectof A stamped addressedenvelope,threepenny stamps, and the query coupon from the current human life and conduct.The intention of issue, which appears on page iii of cover, must be every word in the Course is to make clear to enclosed with every letter containing a query. men and women the means by which they Every query and drawing which is sent must bear can their the name and address of the reader.Send your develop powerstothefullest Thermo -couples queries to the Editor, PRACTICAL MECHANICS, extent so that they can live more happily HAVE recentlyseenreferencestoa Geo. Newnes, Ltd., Tower House, Southampton and be more successful-so that, on the one thermo-electricdensitometeremploying Street, Strand, London, W.C.2. hand, they will make and use occasions for a silver -bismuth thermo-couple. profit and advantage and, on the other hand, Can you pleasegive me thegeneral be at ease in any company.Both conditions principleofsuchathermo-coupleand (4)I want to obtain an arc lamp. Can youare necessary to complete self-respect and a its approximate sensitivity to light? Howtell me of a good firm where I may obtainfull life. would it be used in this instrument ?Area second-hand one at a reasonably cheap Pelmanistsarenotlefttomakethe these thermo-couples purchasable,ifso, price ?-J. S. E. Gilbart (Bury St. Edmunds).applications themselves.An experienced can you give me the approximate cost ? -- APHOSPHORIZED ether is merely aandsympatheticinstructionalstaffshows G.Omerod (Abu-Sueir, Egypt). solutionofyellowphosphorusinthem,inexactdetail, how toapplythe TIHERMO-COUPLES are notsensitiveether. It is a dangerous solution to prepare,principlesof Pelmanism totheirown to light rays. Some of the more delicateand still more dangerous, perhaps, to keep.circumstances and aspirations.Thus every thermo-couples, however, are sensitive toWe would advise you not to attempt toPelmanCourseisanindividualCourse. the heat rays accompanying some lightprepare this solution. Over and overagain our correspondents rays, and, in virtue of this fact, are able (2) Ethyl iodideinvariably undergoessay ineffect,"I feel that this Course was to give some measure of the radiationslight decomposition, with the consequentpreparedforme,and meonly." Sub- passing througha given medium andliberation of free iodine, when allowed tostantiallythisisso,fortheinStructional falling upon them. The silver -bismuthstand in contact with air, moisture and/ornotesandlettersofadviceareentirely thermo-coupleoperatesuponordinarylight.In order to obtain perfectly colour-personaltotheindividual;theyarefor thermo-couple lines, that is to say a silverlessethyliodide,you must distilthehim or her only. element and a bismuth element makeliquid in, vacuo at as low a temperature as H.M. FORCES c intact at one end, the opposite ends beingpossible, and the distilled liquid must be All serving members are now entitled to receive the couplets connected together through an externalsealed up in a tube or other vessel and then Pelman Course with full tuition and guidance at circuit containing the necessary current -stored in the dark.Even under these One -Half Usual Fee measuring apparatus.Heat- falling uponconditions, the ethyl iodide may gradually Immediate application should be made for Special Enrolment the contacting ends of the two dissimilardarken in colour, particularly if it is slightly Form (Services). metals sets up a thermo-electriceffect,impure, and if air and moisture remain Approvedby the rat- Office. the result being that a very small currentwithin the tube. fl ws in the external circuit.In order to (3) To convert grams into grains, multiply The present dominant aim for every man i..crease the amount of current, thermo-by 15.43:To convert grains into grams,and woman must be to show a courageous, coupl ,sareoftenconstructed by com-divide by 15.43. confident, well-equipped mental fron.This bining a number of single thermo-couple (4) You may be able to obtain a second -assured, then all else will be achie*Ved, and contacts in the one instrument. the world has no more proven method than As we have already explained, the silver - Pelmanism toattainthisend. Mqy of bismuththermo-couple(oranyother THE P.M.LIST OF BLUEPRINTS thegreatestLeadersinvaryingspheres thermo-couple,forthat matter)isnot testifythis.You may read what thel, Say actually sensitive to light.Its sensitivity F. J. CAMM'S PETROL -DRIVEN in the Free Book offered. to the heat rays admixed with light depends MODEL AEROPLANE 7s. 6d. per set of four sheets, full-size. A True Philosophy upon their radiating source and the screen, The "PRACTICAL MECHANICS" E20 CAR medium or filter through which they have (Designed by F. 1. CAMM) Pelmanism is a true philosophy ci,f living. for passed.It is possible, however, to make 10s. 6d. per set of four sheets. ordinary sensible people who wish TO male very delicate thermo-couples. Some of "PRACTICAL MECHANICS" MASTER the best of themselves at all' timesr BATTERY CLOCK The Pelman Institilto has these are fixed in the eyepiece of a tele- BlueprintIs. all circumstances. scope, and are able to measure the heat The "PRACTICAL MECHANICS" OUT- won and held its unique position ttirmigh all radiationsofstarssituatedcountless BOARD SPEEDBOAT wars and worries,trialsandtribulations, millions of miles out in space. We doubt 7s. 6d. per set of three sheets. during the last half century. To-dayelmanism whether you will be able to purchase a A MODEL AUTOGIRO is appreciated as much as ever.The test of silver -bismuth thermo-couple of the type Full-size blueprint, Is. time has proved the Power of Pehninisrn and you mention.You might, however, try SUPER -DURATION BIPLANE. in these exceptional and ever-cllnging times the General Electric Company, Wembley, Full-size blueprint, Is. it playS its part in the National Effort. and,also,Messrs.ElectradixRadios, The P.M. "PETROL" MODEL 214 Upper Thames Street, London, E.C.4. MONOPLANE Remember thisEverything you do is Complete set, 5s. preceded by your attitude of mind: The I-c.c. TWO-STROKE PETROL ENGINE Phosphorized Ether Complete set, 5s. The Pelman Course isfully explained in give me STREAMLINED WAKEFIELD "The Science of Success. The Course is SHALL be gladif you will MONOPLANE -2s. simple and interesting and takes up very little Iinformation on the following subjects: A LIGHTWEIGHT GLIDER (1) What is phosphorized ether, and how Full-size blueprint, 2s. time.You can enrol on the most convenient can I make it ? MODEL DURATION MONOPLANE terms.The books will be sent you, gratis (2) I have some ethyl iodide, whichI Full-size blueprint, 2s. and post free, on application to -day to :- have prepared myself by the usual method, WAKEFIELD MODEL Full-size blueprint, 2s. Pelman Institute phosphorus, and ethyl (Established over 40 years) from iodine,red "FLYING" LOW -WING PETROL MODEL alcohol. How can I keep it to stop it from PLANE 130, Pelman House, Bloomsbury St., London, W.C.I. going brown,duetotheseparationof Full-size blueprint of wing sections, 6d. Readers who can call at the Institute rill be retreated. The iodine,asitinvariably does in ordinary LIGHTWEIGHT DURATION MODEL Director of Instruction rill be pleased to have a talk with thent, circumstances ? Full-size blueprint, 2s. and no fee will be charged for this advice. I have, in my possession, a very good P.M. TRAILER CARAVAN PELMAN (OVERSEAS)INSTITUTES: NEIL' (3) Complete set, 10s. 6d. YORK: 271 North Avenue, New Rochelle. MELBOGIRNE: set of chemical weights, but they are in 396 Flinders Lane. JOHANNESBURG: F.O. Box 491g. grains;as most modern chemical books The above blueprints are obtainable post free from DURBAN: Natal BankChambers(P.O. Box1489).DELHI: give the weights in grams, how may I Messrs.G.Newnes Ltd.,TowerHouse,Strand,W.C.2 10Alipore Road. CALCUTTA :102 Clive Street. JAVA: convert grains to grams, and vice versa ? Matabartreg, Malang. 278 NEWNES PRACTICAL MECHANICS April,1941 hand arc lamp from Electradix Radios, Ltd.,spindle a shrinkingfit,and proceeded toby trial -and -error methods, as pure design 214 Upper Thames Street, London, E.C.4.heat the roller. He removed the roller fromis practically impossible in the majority of the fire, however, when the metal imme-cases. The pull of a solenoid on its iron diately around the bores was red hot, butcore is so variable in relation to the distance Re -conditioning Lubricating Oil the outside of the roller was still comparativelyby which it is immersed within the coil that I UNDERSTAND that most beans growncold.It was found that the spindle did notit is impossible to obtain a steady tractive in Britain contain about 50 per cent.slide into the roller as was expected.Theeffort through any considerable distance carbohydrates. Could you please tell meroller was left to cool, and it was then foundwithout resorting to some device in the if an oil (or grease) can be extracted fromthat the bores were smaller than they hadnature of equalising cams. The whole these, which could be used as an enginebeen before heating.Even the old spindle-design must of necessity be experimental lubricant, and ifso, how isthis accom-could not be driven in. Was this contractionrather than a calculation.In your sketch plished ?Would you alsoplease informcaused by the pressure set up between the(not reproduced) the core is so short that me how to recondition used lubricatinghot and cold parts of the roller. Why did theit would certainly not traverse the whole oil in order that it may be re -used.How,bore not come back to normal on cooling,length of the solenoid unless the winding and from what plant is cellulose obtained,and did the break in the circles caused byweresectionised,andsuccessivecoils in a fairly pure state.-John Gillan (Glas-the keyways help the hot parts to expandenergised progressively as the core is drawn gow). inwards, thus tending to close the bores?-in.On 12 volts the current consumption YOU cannot extract an oil or a greaseJohn Main (Lossiemouth). might amount to 15 or 20 amperes, at least. from beans, for the proportion of oil contained by them (or by their pods) is WITHOUTactuallyexaminingtheDynamo for Windmill very small, and, in any case, is of no use roller and spindle which you des- WILL you please tell me how to alter a as a lubricant. cribe, it is impossible to say with certainty car dynamo so thatitwillstart The precisemethod ofreconditioningthe exact cause of the parts refusing to fitgenerating at about 250 or 300 r.p.m.I wish used lubricating oil depends mainly upontogether as expected.It is very probable,to make a small wind -driven electric light the viscosity of the oil and the averagehowever, that the whole trouble was dueplant. Can you recommend a book that will nature of its impurities.Frequently theto what is known as " molecular deforma-explain the alterationsI have to make ?- oil is redistilled or filtered under pressuretion " of the metal. Donald Keeley (Buckley). or vacuum through a bed of kieselguhr, Some metals, particularly " crystalline "IT is unlikely that a standard car dynamo magnesium carbonate and/or charcoal. Inmetals, such as cast iron,aresolidified of English manufacture will be found to your case, the best thing to do is to con- under strain. When such metals are heated,run at so low a speed as 250-300 r.p.m. and struct a three or four -inch deep bed of thesethe internal strain alters in some way, and,give any useful output. The Lucas " A;900 " latter materials mixed in approximatelyat times, even vanishes, and, in so doing,generatorspeciallywoundfor wind - equal proportions and to allow the oil tobrings about a deformation of the metal sooperated plants is designed to commence percolate through the bed.The filteringthat it is no longer the same size as it wascharging at the exceptionally low speed of bed should be constructed with the leastbefore it was heated. Such a phenomenon450 r.p.m., and with a suitable airscrew amount of " packing " of its materials inis responsible for those occasional instancesthere should be no difficulty in making this ordertoallowofa" loose "-grainedof a mass of metal appearing to contract onserve the purpose. Most of the other British filtering medium being obtained.If theheating and expand on cooling. Again,car dynamosgivepracticallynegligible oil is at all viscous, its time of percolationfrom what you say, it would appear thatoutputs under 700-900 r.p.m., and although through even the best of these filteringyour roller parts were not equally heated.the speed may be reduced by rewinding the media will be lengthy, but, without apply-This might easily bring about a species offield coils with one gauge larger wire, this ing pressure or vacuum filtering, you cannotapparent warping of the metal, owing todoes not make a great deal of difference, avoid this drawback. Cellulose is obtainedexcessive and unequal pressure being set upand the voltage regulation may not be so from the cotton plant, and raw cotton woolin the sides of the roller. We do not thinkgood, as well as tending to a higher tem- is very nearly pure cellulose. the presence of the keyways had anythingperature. To obtain any appreciable output to do with the trouble.Rather, we thinkat very low speedsitisnecessaryto that the trouble was due to the effect ofseparately excite the fields of the generator, Liquid Stove Polish moleculardeformation,"asexplained I N an attempt to make up a liquid stoveabove, and also, perhaps; to the unequalby disconnecting the fieldcoils entirely polish, I have used graphite and methyl-pressures set up between the hot and coldfrom the brushes and taking excitation ated spirit.I have also tried vinegar, but current direct from the battery terminals. parts of the roller, as you point out in yourThis naturally leads to a continuous small fail to get the black lustre and shine, whichletter.When heating articles and com- commercial stove polishes give.I shouldponents in order to effect shrinking fits,discharge from the battery, which is re- welcome any suggestions you can give me,the heat should be applied slowly, andturned, of course, all the time the dynamo which mightgivebetterresults.-A.J.equally so that there are no differences inis generating any EMF in excess of the Umphray (Foula). temperature between various parts of thebattery voltage. YOUR trouble seems to lie in the qualitysame mass of metal. of graphite which you are using.For Cleaning Petrol Can your particular purpose, the graphite shouldSolenoid Winding HOW can I clean a petrol can so that it finely powdered condition, andit will hold water without contaminating be in WILL youplease advise me as to theit ?-N. P. (Knebworth). should be pure. Many samples of so-called following problem:-I wish to make graphite or " blacklead " are adulterated that the petrol can has only a solenoid coil, capable of lifting a corePROVIDEDcontained petrol,itis not a difficult with ordinary carbon, which, of course,weighing 1 lb., a height of about six inches.matter to clean it thoroughly.The best detracts from the quality of the graphite.The dia. of the core is 1 din. The voltage it is The stove polish should not be too thinly way to go about this job is to pour about proposed to use is 12 v. Would it be quickerhalf a pint of methylated spirit into the can, liquid. Itisadvantageous,also,ifitacting if a higher voltage was used andshake the can vigorously and then to contains a trace of wax-either beeswaxwhat amperage would be needed ;Also or paraffin wax-which not only acts as a drain the spirit away. This operation may what is the size of wire required, the numberbe repeated with the fresh lot of the spirit. binder for the graphite particles but alsoof, turns, and would the solenoid require to The can should not be placed in a warm improves the lustre of the polish. Thebe wound in sections ?Would it be neces-situation in order to allow the traces of wax isincorporated with the polish bysary to place an additional winding around dissolving it in the methylated spirits, only methylated spirit in the can to evaporate the lower entrance to the coil, to lift thecompletely. a small amount of it being used. A smallcore into the coil, the top of the core being After this, a little soap powder and a quantityofturpentine,alsodissolvedjust below the lower entrance,not justsmall quantity of soda should be placed in in methylated spirits may also improveentering the coil ? the can, water poured into half fillit, the shine of the polish. Can you give me the title of any bookand the can placed on a gas -ring in order Do not use vinegar or other waterythat is written on Solenoid Coils ?-Jas. H.to brin,' the contents of the can to a boil. fluids,since theselessen the degreetoFowles (Handbridge). which the graphite can be polished. Alongbrush should now be inserted into WE do not know of any book dealingthe can or, alternatively, a clean stick with of exclusively with theconstructiona piece of rag tied to the end of it, and " Molecular Deformation and winding of solenoids. S. P. Thompson'sthe inner sides of the can should be very Metal " The Electromagnet "isthe only onevigorously mopped and cleaned. N the course of my work recently I wasdevoting much space to the subject, and Finally, the soapy water should be poured Iconfronted with a rather curious problem.this being long out of print is unobtainable.away and the can rinsed several times with A fellow -workman drew my attention to aPerhaps a copy can be seen at your nearestclean, hot water.It should then be in a fit job that he was doing.In fitting a newtechnical library.Most of the apparatuscondition to hold clean water without con- spindle to a cast-iron roller he turned thecalling for the use of solenoids is developedtaminating the latter in any way. April, 1941 NEWNES PRACTICAL MECHANICS 279 The RAF wants men THE FLYING REFERENCE BOOK ltew hand g with machines as HALF-PRICE OFFER RIGHT MECHANICS to Get a job you can be proud of - maintaining AIR CADETS Britain'sfighters and bombers in the finest of PUBLISHED AT V fighting trim. Skilled and semi -skilled tradesmen are wanted, also unskilled men handy with tools RAF MEN and with spare -time interests such as motor repairs, qours anti all model -making, wireless, etc. You may volunteer FOR ONLY even if 'you have registered for one of the other in AERO and services.The R.A.F.couldnotmaintainits supremacy without the co-operation of the men on allied trades the ground.VOLUNTEER NOW and use your skill whereit is needed most! Ask at the R.A.F.

In order that all readers inter- Section of the nearest Com- ested in aircraft and aeronautics professionallyorotherwise, binedRecruitingCentre may possess an authoritative and comprehensive guide to (address from any Employ- flyingmatters,thecurrent editionof THE FLYING ment Exchange) for full REFERENCE BOOK will be presented at half-price for a details of technical duties limited period.The book is uniqueinthatthereisno in the R.A.F., or post other work of reference like it the coupon below.

..M11111,)

THE FLYING REFER- ENCE BOOK is a mine of aero knowledge never before gathered together in the pages of one handy book.The illustrations shown are from actual photographs of the work, the lower reproduction showing two pages from the useful glossary of acro wants terms and phrases. 1 Ovet 200 pages Cloth hound. these men PACKED WITH FACTS AND FIGURES - RAF THE WHY -WHAT -HOW -WHEN OF AERONAUTICS! RECRUITS SKILLED AND SEMI- FOR TRAINING AS SKILLED TRADESMEN Contents include Commercial Aircraft Specifications, Military Aircraft Fitters (18 to 50) Flight Mechanics of the World, British Aero and Aircraft Manufacturers, Aerodromes and (18 to 42)Electricians(i 8 to 38) Airports,Aircraft Number Plates, International Aircraft Markings, Wireless Instrument Operators (18 to 30) Careers in Aviation, Illustrated Aircraft Dictionary, The Rule of the Air, Repairers(18 to42)Wireless Airships and Balloons, Air Routes of the World, Largest Aircraft, Radio/Wireless Mechanics(18 to 50) Ground Markings on Aerodromes,Important DatesinAviation Mechanics (18 to 30)Instrument Repairers (18 to 58) History, Clubs, Schools, Associations and Societies, etc., etc. Wireless Radio Operators (18 to 25)Mechanics (18 to 50) To C. Arthur Pearson, Ltd. (Book Dept.), Tower House, Southampton Street,London, W.C.2 POST COUPONTODAY Please send me THE FLYING REFERENCE BOOK at the Please send me details of Technical Duties inthe R.A.F. special price of 2s. 6d., plus sixpence towards postage, etc. I enclose P.O. value 3s. No NAME

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P,M,441 To Air Ministry Information Bureau, Kingsway, London, W.C.2. TH 106 280 NEWNES PRACTICAL MECHANICS April, 1941

CRACKED GALPINSCEILINGS! LEAKING ?itt%tvip11°1 "...ELECTRICAL STORES.....ROOFS! Owing to war circumstances this isnow transferred to Business DAMAGED 21, William St., Slough, Bucks. FURNITURE! L1111Cill5N "nOne' is noted(or Terms ;Cash with Order. LIGHTING '4v 0 edies pr p Ihre%its preserving TROUBLES! unequalled tor ELECTRIC LIGHT CHECK METERS,small, late type, well- and is knownmakers, ingood condition,electrically IN on alllight machinery. guaranteed for 200-250 volts 50 cylees1phase A.C. BROKEN ett of all kinds 10 amp., 7/6: 20 amp., 9/ - Keeps tools mains.5 amp. type, 6/-; rust. each.Post 1/- on all types. DOORS! clean andtree horn D.C.ELECTRIC LIGHT CHECK METERS,200/250 volts costly 5 and 10 amps., 5/6 each, post 1/. (in new condition). To an PHILIPS HIGH VOLTAGE CONDENSERS. 1 mid. at repairs-lubricate 4,000 voltworking, 5/6 each, carriage 1,6. rdoym ae.vseaenvddrevaierf-ani EX R.A.F. GLASS ACCUMULATOR TANKS, 5 x 5 x 8 tools. in., new and unused, 3/6 each, post 1/-. Pmrachinery and EXR.A.F. SWITCHPANEL, with case (new), fitted Three -in-One, with' ti small knife switches, leads, cords, and cleats, complete allr in wood case,2/6each, post 6d. D.C. MOTOR BLOWERS,2 in. inlet and outlet.Alu- and minium body, laminated field, ideal for dug -out ventila- Ironmongers tion.100 volt,25 Hardware Dealers. Purchase lex HIGH -VOLTAGE TRANSFORMERS,useful for all test work Exempt ham or television.Input 200/240 volts, output 5,000 and LUBRICATES &QUANTITY 7,000 volts, 716 each, post 1/-. QUALITYUNC E.CLEANS PO0514715 HANGED VOLTAGE CHANGING TRANSFORMERS. (Auto -wound). PREVENTS RUST &TAR 100/110to 200/240 v., or vice versa, fully guaran- teed, 1,000 watts,60,-;2,500 watts, 110/, DUG -OUT LAMPS,ex R.A.F., solid brass construction, glass dome, complete with 12 -volt bulb (any bulb can Get this be fitted), wall fitting,3/-each, post 6d. ;Ditto, wing GAIN HEIGHT NOW type, as new,2/6,post8d. COMPLETE ILLUSTRATED The Challoner Way DUG -OUT LAMPS,ex R.A.F., porthole type, or can be bracket fitted, glass dome, three colour fitting, white, Many have already obtained those red or green, solid brass construction, 6 in. dia., complete HOUSEHOLD GUIDE vital extra inches with the aid of with bulb ;any size bulb can be fitted. Price5/-,post Challoner's Famous Formula 6d. 408 pages of Valuable Information H. T. N. TABLETS 1 kW. TRANSFORMER,100v.input at 100 cycles 30/-,carriage and easy system ; well tried and safe. output 10,000 volts, centre -tapped, price At any time you may be called upon to cope No strenuous exercisesor old-fashioned forward. appliances.If one box is insufficient EX R.A.F. AUTOMATIC CHARGING CUT-OUTS AND with Air Raid damage to your house. Would we guarantee to supply a further box 'VOLTAGE REGULATORS,tosuit any dynamo up to you know how to mend broken doors, dam- FREE. G.Y. (Watford) writes: "I 20 volts at 15 amps., fully adjustable, wiring instruc- have never had confidence in any sys- tions, complete in metal case.Price3/6,post Od. aged furniture and household appliances-in tem till I tried yours, now I've gained DYNAMOS,all shunt wound andfullyguaranteed, fact, how to do your share as a handyman in inheight, weight and fitness."Act 50/75 v., 15 a., £6/10/-:50/75 v., 25 a., L8/10/-;all now!Full particulars 2id: Sample Od. carriage forward. making your home habitable ? EverythingBook on height improvement 3d. stamps or P.O. only. Sent under plain sealed cover. 25 VOLT D.C. MOTOR,maker " Crompton,"i-h.p., you want to know about household repairs THE CHALLONER CO., Dept. 089, ball -bearing, in perfect order,E3,carriage forward. HYDE HEATH . AMERSHAM BUCKS 100 -VOLT D.C. MOTOR,' totallyenclosed,ratedat you will find in 8 amps., ball -bearing, in new condition, make good slow -speed dynamo, 1215/-, carriage forward. GUNMETAL PULLEYS, 7 in. diameter, to take 1 in. dia. rope, complete with rope guard and hook, 7/6 each, post 1/-. CJ/J®vrlib PHILLIPS TRANSFORMERS,220 v. input, output MAKE 2,000-0-2,000 volts, 200 m/a., and two L.T.s, 40/, Ittt carriage forward. AND ytooks"ocrAt 2 kW TRANSFORMER CORESforrewinding, sound windings but Eating unknown, 20/- each,carriage forward. STEEL CABINETS,suitableforlargeamplifiers,etc. The dependability of Myford size 42 in. by 24 in. by 16 in.Price35/-,carriage forward. MEND 31",34 -"and 4" Lathes has made 110 M.P. v. D.C. MOTOR,in good working order,25/, carriage forward. the book whichiswritten for novice and them Leaders in their class. SLIDERRESISTANCE,2,500 ohms at 200 m/a., worm isclarifiedby Write forII ustrated list. and wheel control,25/-,post free. handyman alike. Each job MILLIAMPMETERS, 2 in.dia. 0-30 m/a., 25/-;24 in.specially -taken photographs and explanatory MYFORDENGINEERINGCo.Ltd. dia., 0-100 m/a.,22/6 ;0-500 m/a., 22/6 ;all high grade Beeston, Nottingham. 'Phone: Beeston 54969 moving coil. drawings. AERO DYNAMOS,output 12 volts 12 amps., as new 15/-, carriage pass. train 2/6. CONTENTS INCLUDE: FLOOD LIGHTS,12 in.dia., multi mirror type with Door Lock Faults and Repairs 5 in. dia. mangin mirror centre, any lamp can be fitted, BARGAIN OFFER COPPER WIRE 15/- each. Air Raid Precautions in your House Price per lb. for Double Cotton Covered. How to Repair Broken Furniture CHARGING DYNAMOS,all shunt wound, and in perfect 28 SWG 4/4 32 SWG 6/3 36SWG8/10 working order,12/18 volts 10 amps., 35/.;100 v. Repairing Cracks in Plaster 30SWG 5/3 34 SWG 7/6 37SWG11/ - 4 amps., 50/- :20 v.8 amps.,35/-;allcarriage Making a Defective Ceiling Safe Price per lb., for Double Silk Covered. forward. Gas and Electric Lighting Troubles 28 SWG 6/6 32 SWG 8/. 36 SWG II'9 30 SWG 7/- 34 SWG 9/6 40 SWG 18- LAMPS,110 v., 150 watt., half -watt gas -filled, Ediswan Repairing Water Pipes screw fitting, 2/6 each, 25/- per doz. Postage 7d. Reels and Winding 6d. nee red. A.C. MOTORS I B.N.P. MOTOR,direct current, 240 v., shunt wound, Best Value in England small size,E4. No Radio Interference. D.C. MOTOR,220/240 v., compound wound,H.P. ; H.P. split phase, 25/- 30/, NET i H.P. split phase, 85/- ROTARY CONVERTOR.110 v. D.C. input; output 600 v. 51.1. + H.P. capacitor, 92/6 at 150 m/a, D.C., also 6 volts at 5 a.; price50/-. H.P. repulsion, 100/- 1,000 WATTAuto cores forrewinding, 12/6each, i H.P. repulsion, 115' - carriage 1/-. (By post 5/6) SMALL INDUCTION X-RAY TRANSFORMER120v.A.C. input,70,000v. MOTORS output, 2 K.W.Price (10, carriage forward. Of allBooksellers, or by post from the Publishers, Leaflets 1/10 H.P., 3,000 45'- GEORGE NEWNES,LTD.,(BookDept.),Tower 21d. s/amp Geared type, 47 R.P.M. 38 - LARGE RESISTANCE.,staggered studs, make splendid House, Southampton Street, London, W.C.2. Geared type, 3 or 6 R.P.M. 32/- dimmer, 220 v. carry 10 amps.Price50/-,carriage L. WILKINSON, Guildford Place, High St., TAUNTON forward. April, 1941 THE CYCLIST 83

.4ll letters should be addressed to the Editor, THEC YCLIS T,"George Newnes Ltd., Tower House, Southamp- ton Street, Strand, London, W.C.2. 'Phone: Temple Bar 4363 Telegrams: Newnes, Rand, London

VOL. IX APRIL, 1941 No. 230

Comments of the Month In this respect we gratefully acknowledge the hundreds of letters we have received ByF. J. C. from readers of The Cyclist who continue to read the Cyclist Supplement whichour present ration of paper has compelled us to After the War They will be in a sorry state of repair whenprovide as a substitute. the war is finished, for very little money is We are laying plans for the post-war ITis intriguing to consider the position ofbeing spent in maintaining them.It willperiod now, and have in hand some excellent Icycle sport after the war, and to envisagetake at least two years, after the war, tocycling material. the place which the pastime will occupy inbring them back to their pre-war state. We our lives. Many millions of people aredo not think that this will operate against compelled during the war to use the bicyclecycletouring,butitequallywillnotOne Amongst 39 ! instead of normal means of transport, andoperate for it. there are those who think that most of BRITISH cycle manufacturers are plan- these will maintain their interest in theRear Lights and Cycle Paths ningtoexport overone million pastime and continue as devotees.If the bicycles this year.This means that those last war is any index of tendency, we do ON the legislative side will there be theavailable for the home market will be not think so, even though we may hope so.\-1 same old war about rear -lights andgreatly restricted, and as a fact, only one In the 1914-1918 war many thousands ofcycle -paths, and taxes ;there is, in ourcyclist in thirty-nine will be able to buy a people used motor -cycles who had neveropinion, bound to be a struggle, after thenew bicycle.The sales manager of one of motor -cycled before, and the motor -cyclingwar, for the abolition of rear -lights whichour leading companies issued an appeal to movement was hopeful that those who hadnow we are compelled to carry, and we hopecyclists overseas, explaining that they can joined the ranks, though vicariously, wouldit is successful. But the war is compellingassist our war effort by buying British provide the nucleus for the post-war move-the public to accept conditions againstbicycles. The British Government has ment.In those days, petrol .was not sowhich, in normal times,it would havedecided that 75 per cent. of British bicycle severely rationed as it is to -day, but whenresisted.Will the public be in the sameproduction must be exported to help re- the. war ended, there was only a temporaryframe of mind when this war is over ?plenish Britain's reserves of foreign exchange boom in the sale of motor -cycles, and thenWill it be in the frame of mind to fight forFor every three machines sold abroad. the trade slumped. the pre-war principles ? Will the nationalmanufacturers are permitted to make one In the last war, too, tens of thousands oforganisations be so successful in gaining afor the home market.It is obvious, there- people purchased bicycles, but deserted thehearing ?These are questions which arefore, that as the overseas sales go up, the pastime when the war was over and normalurgent and intriguing. It may be that whennumber of machines availableforthe conditions returned. the war is over, the fortunes of the cyclingBritish market will rise commensurately. The hard core of the cycling movementmovement will be in the hands of differentIt is estimated that about 320,000 bicycles seems to be comprised by about 100,000men, with different outlooks, under differentwill become available this year for Britain's people, representing the combined member-conditions.It may be that the cycling12,000,000 cyclists. ship and to some degree, an overlappingmovement will be purged of many of those membership, of the C.T.C. and the N.C.U.who are not in it for the good of the sport, It is my view that the 100,000 figure is onand who operate by subterannean intriguePhotographs the high side, but we will accept it.Theand subterfuge. war conditions, however, have brought the In any case, the war is the time to cleanse WE shall be glad to supply to readers, inevitable depletion of membership and, sothe Augean stables, to clear the decks for for a nominal sum, copies of the far from post-war membership showing anthe post-war period.Cycle touring andphotograph which we published last month, increase, we think that the national associa-foreign touring are practically non-existent,showing C. A. (Bath Road) Smith, presenting tions will be hard-pressed to get back towhilst the sport is struggling to carry on.the original Bath Road " 100 " cup, which their pre-war level. National bodies might well, therefore, usehe won in 1891-1892, to the President of the war period to examine their rules andthe Bath Road Club.It must be noted regulations, to emend their organisations,that this photograph is the copyright of Difficult Times and to elide those clauses in their con-this journal, and it may only be reproduced

stitution which provide the loop -holes forby permission of the Editor. . DURING the war there is little that thethe intrigue to which we have referred. associations can do, for cycling news We should like to see the sporting move- is scarce, and the sport, during the war, isment run entirely by sportsmen, and allThe New Call-up going to have a difficult time. Those clubsthose who do not fall within that category which anticipatedthis difficult time byremoved from office. MR. BEVLN'S new call-up will not only cancellingeventshavebeenseverely affect the male side of the cycling group, criticised by those who arenot reallyThe Cyclist in Weekly Form! but also the female, for women between the genuinely interestedin maintaining the ages of nineteen and thirty are to register, sport, except for motives unconcerned with THERE is one post-war development toand will finally be absorbed into the war it, and in some cases clubs have reinstated which cyclists all over the country areeffort.Several clubs have delegated their their programmes this year.Already theylooking forward.It is the reappearance oftasks to women officers, so it seems that the are meeting the anticipateddifficulties.The Cyclist in its weekly form, with its un-cycling movement will suffer a further blow Refugees are occupying well-known clubrivalled news service,its impartial andunder the new scheme. racing headquarters, and it is difficult tofrank criticisms, and the journalistic scoops On the sporting side we learn from some find accommodation. A solution may bewhich established it as the leading cyclists'club secretaries that their plans to carry on found by providing tents, but this is anews magazine. this year are not likely to fructify, although somewhat meagre substitute for the con- It will be observed that we have main-they will do their best to carry out as large viviality of the bar parlour. tained some of the features for which thea part of the programme as possible.We There are others who think that thejournal has become famous, and that wehope that every club will endeavour to do scientific developments of the war willare still served by the contributors whoso,notwithstandingtherestrictionsof automatically develop the bicycle. Wehelped to make the journal famous. Theyovertime and Sunday work, but always pro- hope this is so, for there are many directionsare retained against the time when Thevided that the sport does not interfere with in which the bicycle needs to be improved. Cyclistwill reappear as a weekly, andwar effort.Our main consideration must Then thereisthe question of roads.provide the link at present missing. to be win the war. 84 THE CYCLIST April, 1941 Glasgow Wheeler now in Near EastS. Parker inthe Near East "KING oftheMountains "inthe 1939 SYD. PARKER, Ealing C.C., former holder of the Manx T.T., Donald Morrison, Glasgow s' London -Bath -London tricycle record and holder Wheelers, is now in the Near East with the of the 12 -hour record for the same type of machine, is R.A.F. now in the Near East. Well -Known Clubman's Bereavement Club Member " Missing BERT HOUGHTON, who has figured prominently REPORTED " Missing " in June last, news in R.R.A. and S.R.R.A. records in the past, has " has now been received that Guy Crowe, suffered terrible bereavement.His wife and their two Crouch Hill C.C., must he Presumed Dead." children. have been killed during an air raid.They The boat on whichhe was returningto had been evacuated fur safety. England from Dunkirk was sunk as the result

of enemy action. Popular Clubman Killed THE Victoria C.C. have learned with regret of the Coming S.C.C.U. Events death of one of their members, Ernie Wirth, who, when working with a Bomb Disposal Squad, lost his SIX 25 -mile events and two at 50miles are life. He was one of the club's most popular and active scheduled for competition by the Southern members. CountiesCyclingUnion. The Ullit.111 has acceptedtheresignationofpresidentJas. Club President's Loss Blair and elected, in his stead, W. A. (" Wally") Smith, a founder -member of the Union. SIR CHARLES McCREA, popular president of the Highgate Cycling Club, has suffered a tragic loss in the death of his son, Hugh McCrea, who was killed Sweden Solves a Transport Problem in action. He was a Naval Officer. CHORTAG E of petrol in Sweden has createdHill Climbing Champion in Iceland '-' a new form of goods. transport. -Tandems pulling specially -made light steel trucks withTHEhillclimbing champion ofthe Rotherham pneumatic tyres are to be seen in the streets of Wheelers,It.H. Flower,isnow stationedin Stockholm. Iceland.

Racing Cyclist Passes Over Leading Scots Join Up RICKMANSWORTII C.C. are mourning the lossof TWOof the best Scots speedmen have volunteered E. S. Orbell, well-known in North London racing for the Forces.They are Alex. Humphreys, who circles, who was killed in action while serving with the started in 1940 as a road novice, and then went on to anagramswin several opens, and Tommie M'Nulty, madman, tk.A.F.With his two brothers, J. H. and A. J. Orbcll, he volunteered for service and, fora time, all three were trackman, and hill -climber.Humphreys has joined stationed together. the Navy, and M'Nulty the Air Force. Both are members of the Glasgow Wheelers. Old Clubman in London's Fire Blit& Kentish Wheeler asVocalist Peakland Valley Safeguards NOW recovered from hisinjuries sustained when FRED LATHAM, Kentish Wheelers, who is probably " serving with the A.F.S. in London's tragic fire in known to a wider world as a dance -band vocalist,EDALE Valley,popular with Sheffield and Man- December, Ron. White is back again with the Highgatehas been doing some excellent work with E.N.S.A. in chestercyclists,hasbeenfurthersafeguarded C.C. and will again supervise arrangements for theirthe North of England. against despoliation by the National Trust, which has annual open " 100." acquired three hundred acres at the head of the dale. Crack Riders to Wed Well -Known Ten -miler Dies Bicycle Trailers in Holland GEORGE FLEMING, the Belle Vue road crack, isLACK of petrol in Holland has caused greater use of WINNER of the Southgate Cycling Club paced to wed, and so is Alec Horwood, D.C.M., of the bicycle trailers. ten -milechampionshipin1890,RupertW. Bath Road Club.Fleming hopes to compete in road These are now being used for Davey has died. events this year. transport of all kinds of goods in town and country. Scots Girls Time -Trial University C.C.'s Open " 30 Advice from Lord Keith SPEAKING at a gathering of cyclists and walkers SCOTS girls are to promote their own open cyclingTHEUniversity C.C. open 30 -mile fixture for tandems organised in Edinburgh by the Scottish Youth events this season ;ifatime -trialopeningis will be held this year but, in view of the probable Hostels Association, Lord Keith advised all who could encouraged.This is one of the decisions made at the shortage of tandem crews, it will be held in conjunction to go into the country in these difficult times and get annual general meeting oftheScottish Women's with a " 30 " for singles.Winners on each type of the benefit of fresh air and healthy exercise. Cycling Association held recently. machine will be suitably rewarded. Some hundreds attended the gathering, the best- attended outdoors meeting held in Edinburgh since Club Vice -President's Wedding Gift East Anglian Events the start of the war. EF. ANGRAVE, Lichfield City Cycling Club, was willbe atleast six openand semi -open presented with a -barometer by fellow members.THEREevents in the East Anglian area this year, including Bicycle Boom in Eire This was not only to mark his services to the club of the noted Wisbech Wheeler's open " 25." PETROL scarcity is causing a bicycle boom in Eire. which he is a vice-president, N.C.U. delegate, and Delivery of new machines is not gbod, and second R.T.T.C. handicapper andtimekeeper,butasa Oak C.C.'s 25 " hands are being sold at very little less than the price- wedding gift. of new bicycles. THEOak C.C. are taking over the usual Kingsdale Lighting Offences Rough Rider's 25 -mile fixture to be held shortly. Mid -Scotland Promotions for t941 AT Tottenham (London, N.) police court recently,Southgate C.C.'s Open Events THESlid -ScotlandTimeTrialsAssociationhas over70cyclistswere summonedforalleged compiled Its 1941 programme.There are eight lighting offences.Fines ranged from 10/- to 30/- and. DEVERSING their 1940 decision, Southgate Cyclingevents including two 25's and a 10 by the Association, in nearly two hours £00 (or ten shillings a minute) had " Club are to hold their open " 25 " and to promote a 25, a 10, and a hill -climb by the Hamilton C.C., and been collected. club events at 25, 30 and 50 miles. Perpetual trophies 25's by the Royal Albert C.C. and the Shotts Wheelers. in these events will be competed for. Because of the large number of reserved workers in Famous Speedman Marries thearea covered by thisAssociation,itsofficials Hon. Treasurer's Twenty Years Service believe that it should be possible to run off the events, FRED TURNER, famous Cheshire Roads speedman which are fewer than in previous years. of a decade ago, has married Miss Marjorie Beecroft, FOLLOWING his re-election as hon. treasurer,Mr. sister of a fellow member. A. J. Ballantyne enters his twentieth year as anDundee Promoting Opens official of the Southgate Cycling Club. Luton's Open " 25's " nliNDEE cycling bodies propose to organise events Popular Glasgow Rider in Royal NavyLi this summer at distances of 10, 25, 50 and 100 LUTON Wheelers have decided to hold two open miles, and the local cycling league, which was a success " 25's " this year. ALEC CALDER, GlasgowCyclingandyouth - last year, is to be re-formed. hostelling enthusiast, now in the Royal Navy, has These decisions were reached at the animal general Former N.C.U. Official Joins the Armywritten to a friend in Glasgow from a remote corner ofmeeting ofthe Dundee and District Time Trials the world.His letter took two months to reach its Association. New secretary of the Associationis Aformer official of the London Centre N.C.U., the destination J. Hunter, 33 Leng Street, Dundee, Angus. North Middlesex and Herts. Cycling Association, and the West London Cycling Association,Stan. Record Holder in B.B. Unit Women's Record Passed Thomas, keen track official of the Catford C.C., has joined the army. HOLDER of the National Fifty -mile tricycle record,THE.Women's Road Records Association, meeting AlbertWatson,well-knownEdinburghtime- in London, has passed the British 50 miles record Catford C.C.'s Activities trialist, is with a Balloon Barrage unit. for women set up on October 6th, 1940, by 'Ann Briercliffe, West of Scotland Clarion C. & A.C.Her THECatford C.C. will this year hold its open " 50 1Club's Track Meetings time was 1 hr. 59 miss. 14 sees. and its classic Hill Climb. The club has a member- ship of 270 and has re-elected W. W. Lucas as president.MARLBOROUGH Cycling and Athletic Club have Cumnock Rally Date decided to promote eleven evening track meetings MEETING late In February, the West of Scotland Old Timer's Versatility on Paddington track. Cyclists' Defence Committee fixed the date for this year's Cumnock rally. The rally will be held on the COUTHGATE Cycling Club's president is Mr. A. T. Australian Racer in R.A. Navy week -end June 28th -29th. Green, one-time hon. sec, of the now defunct Wood For the first time, Harry Price, secretary of the Green Cycling Club, who despite his 77 years stillHAROLD SMITH, the Australian who competed inScottish Amateur Cycling Association, is serving on cycles.He is a member of the F.O.T.C. and chairman" one of Wembley's Six Day races, was recently in theCommittee, and was appointedwithMessrs. of the Concert Artistes' Benevolent Association on English waters.He is now a sub -lieutenant in theDunsmore, Marshall, Gormley, Briercliffe, Davidson, whose committee he has served for 40 years. Royal Australian Navy. and Mailer, to the executive. April, 1941 THE CYCLIST 85

Chrome Molybdenum (KROMO) isthe strongest and Accles & lightest steel for tubular cycle parts, but it happens to be Pollock Ltd the best for Aeroplanes too !-so although you can't get the Steel Tube KROMO tubes now the name is well worth bearing in mind Specialists

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REMINDS YOU OF WILLIAMS No. 2.THE VILLAGE CLOCK None of the " locals " ever seem to remember how long the Village

Clock has been " a -going on " in dependable day -in -day -out service. . just a case of faithful wheels " shouldering " their responsibilities as wheels should. Out on the road=the cyclists flick by on gears sponsored by Williams- who have " shouldered " smoother transmission for so many years per a patent " flanged " design. Depend upon it-Williams Flanged represents a " something " not found in any other transmission set.Ask your friends.They'll tell you.

EDWARD WILLIAMS FOUNDRY LANE BIRMINGHAM ECONOMISE!

The universal cry to -day is "save." The adviceis good even ifit is not always easy to follow. The cyclist wishes to save not only expense but energy.By fitting first-class brakes he certainly saves money in the long run.By fitting CANTILEVERS he conserves energy at once.The most powerful cyclebrake in the world Write for a free copy of an Illustrated booklet. the "CANTILEVEA: " CANTILEVERS "cost 12/- each, front or rear in nickel or enamel finish ChromiumPlated,14/-. For Tandems I3/- each. THERE SIL1ON VI front or rear(chrome 15/-) 200. LIVERPOOL ROAD. LONDONN.I.

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now-and for the time being, only-to carry the burden of additional and restrictedlighting(that sounds contradictory, but it isn't I), and we suffer from the fact, that motor trafficis of necessity inadequately illaminated. Beyond that, of what is there to complain ? Not much. Yesterday (as I write), I4iad tea at a farm- house which at long last has ceased to display lump sugar, though there was plenty of the soft variety. Three dishes of jam were placed before me, in place of the usual four, but there was no change in the quality or quantity of the home-made cakes with which the table was laden. As I travelled homewards, filled with a splendid feed, I came to the conclusion that it wasn't such a bad old war after all I But here is a point where we may hit snags.. On a Saturday afternoon a few weeks ago I made a dive into Shropshire, there to enjoy (as I hoped) a slap-up tea at a favourite house of call.Alas 1 My hostess met me at the door and was sorry she couldn't oblige. Her house had been filled with evacuees and no accommodation remained for old customers.So I turned sorrowfully away and found another (and an inferior) place for tea. Moral :beware of the possibility of our rest -houses being crowded out with folks who, unluckily, have been expelled -from their homes by bombs.Another instance:1 gave a good country address to a friend who wanted a quiet week -end. As be neared his destina- tion, he observed that an A.A. gem had been installed in itfield at the back of the house, and he decided to "give it best."Moral: the barrage spreads far and wide. Beware of the possibility of the quietude of yesterdaybeing transformedintoa hideous and sleep -disturbing cacophony. Of course, the farthei we go afield, and the more we keep away from the large Some Members of the Famous Bath Road Club, on the occasion of their Annual Photo Run. centres of population and from legitimate military The picture was taken in the grounds of " The Angel" at Thames Ditton. objectives, the less likely are we to encounter noises that shatter the night. AROUND THE WHEELWORLD-By Icarus ThisisHow BELIEVEit or not, there are still some cyclists who do not know how best to see to it that, after an Abbreviations It most notbeforgotten that timekeepers are onadjustment, they have finished up with the handle- committees which elect timekeepers, and they are thus bar in the right position.You may do the trick by IT seems necessary that someone should produce, forIn a position to keep out those who, genuinely interested getting the bar at right -angles to the front wheel, the edification of those somewhat new to the cyclingIn helping clubs during the difficult times, offer their first making sure that the front wheel is exactly straight. movement, whether theyaredescribedas `Greatservices and the use of their watches without fee. I The proper way to do it is to take the line of the front Cycling Authorities or not, alistof the standard do not think, therefore, that there will be a panel of hub. When the handle -bar is parallel with that, it is abbreviationsadoptedinthecyclingtrade.We voluntary timekeepers. have in this country the British Standards Institution, correctly placed. whose jobitistostandardise the nomenclature ofvariousindustries. Isupposethateveryone Cycling Broadcasts The Purchase Tax fromourcontemporary claiming even nodding acquaintance with cycling, HEREWITH quotation SEVERAL dealersstilldo not seem to understand knows that the abbreviation Mjc. means machine. Practical IV irelesg: I am pleased to note, as the correct basis of assessment of the Purchase Apparently not everyone, however, understands this, an old cyclist, that the B.B.C. is devoting considerately Tax. As agreed betweA1 the Manufacturers' Union and for a friend of mine was mortified to find that this more programme time to cycling matters.Ihope the Customs and Excise, the wholesale value of bicycles abbreviation which he had used in a letter, had beenthey bring to the microphone real cycling authoritiesis determined by deducting 30 per cent. from the retail interpreted as meaning motorcycle. As a result, hesuch as Frank Urry, " Wayfarer," Percy Brazendale,price, and then adding 33I per cent. to this figure as has had his leg well and truly pulled, for he has beenand others of similar lifelong experience.Each ofthe amount of purchase tax. a cyclist all his life, and his name has never beenthese men has been cycling all his life for the love of associated with thepetrol -driven two -wheeler. Of the pastime.They are free from commercial Interests, course, no reader of The Cyclist would be guilty of and could bring richness Of experience, and wealth ofThe Accommodation Problem making this error, but it does seem to me that the neweranecdote as flavouring essences to their talks.The generation of cyclists, who seem quite unfamiliar with sport of lycling should not be given much programme FROM the number of telephone callsIhave bad technical terms, need to have some explanatory leaflet space.It Interests at the most 30,000 people in this asking for assistance in the matter of transport of to .prevent them making such elementary mistakes, country, whereas there are 12,000,000 cyclists.The helpers, loan of my watches, use of my car, etc., it which not only offend the writers of letters but are part cannot be greater than the whole.' seems that promoters of road events are meeting the likely to hold up to ridicule those who comment upon snags which some of the older dubs anticipated when such letters.It has always been my contention that they cancelled events last year.Of course, 1 am most those entrusted with thecriticismofmechanical Cycling in the Netherlands anxious to help and I am giving every available minute matters should have an engineering training.If that SHORTAGE of timber in the Netherlands has led each week -end to the transport of helpers, timing, and is not possible, then they should be trained in the very to the demolition of a great number ofcycling so on.Very naturally, I cannot be in two places at elementary terms connected with engineering.As a tracks.The famous Rijswijk track near the Hague, once, and so clubs will understand that If I have to start I suggest that they memorise the following : the scene of many great cycling events, is the latestdecline their offers it is because I have a prior engage- T.p.i. means threads per inch;Wh. means Whit- victim of this German drive for timber.Before long ment.And quite naturally, I am giving priority to worth ;Cl,. means cast iron ;W.I., wrought iron ; only the concrete tracks will remain.The number of those clubs which have not opposed the voluntary C.S., cast steel ;m.p.h., miles per hour ;d:n.s., did timber tracks in Holland, however, is much greater as timekeeping which 1 suggested in the early days of the not start ;d.n.f., did not finish.It also seems neces- the last few years only timber tracks were built. war.Whilst clubs are finding it difficult to find the sary to remind them that the bicycle is not the most prize -money and are teeing put to extra expense in difficult vehicle to immobilise, and that it consists ofThe Cumnock Rally other ways, it Is my firm view that those who offer two wheels with thirty-two spokes in the front wheel their services as timekeepers free of charge should and forty in the back, that the saddle Is the apparatusTHE West ofScotland Cyclist Defence Committee have been encouraged. Unfortunately, there are many on which the rider sits, that the cranks provide the will again promote the Cumnock Rally this year. timekeepers Who oppose this point of view and still means of propulsion, and that the tyres are inflatedThe date is fixed for June.In the last three years insist upon their pound of flesh.They have, in some - with air. attendances at the Rally have been 6,000, 10,000, and cases. succeeded in obtaining the backing of certain I am thinking of starting some evening 4,000 respectively.Robert Marshall will organise the clubs.These latter are now appealing for voluntary classes on the subject, and for full terms apply to me event,supportedbythethirtyassociationscom- help, and they cannot lee surprised because the help is prising the S.C.U.S. not forthcoming.You cannot expect the owner of a Historians Please Note watch or the owner of a car to be made use of in this THE standard work on the history of the bicycleit - way, especially when their attitude has received the I "Cycling," by H. IL Griffin, which originally wasC. K. Mills quasi -support of some of the R.T.T.C. officials.Those published by George Bell & Sons.This book has I REGRET to record the passing of my old friend, anxious to help the sport and are willing tee put them- been out of print for many years, but the copyright of C. K. Mills, who, from 1838 to1041 had beenselves to some expense, and not a small amount of the book was purchased by the editor of this journal aassociated with the sport of cycling without break. trouble,inhelping clubs have been positivelydis- couple of years ago, and is owned by the' proprietors of 1 say that he had been associated with the sport ofcouraged by officialdom, and it is not surprising that The Cyclist.I am asked to remind all those who cycling, but it was chiefly on the executive side, for he those who originally volunteered to help the sport write or talk /MOM the history of the bicycle that we was never a record breaker nor one who distinguishedalong during the difficult war period have withdrawn intend to safeguard our rights in this work, and that himself at racing.It. was chiefly in connection with their offer. quotations fromit,either spoken or written,are the N.C.U. and as a delegate for the North London There needs to be a totally different atmosphere in expressly forbidden without our permission, and inC.C. that he distinguished himself.He served forthe sphere of cycle sport ifitis to survive.There any case may not be made without acknowledginent severalyears onthe London centre andGeneral are far too many associated with the sport who are in to The Cyclist. Council.A patent agent by occupation (I dislike theit her what they can get oat of it, and they speak of word profession), he met most of the so-called inventory the sport and maintaining its traditions with their VoluntaryTimekeepers in the boom -years of cycling.Yes, and the racketeers, tongues in their cheeks.Indeed. many of them keep from which the movement has never been entirelygood people out of the sport, for good men do not like I\VAS somewhat amused to read in a contemporary free. Whilst he never did anything spectacular, his to be associated' with them. the suggestion that there should be a panel of time- pleasant manner, and his wise judgment endeared him Curling should not be brought down to the level of keepers who arepreparedtooffertheirservice, to a wide circle. and !fumy will deplore his passing. the kerb -stone wheelers, and if kerb -stone wheelers are voluntarily.I am not really amused at the suggest i011, permitted to take a leading part in the sport, that is with which I, of course, agree, butatthe reception what it will descend to, for like begets like. such a suggestion willreceive.Whilst many time- To -day's Accommodation. keepers pay lip -service to the sport, its clean traditions of us-indeed, all of us-are affected by the and freedom from sharnateurism, they still like to earn MOSTwar in one way or another.Possibly we cyclists their casual guineas from clubs which can ill afford still remain in the category to which 1 once applied the money.There are ninny timekeepers who resent the political and economic phrase of " most -favoured Order your Copy the suggestion that timekeeping should be undertaken nation."In normal Dines, aswell as In this abnormal in an honorary capacity, even in an amateur sport. era, we are particularly blessed. It is true that we have 88 THE CYCLIST April,1941 WAYSIDE THOUGHTS By F.J. URRY Take the Chances BY the time you read these notes, March will be on theworried with the needs of wanderers.I remember torn off pad, the month that ushers in the spring,being in the south-west country in 1920, and my wife or at least givesus some merry glances of thatand Ioften experienced real difficulty in securing fresheningperiodthat puts another inch in your accommodation during a fortnight's tour, and to some stride.True enough, there will be a few east windsextent our holiday was spoiled because of the time with an edge like a whetted knife to remind us thatwasted in seeking quarters.It is to be hoped our winter still lingers, but there will also be sparklingcatering friends will not make the same mistake again, days with tufts of green among the sheltered hedge-but will endeavour to retain some sort of accom- rows, and the gay pink flags of the almond awake, to modation, so' that when peace comes the stage will be say nothing of the daffodil that will line a route I set for wide -spread touring.In the meantime the know running from a British Camp on the Malvern,difficulties of catering will not stay me from wandering. to the warm valleys by Eastnor Castle.Nor shall A thermos of coffee, and whatever the home larder we have to await for the extra hour of daylight thiscan provide will keep me going for a day-and I shall year until after Easter, for we have it with us now, refresh where loveliness lies in my eyes. and the illumination we spent in the dark mornings of mid -winter will bring their full dividend.Maybe, as one grows older, it is natural that the turn of theMaking Friends year seems more delightful than ever, and to make a URING the last month I have received numerous little holiday of the odd hours of leisure during these Dinvitations to visit corresponding friends at their distracted times is surely part of the heaven uponhomes, or, alternatively, go riding with them any day earth.Work, yes, with all your might ;but when of the week, or if that is not possible, any week -end. you have a short space of leisure, I know of no moreSuch gestures are nice to receive because they carry a delightful manner of using it than taking the keen genial compliment ;but unfortunately-or otherwise, Daily Conditions sweet March air on a sunny day to see the landaccording to outlook-I am hard at it for at least five - WHATEVER the spring and summer mayhave stretching itself, as it were, after the long dark slumberand -a -half days a week, and have occasional night - in store for road users, we certainly know whatof winter.Some people walk, which is good for them, duties that make me asleepy individual on the happened to us in the first month of this year of grace. lint limits their horizon ;I prefer to ride, to stay awhile following day.1 have, however, made one or two Authority tells us we had a foot and a quarter of snowhere and there where " the quick cloud shadowssuch assignations, and will let you know how they in the Midlands: and yet I was only divorced from trail " and smoke, watch the waking woodlands rejoice, turn out, because, to be candid, I am inclined to the the saddle for a couple of days, which I think is aand hear them talk of the summer to come.And atview that actual contact following correspondence is compliment to the Cityof Birmingham scavengerthe end of such a day I generally find that sixty milesfrequently a disappointment.For you only know an department for dealing so promptly with the mainor so of perfect movement has been packed into anindividual well when you have tried him out, and roadsofthe district.They-theauthorities-unspoken poem ;and it is then I thank all the godsparticularly when you have trusted him, and these evidentlytookwarningfromtheexperiencesof there be that I can still ride a bicycle, and claim theconditionsare not possibletoattain during the January 1940, when it was nearly a fortnight afterrelief from the many pressing things that now makefleeting hours of a day along the road.But what a the heavy snowfall that I was able to ride a bicyclelife so urgent, and sometimes so adventurous.It is tine game this cycling must be when folk who know with any reasonable degree of safety.On this recenteasy to do as the world usually does on its leisure nothing about me, and the little idiocyncrasies that occasion I was lucky in obtaining friendly lifts from days ;but if you would jewel life with bright memories, handicap every human, are prepared to take the risk the regular motorists who parade my pitch, for which go and look at the countryside in spring, eschew theof disappointment.I tell you, there is nothing more many thanks ;but oh Ihow they pulled my leg armchair, and write your own story of simple happiness inducive to friendship than cycling, and its highest because the bicycle wheels had ceased rolling for theintertwined with the nines of travel. expression is to be found in touring.1 have perhaps moment. A week later, however, 1 had the satisfaction of leading a string of them home in the fog, for they could follow my tail light with ease, whereas " on their own " the freezing mixture completely blinded them. For some ten days after that snowfall the roads were truly awful, and my poor old bicycle looked as if it was enamelled with earth, as indeed it was.I gave the bearing and brake parts a generous dose of oil every other day, while the oil bath case of the old Senbeam took every care of the rest of the trans- mission, and so we slurred through the mud without much trouble.But I noticed in passing, and being passed by other cyclists, that chains were crackling with the mixture of snowy slush, and there will be sprockets to scrap and chains to replace on many machines before the full flavour of spring is in the air. That kind of weather is the mixture that a Sunbeam loves, and my old favourite of 23 winters faced it as merrily as ever, and looks little the worse now it has had a clean.But I must admit I do not like carrying around the weight handicap of a gear case except in really bad conditions, and then it is worth the added poundage many times over. Supplies I DO not want to sound a pessimistic note, but let me advise you to buy a new bicycle-if you want one- or have the old one rejuvenated, as soon as possible. Materials are becoming more and more difficult to obtain, and the immediate position is that as stocks are exhausted, no one knows when they are likely to be replaced.I will not go as far as to say they will not be replaced until after the war, because at the moment of writing, quotas for material are in the air ; yet everyone connected with the trade knows such a half -a -dozen friends near my own age with whom I conditionofthings may transpire.Itisno useCatering Troubles roam the land whenever the chance of a holiday comes blaming the maker or the dealer if you cannot get what ABOUT a year ago I wrote aparagraph in another along, and half the pleasure of our journeying is de- you require, for the former is very strictly controlled; place, saying that in my opinion the difficulties of rived from sharing the loveliness through which we and the latter is necessarily entirely dependent on hiscatering for the touring or week -ending cyclist wouldtravel, and the little adventures by the way.I can, supplier.The same thing can be said on the questionincrease as the war period extended, and I received and do, enjoy lonely cycling, but the best form and the of replacements, and I tell you franklyI have putnumerous letters from young folk who, because theydeepest impression of the pastime have undoubtedly into my shed a small stock of covers and brake blocks, were welcomed in most placeslast summer, werebeen garnered in the company of sympathetic com- so that I shall not be held up from fitting my par-inclined to the opinion that my early remarks were panions.And so I say to you, make friends awheel, ticular fancy in these things. This may be selfish; pessimistic.As amatter offact,and from my for by sharing the pleasures of the road you enhance that I have not fully determined, but I am sure it isexperience, we have reached the difficult stage much them, and by dividing the little troubles that are bound wise. Chains I can always get becauseI have asooner on this occasion than in 1914-18, for ifI to come, you reduce them to a jocular outlook. brother who helps to make them.Old cyclists have remember rightly, it was not until the summer of 1916 their special favourites in the matter of fitments, andthat accommodation became a problem.But it only though it may seem absurd, itis nevertheless trueshowed itself a problem to be fairly easily solved.Hostels After the War that unless their machines are equipped according toThen, as now, there were few folk fortunate enoughIN February, the Scottish Youth Hostels Association their notions, they never think the bicycle is performing to enjoy a prolonged holiday ;our cycling excursions held its first formal gathering, a supper in Edinburgh to the top of its form.In this they are no differentwere mainly confined to a day's outing, with anto celebrate the foundation of the movement ten to other sporting people like the cricketer, the tennis occasional week -end to a spot where we knew accom- years ago player or the golfer, who have their favourite imple-modation was available.So we started packing our Amongst those present was Lord Salvesen, Lord ments, and if these are missing, blame all bad shots food and using the rest houses still available for " tea Keith, and J. A. Waters (Editor, The Scotsman), and to their absence.It is a lucky thing for us thatonly," frequently taking the herb and the sugar (ifthey spoke of the success of the Association, even in bicycles last such a long time with a minimum of care, any) with us.That was the start of the " tea only " the first year of war. for replacements of worn parts, even in these days, are habit which has persisted, and spread to most parts Also present were pioneers of the movement like not abnormally expensive ;were it -otherwise, many a of the country, and it was also the beginning of the R. B. Fasken, present chairman of the Association, machine would go out of commission.As things are, much wider picnicing habits which have appealed toJohn Francey, and Alex. Beith. get your machine in perfect order, and if you are luckyevery type of wanderer.To some extent the hotel Mr. Beith, a former member of the C.T.C. Council, enough to have two, or more, see that they are in folk and the caterers encouraged this 'habit of in-said that in the lean years which would doubtless sound condition.You may need them, and in any dependence for some time after the close of the Greatfollow the war, there would be greater need than ever case it is always pleasant to be in a position to lend War, because, having got used to making money easilyfor the facilities the Association provided for cyclists one to a friend. by pulling the beer -engine handle, they could not be and walkers. April, 1941 THE CYCLIST 89

111C !--that my friend had been to Connemara., and that he was concerned in a factory which had been built near the River Corrib in Galway City.We were instantly on common ground.He knew Ireland from a commercial standpoint :I knew the country as a cyclist, and we found plenty/6 talk about-the roads, the folks and their habits, the mountains with their My Point marvellous colour scheme, the vast lakes, the fretted coast -line, the huge spread of ocean known as Galway Bay, and the distant islands which form a sort of natural breakwater.And so, thanks to the bicycle, of View which has made me a " travelled man," the door was opened to a pleasant talk, which happily whiled away " the rest of the time I spent with that business man- and which, I found, did the no harm.What a debt of gratitude we owe, in one way and another, to the QYWAYA12EF-2 bicycle ! The Slothful Way N a lazy moment, the other morning, when one of my Ityres refused to accept the supply of air it needed, followed the line of least resistance by slightly heating concerns those empty roads of which I the valve shell with a match, and then the pump was have spoken, and it seems to me thatallowed to " do its stuff."1 knew quite well that this cyclists who are failing to take advantage expedient was purely a temporary one, and, Sure of current conditions are doing them-enough, two days later-when, it need hardly be said, selves a great disservice.So, my friends, I was pressed for time-the valve went on strike, and if your bicycle is out of commission, have it was necessary for me to fit a new rubber tube. That it "tuned up" without delay and put it was punishment for my lazineseLHow much better back on the road again. All the old joysit would have been to do the right thing when it was Mani Ike Vie m. Adderlsuty0s.s.` ofcyclingawaityou,plus the new borne in upon me that the tubing was on its last legs ! St.efasek /gnu joyswhich arise from the diminution As a matter of good form (so to speak), the process of of traffic. If you are working hard,heating the valve shell should be reserved for those there isall the more reason why you should insistoccasions when it is desired to remove an obstinate Not Quite the Same upon obtaining your share of our glorious pastime. length of rubber front its lair ;it should not be used to AA SHORT time ago I called at a tiny pub. in the If your leisure moments are few and far between, extend the life of a vital portion of the air inlet. very heart of the country --in the Midlands-for cycling is the very best method of occupying them, - a spot of refreshment, and was surprised to find the for in no other way can you so easily and convenientlySacrifice place fullof people who, at midday, were makinomake use of your spare time.I know front long merry.Well oiled, they raised their voices in what", experience that the effect of an hour or two devoted AT the breaking out of the war, I heard of a business presumably, man who, on the announcement of petrol rationing, wouldbecalled" song "-andthe to cycling, especially when life is full of worries and said :" Well, I'll buy a bike now. It won't beinfest dig results were not exactly musical.' Who are your problems, constitutes a splendid tonic, which enablesto cycle I"I could have kicked his shins !He was friends ? "I enquired of the publican. Seafaring you to return to your " grind -stone " refreshed and nobody of any importance -a £500 -a -year man who folk,"sayshe.My faceregisteredastonishment,' strengthened.The great " versatility " of cycling-was provided by his employers with a motor car,the because the nearest salt water was about 100 miles good for an hour or a week :good in fine weather orpossession of which had evidently endowed him with away ;and then it was explained to me that the wet :good in sunshine or frost :good in daylight orbigger ideas than his salary justified, and made hint clamorous people concerned were barge -folk from the darkness :goodfora lounge or a" scorch "-is something of a snob.But there are many such-and 'adjacent canal, which is not quite the same thing as enhanced by those empty roads to which reference isthere are thousands of others who refuse to ride the sea ! here made.It's a grand game-and it now has greaterbicycles because " it isn't done " :because the family possibilities than ever before. meat and the family newspapers are delivered to their Empty Roads houses by boys mounted on bicycles :because every AS I may have remarked before, these are great days Thanks tothe Bicycle tyke you see careers about the country on a bicycle. from the cycling point of view.At least,1 find RECENTLY, when I was engaged in conference with No :" It isn't done."These worthy people are pre- them so, and I revel in current conditions.What a man with whom it was desirable for me to standpared to sell their birthright for a mess of petrol, and strikes me as much as, anything is the series of empty well, the conversation lagged, and we were in dangerto give up all the undeniable joys accruing from the roads which are encountered, taking one back to of drifting into an awkward silence. The situation was pastime of cycling because-forsooth !-so many of pre -motor days.It might be thought that the great saved by his telling me that he had just completed atheir fellow -men indulge in cycling.My view is : let increase in the amount of military traffic would more business visit to Ireland, travelling to and fro. by air. all who will, cycle. As for me, I ant an adherent to the thancounter -balancethewithdrawalofprivate After that we went along swimmingly, for cycling has finest pastime in the world, and I have never been one motoring which arises from the strictrationing of given me a deep interest in and knowledge of " theto give up the best for something inferior-even if the petrol,but suchisnot the case-so faras my Island of the Saints."A question or two brought. forthinferior thing seems more " respectable." Members of experience goes. The main impression left on my 111111C1 the information-very attractive and provocative tothe snobocracy earn my greatest contempt. Notes of a Highwayman By LeonardEllis has been swept away in an endeavour to clarify a once Where Shires Meet wildly -contorted boundary line. FRONTIERS have always fascinated touring tvelists On the road northward front Tantworth to Ashby-- becauseIbelievethatnearlyalltouristsare de-la-Zouch, there is a little inn named by someone romantic and imaginative.: To them isgiven the with a " boundary complex."It is called the " Four power to see beyond the simple stone or post, and to Counties Inn," and although the boundaries of Warwick, conjure up visions- ofstrange lands and stranger Leicester, Stafford and Derby are not far distant, it customs.Since it is necessary to go abroad to find must be regretfully admitted that all Mar boundaries frontiers it might seem that this little hobby is eon - do not touch the point. It might be ttalF to say that fined to the fortunate few who can tour abroad. all four can be seen front the window's of the house; Luckily, however, a similar thrill usually accompanies it might even be that once the boundaries did come the crossing front one British country to another, and together. strangely enoughtheborder -lineseemstobe a A romantically named point on a romantic road is veritable magnet for romance and romantic tales.I County Gate, in North Devon.This, without doubt, can always recall with a thrill my first sight of the marks the dividing line between Devon and Somerset, Scottish boundary, simply marked by a St. Andrew's and is situated on one of the most glorious touring Cross, and the legend " Scotland."It was an event, roads in the south-west.At this spot a gate once and we solemnly marked the occasion by dismounting marked the boundary between Wessex and Devonia. and reverently gazing at this symbol of our arrival, and our welcome to a new land.I have stood wistfully at The Haunt of the Bad Men the frontier of a country not named in my passport I THINK however that one of the most fascinating and could always imagine that there must be many shire spots is that marked on the maps asThree most desirable things to see because they were tem- Shire Head."It is not an easy place to find, but once porarily beyond my reach. found it will be easy to realise the truth of many of the strange stories woven around it.It is a wild spot in The Fascination of County Boundaries a hollow of the Dane Valley in Macclesfield Forest. cVEN county boundaries have a decided fascination, Herei Derbyshire, Cheshire and Staffordshire come " and here, again, others have felt the urge to mark together, and this very proximity of counties was the the spot, and to invest the scene with romantic tales. reason for its notoriety.It issaid that in the old There are several places in these Islands where two or prize -fighting days the ring would be pitched in one more countiescome together, and the spot is generally county, and the battle would proceed until the police marked by some tangible object, and is often known of that county pounced.Then up came the ring by a name -that explains its importance. posts to be transported a few feet into another county Near Moreton -in -the -Marsh, in the Cotswolds, and where the police were powerless to act.We are not on the road to Stow-in-the-Wold, stands the very told what happened when the policeofallthree well-known square stone pillar surmounted by a stone counties arrived on thescene.To complete the ball, marking the spot where the counties of Warwick, picture of its ill -repute we must move over to Flash, Worcester,OxfordandGloucestertouch.Itis, or, as itis alternatively called, Quarnford.Around incidentally, a tragic example of the vandalism that this district in the bad old days, the tinkers and characterises a certain class of traveller.The stone tramps would congregate during the winter.They isshockingly mutilated by scoresof names and had their own customs and their own slang, and in initials.It is difficult to understand how Worcester order to pass away the dreary months in a profitable comes into the picture, and I sometimes wonder if one - way, they manufactured spurious coins.Even to -day of those queer little " islands " once existed here and Four Shire Stone, Moreton -in -the -Marsh. such money is often calledflash money." 90 THE CYCLIST April, 1941 The messengers, who must he thirteen years of age or over, are chosen not only for their ability to ride and repair their bicycles, but for their dependability News and Notes and initiative. West of Scotland Programme Douglas Champion Volunteers THE West of Scotland Time Trials Association and Honour for Union Chief its affiliated clubs propose to hold seventeen open MMAJOR H. R. WATLING, Director of theBritish V ENNETH COCHRANE, club champion of theevents during 1941.They include Glasgow Eastern Cycle andMotorCycleManufacturers.and "`Douglas C.C., of Glasgow, in 1940, has volunteered10 and 25, Glasgow Wheelers 25, West of Scotland Traders Union, Coventry, has been added to the for the lt.A.F. and is now serving.Nineteen years ofClarion 25 and 100, Ivy 25,Lancia 25 and 50, Commission of the Peace for the County of Warwick. age, Cochrane was the most promising youngster inNightingale 25 and 100, Glasgow United 50, Lomond the Douglas, and held club records. Roads 50, and Association Novice 25, 25, 50, 100, and New Container for Bicycle Oil hill climb. Mid -Scotland Guarantee While officials are prepared to run these events, rYCLISTS who have been finding difficulty in difficulties may arise in securing entries as most of the, obtaining B.S.A. lubricating oilwill be glad toTHE Mid -Scotland Time Trials Association has de-remaining young men are in the forces. hear- that a new type of container has been devised to cided to guarantee to, its affiliated clubs that if overcome the war -time difficulty of obtaining adequate they are unable to promote any of their listed events, theAssociationwillstepin and run them.The supplies of the familiar tins. Although the new B.S.A. affiliated clubs propose to hold metallisedcontainer holds exactly half a pint ofAssociation and its lubricating oil-considerably more than the tin-iteight open events this season. costs only 7fd., compared with the present price of the tin which is 9d. The container is -used by punching Over One Hundred at Aberdeen two sma II holes in the top, when oil can then be poured into an oil -can as required. Priegiying MOST successfulAberdeen social event of recent years was the annual presentationofthe Strike Because of Borrowed Bicycle North-East of Scotland Time Trials Association, held nURING February, 400 apprentices employed in jointly this year with the Aberdeen Wheelers. '-'Leith shipyards struck work because one of them Councillor Fraser McIntosh presided, and Jame. was dismissed by the management of one firm forOgilvie was the leading prizewinner. borrowing a bicycle during the dinner hour. The owner of the bicycle was one of those who came out on strike in support of the dismissed apprentice welder. Scots Girls to Promote AT the annual generalmeetingof the Scottish Women's Cycling Association in Glasgow, it was Flooding at Shrewsbury decided to promote open events during 1911.A trial AFEW weeks ago, Shrewsbury, the popular Midlandevent is to be run off early in the season, and if this is cycling centre, had the worst floods for forty years.successful, further events will be organised.Many of All the main roads into the town were flooded, exceptthe members of the Association are at present working for one. week -ends. All vehicles were held up, but cyclists were amongst All the retiring officials were re-elected, with Ann those who tried to pass through the floods.For miles Briercliffe,16 Scotstoun Street,Glasgow,W.4, as upstream, fields and roads were under water. general secretary. New Youth Hostel Oldham's Messenger Cyclists "THE finestyouth hostelinScotland " (officialTHE CountyBoroughof has description) is to be opened in April at " Dun- Oldham,Lancashire, selma," Strone Point, near Dunoon, Firth of Clyde. what Is believed tobe The ptcturesque 1.9kcentury gate A four -storeybuilding,formerly owned by thethe best A.R.P. boy messenger liaririfru3the Coates family, of Paisley, " Dunselma " will be theservice in the country. The MONNOW BRIDGE most up-to-date hostel north of the Border.Electric boys,who come from the senior alMONMOUTI-1 light and water supply are duplicated, and there is adepartments of local schools, first-class air-raid shelter in the basement. report for duty at the Old- The hostel has been obtained through the good ham Education Offices on the offices of the Forestry Commissioners. morning after heavy raids.

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Make sure of itby fitting WORKSHOP CALCULATIONS, Fibrax, the brake blocks that give a swift, smooth stop every mention TABLES AND FORMUL/E time.Made of special By F. J. CAMM extra -tough material, A handbook giving meth, di of calculations, solutions of workshop The problem, and the rules and formula necessary in various workshop Fibrax also give longer processes. All the information a mechanic normally requires, Of all Booksellers. 5s. Od. net, or by post 5s. 6,1. from George wear. Newnes Ltd. (Book Dept.), Tower House, Southampton Street, That means you London, W.C.S. are saved money and Cyclist trouble on replace- .t4 0tehontet MARDI THECYCLOMETER I-----01 ments.It pays to insist MANUFACTURERS on Fibrax. Standard Model - 2/11 each De Luxe Model - 3/6each rol.ile To Fit 24",26" or 28'' Wheel,. BRAKE BLOCKS & LINERS chromium H. J. Thormann Engineering Co. Ltd. 6 \ Plated BRITISH. FIBRAX LTD., 2, Tudor Street, London, E.C.4 PERREN STREET, LONDON, N.W.6. MADR BUY, EXCHANGE OR SELL Advertisements are accepted for these columns at 3d. per word (minimum 12 words at 3s.-advertisements of less than 12 words are charged at the minimum rate of 3s.) subject to a discount of 21% for 6 consecutive monthly insertions or 5% for 12 consecutive monthly insertions. TERMS :-Cash with order. Cheques, Postal Orders, etc., should be made payable to George Newnes, Ltd. The Proprietors reserve the right to refuse or withdraw advertisements at their discretion.All advertisements must be received on or before the 5th of the month preceding date of publication and should be addressed to the Advertisement Manager, " Practical Mechanics," George Newnes Ltd., Tower House, Southampton Street, Strand, W.C.2. WATCHMAKING LITERATURE MISCELLANEOUS A HANDY BOOK FOR RADIO ENGINEERS. TELESCOPES, MICROSCOPES. Scientific WATCH & CLOCK REPAIRERS. Send &I. for " The Radio Engineer's Vest -Pocket Book," by F. J. 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