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11

November, 1938 NEWNES PRACTICAL MECHANICS 57

SHERLOCK HOLMES SC/V...IIutuceateveveqRADIO Or ELECTRICAL

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SHEET -METALWORK

This entirely new and practical book deals fullywith present-day methods adopted by Sheet -MetalWorkers in the most up-to-date factories in the country.It includes not only a sound working knowledge ofall the long-established workshop methods, but alsodescribes in detail the most recent developments,especially those employed in Aeroplane and Auto-mobile Manufacture. It also contains valuable chapterson Plastics and Plastic Processes. "Sheet -MetalWork," while essentially a practical book for thepractical man, will also be found invaluable by anyoneconnected in any way with the Trade, as a referencework and as a means of brushing up his knowledge.

THE AUTHORThe author is Mr. F. Homer, who needs no introduction

to those in the Engineering Trade. He has been assisted byeight recognised experts and the work has been 'edited byMr. A. Regnauld, B.Sc. (England), A.R.C.Sc., M.I.E.E., whois the Senior Lecturer at Faraday House Engineering College.

SOME OF THE SUBJECTSThe principles of Sheet -Metal Woiking, Sheet -Iron and other

Sheet -Metals, Preparation of Sheets, Aluminium Working,Copper Working, Lead and Zinc Working, Art -Metal Work,Tinsmiths Work, Plastics, Shearing, Machines, PunchingMachines, Bending and Forming Machines, Power Presses,Sheet -Metal Factories, Useful Data, Blanking Presses, Coin-ing and Other Presses, Machines for Miscellaneous Operations,Dies used in Presses, Drawing Dies and their Operation, Diesfor Bending, Die -making, Plakic Processes, ResistanceWelding, Oxy-acetylene Welding, Electric Arc Welding,Spot Welding, Soldering and Brazing, Portable Tools, Machinesfor Can Manufacture, Finishing Processes, Spinning Lathesand Processes, Mass Production.

ILLUSTRATIONSThe work is profusely illustrated, it contains over seven

hundred illustrations in the text in addition to 24 full -pageplates. All the illustrations have been chosen for theirpractical value in helping the reader to follow the text.

- A FREE BOOKLETTo the Caxton Publishing Co., Ltd.,

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Please send me, free of charge, Illustrated Bookletdescribing " Sheet Metal Work."

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58 NEWNES PRACTICAL MELHANICS November, 1938

AMBITIOUS ENGINEERSTHIS IMPORTANT HANDBOOK

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The Handbook contains, among other intensely in-teresting matter, details of B.Sc., A.M.I.E.E.,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., CIVIL SERVICE, and other importantEngineering Examinations : outlines courses in allbranches of CIVIL, MECHANICAL, ELECTRICAL,AUTOMOBILE, RADIO, TELEVISION and AERO-NAUTICAL ENGINEERING, BUILDING, GOVERN-MENT EMPLOYMENT, etc., and explains the uniqueadvantages of our Employment Department.

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Copyright In all drawings, photographs, andarticles published in "Practical Mechanics"is specifically reserved throughout thecountries signatory to the Berne Conventionand the U.S.A. Reproductions or imitationsof any of these are therefore expressly

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Engineering OpportunitiesTHE recent crisis, now happily over,

I has served the useful purpose ofdrawing the attention of the wholecountry to the great need for skilledpeople in all the creative branches ofindustry, and by this term I am referringnot only to engineering, but to thewoodworking, building, and otherpractical crafts. We must not blindourselves to the fact that this country isshort of skilled people, whilst it is some-what over -weighted with executivepeople who have nothing to execute.I have before remarked that the failiireof the apprenticeship system immedi-ately after the last war has been re-sponsible. No doubt in the wave ofenthusiasm which broke out when thelast war finished, people imagined thatwe had put war behind us for all time.Recent events have shown how mis-placed was that notion and we are nowwarned that we must re -arm on a war-time basis to make our internationaldiplomacy effective. All shades ofpolitical opinion, I think, are agreed uponthat, and I hope I shall not be accusedof raising political issues if I say thatthe first thing we must do is to encour-age people to take up those trades andprofessions upon which rearmamentdepends. If it is our intention toencourage engineering, certain thingsmust be done at once, and not the leastimportant is that the terms of apprentice-ship must be made attractive. I do notregret my own apprenticeship period forone moment, although, compared withmodern conditions, the hours seemmost fantastic. We started work at6 o'clock in the morning, and wefinished at 7 o'clock at night. We couldlegally claim only two days' holiday ayear-Christmas Day and Good Friday.We were not allowed to have holidayswith pay, and a fairly heavy sum hadto be paid to the employer. Thefull term of apprenticeship was usuallyseven years, and the salary was 4s. aweek for the first year, with 2s. annualrise, reaching 16s. a week in the last year.

I do not comment one way or the

PRACTICALMECHANICS

Editor : F. J. CAMM

VOL. VI. NOVEMBER, 1933. No. 62

Fair CommentBy The Editor

other on the fact that to -day we havenot only shortened the working day,but we have shortened the number ofworking days. There are now holidayswith pay, and conditions in all tradeshave improved out of all recognition.No doubt the workshop conditionsprior to this state of affairs neededdrastic remedies, but there is always therisk that the pendulum may swing toomuch the other way. It is, unfortunately,very true that the average youth wishesto start his business career at a highsalary and that he wishes to short-cutthe uninteresting jobs from which hewould gain considerable experience.There seems to be a tendency to encour-age the modern youth to believe that hecan start at the top of the ladder.

We must therefore encourage peopleto become efficient by introducing somesystem which has the advantages of theapprenticeship system and none of thedisadvantages, and we must also demon-strate that the well -paid positions areavailable to those who have madethemselves qualified. If such a systemis introduced, the present tendency toemploy a man because influence isexerted on his behalf, and irrespectiveof his ability, must stop. The soldieris taught that a field marshal's batonreposes in his knapsack. We mustdemonstrate that this is a fact and not apiece of sententious flummery just aform of words without sincerity behindthem. We must also see that from apecuniary point of view the skilledindividual is worthy of his hire.

Conditions have improved but therehas been the risk of improving them tothe point where the public believesthat they must do less work, and thatthe less they do the more they must bepaid.

In the position in which the countrynow finds itself, excellent opportunitieswill exist for many years for those whoassiduously apply themselves to the taskof making themselves capable, and thistask is rendered the more easy now thattechnical institutes and classes all overthe country bring the boon of educa-tion within the means of all. The oldcry that education was the prerogativeof the rich does not apply to -day. Thecountry needs ability and is prepared topay those who can supply it. It is nouse expressing the will to do anything,you must be able to do something reallywell. The man who says he can doanything, can usually do nothing.

Workshop Calculations, Tablesand Formulae

I N a preliminary announcement of mynew book last month, _the price was

wrongly stated as 2s. 6d. This shouldbe 3s. 6d. The book is, of course,bound in cloth, printed on excellentpaper, and is specially designed forfitters, turners, draughtsmen, mill-wrights, foundrymen, tool makers,technical students, and all thoseengaged in the mechanical crafts.

"Practical Mechanics" HandbookNOW that the presentation offer of

the above volume has closed, aspecial bookstall edition has been produc-ed at 6s. Copies are available from orthrough any newsagent, or direct fromThe Publisher, George Newnes, Ltd.," Tower House," Southampton Street,Strand, W.C.2.

Index & Binding Case for. Vol. VI NDEXES for Vol. V are now ready,

price by post 7-1d., and the bindingcase, including title page and index, costs3s. 6d. by post from The Publisher,George Newnes, Ltd., "Tower House,"Southampton Street, Strand, London,W.C.2. I advise all reader to have theirissues bound; loose copies are easilylost, borrowed, or mislaid. The in-formation published in PRACTICAL

MECHANICS is well worth reserving forfuture reference

60 NEWNES PRACTICAL MECHANICS November, 1938

Fig. 1.-This sectionalview of a house shows acomplete Master and

Slave Clock system.

'SI

.21SLAVE

Q CLOCK

? ,littatim

fil

ttl

'........MASTER CL

BATT ERIESIN STAIRCUPBOARD

N 7 he P .M Battery Clock:In Last Month's Issue We Gave A Blueprint And

SL AVECLOCK

SL AVECLOCK y.

This Month We Explain How To Install Slave

_11_2U hta

h

THE Blue Print which we gave lastmonth explained how to make asimple, but most reliable master

battery clock. Many hundreds of theseclocks are already under construction andour preliminary supply of dials was soonexhausted. If you are building the clockyou should obtain one of these dials bysending Is. to the publisher, Geo. Newnes,Ltd., Tower House, Southampton Street.Strand, W.C.2.

The recent crisis brought a large demandfor battery clocks, for it was realised bythose who were using mains operatedclocks that in the event of a cut-off of theelectric mains supply they would have beenwithout a timepiece. In homes where theelectric supply is not available a batteryclock provides a solution to the problemof clock winding, for our clock will runfor at least two years, from one pair of cells.

Unlike the synchronous mains clockwhich cannot easily be adapted for suchpurpose, our battery electric clock willcontrol a number of slave clocks through-out the house, and this month we show how,by adapting some cheap alarm timepieces,you may instal in your home a completeelectric clock system controlled by the onemaster clock, which, once adjusted tocorrect time, will give you accurate timein every room in the house.

The Works of the " Slave "The first thing to obtain is an old clock.

Remove the spring and take out all thecogs except the two behind the face. Fixthe frame of the clock together again andreplace the fingers if these have been re-moved. It will be seen that when the knob,which was for adjusting the fingers, isturned, the fingers move round rapidly andeasily. This constitutes the mechanicalpart of the clock.

A cog wheel must be made with sixtyteeth. This requires some care, but it maybe easily made, provided that the diameter

is large enough. Mark out on a sheet ofbrass or mild steel about 1/16th thick, acircle 3 in. in diameter. With the samecentre draw another circle 2f in. in dia-meter and move this radius lt in. round,marking on the circumference of thesmaller circle. This is divided up ir./ sixequal parts, each of which must be dividedup into ten equal parts. The teeth are cutto the shape shown in Fig. 3, and aretrimmed off by using a three -corneredfile.

When the wheel is complete, it mustbe soldered on to the shaft passingthrough the clock.

The Electric Part of the ClockThe electric part of the clock con-

sists of a powerful electro-magnet.Obtain two carriage bolts, if in., x 1 in.,and file the heads flat. Cut a bracketof soft iron and drill it to take thecarriage bolts. The holes should be1 f in. apart. Fix the bolts in thebracket and wrap them with insulatingtape. Wind the bolts with No. 24D.C.C. wire, packing it on as neatlyand tightly as possible. Cut a stripof spring steel for an armature andleave a small lug projecting so that itmay be screwed on to the back of theclock. Cut the back for the clock fromf in. wood and by means of thebrackets mount the clock in thecentre. (See Figs. 2 and 5.) The endof the armature is bent at right anglesand the end is then bent again at rightangles to form a small hook. A piece ofsoft iron is riveted to the armature stripto aid the attraction of the magnets.Mount the armature so that the small hookengages with the wheel, and mount themagnets so that they will easily attract the.armature. The construction of the stops A(Fig. 2) is clearly shown in Fig. 4. Theyconsist of 1 in. nuts and bolts, with the nutssoldered to the metal brackets, and should

A stout art board dial can be obtained for Is., post free, from the publishers, Geo. Newnes, Ltd..Tower House, Southampton Street, Strand, W.C.2.

be mounted in the position indicated. (SeeFig. 4.) The arm B is a strip of mild steelcut and mounted as the armature. Twoterminals should be fixed on the back towhich the magnet coils are connected.

Testing the ClockTest the clock as follows : Connect

it in series with two dry cells and amorse tapper. Press the key andadjust the stops so that the wheeladvances one tooth each time thecircuit is completed. The spring Bacts as a ratchet and, when thecurrent is switched off, the armaturesprings back and the wheel remainsin its position. It will be seen thatfor each tooth the wheel advances,the finger moves on one minute.This should be tested for all sixtyteeth.

On the spindle of the second fingerof the master clock, fix a contactabout 1 in. long. This may be a pieceof wire twisted round the shaft and

secured with a blob of solder. On the backof the clock an insulated contact is fixed sothat once each minute the two contactsmeet. Solder a wire to the frame of theclock and another to the insulated contactand connect them in series with the clockand two dry cells. (See Fig. 7.) Once eachminute the circuit is completed, and thewheel advances one tooth and the minutefinger travels on one minute. Once the

60 TOOTH ORIPYNG ~ELMVPS MOUNTED ON N/NOTESNAM) SP/LADLE

Fig 2.-A front viewof the slave clock show.

ing the construction.

clock is installed itneeds no attention,except for the occasional renewing of thebatteries.

To finish the clockoff, build a case roundthe " works " anddesign and cut a suit-able face, then stainthe whole a darkbrown.

Any number of these Fig. 3.-The cog wheelclocks may, of course, is cut with 60 teeth.

..-


The" Slave" MechanismInstructions For Making A Master Battery Clock.Clocks, Each Controlled By The Master Clock

be operated from the " Master " clockwhich was described last month, and theonly question is the carrying of the necessarywires from master to the slaves. Thebest arrangement will be found to includeall the slaves in parallel, that is, two wiresare run from the master to the furthestslave, and branches taken from the twowires to each clock as desired.

ChimesIf chiming or striking mechanism is

required, this will most conveniently bearranged on the master clock, or in itsvicinity, although there is no reason whythe master should not be built (without thesmall indicating clock at the top) and in-stalled in a cellar or attic; out of the way,and each room fitted with a slave: In thiscase the striking or chiming mechanismcould be fitted in the required room or in thehall. It is not proposed to give any actualconstructional details at this point forinstalling a suitable chiming mechanism.There are numerous different methods offitting such apparatus, which may beelectrically driven or clockwork operated,the actual mechanism being set intoOperation by electrical means at therequired time.

Westminster chimes, consisting of ordin-ary brass rods clamped to tune to therequired notes, constructed,and the four hammers operated by arotating drum fitted with small projectingfingers or cams. A small electric motorcould be set into operation for this purpose,very little power being required. The smalldry cell would operate this. Alternatively,large diameter brass tubing could be usedto provide heavy churefilike tones, andhammers for these Could be power operat.id,each by a small magnet or motor, theindividual motors or magnets being setinto operation through the medium of arotating contact maker, itself driven by asmall motor.

It should not be difficult to arrange asmall operated wheel on the lines shown inFig. 2, with contacts at the four quarters.The hour -striking mechanism will, of course,have to be separately controlled, owing tothe time taken when chiming the longerhours, unless some scheme can be in-corporated for giving continuous action onthe striking mechanism whilst the minutewheel continues to move.

r/BRE BUSHf "YRS/ft-RS

SOLDERED TOCLOCHFRAME

INSULATEDCONTACT r

WIRECONTACT

SECONDSWHEEL

4.-How the stops are mounted.

Radio InterferenceIt will probably be found that every

time the contacts close in the Master or ,slave clocks a `click' will be heard in theloudspeaker if a radio set is in use. Thismay be prevented by wiring a largecapacity condenser across the actualcontacts. A value of 2 or 4 mfd. will befound quite suitable. This will also pre-vent the points of the contacts frombecoming pitted due to the arc whichtakes place. A lamp may, of course, beused in place of the condenser, but thelatter component is to be preferred.If it is desired to economise on the drainon the dry batteries, these may be dis-pensed with and the clock operated froman ordinary battery trickle -charger. Inthis case a really reliable charger shouldbe used, capable of giving an output ofabout .8 amps at 6 volts. To avoiddamage to the. 'harger due to the backE.M.F. which will take place when thecontacts are made and broken, it isdesirable that an artificial load shall beapplied to the charger. A very usefulload may be adopted by connecting anold accumulator' across the terminals ofthe charger (the cell being filled withacid, of course), or alternatively, a largecapacity mansbridge condenser having acapacity of 2,000 mfds.

ReliabilityOne of these clocks has been in use

HANDS

DIALWHEELS

0144.

BRACHETS

CLOCHFRAME

DRIVINGWHEEL

.;ig. 5.-A side view of the slave clock.

for several years with a trickle chargeras the source of supply with a 2,000 mfd.condenser (12 volt) across it, and notrouble of any kind has been experienced.The contacts have not been touched orcleaned and the trickle charger stillfunctions perfectly. The charger wasactually screwed to the back board of theMaster clock behind the dial and a twin -flex lead is taken from the back of theclock to a mains socket on the wall nearit. Ordinary standard twin -laid bellwire is used for connection between th3various slaves and this is carried in thepicture rail in some rooms and along thetop of the skirting board in other casesand is thus more or less invisible.

Fig. 6.-The master clock which was described lastmonth.

Fig. 7.-Wiring of the master contacts and slave clockmagnets.


Watch Repairingand Adjusting 3

Adjusting the balance and other vitalparts of the watch

THE balance, before being removed,should be thoroughly examined, as itis one, if not the most important part

of the watch. If the balance is not vibrat-ing lead it around sufficiently with thepoint of the tweezers to cause it to vibrate,and watch the action. The balance wheelshould have no " up and down " movementas it revolves, and when viewed from abovethe, wheel should be perfectly circular.Any irregularity in this direction will havean adverse effect on the timekeeping.The type of balance likely to give mosttrouble in this way is the bi-metallic com-pensation type-a balance consisting of twometals fused together, usually brass andsteel, and having the rim cut right throughin two places to allow for expansion andcontraction to counteract changes of tem-perature. Extreme care should be takenwith this type of balance as it is possible tocause distortion even by handling. Fewbalances are so badly damaged that theywill not respond to treatment with a pairof tweezers or brass nosed pliers, but thereis really no cure for a balance which is verymuch out of round ". A new balance isthe only remedy. Fig. 1 shows a plainbalance and a compensation balance.

Curb PinsExamine also the clearance between the

arms of the balance wheel and the bottomof the hairspring stud-the small detachableblock to which the end of the hairspring ispinned-and the curb pins-the two pins

extra long balance screws from fouling itwhen the watch is lying in a dial up position.

EndshakeThe small amount of free space between

the ends of the pivot and the flat surface of

Fig: 1.-A

should be just clear of the other endstone.In some cases it is possible to tell whethera balance has endshake by turning themovement first one way and then the otherway and listening to the drop of thebalance, the sound will be decidedly metallic.With brass set jewels excessive endshakecan be corrected by reducing the shoulderof the brass jewel setting. Whicheversetting is altered will depend to a certainextent upon the position of the roller withthe pallet fork.

Adjusting the JewelsIf the upper disc of the roller is so near

the fork as to be likely to cause friction incertain positions, the bottom jewel must beraised. If the roller adjustments arecorrect the top jewel should be lowered.It is quite possible the jewel screws will notkeep the endpiece tight after such analteration. The" quickest and neatest wayto overcome this trouble is to select a new

compensation balance and a plain balance

the endstones is known as endshake-inthe case of ordinary train wheels betweenthe, shoulder of the pivot and the jewel hole-and correct endshake is an importantcondition in any watch.

Too much endshake is as great an evil asno endshake. Very little of the jewel hole

in the regulator. Little trouble is likelywith curb pins consisting of the two pintype, but the type which consists of onepin and a movable block often called theboot -piece from its shape needs more carefulattention. Fig. 2 shows the two types ofcurb pins. The sole of the boot -piece isoften left too thick, thereby leaving onlyvery little clearance between it and the armsof the balance. As the object of the boot -piece is to prevent other coils of the hair-spring from being caught in the curb pinsthere is no necessity for the sole to be leftthick. It is quite a simple matter to reducethe thickness with a fine file when theregulator has been removed from the balancebridge. Lay the regulator upside down ona boxwood block and turn the bootpiece tothe closed position. Hold the regulatordown with the forefinger, and with thesecond finger as a guide to the safety edgeof the file make one or two forward, cutsuntil the 'thickness has been reduced to aminimum. Re -cut the screw driver slotwith a slitting file if it appears to be shallow.Before replacing the regulator it is advis-able to file off the outside corner of the boot -piece. This will prevent the points of

Fig. 2.-Twotypes of curb

pins.

is actual bearing surface. Should, therefore,there be too much endshake, there will bea tendency for one or other of the pivots tocome out of the bearing hole when the watchis in either a " dial up " or " dial down "position. Apart from the damage likelyto occur to the pivots, the balance wouldhave every opportunity of fouling thecurb pins, the hairspring stud, centre wheeland pallet bridge. Contact with any ofthese would spell disaster. Fig. 3 shows apivot in a jewel hole with the correctamount of endshake. When one pivot isresting on an endshake the other pivot

Fig. 3.-A pivot ina jewel hole with thecorrect amount of

endhsake.

Fig. 4.-A sectionof the pallets and

pallet bridge.

brass -set endstone, place it in a suitablelathe chuck, and turn it to fit, leaving itflush with the plate. Insufficient impor-tance is given to jewel settings, for I amfrequently finding watches with loosebalance and other jewels. It is quite easyto appreciate the amount of friction createdwhen a pivot is rotating in a jewel hole andthe jewel hole itself is moving in its setting.

There should be a reasonable amount ofclearance between the underside of the '

balance wheel and the upper surface of thepallet bridge. As long as daylight can beseen between these two surfaces, it willsignify that they do not touch, but withsuch a small margin, the smallest speck ofdirt or the tiniest hair is quite likely toimpede the vibration of the balance.

The Pallet BridgeTo be on the safe side it is advisable to

reduce the thickness of the pallet bridge.Remove the bridge and place it upon apiece of cork, and with a sharp file carefullyreduce the surface. Exercise great care,for it is easy to bend a delicate bridge ofthis type. Brush away any file dust and

(Continued on page 104)

November, IV.33 NEWNES PRACTICAL MECHANICS 63

THE STORY OF THETELEPHONE

(Left) One of the first desk telephone instruments. TheBlake' transmitter, 1879. (Right) An early telephonewall set of 1878, dubbed "Williams' Coffin I "

THE telephone has behind it a storywhich, in every detail, is peculiar toitself. No well-equipped research

laboratory staffed with professional scien-tists and having at its command all theavailable resources of electrical sciencebrought the telephone into the world. Theorigin of the instrument did not take placeat the hands, even, of any acknowledgedelectrician. Rather, in fact, the opposite wasthe case, for the inventor of the telephonecomprised an individual who had acquiredjust sufficient mastery over electrical theoryto guide him through his necessary experi-mental work, but of chemical and relatedscientific knowledge he possessed but little.

Alexander Graham Bell-the name isnow world famous-was the first' inventorof the telephone, anda rough garret above ashop in the American city of Boston con-stituted the birthplace of the instrument.Bell, whose native city was Edinburgh,having been bdrn there in 1847, hademigrated to Canada with his parents in1870. Quickly he found his way over intothe States and two years later, in 1872, wefind him taking up permanent residence inthe city of Boston.

Speech TrainingBell's father, Alexander Melville Bell,

had developed a system of speech training

Alexander Graham Bell-the Name is Now WorldFamous-Was the First Inventor of the Telephone.

which his son, Alexander Graham Bell,subsequently adapted for use in teachingthe deaf. The latter obtained a lectureshipin Boston University, becoming " Professorof Vocal Physiology," as well as a privateteacher of speech for the deaf.

Graham Bell had for some time beeninterested in electrical matters. His in-genious mind had pondered long over thenature and principles of human speech andthere is no doubting the fact that even atthis early period the idea of transmittingspeech from one place to another by someunknown electrical means had occurredto him upon more than one occasion.

All sorts of curious notions passed throughthe brain of Bell and many of these wereconnected with his hobby of electricity.In 1874, we find him busily engaged duringhis spare time in the construction of whathe termed an " Harmonic Telegraph "which was to be an instrument by means ofwhich he expected to be able to transmithalf a dozen or so Morse telegraph messagesover a single wire.

It was about this time that Bell got intotouch with a skilled instrument -maker,one Thomas A. Watson, by name, who wasthen employed in a Boston electrical shop.Watson, under Bell's direction, put all hisskill and practical experience into the con-struction of Bell's " Harmonic Telegraph "and, in addition, he gave up a considerableproportion of his time to assisting Bell inhis experiments and trials with his tele-graph instruments. Watson, in fact,quickly became Bell's right-hand man.His innate practical ability was most usefulto Bell and the latter, ultimately, regardedhim not as a mere assistant but as a closefriend.

The " Harmonic " TelegraphIt was during the course of some experi-

ments with the unsuccessful " HarmonicTelegraph " that Bell first confided someof his dreams of a working telephone toWatson.

" I have never forgotten his exactwords," Watson wrote years after thedeath of Bell, " they have run in my mind

Bail's "Harmonic telegrafih transmitter ( eft)i and the receiver (righdevices save Bell his idea of the telephone.

Exberimenis with f ese

ever since, just like a mathematical formula.' If,' Bell said, I could make a current ofelectricity vary in intensity precisely as theair varies in density_ during the productionof a sound, I should be able to transmitspeech electrically.' "

Bell then sketched out for Watson somerough ideas of his on the subject of project-ing speech electrically, but they were muchtoo complicated and theoretical in natureto impress the more practical Watson.

Meanwhile, the experiments with the" Harmonic Telegraph continued, much

A side view of the first Bell telephone model, showingthe mouthpiece.

to the discomfort of Watson, who admitsthat he was beginning to grow tired of theunsuccessful device.

The experiments were being conductedin an upper workroom, little more incharacter than a garret, above a shop in109, Court Street, Boston. The attic wasroughly partitioned off, the transmittinginstruments being in one section of theattic and the receivers in another.

One afternoon-on June 2, 1875, to beprecise-Bell and Watson were in the attioat 109 Court Street, Boston, tuning thereceivers of Bell's " Harmonic Telegraphi'apparatus. Watson was vibrating thetransmitter and Bell was listening at thereceivers in addition to tuning the latter.Suddenly Watson heard a shout from Belland immediately afterwards Bell rushedin to Watson. What did you do then ? "he cried. " Don't change anything ! Letme see ! "

What had actually happened was thatBell's " harmonic " receiver had picked upthe transmitted hum of a vibrating reed inthe transmitter and Bell had immediately


been .struck with the fidelity of the trans-mitted note.A Simple Principle

The principle of Bell's unsuccessful" Harmonic Telegraph " was a simple one.A flat metal strip or " reed " was free tovibrate over the iron core of a bobbinelectro-magnet. The vibrational frequencyof the spring or " reed " could be tuned bymeans of adjusting -screws and Bell hadhoped that the transmitted currents froma series of these vibrating reeds would, atthe receiving end, all sort themselves outand each set of currents cause similarly -tuned reeds at the receiving end to vibratein sympathy. It was a clever idea, butBell never obtained any success from it.

On the memorable occasion above men-tioned, the contact point of the " HarmonicTelegraph " transmitter was screwed downupon the flat reed, making, when the reedwas vibrated, not, as in the case of theother pairs of transmitters and receivers,the make -and -break current of telegraphy,but the uninterrupted undulatory currentof telephony. Thus the whole " voice " ofthe reed, including its vibrational overtones,was transmitted. Bell heard, understoodand realised the tremendous importance ofthe received sound.

Within an hour or two, Bell had thoughtout a scheme for building up an electricaltelephone and before he left the buildingthat evening he had given to Watsondirections for the construction of such aninstrument --the first telephone. Watsonwas to mount a small drum of gold -beater'sskin over one of the " Harmonic Telegraph "receivers and to attach the free end of thereceiver -spring or reed to the centre of theskin diaphragm. Finally, a mouthpiecewas to be fixed over the diaphragm.World's First Telephone

This crude arrangement constituted theworld's first telephone. It was tried outbetween the attic of the Court Streetbuilding in Boston and a room two storeysbelow. The first results from the telephoneinstrument were very meagre, but, all thesame, they sufficed to convince Bell ofthe fact that he was on the righttrack in his conception and design of the

atrument.It was not until February 14, 1876, that

Bell filed his application for his first tele-phone patent and, indeed, not until amonth after this date-March 10, 1876-that the first complete sentence was 'in-telligibly transmitted by telephony. Wat-son afterwards recounted the fact that thismemorable sentence took the form of :Mr. Watson, come here; I want you .1-whichwas uttered by Bell.

After Bell's fundamental experimentshad been completed, the telephone devel-oped rapidly. The instrument was ex-hibited at the Centennial Exposition atPhiladelphia in the June of 1876, itsinventor being awarded one of the Exhibi-tion's medals. Incidentally, it is of interestfor us to note that the renowned Sir WilliamThomson, afterwards Lord Kelvin, a greatEnglish electrical pioneer, was Chairmanof the Committee of Judges on this occasion.

In the following August occurred thefirst one-way telephonic transmission ofspeech over any considerable distance. Ittook place between Brantford and Paris,Ontario, a distance of eight miles.Development of the Invention

Bell, at this juncture, had put so muchtime into his experiments that his privatepractice as a teacher of speech and of thedeaf had begun to suffer badly. Heartnears, however. to have given scant

consideration to this fact, for now almostthe whole of his energies were given over tothe technical and scientific development ofhis new invention.

In the February of 1877, Bell began aseries of public lectures on and demon-strations of the telephone. The first ofthese was given to a scientific societyknown as the Essex Institute at Salem,Mass., in which town Bell then resided.Watson, as usual, was his main assistant atthese lectures, being located at the otherend of the telephone line and shouting intothe instrument such phrases as " Goodevening ! ", " How do you do ? ", Whatdo you think of the telephone ? " and so on.Then the faithful Watson would sing intothe instrument, the song being reproducedin the receiving instrument displayed in thecentre of the lecture platform.

These lectures became very popular andBell achieved much fame by them. Lectur-

C. E. Hubbard, Thomas Sanders and theever -available Thomas A. Watson.

On January 28, 1878, the first commercialtelephone Exchange was opened at NewHaven, Connecticut. This served 21 tele-phones by means of eight lines.

Rapid ProgressBell's instruments were crude at the

beginning, but leaving all further develop.ments to the Company bearing his name, helived to witness a rapid and remarkableprocess of evolution in the sphere of tele-phone apparatus and appliances.

At first the commercial telephone had nocalling -up device. You just tapped thediaphram of the transmitter with a penciland awaited results. Next came a buzzercalling device and, after this, the magnetowall -set telephone, an instrument com-prising a long narrow box to which werehooked the telephone mouthpiece and

Telephone transmitter exhibited by Bell at the Philadelphia Centennial Exposition of June 1876.

ing on a scientific novelty, however, wasone thing, but exploiting the telephonecommercially Bell found to be quite anothermatter. Indeed, he took but little interestin the commercial side of his instrument.He was, however, helped in his commercialaffairs by Nil) noted men, Thomas Sandersand Gardiner Green Hubbard, who wereinterested in Bell's work for the deaf aswell as his inventions in electrical communi-cation.

Bell Telephone CompanyThe first Bell Telephone Company was

floated on 5,000 shares, the interest in theCompany being divided up between sevenshareholders, Alexander Graham Bell, Mrs.Bell, Gardiner G. Hubbard, Mrs. Hubbard,

earpiece. These instruments were theinvention of a man named Williams and,owing to their elongated shape, they sooncame to be known as " Williams' Coffins."They were used in conjunction with a handswitch which in one position put themagneto calling -up device into operationand, moved the other way, placed thetelephone circuit proper into action.

" Williams' Coffins were made by thehundreds. After them, came the Blaketransmitter, the invention of FrancisBlake, which gave louder reception andtherefore greatly popularised the earlytelephone system.

It was not until some years afterwardsthat Bell's telephones gained popularity inEngland.

The Handiest Book Yet Published for Draughtsmen, Fitters, Turners,Mechanics, Pattern -Makers, Erectors, Foundrymen, Millwrights and

Technical StudentsWORKSHOP CALCULATIONS, TABLES AND FORMULA

By F. J. CAMM(Editor of Practical Mechanics)

316, or 3/10 by post from Geo. Newnes, Ltd., Tower House, Southampton Street, Strand,London, W.C.2.

Its Comprehensive and Fully Illustrated Contents include:-The Micrometer and Vernier;Mensuration; Trigonometrical Formulae; Extracting Square Root; Extracting Cube Root;Continued Fractions; Arithmetical Progression; Geometrical Progression; Harmonica!Progression; English Weights and Measures; Horse Power; Force, Energy, and Power; Heat,Time, and Velocity; Electrical Units; Comparison of Thermometers; Pulleys; ParallelogramForces; Pendulum; Levers; Centrifugal Force; Moments of Inertia; Metric Systems; ScrewCutting; Tool Grinding Angles; Lubricants for Cutting; Spur Gearing; Tapers and Angles;Bevel Gears; Worm and Worm Wheels; Spiral or Screw Gearing; Pulley Calculations; TheDividing Head; Differential Indexing; The Slide Rule; M.P. Required to Drive Shop Tools;Table or Cutting Speeds; Proportion of Keys and Cotters; Standard Screw Threads; DrillSizes; Circle Spacing Table; Tapers and Angles; Melting Points of Metals ; Weights ofMaterials; Twist Drills for Wood Screws; Wood Screw Proportions; Weights of Woods;Powers and Roots of Numbers; Wire and Sheet -Metal Gauges; Natural Sines, Cosines andTangents; Logarithms and Antilogarithms.


AT IC MECHAN

Dr. A. 0. Nier of Harvard University, with the most delicate atom "sifter" known to science. Theapparatus which he recently perfected is technically known as a mass spectrometer, and is designed todetect the presence of rare isotopic forms and to give the most accurate measurements ever made of therelative abundance of different isotopes present in an element. By using this atom "sifter" in the studyof the lead atom scientists may be able th exteni their knowledge of the earth's history back farther

than ever before.

RUTHERFORD was led to the Nu-clear Theory of the Atom by theexperimental study of the deviations

suffered by high energy alpha -particleswhen they were projected into atoms, atheory which was clearly pointed to by theaccumulated results of the research in thisbranch of physics carried out during thefirst ten years of this century.

The high speed alpha -particles wereprovided by various radioactive elementswhich ejected them during the spontaneousbreaking up of their atoms, and theirdeviations in transit through thin metallicfoils were measured by observing the pin-point flashes of light made by the impact ofthe alpha -particles on a screen of zincsulphide. The two outstanding facts re-vealed by these observations were that onlya small percentage of the alpha -particlesfired into the foils underwent any deviationat all, but that amongst this minority therewere some which were scattered throughsurprisingly large angles. This suggestedthat the atom is a highly porous structurewith the majority of its mass concentratedin some very small region, enabling most ofthe alpha -particles to pass straight through,while a select few made glancing or directhits on the concentrated mass, being widelydeflected as a consequence.

Central NucleusIt was conjectured, therefore, that the

great majority of the mass of the atom iscollected together in a very small centralnucleus which also contains all the positivecharge of the atom, and that this nucleusis surrounded by a distribution of electronsmoving in relatively immense orbits, theirnumber being just sufficient to make thecomplete atom electrically neutral. Onegrave difficulty involved in this theorybecame immediately apparent. In order to

O / 2

maintain the distance of separation betweenthe negatively charged electron and thepositively charged nucleus against their

ins -aBy R. L. MAUGHAN,

M.Sc., A.Inst.P.

be considered to be in a state of continuousmovement in an orbit round the nucleusto give it the outward centrifugal forcenecessary to counter -balance the inwardelectrostatic force. Such a motion in acurved path implied, from classical 'theoryconsiderations, that the electroft must bein a state of continuous radiation so that itmust eventually radiate away all its energyand disappear completely- On this hypo-thesis, therefore, the atom seemed doomedto instability.

A solution to the problem was offered byNiels Bohr in 1913. Its brilliancy can bejudged from these facts : in a single strokeit preserved both the nuclear theory andthe notion of atomic stability, by boldlyapplying the oinantum theory to atomicmechanics (a hypothesis which was rela-tively new at the time and distinctly revo-lutionary in its concepts); it gave a simpleand convincing elucidation of the quantityof apparently unrelated spectroscopic datawhich had gradually accumulated duringthe preceding fifty years; and it provideda working model of the atom which washighly successful in accounting for new,facts which were discovered in the subs.-quent ten years.

Hydrogen Line SpectrumIn formulating his theory Bohr was

guided by the prime consideration that insome way the number and order of the linesin a spectrum are related to the arrange-ment and behaviour of the particles in theatom. The internal mechanism of the atom

Exploring the Structure andInternal Mechanics of the Atom

mutual force of electrostatic attraction, andto prevent the atom from collapsing intopractically no size at all, the electron must

irm..4n/ fewas53 4

St41E /4, /00,000,000Ar. Of CENT/AMT.9E

Fig. 1.-Diagram to scale of the original Bohr model ofthe atom showing the possible electron transitions betweenorbits giving rise to the Paschen, Balmer and Lymanseries of spectra. Only the first five orbits are drawn.

is clearly responsible for the emanation .fthe light since an analysis of this light bythe spectrometer shows that the same linesare always produced by the same atoms,and that every element has its own charac-teristic emission spectrum. A single spec-trum line is discussed in terms of its threeproperties, intensity, polarisation, andposition (wavelength of frequency), and acomplete spectrum in terms of the regular-ities in the distribution of the lines. Asuccessful atomic theory, therefore, has toexplain both the law of arrangement and theindividual characteristics of the lines.Bohr's first task was to explain the law ofarrangement in the simplest of all spectra,the hydrogen line spectrum.

The relative simplicity of the hydrogenspectrum had already attracted the atten-tion of several investigators, and as earlyas 1884 Balmer had established an empiricalformula which expressed as a mathegpaticalseries the wavelengths of certain outstandinglines in the visible part of the spectrum. Alittle later, Paschen evolved a similar for-mula for a series in the infra -red, and Lymanproduced one for the ultra -violet. All ofthese formula) are contained in the singleexpression f =--R.(et -di) where f representsthe frequency of a particular line in aspectrum, n and m are suitably chosenintegers (1, 2,* 3, etc.), and R is someconstant quantity. As this formula was


purely empirical, an equation deliberatelymanufactured with the sole purpose offitting the experimental facts, nothing muchwas known of its ultimate nature other thanthe fact that it always remained constant.

Bohr's TheoryBohr based his theory on two funda-

mental assumptions whose only justificationwas that by means of them the above formulacould be deduced from theoretical con-siderations, enabling an almost completeexplanation of spectroscopic data to bemade in terms of the nuclear atom modelreinforced by these two assumptions. Heasserted that first of all the electrons in theatom could only exist in those orbits inwhich the angular momentum is an integralmultiple of the quantity haw, where h isthe universal Planck constant of action,and that they rotated in these orbits with-out emitting or receiving any radiation.Secondly the emission or reception ofradiation by the atom occurred only whenan electron made a transition from oneorbit to another; when the electron passedfrom one orbit to one more remote from thenucleus the atom absorbed a quantum ofradiation, when it passed from an orbitto one nearer the nucleus the atom emitteda quantum.

It became immediately possible, by theapplication of these quantum assumptionsand the well established principles ofparticle mechanics to the whirling electronsand the central nucleus, to calculate withprecision the, diameters of the variouspossible orbits which this theory permittedand so to draw on a large scale a picture ofwhat the actual atom was envisaged to be.like. (See Fig. 1) In the simplest of allatoms, that of hydrogen, a single electronrotates about a single proton which servesas nucleus. Its possible orbits form asystem of circles concentric about thenucleus whose diameters are proportionalto the squares of the integers, so thatpassing from the nucleus outwards suc-cessive orbits have diameters which arerespectively proportional to the numbers1, 4, 9, 16, etc. The figures which give theactual orbit sizes and electron velocitiesare somewhat staggering and are practicallyimpossible to appreciate fully in theimagination. For example, the calculatedvalue of the diameter of the innermostorbit of the hydrogen atom is 0.0000000333centimetres, and the electron in it performsjust over two thousand million millionrevolutions per second, moving with aspeed of just under 70 million centimetresper second, (approximately 432 milesper second). The calculated values of theenergy changes in the atom whichaccompany the transitions of an electronbetween these various orbits agree exactlywith the observed frequencies of theemitted light expressed in the formulae ofLyman, Balmer and Paschen, and thisclose correspondence between theory andexperimental fact amply justifies thearbitrary assumptions upon which thetheory is founded.

Newly Discovered FactsNot only was the Bohr atom found to

account for spectroscopic phenomena whichhad been observed before the advent of thistheory, but it also lent itself, after furthermodification, to the explanation of newlydiscovered facts. "A spectrometer of highresolving power shows that each apparentlyindividual line in certain spectra has amultiple structure, consisting of a series ofexceedingly fine lines grouped very closelytogether, so closely that an instrument oflow resolving power would interpret the

whole group as one single line. In orderto account for this multiple structure itbecame necessary to introduce extraorbits into the atom model other than thecircles, so that the transition of an electronbetween one of these new orbits and acircular one involved an energy changesufficiently small to explain the smalldifference in frequency between the linesof fine structure m one group.

The resemblance in design between theBohr atom and the orbits of the planetsabout the sun in our solar system, suggestedthat elliptical orbits were possible in theatom, and after more exact considerationsSommerfeld in 1916 modified the Bohrmodel by introducing the elliptical orbitscalculated to account for the fine structureof the hydrogen spectral lines. Thus beganthe era of precise atomic pictures, a periodof approximately ten years during which theatom of every known element was repre-sented by a drawing made to scale of asystem of circular and elliptical electronorbits arranged about a central nucleus.The eventual downfall of the Bohr-Sommer-feld theory by the advent of Heisenberg'sQuantum mechanics and Schrodinger'sWave mechanics in the years 1925, 1926,carried away with it the notion of precise_atomic pictures, for it has been found thatthe effect of an electron rotating about thenucleus of an individual atom cannot berepresented by a definite circular or

14r 14z I-:.

4

SCALE In /00,000,000 OF 4 CENT/METRE

Fig. 2. Diagram to scale of Bohr-Sommerfeld atommodel showing the fourth circular orbit and its three

associated elliptical orbits.

elliptical path drawn about a definite pointas nucleus.

Sommerfeld's MethodSommerfeld's method of computing the

necessary elliptical orbits is based on theidea that each circular orbit has associatedwith it a series of ellipses whose major axesare equal in length to the diameter of thecircle, and whose minor axes are certainfractions of this diameter. Thus the secondcircular orbit is associated with only oneellipse, whose major axis is the same asthe circle's diameter and whose minor axisis half this diameter. The circle is denotedby the symbol 22 and the ellipse by 21, thesuffixed number referring to the lengthof the minor axis. The fourth circular orbitfor example has three ellipses associatedwith it, denoted by 43, 42, 41 respectivelyto indicate that all the ellipses have amajor axis of 4 units (equal to the circle'sdiameter), and successive minor axes ofone third, one half and one quarter of thisdiameter. The nucleus of the atom servesas the common centre for all the circles

and a common focus for all the ellipses.(See Fig. 2).

A further refinement was introduced intoatomic mechanics by Sommerfeld by theapplication of Einstein's Relativity lawof variation of mass with speed to the elec-trons moving in circular and elliptical paths.The variation of the mass of a moving bodywith its velocity is perceptible only at veryhigh speeds, and the enormous speeds oforbital electrons in an atom are sufficientlyhigh for this purpose. The calculateddifference in the mass of an electron movingin a circular and in an elliptical path isjust sufficient to account for the minutefrequency differences which characterisemultiple structure of spectral lines.

The Quantum TheoryAlthough the quantum theory of atomic

mechanics was ushered in with such strikingsuccesses, there gradually appeared amongstits many achievements certain weaknesseswhich when probed and examined with themeticulous care which always attends theunfolding of scientific theory, led to itsultimate downfall and abandonment.

In 1925 the problem was taken up byHeisenberg, Schrodinger and their col-laborators. They based their New QuantumMechanics on the fact that matter andenergy exhibit a dual nature inasmuch asany particle of matter can be representedas a wave of energy, and any wave ofenergy as a particle. This theory hasflourished during the last decade and at thepresent time almost all chemical andatomic phenomena can be explained interms of the behaviour of extranuclearelectrons. Nuclear theory is still incomplete,but it is believed that when an understandingof inter -particle forces is arrived at, theapplication of the quantum theory mightsolve the problem of the nucleus.

SLEEVE , VALVES FORAERO ENGINES

A New British Engine Achievement

THE sleeve -valve engine, familiar tomotorists, has now taken to the air.

When the new long-range flyingboats of Imperial Airways go out on theEmpire air routes and on to their specialduties on the Atlantic, Tasman, and Pacificroutes, the quiet hum of their engines willbe the announcement of a new achievementin British transport engineering.

Every country in the world has attemptedto translate the advantages of sleeve valvesto standard aero engines.

Britain-through the Bristol AeroplaneCompany-has succeeded.Commercial Air Transport

The new Imperial flying boats-identicalin appearance with their 30 sisters on theroutes to Durban and Sydney, butstrengthened to lift an extra six tons-willbe fitted with four Bristol Perseus XIIomotors.

They have been specially developed foruse in commercial air transport.

Together they muster 3,560 h.p. for thetake -off of the new flying boats, and eachis internationally rated at 680/710 h.p. at2,500 revolutions per minute at 4,000 ft.Advantages

Their advantages are many. Theyeliminate valve maintenance; the numberof parts is amazingly small compared witha poppet engine; they effect a substantialreduction in fuel consumption; they lessenmechanical and exhaust noise; and they areextraordinarily simple.


ECK EIS F P L IS MAThe Art Of Preparing Different Kinds Of Polishes Explained For The

Benefit Of The Handyman And The Small Manufacturer

THE traditional beeswax polish soextensively used in former days onfurniture of all kinds has many

virtues, so much so that it is still employedregularly as a nourisher and preserver of oldfurniture in many of the old homes ofEngland.

On modern furniture, however, the purebeeswax polish, which is made simply by

Polishing cloths. Here is shown the making of one ofthe well-known" polishing cloths," as described in this

article.

dissolving beeswax in warm turpentineuntil a pasty mass is obtained, is not sosuccessful. The polish is a soft one, and,particularly on the smoothly shellacked andsynthetically -finished furniture of moderndays, it is apt to fingermark badly. Bees-wax polish is a relatively expensive prepara-tion. Moreover, it is not an antiseptic one.Furniture treated with it and allowed tostand in damp situations or in damp climatesis liable to attacks of the furniture mite,that pin -head -sized little white creaturewhich, although harmless in itself, iscertainly obnoxious, since it feeds upon thewax on the furniture under conditions ofdamp, and often appears in large numbers.

An All-round PolishAnd all-round 'polish for all types of

furniture, except, of course, the French -polished varieties, can be made by dissolvingequal quantities of beeswax, paraffin waxand grey carnauba wax in a mixture ofequal quantities of turpentine and whitespirit.

The two latter liquids should be placedin a glass jam jar, or similar vessel, whichis heated by being immersed in a pan ofwater. Care must, of course, be taken tosee that the turpentine does not catch fireduring the heating process, but, using asmall gas -ring for the purpose, there willbe very little danger of this occurring, whilstthe employment of a domestic electricstove or immersion -heater will entirelyeliminate this slight risk of fire.

After the turpentine -white spirit mixture .has been made hot, about one-third of its

weight of a mixture of the three above -mentioned waxes, finely shredded, areadded to the liquid, portion by portion, withconstant stirring.

Colouring the WaxIf it is desired to colour the wax, this can

be done now by adding a small quantityof any suitable wood stain dissolved inmethylated spirit. The spirit solution ofthe dye should be a concentrated one sothat very little of the, solution need beused.

Finally, in order to render the waxpolish antiseptic, mould and insect -proof, itis a good plan to add to it at this stage ateaspoonful or two of zinc oleate. This willdissolve at once in the warm liquid andwill render the preparation highly antiseptic.Similarly, barium oleate, zinc or bariumnaphthenates, or the synthetic chlor-naphthalene wax manufactured by ImperialChemical Industries, Ltd., and known as" Seekay wax," will, when added to theliquid in small amount, confer high anti-septic properties on the wax preparation.

If cheapness is an asset in manufacturingthis wax preparation, the turpentine -whitespirit mixture may be " let down " withhalf its bulk of paraffin oil and a few dropsof eucalyptus oil and/or methyl salicylateadded to disguise the smell of the paraffin.

On cooling, the wax will set to a plasticmass. It is economical in use, for a littleof it can be made to cover a relatively largearea of furniture, the paraffin wax ingredientof the mixture having good " spreading "properties and the carnauba wax componentconferring hardness upon the surface filmof wax which is thus laid upon the wood-work.

The above composite wax preparationwill not fingermark, unless, of course, it islaid upon the woodwork surface excessivelythick. It will not grow mould or encouragemites or other insects.

By increasing the quantity of waxingredients dissolved in the mixed liquids, a

A novel polishing liquid. Emulsified wax, preparedaccording to the directions given in this article.

wax almost as stiff as bootpolish car beobtained. This is preferred by some, sinceit can be brushed on to the woodwork.

Polish for WoodworkQuite a new polishing preparation for

woodwork of all kinds is emulsified wax.This has the advantage of being cheapand adaptable.

To make it, obtain an ounce of TurkeyRed oil and add it to a pint of hot water,stirring the liquid well. Now, add a fewdrops of ammonia until the liquid smellsstrongly of the alkali. Finally shred intothe liquid about half an ounce of the waxwhich it is desired to emulsify-paraffin

Making the well-known beeswax turpentine polish.

beeswax, or carnauba, or a mixture of thesewaxes, and then boil the liquid for aboutone minute.

The liquid must now be allowed to cooland it is essential that it be rapidly stirredall the time it is cooling. When cold, filterthe liquid through cloth in order to removefrom it any hard lumps of excess wax. Amilky liquid will result, the milkiness beingdue to the presence of innumerable globulesof wax suspended in the water.

Emulsified wax of this nature is simplybrushed on to the furniture and woodworksurface and the water allowed to evaporate.A very fine film of wax will be left behindon the woodwork surface and, on beingrubbed over with a soft cloth, it will giverise to a high polish.

This type of emulsified wax polish i.;very suitable for covering carved pieces ofwoodwork, since the wax, being in emulsionform, can obtain access to the smallestcrevice of the woodwork. It is also ofvalue for using as a grain or wood fillerbefore shellac -polishing woodwork.

Shellac PolishesShellac polishes for wood are easily made.

Orange shellac is dissolved in warm methyl-ated spirit until a thick solution results.This forms the common " button " polishwhich is applied thinly to the woodwork


surface with a soft rag or a brush. Shellacpolishes may, of course, readily be colouredby adding to them small amounts of spiritsoluble woodwork stains dissolved inmethylated spirits.

Much use is made of shellac polish forfurniture in modern times, for it is hard,inexpensive and easily applied. At thesame time, however, if the polish is laid ontoo thickly, an " over -gloss " effect isobtained, the woodwork being renderedsticky or treacley-looking.

Cellulose polishes are nowadays beingintroduced for woodwork of all kinds.They are, actually, perfectly colourless andtransparent lacquers which, drying with ahard film, preserve the natural appearanceof the wood. For this reason, therefore,they are being used a good deal in the surface finishing and polishing of " limed,"light-coloured and unstained woods.

A good cellulose polish may be made bydissolving clean scrap celluloid in amyl orbutyl acetate. The liquid may, if desired.

can be given a bright green, a scarlet or anyother highly coloured glossy finish. Thecellulose polish is also applicable to metal-work of all kinds, provided that the surfaceof the latter is reasonably clean and grease -free.

For polishing, or, as the term is, " reviv-ing " French -polish surfaces, such as thecases of pianos, the following preparationis an excellent one and is, in fact, identicalin composition to many of the present-day" polish -reviver " preparations :Vinegar (or dilute acetic acid) ... 6 part,,White spirit l j

To every pint of this liquid add onesaltspoonful of best eastile soap powder andan equal amount of French chalk. Alsoadd two or three drops of shellac varnish.

The above " reviver " is used by beingrubbed over the polished woodwork surfacewith a soft rag, the rubbing treatmentbeing finished with a dry cloth. The reviverpreparation must be well shaken in itsbottle before application to the furniture,

Cellulose polish. Shredding scrap celluloid preparatory to dissolving it in amyl -acetate for thepreparation of a glossy cellulose polish.

contain a third of its volume of acetone,which will cheapen production somewhat,but this proportion of acetone must not beexceeded, otherwise the polish film will drytoo quickly and produce an objectionable" bloom " on the woodwork surface.

After the solution of the celluloid in theamyl -acetate or mixed solvents is complete,add to the solution castor oil at the rate ofhalf a teaspoonful of the latter to everypint of the celluloid solution. This additionis essential, since the castor oil preserves theflexibility of the cellulose film.

Tile celluloid or cellulose solution, whensuitable for woodwork polishing, shouldhave the consistency of varnish. It isrubbed on to the wood surface with a softrag or' by means of a brush. Two hourswill be necessary for its complete drying andhardening. If desired, a second coat of thepolish may be applied.

Dyeing the PolishNovel effects may be obtained on wood-

work by dyeing the polish with brilliantcolours. This is simply effected by addingto the celluloid solution a small quantityof methylated or surgical spirit in whichsome spirit -soluble aniline dye has beendissolved. In this way, white woodwork

for its ingredients do not mix together." Polishing cloths " are favoured in many

households for polishing woodwork, metaland other objects. They are readily madeby soaking ordinary woollen cloths in asolution of 4 parts of soap in 20 parts ofwater, about 2 parts of jewellers' rougebeing added to the solution. The cloths,after immersion in the liquid, are lightlywrung out and allowed to dry without heat.For many uses, these give excellent results.

Metal PolishesMetal polishes are, of course, legion in

the modern world. Intrinsically, theyconsist of a suitable abrasive materialmixed with an oily liquid. For instance, anexcellent liquid metal polish can be preparedby adding 10 parts of talcum powder orkieselguhr (infusorial earth) to 100 parts ofwhite spirit containing a little ammonia.A few drops of a " perfume " such as methylsalicylate (oil of wintergreen) can be added,if desired, in order to disguise the odour ofthe white spirit.

Metal polishing pastes may be made bysaturating 8 parts of kieselguhr with 2 partsof white spirit and by adding to the resultantpaste a small quantity of thin lubricatingoil and a trace of soap powder. A drop or

two of nitrobenzene added to this prepara-tion will impart to it the odour of manycommercial metal polish pastes. Needlessto say, the ingredients of the preparationmust all be well mixed together.

PowdersPolishing powders for metal objects

frequently consist of pure magnesiumcarbonate mixed with one quarter of itsbulk of jeweller's rouge. Alternatively, amixture of common whiting and Venetianred (equal parts) can be used.

" French polish " is, of course, notmerely the name of a special type of shellacpolish. Rather, it is the description givento a method of applying shellac polish towoodwork, a method which calls for muchskill and experience, and one which cannotbe successfully attempted by the uninitiatedamateur.

Boot polishes are, for the most part,mixtures of equal quantities of carnaubaand Japanese waxes, the mixed waxesbeing dissolved in about five times theirbulk of turpentine or turpentine -whitespirit mixture, lampblack being stirred intothe liquid as it cools down. In place oflampblack, various dyes and stains may beadded for the preparation of non -blackshoes polishes.

HIGH-SPEED MARINEENGINE

THERE is always a demand amongmodel boat builders for a reliable,

efficient and well -constructed steam engine,and the "Eclipse" engine shown herewithfills all these conditions. It has beendesigned by men of practical experienceand fully tested out before the final designwas decided upon. The engine is suitablefor boats of good lines up to 3ft. long wherea good turn of speed is required. Suitableboilers for this engine are the Twin DrumMinor and the Streamlinia type.

The engine is made throughout of hardbrass castings and non -rusting material,has long and properly fitting bearings andlarge capacity displacement lubricator.The height to the top of the cylinder is31 in., and the base measures 2in. x 'fin.The direction of rotation of the engine canbe revert el by adjusting the eccentric by thegrub screw. Each engine is thoroughly testedunder steam at working pressures from201b. to 751b. per square inch. It weighsl3oz., and costs 18s.

The -Eclipse model marine engine.


Tricks WithSimple and Amusing Tricks can bePerformed with Bottles which havebeen Specially Constructed. ThisArticle tells you how they aremade and Adapted for Various

Tricks

THE simplest form of conjuring trickwith a' bottle for which nothing in theway of mechanical apparatus is

necessary consists of making 'one or twosilk handkerchiefs disappear and re -appearinside a glass bottle which has previouslybeen shown empty and corked.

The trick is done by exchanging the emptycorked bottle for a duplicate bottle con-taining handkerchiefs identical, with thoseto be vanished. The bottle being of trans-parent glass must, of course, be covered insome way while the trick is done and theobvious way is to wrap it in paper. Undercover of this wrapping process the emptybottle, is exchanged for the full one as shownin Fig. 1. The bottle- containing the hand-kerchiefs is laid on the table and a -sheet ofpaper placed over it, the back part of thepaper being curled slightly the better tohide the bottle. There is a bag on a lightmetal frame attached to the back of thetable and hidden by the cloth.

A Duplicate BottleThe visible bottle having been shown

empty and corked, it is held in the righthand as the table is approached. Theperformer then makes a sweeping movementwith the hand holding the bottle, at thesame time lifting the back edge of 'thepaper as though to wrap up the bottle.Actually he lifts the hidden bottle under thepaper and, as his right hand comes behindthe paper he drops the empty bottle into thebag and continues the movement, wrappingup the hidden bottle. (Fig. 2.) The wholething is quite simple and needs practisingonly to give confidence so that there shallbe no hesitation. Small bottles should beused, such as those used for olive oil, andthe wrapping up movement should bedeliberate and quite leisurely.

-The vanish of the handkerchiefs can bemanaged by any of the methods given inprevious articles of this series.

Fig. 1.-A duplicatebottle concealed behindpaper

Elott lesorman untor

(The Well-known Conjurer of"Maskeyne's Mysteries")

Further Articles on the Secrets ofConjuring will appear Regularlyand Exclusivey in this Journal

Fig. 3.-A hollow bottle of metal haying a compart-ment at the top for holding liquid, and a loose bottom.

The same method of exchanging onebottle for another can be used to producedifferent effects. For instance an emptybottle could become filled with any kind ofdrink chosen by the audience. To do this,have the hidden bottle filled with, say, Stout.Show a duplicate empty bottle and do thewrapping up exchange, giving the fullbottle to someone to hold. Now ask theaudience to call out the names of things

Fig. 2.-Empty bottle dropped into bag behind tableand full one wrapped up in its place.

they like to find in bottles. Whatever iscalled out you write the word " stout "down every time, using a different slip ofpaper for each word. After about a dozendrinks have been called out, among whichsomeone is certain to name stout, spread outthe papers, writing side down of course,and ask the person holding the bottle totake one. The result when he finds thebottle he has been holding full of the drinkhe has chosen will be both surprising andeffective.

Fig. 4.-A pair of trick bottles made of metal. Bothare hollow and the inner one has a partition justbelow the shoulder so that liquid may be poured from

the upper part.

A Card TrickAnother type of trick in which the bottle

is not prepared is that in which a chosencard appears standing on the neck of thebottle. The card is forced as described inmy article on card tricks and a duplicateof this card is attached by a clip to a wirearm operating on a spring at the back of thetable as shown in Fig. 6. The wire arm isbent to the shape of the bottle and whenreleased swings out and up from the back ofthe table, bringing the card into position onthe top of the bottle. The bottle is placedin a previously marked position at the backof the table and, the card having beenvanished, or burned, the catch is released bypulling a thread and the card duly appearson the bottle.

Another method of producing the sameeffect is explained in Fig. 6. Here the cardis concealed under the label of the bottle.The label is steamed off and stuck on againby its edges, forming a pocket into which thecard will slip. A small screw eye is driveninto the cork and a length of fine blackcotton is led through the eye, attached toone of the short sides of the card which isthen tucked into the label pocket. Theother end of the thread can be in the handsof an assistant who gives it a sharp pullon the given signal, or it may be tied to asmall lead weight supported at the back.edge of the table just behind the bottle.The performer then causes the card toappear by picking up the bottle, tipping theweight off the table which causes the card tofly up to the neck of the bottle. In this


case the movement of the bottle helps todisguise the flight of the card.

Prepared BottlesNow we come to specially prepared bottles.

Fig. 3 shows one type. It is made of metaland has a loosely fitting bottom. The bottleis filled with rice or bran and the bottomplaced in position. By slipping a fingerunder the bottle as it is picked up the bottomis held in position and the bottle may befreely shown. It is then placed on a trayand covered with a paper tube. When thetube is lifted the bottle is picked up with itand the rice or bran gushes out in a heap,covering the loose bottom. The hollowbottle is disposed of into a bag behind thetable while attention is drawn to the trans-formation and the tube can then be tossedfor inspection.

At the outset the two bottles, nestedtogether, stand on the table with a glassinside. Two paper tubes are shown andone is placed over the nested bottles. Thistube is instantly removed and the othercover placed on the bottle, to show thateither cover will fit. Actually when thefirst tube is removed the outer shell bottleis brought away with it. The inner bottlewith the glass inside is now left coveredby the second tube and the presumedempty tube is placed over another glasson the other side of the stage. The stateof affairs is now as shown in Fig 6. A is theouter shell covering a glass,- B is the innerbottle also hiding a glass, both being coveredby paper tubes. The performer is now in aposition to show either a bottle or a glassunder either tube and the trick of makingbottle and glass change places could berepeated as often as desired. Actually it isbetter not to make the change more than

PAPER TUBE PAPER TUBE

OUTER SHELLBOTTLE

GLASS

IIIIIIA.11111,111111111111111

Fig. 5.-A card concealedin pocket formed by label.

An improvement on this type of bottleconsists in having the upper portion of thebottle made into a watertight compartmentto contain a glassful of liquid which can bepoured out before the change and so addto the conviction that the bottle is real.All that is needed is a disc of metal solderedinto the hollow bottle just below theshoulder. This is just visible in Fig. 3.

A simpler method of making a bottle ofthis kind is to turn the neck and shoulderfrom solid wood and make the lower partfrom sheet metal. The neck can then bedrilled out and a metal tube inserted tocarry a small quantity of liquid.Different Effects

This trick bottle also is amenable tovarious kinds of treatment to producedifferent effects. For instance instead offilling the hollow space with bran a miniaturebottle may be placed inside and the largebottle shrunk by placing the cover on. Oragain the large bottle may be convertedinto three or four little ones or it may betransformed into some totally differentobject such as an apple. In this case a ciderlabel on the large bottle will provide anelement of logic for the trick.

Fig. 4 shows a further development ofthe hollow or shell bottle principle. Herethe bottle with compartment for liquidas already described is fitted with an outershell bottle. This outer bottle slides easilyover the inner one and it is of course hollowthroughout. The two bottles are usuallyemployed for a trick known as the PassePasse Bottle and Glass. The effect in thiscase is that of causing a bottle and a glassto change places.

INNER BOTTLEWITH SPACE FOR

GLASS

1.1,111111 111111 'R11111111111 1111111011321111.

twice and finally leave the inner bottlevisible, having the outer bottle inside oneof the tubes. This outer bottle can then bedisposed of by permitting it to slide overthe inner bottle as the latter is picked up.A Watertight Compartment

The watertight compartment in theneck of the inner bottle permits of liquidbeing poured from this bottle during thetrick and each bottle has a hole about thesize of a shilling at the back an inch or sofrom the bottom through which the secondfinger may be placed to press the concealedglass against the inside of the bottle whenpicking up the shell.

With the same pair of bottles and anappliance for changing one article foranother, an entirely different trick can beperformed. In my own performances I usean opera hat fitted with a hinged partitionpreviously described in this series butillustrated again here for the sake of com-pleteness. The trick is a sort of GeneralPost effect. A bottle is placed on onetable and covered with a paper tube.Another paper tube has a couple of silkscarves tucked into it while a few handfulls

..s."11101

/7's:

BASKETOF BALLS

TWO SCARVES

HAT WITHSWING OVERPART/T/ONDUPLICATESCARVES /NONE SIDE

CATCH

CARD

WIRE ARM BENT \TO SHAPE OF \BOTTLE

SPRING HINGE

_ - -

Figs. 6 and 7.-(Above) A hinged spring amtcarries card to top of bottle. (Left) In this effecta bottle and glass are made to change places.

of little coloured balls axe poured into thehat. On the word of command the bat isturned over and the two scarves drop out,the balls having vanished. The tube intowhich the scarves were tucked is lifted andthere is the bottle. The other tube whichwas originally placed over the bottle is thenpicked up and out fall the missing balls.

At the start of the trick the two bottlesare nested and the inner one is filled withthose soft, coloured balls sold for throwingabout at carnivals. The loose bottomshown in Fig. 3 is placed in position. Twoscarves are laid over a chair and two dupli-cate scarves are tucked into the hat on oneside of the partition which is then swungover to hide them. The disposition of thearticles is shown in Fig. 8.

Nested BottlesThe nested bottles are first picked up,

the loose bottom being held in place by afinger crooked underneath, and placed ona table to the performer's right where thereis a small tray to receive them. The two

NESTED TWO CARDBOARDBOTTLES W TH TUBES TO FITBALLS INSIDE OVER BOTTLESINNER BOTTLE

Fig. 8.-The apparatus arranged for a "general post" trick.

November, 1938 N EWN ES PRACTICAL MECHANICS 71

INNER BOTTLE

CARDBOARD TUBE

STACK OF WOODEN D/SCS

PIECE OF GLASS

CARDBOARD TUBE

OUTER SHELL BOTTLE

III IP III 1111.111111,

Pg. 9.-The penetrating bottle.

covers are placed on as in the Passe Passebottle and glass trick already described,the outer bottle being removed in onecover while the second one is left over theinner bottle.

Going to the left side of the stage, theperformer picks up the two scarves andtucks them into the tube he holds in hishand, where of course they go inside theouter shell bottle. The tube is then stoodon a table. The hat is then picked up,shown empty with a sweeping movementand the balls poured from the basket into thehat.

To produce the effect, the partition inthe hat is swung over and the scarvesallowed to flutter out. The cover is liftedfrom the bottle on the left, revealing thebottle in place of the scarves. Finally theright-hand tube is picked up and the missingballs roll out. The whole trick should beworked fairly rapidly and the covers carriedoff as the performer makes his exit at theend of the trick.Another Trick

Another totally different 'effect, alsousing the two nested bottles is as follows :

A'bottle is placed on a disc of glass ontop of a cardboard tube previously shownempty. Another tube is placed over thebottle. The upper tube is lifted and thebottle has vanished, to be found in thelower tube, having apparently passed cleanthrough the glass.

Here again the trick starts with the twobottles nested. The cardboard tubes areshown empty and placed one after theother over the bottles as before. The firsttube is removed with the outer bottleinside and on this is placed the glass. Theinner bottle is stood on the glass andcovered with the second tube. Fig. 9.The trick is now virtually done as all thatremains is to lift the top tube and with itthe bottle, remove the glass and lift thelower tube, revealing the outer bottle.

The trick gains in effect if the spaceInside the inner bottle is occupied by astack of coloured discs of wood or a handfulof sweets, which appear in place of the

bottle in its supposed journey through theglass. I frequently performed this effect atMaskelyne's with a story about a partybeing given in a first floor flat. During theparty a rich but teetotal auntie called. Thepeople instantly sent the drinks downstairs,as illustrated by the passage of the bottleto the lower tube, and pretended to beplaying draughts as shown by the discs.Thus everything was perfectly all right,but " the people downstairs got the beer. "

A totally different type of trick with abottle is that in which the bottle is heldupside down and dropped into a papertube. The tube is lifted for a moment show-ing the bottle resting neck downwards onthe palm of the hand. The tube is loweredand at once lifted again when the bottle isseen to have turned completely over and bestanding right way up.

Double -necked BottleThe special bottle for this trick is shown

in Fig. 10. It consists of a double -neckedbottle, turned from wood and fitted with afairly loose outer covering which slides upand down. Fig. 11 will make the detailsof the construction clear. The outercasing is best made from a length of seamlessbrass tubing as its weight will facilitatesmooth working of the trick.

To perform the effect the dummy bottle ispicked up and the little finer slippedunderneath to prevent the bottle properfrom dropping out of the casing. Thepaper tube is then held in the other handand the bottle is dropped into it neck down-wards. The sliding outer casing of the bottlewill naturally settle down inside the papertube. When the paper tube is lifted toshow the bottle still upside down the outercasing is gripped through the paper andlifted as well, revealing the lower neck ofthe bottle. Finally the tube is lowered andthen entirely removed, leaving the bottlestanding right way up.

If desired the bottle can be constructed

Fig. 10.-An upside-down bottle, The bottle proper isturned from wood and has a neck at each end. Theouter casing is a piece of seamless brass tubing. Accord-ing to which end the casing is slid the bottle will appear

right way up or upside down.

so that liquid may be poured from it, bydrilling out either or -both of the necks andfitting them with tubes and corks.Pouring Out Drinks

Pouring out any drink called for by theaudience from an apparently ordinarybottle is a trick that was very popular someyears ago. The secret lies in the bottle,which is of metal and is divided into threeor four compartments. Each compartmentruns the entire length of the bottle, rightto the mouth and each compartment is'filled with a different drink. In order tocontrol the pouring out of the drinks a fine

tube was connected to each compaktraentand led to a tiny hole in the outer batsingof the bottle. The tubes wore necessary inorder that the air holes might be arrangedin a row on the outside of the bottle. Towork the trick the bottle was held in theright hand with all the air holes closed by afinger pressing on each. To pour out anyof the three or four liquids the correspondingfinger was raised to admit air to the com-partment, rather like playing a sort of flute.Sometimes the bottle had' an additionalcompartment, down the centre which had noair hole and a wider mouth so that it mightbe filled with water via a funnel in front ofthe audience and the water either pouredout again to prove the bottle without pre-paration or else left in and be presumablyconverted into the various drinks.Concealed Glasses

Of course, three or four different drinkswould not be sufficient to satisfy the demandsof an audience so a further expedient isbrought into play. One of the compart-ments is filled with pure spirits of wine andsome of the glasses to be used have a smallquantity of different flavouring essences inthe bottom. The idea is that in the excite-ment of watching the trick individualmembers of the audience would not noticethe difference between say genuine port andspirits of wine mixed with flavouring essence.Actually I think it very unlikely that thisold conjuring device would be very con-vincing. It would be better to have a fewsmall wineglasses already three parts fullof some different wines hidden behind thestack of glasses on the table ready for thetrick. When a drink was asked for that wasnot in the bottle but was " in stock " thecorresponding glass would be picked upwith the fingers concealing the liquid.Keeping all fingers firmly pressed on theair holes a generous glassful of nothingwould be poured out, the fingers round theglass shifted to reveal the wine and the glassof quite genuine wine handed to the correctmember of the audience.Ale and Stout

By the use of this expedient the trickmight very well be done with an unpreparedbottle filled with ale or stout. When aleor stout as the case might be was asked forit would be poured openly and lavishly intoan obviously empty tumbler. When anyother drink was required the required glassalready charged would be picked up frombehind the others as already described andthe bottle given a slight tilt, not sufficientto pour out any of the beer, but simplyto carry out the illusion of pouring out theselected drink.

In this form the trick could terminate byhanding the bottle for inspection. Needlessto say in any trick ofthis description, de-mands for drinks whichcannot be produced aresimply not heard bythe performer, who willusually find he is in-undated with requestsfor the few he cansupply. It is just amatter of acknowledg-ing the demands forwhat can be producedand ignoring the rest,often a useful dodge inconjuring.

Fig. 11.-The "up-side-down" bottle.

DOUBLENECKEDBOTTLE

OUTER SLIDINGCASE

72 NEWNES PRACTICAL MECHANICS November, 193d

The world's biggest liner, Queen Elizabeth,

Two More MoonsI T is learned that the Harvard Observatory,

Massachusetts, United States, have dis-covered two new moons of the giant planetJupiter. They were detected through the100 -in. telescope on Mount Wilson, Cali-fornia, which is the largest in the world,but the moons are very faint. Dr. SethNicholson made the discovery of thesatellites of the planet by examining photo-graphs taken in July and August. Theyappeared as tiny scratches on the pictures.The total number of Jupiter's moons atpresent known is now eleven. The ninthwas first noticed in August, 1914.

A New ParachuteA BRITISH firm have produced a new

type of parachute which is consideredto be a tremendous improvement on thosealready in use. Whereas the present typenecessitates a bulky package danglingbehind the knees or on the chest this newparachute is part of a flying suit.

5,000 Years HenceAN 800-1b. " time Capsule " has been

recently shipped to New York whereit , will be packed with records of thecivilisation of 1938, and deposited for 5,000years, 50 ft. into the earth beneath theWestinghouse exhibit at the 1939 World'sFair. The 7 ft. capsule is made of cupaloy,the result of 5 years research to make copperas hard as steel. It will contain a recordof modern achievements in science and inart, as represented in newsreels and books,all reproduced on microfilm.

9,000 Miles Per SecondI N the Science Museum, South Kensington,

is a brass box measuring a foot squareby two inches deep in which protons can bemade to travel at the astounding speed of9,000 m.p. second. With the energy of amillion and a quarter volts behind them,protons, invisible to the naked eye, travelat a twentieth of the speed of light, whichis 186,000 miles a second. Professor E.Lawrence, of California, is the inventor ofthis box, which was formally designed foratom splitting. It was found, however,that by bombarding non -radio -active sub-stances with protons and splitting their

nearing completion prior to Launching.

New German ZeppelinTHE LZ 130, the new German airship,

recently set out on its first trial flight.Dr. Eckener, the designer, and 74 passengersand crew were on board. Work on theairship was commenced two years ago, andalthough built on the lines of the ill-fatedHindenburg, incorporates many improve-ments.

Control by TelewritersTHE smooth working of a large motor

factory employing "flow" productionmethods depends upon exact synchronisa-tion of operations in every one of the myriaddepartments. The correct parts andassemblies must be ready when and wherethey are wanted, for a hitch at any onepoint may dislocate the entire organisation.The way in which the activities of thousandsof men are controlled is one of the real"marvels" of modern manufacturing.

A new system, employing an unusual typeof telecontrol machine which reproduceswritten orders simultaneously at manydifferent points, is used at the Ford factoryat Dagenham to assist in achieving thisessential correlation of effort throughout

THIS MONTH INSCIENCE AND

atomic structure, entirely different sub-stances with qualities similar to those ofradium could be produced.

A scientific authority says, " The boxcontains a piece of metallic lithium. Thisis the target or substance, the atoms ofwhich are to be bombarded. The box issealed and the air pumped out, and it isthen slid between the two poles-pieces ofelectro-magnet. This and the short-waveoscillator are switched on and the protonsmove with energy equal to a quarter ofa million volts behind them. At this speedthey bombard the lithium and smash-upits atoms until they change and become theatoms of helium."

the works. The system has proved to haveconsiderable advantages over earliermethods.

It consists of a telewriter transmittingset on the frame assembly, and receivingstations installed at various points in thefactory, such as the wheel and tyre assembly,the body department, the main assembly,and the building superintendent's office.

The transmitter is in the charge of theman responsible for scheduling the produc-tion, who issues written orders. The orderis. then produced in a receiving station,and simultaneously transmitted to the otherreceiving sets, on which it is reproducedexactly as written originally.

The new Graf Zeppelin as she took the air at the start of her trial flWht


What the system does, in effect, is tooperate several different pens at pointswidely separated. The original messageis written with a lead pencil on writing paper.At the receiving end the order is reproducedon a strip of paper which gradually unrollsas the mechanically -controlled pen tracesthe words, reproducing the hand -writingexactly.

The system gives immediate communi-cation with many different departments,which would not be possible if the messageswere delivered by hand. There is far lesspossibility of error than would be the case ifthe orders, were telephoned.

Weather made to OrderALL conceivable combinations of bad

weather-storms, dust, sleet, rain,extreme heat or cold-can be created toorder. They are produced in a new"weather tunnel," the first of its kind to bebuilt expressively for scientific research intomotor -car design and operation.

Thus an engineer may direct a 70 m.p.h.sleet storm directly at a car running at aspeed equivalent to 60, 70 or 80 m.p.h.At will the temperature may be dropped to20 degrees below zero, or raised to 150 degrees

Swing doors can also be made into areliable air -lock by the fixing of cushions oflatex rubber at the hinges and edges of thedoor. When the swing door closes, the rubberpads are automatically compressed (as isthe cushioning at the base of the door), thusrendering the room itself proof against anycontamination from outside.

World's Largest ShipTHE largest ship in the world was

launched on September 27th. It wasnamed the Queen Eliztlbeth, and is 10ft.longer than the Queen Mary. A featureis that she has only two funnels instead ofthree, which gives her a more generousallowance of deck space.

Choose Your OwnLanguage

AN innovation recently introduced in theBudapest , telephone system enables

foreign visitors to obtain information inEnglish, German, Italian and Esperanto.All they have to do is to dial a certainspecified number for each language.

THE WORLD OFINVENTIONabove, simulating conditions met in thedepths of winter or in the tropics.

The tunnel is 124 ft. long, 35 ft. wide, and14 ft. high. A 400-h.p. motor drives a 10 ft.propeller to create wind velocities up to85 m.p.h. Dust or sand blown into the tunnelthrough a jet is converted into violentstorms, while water pipes can produce any-thing from a light fog to a cloud burst.

Beam RadioTHE first of the test transmissions on

the new radio telephone installation forthe Hebrides will shortly be taking place.A station 1,000 ft. up on the mountains nearCastlebay Barra, is to work in conjunctionwith another station near Oban. The radioinstallation is intended to take the place ofcables which are often out of action dueto the effect of the storms which are experi-enced in the vicinity.

Rubbered RoomsANEW and effective means of sealing

doors and windows against gas, andone which lends itself specially to A.R.P.work in hospitals and similar institutions,consists of wooden panelling in which thinstrips of latex rubber cushioning (Dunlopillo)have been embedded.

When the panelling with its projectingstrips, of cushioning is clamped to the doorframe and floor, the rubber is, compressedto form an air -tight fitment which is neatand absolutely fool -proof.

The panelling itself is no bigger than thatrequired for light picture frames; it takesup very little room, and, in an emergency,can be brought out of store and quicklyplaced in position.

The rubber cushioning forming the air-lock is more effective than sponge rubberbecause it retains its vitality and "spring"for any length of time.

Windows and floors, as well as doors, canall be rendered absolutely gas -proof by theseunobtrusive wooden fitments.

A Living BatteryI N their efforts to find just what their

batteries can do, Exide technicians havecarried their experiments as far as to obtainan electric eel from South America.

These electric eels can generate sufficientelectrical energy to stun a horse or evenkill a man, and " Exide " as the eel is nameddemonstrates his ability to produce elec-tricity by lighting a neon lamp. Although" Exide " is only 18 in. long, he is a com-parative youngster, and will eventuallygrow to a length of four or five feet.

The batteries of the electric eel (seediagram) are composed of hundreds of

thousands of minute muscular plates,separated by an electrolytic fluid. Becausethe electric tissue is a modified form ofmuscle, it is believed that the chemicalprocesses by which energy is released inhuman muscles are also utilized in thetissues of the electric eel. Muscular activityis a conversion of energy in two stages :first, from chemical to electrical; second,from electrical to mechanical muscular con-tractions. In the organs of the electric eelthis ratio may be reversed. The eel's electricorgans produce voltages 1,000 times greaterthan is developed by human muscularactivity.

Electric CyclesA N Amsterdam firm state that they haverA at last designed an electric cycle, .forwhich they have taken out a patent. Itconsists of a small motor which is fed by a12 -volt battery, charged in such a way thatit would enable a distance of 80 kilometresto be covered. The speed of the machine isnot stated. The equipment weighs 60 lb.,but the sponsers state that this should notprove a drawback. There are over threemillion cyclists to be seen on Dutch roads,and. the inventor hopes that within a fewyears they will forego their pedals for theelectric cycle.

A Chemical DiscoveryMAGNESIUM, used extensively in the

making of fireworks and flashlights,is the lightest of known metals. It is nowan important constituent of the light alloyswhich are required in large quantities foraeroplane construction.

Bind Your Copies of" Practical Mechanics "

THE binding case for Volume V. completewith title page and index, is now readyand costs 3s. 6d. by post from the Publisher,

George Newnes, Ltd., Tower House, South-ampton Street, Strand, London, W.C.2.- Theindex can be obtained separately if desired for7d., post free. All readers should have theircopies of Volume V bound, and thus be ableeasily to refer to the contents by means of thefully cross-referenced index.- Nue- - -- " z

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74 NEWNES PRACTICAL MECHANICS' November, 1938

W INVENTIONSNoise Production

THIS is the age of the big noise. Manyprotests are made against the ear-

splitting sounds which characterise ourmodern life. There is an Anti -Noise League,whose aim is to abolish cacophony-a jaw-breaking word for ugly sound. It is, there-fore, strange that there should be anapplication to the British Patent Officeasking for protection for a noise -productiondevice. But the mystery is cleared up whenone learns that it relates only to noises intoys. To make a toy realistic it is necessarythat the familiar sounds associated with theobject represented should be correctlyimitated. The purr of the motor, the whirrof the aeroplane, and the rhythm of therailway train, when faithfully, if not power-fully, simulated add materially to the effectof the toys. The object of the inventor is toprovide means for imitating the power unitof a toy device, for instance, the exhaust ofan internal combustion engine in a motor-car.

This should enhance the delights of thenursery.Mechanical ScarecrowI NOW comment upon another noisy

device which has been submitted to theBritish Patent Office.

Ever since man first began to till theground, the bird has levied a toll upon theseed which is sown in the furrows. But it isa moot point whether the tiny marauderdoes more good than harm. As regards thegarden, for instance, the favourite food ofthe thrush is the snail, and we are told thatthe bird destroys at least a hundred snailswhere the gardener can kill scarcely one.

However, the farmer appears to considerthe birds as the foes of his fields. And hehas adopted more than one method inorder to frighten away the depredators.The scarecrow is a familiar object on theland. But its reign of terror does notalways achieve its end. I believe that withironical indifference a crow has been knownto utilise the scarecrow as a perch. RobinsonCrusoe, to guard his crop, hanged a coupleof the feathered culprits like highwaymenat cross-roads, and this proved a deterrento the winged bandits.

Now, the average bird has an inherentfear of a gun. And, therefore, an inventorhas recently applied for protection for adetonator which will produce periodicalexplosions, somewhat on the principle oftraffic lights. Consequently, without thecontinual attendance of a man with a -gun-a practice which used to be adopted-abogus gun will deceive the aerial thievesand keep them at a distance.

The inventor has set himself the task ofproviding automatic detonator apparatuswhich is simple, yet efficient. A character-istic of the machine is that it can be easilyre -charged with a supply of detonators.And, if required, the time interval betweenthe explosions can be varied.

Another feature of the contrivance isthat each explosion takes place outside theapparatus, so as not to interfere with thenormal operation of the mechanism.

This device will replace the farmer's boywho, in the good old times, rotated a bird -scaring rattle.

Artificial Noises

1-1E subject of imitation noises movesto remark that, in the days of the

silent films, the effects were produced by analert member of the staff, who made them

The following information is specially supplied tc"Practical Mechanics," by Messrs. Hughes & Young(Est. 1829), Patent Agents, of 9 Warwick Court, HighHolborn, Landon, W.C.1, who will be pleased to sendreaders, mentioning this paper,free of charge, a copyof their handbook, "How to Patent an Inventior."

synchronise with the action of the. picture.And these artificial noises added materiallyto the realism of the film. But, as theseinnocent deceptions were perpetrated behinda screen, the public were not always awareof the manner in which they were caused.I have myself seen a vigilant effects oper-ator-the forerunner of the sound track-at work while a film was being exhibited.By his side was a bath containing crocks,which he vigorously made clatter whenanything in the picture fell. He also had abig military drum, the surface of which hebrushed with a pair of dandy brushes usedordinarily for grooming horses. This pro-vided a very good imitation of the sound ofthe waves on the seashore. The noise of ahorse's hooves was effected by knockingtogether the edges of a split coconut shell.A smart rap with a cane upon a leather seatclosely resembled the crack of a rifle. Andthat which feigned to be church bellsresulted from the striking of what appar-ently were suspended gas pipes. As thesenoises had to coincide with the movementsin the picture, a rehearsal was necessary.FootnoteI T is remarkable how many inventions

concern footwear. The attention of theinventor is constantly devoted to shoes.For example, a new pneumatic heel is thesubject of a recent application to thePatent Office of this country. The objectof the inventor has been the provision of aheel with improved resiliency, wear, andnon-skid properties. In this instance, arubber heel comprises upper and lowerplates enclosing an air chamber. The upperplate is provided with reinforcing ribs on its

iderside.The next invention to which I refer

relates not to " the light fantastic toe," butis specially designed to reinforce the bootof the miner. It consists of an improvedguard for the toes of boots. In this case,there is a guard -cap of metal extendingover the front portion of the boot, and thisis characterised by the fact that a broadstrengthening and stiffening bridge of strongleather is arranged between the guard -capand the front cap of the boot. No doubt theboot of a miner is subjected to exception-ally hard wear. Certainly this type of foot-wear would have a powerful kick in it.ShoecraftSPEAKING of boots, I am moved to

remark that a London daily paper hasreceived a protest from a correspondentwho objects to the word " cobbler beingused for a heading. He considers that itreflects upon that capable craftsman, theshoe repairer. The paper pointed out thatthe first definition of a cobbler is one whomends shoes, but that a second meaningdescribes a cobbler as one who clumsilymends shoes. In this connection, therecomes to my mind a crude couplet whichwas occasionally quoted in the last century.It ran thus :-

" Why is a cobbler like a king ?Because his nose is above his chin.

Modern machinery enables the shoe-maker to repair shoes in a very effectivemanner. I have seen stitching which isalmost imperceptible.

There are many handy men other thanthe shoemaker who have a last and soleand heel their own shoes. I once met thathighly respectable member of society, abank clerk, who shod both himself and hisfamily. He was one of the noble army ofamateur practical mechanics.

For Juvenile JumpersAN improved hurdle for junior athletes

has appeared. We have all seenchildren in the streets who, by means of askipping rope at varying altitudes, test theleaping abilities of the sporting juvenile.This improvised method is surpassed by adevice of pressed metal, to be fitted tohurdles, which enables the top bar to falland remain down when struck. It alsopermits the top bar to be adjusted to anydesired height by clamping bolts, which passthrough slots in the sides of the hurdle.

This will train our youth to emulate theattainments of the horse in the huntingfield.

Dish -washerMOST housewives dislike that post-

prandial necessity, the washing up ofthe dishes. However, in hotels and institu-tions these ablutions are often mechanicallyperformed. A patent for a new dish-washing machine has been applied forlately. In the case of previously designedmachines of this description, the dishes areplaced on a stand in a container, on whichone or more jets of water are sprayed fromabove. The liquid is fed to a nozzle througha flexible conduit or one with turnablejoints. This, it is stated, has certain disad-vantages, as, for instance, risk ofleakage.

The inventor of the improved device hasproduced a dish -washing apparatus inwhich a broad, thin jet of liquid is sprayedon the dishes without the use of a movablenozzle or a flexible conduit. A jet is directedfrom a fixed nozzle against a reciprocaldeflector or screen, which deflects the jet onto the plates. The jet, which may advan-tageously be a round one, does not thusstrike the dishes directly. The action seemsto be nearly related to the ricochet of abullet.

How to Moor a WalletANOTHER pocket wallet protector has

made its debut on the other side of theAtlantic. This comprises a casing adaptedto be detachably secured to a part of thewallet or article to be guarded, and alsolatch mechanism. It not only nonplusesthe thief, but it prevents loss of the walletdue to some other cause. For example,there has come within my ken an accidentwhich occurred to a pedestrian. He happenedto slip on the pavement and, in anendeavour to preserve his equilibrium,almost turned a somersault. This was theopportunity for the never -variable law ofgravitation, which caused his wallet to fallfrom his pocket. At the time he was notaware of his loss, and when later he appliedto the police, he did not recover his wallet.Now, had he have had the above -mentionedprotector fitted, his pocket would not havebeen picked by gravitation.

Bottle PrintingTO dispense with the adhesive label, a

new process for printing on the glass ofthe bottle has been accepted by the UnitedStates Patent Office. It comprises the useof a quick -drying, hard -setting ink, whichis covered with a synthetic resin varnish.The bottle is then heated for about aquarter of an hour at approximately300 degrees F.

DYNAMO.

November, I 9-.)--J NEWNES PRACTICAL MECHANICS 75

SYNTHETIC RESINMOULDINGS

The Material-ProcessEmfiloyed-Tyfies OfMoulding Dyes And

Their ManufactureFig. 1. Moulded bakelite articles.

THERE are several forms of mouldingmaterial manufactured at present,the most familiar being named

" bakelite."It is a synthetic resin produced by a

chemical reaction in which carbolic acidand formaldehyde (distilled from wood) playthe most important part, but the exactdetails of the process are omitted as notbeing considered essential to the presentarticle.

For the manufacture of utility articlesobtainable in vast quantities, this resin ismixed with a base termed in the trade a" filler," and this filler varies according to theclass of article required to be moulded. Asfor instance some articles have to be hardand necessarily fragile, others perhaps haveto be so light and weak that the filler usedis to gain strength, whilst in other casesthe filler decided upon is one which willstand the constant contact of boilingliquids. In some moulding powders veryfinely ground wood is used as the base,other materials include French chalk-chifiaclay-asbestos and wool fibre, also in themajority of moulding shops all the scrapand waste from previous mouldings arereground and used as filler mixed with afurther proportion of resin. Bakelitemoulding compound is used for fabricating agreat variety of articles such as electricalaccessories, including wireless components ;cups for vacuum flasks, and a vast amountof small attractive articles purchasable atvery competitive prices. It is very durable,not greatly affected by boiling liquids, andis a non-conductor of electrical current.The natural colour of bakelite resin isamber, but any other colour isproduced by the admixture inthe filler of a suitable die.

Cellulose AcetateThis form of moulding material

differs considerably from bakelitein structure, also in manufacture,as although the modern method ofproducing small bakelite articles isby injection (explained later),acetate is always injected intoa closed mould, heated separatelyand being brought, to a fluid con-dition in a container fitted to themoulding press for that specialpurpose.

In Fig. 1 will be seen a smallcup, an ashtray and a wirelesscontrol knob, all produced inplunger type moulds from bakelitepowder loaded directly into themould.

4

In Fig. 2 is shown four coil formers, thelargest of which is moulded in bakelite bythe injection method, the remainder beingfabricated from cellulose acetate.

The Process EmployedThe process used in the manufacture

of mouldings is fairly simple, and does notcall for a great deal of skill on the part of theoperator, quickness in ejecting the mouldedarticle, combined with close application tothe time allowed for " cooking (which isthe period estimated by the controller assufficient to produce in the compound astate as near to perfection as possible) arethe only points the person operating amoulding press has to consider.

Bakelite moulding work cannot in anycircumstances be termed a " pleasantoccupation," owing to the heat which isnecessary and the annoying smell andrapidity under which the operators have toperform their duties.

With all forms of pressure . mouldingthere are many snags and drawbacks. Themouldings shrink upon cooling-whichhas to be guarded against and allowed for;also in time they " grow " by the normalaction of the pressure confined in themoulded object continually struggling forrelease. Moulded metal articles are affectedby this expansion more than syntheticresin, although in all mouldings it is aserious drawback and considerably restrictsthe fabrication of moving parts. Ex.perimenting in this direction is continuous,and one enterprising firm is now mouldingshaft bearings from bakelite with theadmixture of graphite to the resin compound.

TAPr

SPLITS

0

sPRIIE HEADFig. 3.-A small injection mould for coil formers of the type seen in Fig. 2

Fig. 2.--Moideled cellulose acetate articles.

The advantage of this will at once beunderstood when it is explained that theshafting is run dry, without oil or any formof lubrication, owing to the graphitereducing friction to a minimum. Thesebearings have a great welcome in food -producing factories or others where oilbecomes a nuisance.

The shrinkage in mouldings is to a greatextent overcome by allowances in mouldsizes when these are being made, of apercentage averaging 0.006 per inch. Thefigures representing .allowances are usuallyentered on the mould drawing by thedesigner, as much experience is necessary inmaking calculations, also it will be realisedthat bulk and the filler being used in themoulding compound, will considerably varythe amount of contraction. In someinstances the bakelite powder is made intolozenges by the use of special machinerybefore being loaded into the moulds, whichfacilitates the accurate measuring of thematerial being used, but this method hasits limitations, as where moulds havefragile or structurally weak internal parts,the danger reduces the practicability.

Heat and PressureThere are several practical methods of

obtaining and applying these twovery essential elements. In the caseof heat, steam,. gas and electricitycan be used efficiently, whilst inthe case of pressure, hydraulicand electrical are universal, alsohand pressure obtained with a flypress is often used with success

3 where the more elaborate mechani-cal processes are not available.

For good sound mouldings theheat required should be some-where around 300°F. to 350°F.,andall moulds and mouldingapparatusshould be maintained at thistemperature.

With regard to pressure, this isapproximate, but the nearer itapproaches that equalling 1} tonsper square inch, the more durableancIstrong the moulded part willbe.

If the pressure is insufficient


N

Fig. 4.-A three -impression cup mould.

the mouldings will be weak andfragile - termed in the trade"Cokey."

Mould LoadingSome few years ago the only method of

charging a. mould was by taking the upperand lower forces apart and inserting thematerial, but this has now been supersededby the modern method of injection.

For this process special presses or mould-ing machines are needed, and in the formerthey are of the double -action variety, viz.the lower platen rises and closes the mould,then a plunger descends, entering a smallcylinder, which is screwed into the top of thetop of the mould, into which the bakelitepowder or lozenge has been previouslyplaced.

Undoubtedly this is a great improvementon charging the mould direct as it reducesthe " flash," which is a certain amount ofthe resin spewed out between the two mouldforces by the internal pressure, and is agreat trouble should it become thick, havingto be trimmed off after moulding as it isvery unsightly. A further advantageattached to the material being in a fluxedstate when entering the mould is that it isnot so liable to injure weak protrusions onthe inner surfaces of the mould When it is inoperation.Cellulose Acetate Moulds

Moulds for this material are alwayscharged by the injection method. It differsonly from the bakelite injection mould byhaving a cylinder attached to the presscontaining a fairly large quantity of thematerial in a hot fluid state. A great manylarge and elaborate moulds are used in theprocess of forming and casting this classof resin; the mouldings, such as cheapfountain pens, pencils, etc., have to beproduced in very large quantities to supporta competitive market, and maintainprofit

The rapid and effective stripping ofthese small articles after mouldinghas produced many wonderful andelaborate mechanically operatedmoulds, especially for the productionof such articles already mentioned,and having internal threads. P apidityof operation is the most essentialpoint, end the design is alwaysdirected with this end in view. Oneof the most effective mechanicallyoperated moulds at present is madeby having a complete circle of stemsmade of steel which forms the internalbore of a pen or pencil barrel. Thesestems pass through a plate, and onthe back end of each is fitted asmall gear wheel, in the centre ofthis circle of gear wheels, and in meshwith same is a larger wheel to whicha handle is attached-when themoulding is completed this handleis given a sharp turn, which causesall the stems to revolve tog sthcr,unscrewing them from the mouldedthread inside the barrels, but evena quicker method than this has beenrecently invented, and has provedquite practical against considerableadverse criticism, i.e., after moulding,and when the material is still in ahot plastic state, the steel stems withthe moulding thread on descend

SPEW GROOVE

Fig. 5.-A simple flash mouldfor forming an ash tray.

through the plate, stripping off the barrels.It had been found after considerable ex-perimenting that the moulded thread wasnot unduly injured, and regains almost itsnormal shape and size upon cooling. InFig. 3 will be seen a cellulose acetate mouldwhich produces the small coil formers. Thetop sketch is a sectional view showing thedetails, No. 1 being the top force made fromgood quality mild steel and left soft; No. 2,which is the bottom force made from thesame class of material into which the corepins No. 5 made from cast steel, hardenedand tempered, are a press fit just burredover at the bottom end to retain them. Aslight taper will be noted on the core pins,which is very essential to facilitate stripping.

Lecation PinsThe location pins made from cast steel

hardened and tempered, are of differentsizes to locate assembly the same way roundeach time. In the making of this mould,very little bench work is necessary, and theonly real fitting is the three rectangular

Fig. 6.-A strip emerycloth holder for mould

Polishing.

core pin holes, which have to be carefullylocated. The splits, which are made fromeast steel are probably the most trickyjob, there is really two pairs of each whichmust be exactly the same to centralise.They are shaped up to a predeterminedsize, the core pin slots run through on thehorizontal milling machine, then the shallowrecess end milled in the top and bottomsides of each to form the flange on the coilforiner. The outside taper is then machinedon the horizontal milling machine with theaid of the swivel vice to set up for the angle.In some tool rooms, about .010 in. wouldbe left all round to be ground off afterhardening, but in many, just a few thousandswould be left on for the fitter to work offwith a file, in any case all mould surfaceshave to be polished before and after hard-ening, this is very essential with all mould-ing dies to avoid sticking, and also toproduce a finish on the moulded article.Polishing

Emery powder mixed with paraffin oilused on sticks of wood or pieces of fibre,are very handy tools, and afterwards a finalsurface highly polished can be obtainedwith rouge. Polishing is not so essentialwith cellulose octate moulds, as bakelite,the moulding pressure being considerablyless. In quite a lot of modern tool roomsgood quality mild steel would be used for thesplits of this mould, and afterwards skinhardened in the cyanide bath, but it mustbe distinctly noted that it would have to be" black " mild steel which is hot rolled, as" bright mild steel " or " cold rolledsteel " would distort in the hardeningprocess, and render the parts useless.Bakelite Mould Making

The small cup which is shown in Fig. 1was made in a very simple three -impressionmould. The bottom bolster is made frommild steel with cast steel moulding forcesinserted into it, after being hardened andground. The top force is a mild steel platewith plungers to form the inside wall of thedip positioned by a spigot and held on byscrews. This type of mould is fairly simpleto make. A small protrusion will be notedon the top of the plungers entering the topplate, without this the mould would taketwice as long to make, and would mean agreat deal more trouble, which will be easilynoted by following the procedure adoptedfor manufacture. (Fig. 4.)

Best quality mild steel is turned in thelathe to size, representing the bottombolster and the top plate. The top plateoverlaps the body, and a step is turned on

(Continued on page 111

\witiN \ ,

Fig. 7.-An impression knob mould


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NAME

ADDRESS

AGE ICS


Sir Isaac Newton.

ISAAC NEWTON was born at a remoteLincolnshire farmstead near Wools-thorpe, on Christmas morning in 1642.

He was a weakly infant and the circum-stances of his birth were greatly saddenedby the fact that, just previously, his father,a yeoman farmer, had died at the early ageof thirty-six.

Isaac's mother, however, soon re -married,and went to reside with her second husband,the Rev. Barnabas Smith, at North Witham,some distance away. The infant Newtonwas not taken to his mother's new home.He was looked after by his grandmother,Mrs. Ayscough, who came to reside atWoolsthorpe specially for that purpose.

Great must have been the care whichMrs. Ayscough gave to -the infant boy, for,with the passing of the years, he completelyoutgrew his early weaknesses, and, as weshall see later, lived- to the ripe old age ofeighty-five.His Boyhood

When Newton was twelve years of age,he was sent to the King> School at Gran-tham, the nearest town. Strangely enough,he did not show any studious inclinationsand, for a time, he was almost the lowestboy in the class. Like Galileo, much of hisboyhood time was spent in building workingmodels from scraps of materials and inpondering over their pechanism. Heinterested himself in astronomy, too, andthere is a story that once he tied a lanternto the tail of a kite and flew it after dark,making the local folk believe that a comethad appeared.

Newton, however, even at this immatureage, was no characterless lad. One day aschoolfellow kicked him savagely and forno apparent reason. Immediately Newtonrose up and fought the lad, giving him agood thrashing.

The incident had its effect on Newton'smind. If, he thought, he could obtain thevictory over a fellow pupil with his fists,he could surely do so with his brain. Sohe set to work in good earnest with hisstudies and ultimately rose to the top of hisclass.

His schooldays over, Newton was startedat the family occupation of farming. Butthere was no love for the congenial task ofhusbandry in him. He preferred readingbooks on mathematics and physical science.Eventually, therefore, on the advice of thelocal vicar, Newton was sent back to theGrantham Grammar School, this time withthe object of preparing himself for aUniversity career at Cambridge, to whichcity of learning he went in the year 1660at the age of eighteen, entering the famousTrinity College there.

MASTERS OFMECHANICS

Nov 39. Isaac Newton

The Great PlagueThere was nobody very brilliant at

Cambridge when Newton went up there.His studies went on uneventfully .and atthe age of 22 he took his B.A. degree. Ayear later-in 1665-the Great Plaguevisited London, killing off no fewer than100,000 people. The pestilence spread toCambridge, causing the University to beclosed. Newton, as a result, was forcedto return to his family farmstead at Wools -

The modern spectroscope is based directly uponNewtons discovery of the spectrum.

thorpe and to remain there for a period ofsome eighteen months.

But the period was, for Newton, not oneof idleness. For some time previously, hehad pondered deeply over the fundamentalprinciples of mechanics and, in ,particular,over the elements of astronomy. Especiallyhad the subjects of force and gravitationfascinated him, for he had learnt much fromthe writings of Galileo about the newconception of the earth, moon, sun andplanets.

It was thiring his enforced stay atWoolsthorpe that the apple -in -the -gardenincident is supposed to have occurred toNewton. Whether Isaac did actually con-ceive his explanation of the operation ofthe universal law of gravity through seeingan apple drop to the ground in his mother'sold orchard at. Woolsthorpe, or whetherthe well-known narrative is only a story,we shall never fully know. It wouldseem, however, that the story (which wasgiven to the world by the philosopher,Voltaire) has some truth in it.

Law of GravitationCertainly, though, it was at this period of

his life that Newton hit upon the law of

universal gravitation which enabled him togive, later on, a definite proof of the laws ofplanetary motions, thus following up andconfirming the great truths which Galileohad previously enunciated.

In" 1667, Newton returned to TrinityCollege, Cambridge, having been elected aFellow of the College, and from now onwardswe find his career one of almost meteoricbrilliance in the domain of mathematics,astronomy, optics and theoretical mechanics.

In the realm of mathematics, he inventedat this period the binomial theorem,nowadays well known to students of algebra,but his greatest mathematical monumentis what we call at the present day the" differential calculus ", a mathematicalsystem which has ever been of incalculableassistance to the theoretical engineer anddesigner.

As a close student of optics, Newtongave several years to the re-formulation ofthe principles of light. He introduced thereflecting telescope in which the image isnot viewed directly through a system oflenses, but is formed at the focus of alarge mirror or " speculum ", thus obviatingthe many distortions which a direct visiontelescope built on the principle of Galileointroduced at that time.

Newton, too, discovered that if heallowed a narrow ray of sunlight to passthrough' a triangular -shaped piece of glass,called a " prism ", the light ray was notmerely reflected or directed out of its course,but that it was actually split up into sevendifferently coloured component rays which,when allowed to fall upon a whitened sur

An early air pump, made soon after the death ofNewton. With suds simple instruments, many of the

basic properties of gases were discovered.

80 NEWNES PRACTICAL MECHANICS November, l938

face, gave a graduated band of coloursknown to this day as the " spectrum."

Spectrum AnalysisHere, of course, Newton figures as the

father of spectrum analysis, that ingeniousprinciple whereby man has been able toascertain the composition of other worldsand even of the gaseous atmospheres ofworlds separated from the earth by almostinconceivable distances. Curiously enough,however, Newton, although his notes on thesubject were voluminous, published verylittle at this juncture, for the limelight ofpublicity was distasteful to him.

Newton's view of the nature of light wasthat it is composed of streams of tinymaterial bodies which he called " cor-puscles ", these corpuscles being shot offin 'vast numbers and at an extremelyrapid rate by the luminous body. For atime, Newton's " corpuscular theory "prevailed, but it was eventually over-shadowed by the present-day wave theoryof light which assumes light to be a mani-festation of wave motions in a hypotheticalentity which, for convenience, is called theEther.

It is interesting, however, to note thatof recent years, many scientists are inclin-ing more and more to the old corpuscularlheory of Isaac Newton and are creditingight with being a stream if not of actualmaterial bodies, at least of energy units or" particles."

Newton was made a Fellow of the RoyalSociety. The latter body formed such ahigh opinion of his researches in mathe-matical science and in the principles ofmechanics that they decided to ask hisppeermission to publish much of his work.Newton consented. He revised and col-lated his many notes, papers and manu-scripts and eventually gave to the world hisfamous Principia, or Mathematical Prin-ciples of Natural Philosophy."

Remarkable BookThis book, which was written in Latin

and published in 1687, proved Newton tobe a man of towering scientific andphilosophical genius. It has been aptlycalled the " greatest single contribution toscience ever made by any one man," and,although at the time of its publication therewere, perhaps, hardly a dozen men in allEurope who were capable of realising itsdeeper meanings, the work placed Newtonupon a pinnacle of scientific fame.

The Principia of Newton is, even to -day,one of the most fundamental treatises inthe whole repertoire of theoretical andmechanical science. It is difficult toassess the manner in which engineeringscience would have grown without themany principles which it lays down.Even the modern views of Einstein uponthe conception of the Universe in no wayinvalidate the conclusions of Newton'sPrincipia, the latter being inviolable andabsolute.

As a sort of political reward for his work,Newton, in 1695, was offered the post ofWarden of the Mint, an appointment whichhe accepted. Five years later he was madeMaster of the Mint, the position being thenworth about £1,500 per annum. To acertain extent, the post was a nominal one,for Newton still continued his studies atCambridge for a few years afterwards.

From 1703 he held the Presidency of theRoyal Society, an honour which he retaineduntil his death, twenty-five years later.

Nervous BreakdownAnd then, curiously enough, in the midst

of the years which followed upon hisEuropean fame as a philosopher and

scientific mechanician, came a period ofmental unrest, a bad nervous breakdown.Some have averred that the great philoso-pher's mind actually became unhinged atthis period; but there seems little likelihoodof this being true.

Nevertheless, the brilliancy of Newton'scareer had expended itself. The flamehad died down, and during his later days,the great philosopher contented himself inliving a tranquil and uneventful life,devoting a good deal of his time to the studyof Divinity.

A telescopic view of the moon. By carefully observingthe motions of our satellites Newton was led to his

laws of gravity.

Some ten years before his death, whichoccurred on March 20, 1727, he relinquishedall his scientific studies. The master mind,which had given to the world more scientificprinciples than any other single individualhad ever previously done, had worn itselfout and its owner now lay back to follow,whenever possible, the work of others,whose efforts he encouraged to the greatestdegree.

To this period of Newton's final inactivitybelongs those oft -quoted words of his :

" I know not what the world will thinkof my.labours, but to myself it seems thatI have been but as a child playing on theseashore ; now finding some pebble rathermore polished, and now some shell rathermore agreeably variegated than another;while the immense ocean of Truth extendedbefore me unexplored."

Newton was made a Knight by QueenAnne in 1705-some say as a direct rewardfor the publication of his renowned " Treat-ise on Optics ". He never married andmuch of the wealth which came to him inhis later years he gave away in the form ofpresents to friends, acquaintances, and,aye, to the merest beggars.

" How have you managed to make somany discoveries," is a question which wasonce put to Newton. " By always thinkingabout the subjects," was the simple reply,an answer which, in all truth, gives the keyto the workings of the philosopher's mind.

Newton's Many LawsThe mechanical and constructional world

of to -day could not possibly have developedwithout Newton's many laws and princi-ples of force, energy, action at a distance,light, gravitation and mathematics.

In Newton, the work of Galileo whichhad been so. greatly decried by ecclesiastical" authority, found its fructification.When Newton died, mankind no longerbelieved that the sun revolved around theearth. The dead hand of Aristotle whichhad held men in bondage for so manycenturies had been forcibly raised. A newspirit of science and of discovery had beenlet loose upon the world.

" Let mortals rejoice that there hasexisted such and so great an ornament ofhuman nature," reads the concluding lineof the inscription on Newton's tomb inWestminster Abbey. Yea, and let evenmodern scientists, too, of all classes, pauseat times to render at least some measure ofpraise to Newton and to his pioneer work,for without the latter, science would havehad very few enduring principles uponwhich to build its edifice.

THE NEW "STREAMLINERS"Messrs. Bassett-Lowke, Ltd., this season

are featuring in their new locomotive rangein gauge " 0 " all the latest streamlinelocomotives : L.M.S. the " Coronation Scot "and the "Duchess of Gloucester," L.N.E.R.the " Empire of India " and " Dominion ofCanada," and these can be supplied eitherin clockwork or electric a.c. or d.c. at thestandard price of 12 guineas, which isremarkably reasonable for locomotives

hand made throughout, and beautifullyfinished.

This year Messrs. Bassett-Lowke havere -arranged their railway lists and in addi-tion to their new edition Section "A" listout this October, price 6d., which coversall gauges, they are producing a booklet"GAUGE '0' MODEL RAILWAYS" price3d. devoted entirely to "0" gauge. Whynot send for a copy.

The gauge "0" model "Coronation Scot."


Figs. I and 2.-- (Left).-.4 miniature single cylinder traction engine. (Right) .4 copy of Tit Bits- which measures in. a 21 in.

IT'S A SMALL WORLDBy W. J. Bassett -Low ke, M.I.Loco.E.

" OW tiny ! Let me look at it ! "Just the words which expressmost people's fascination for the

miniature. It may be the interest theyhave in very small things made by humanhands, or in viewing the magnified work ofnature, invisible in its beautiful detail tothe human eye except through the micro-scope.

I am chiefly concerned in the making oflarge things small, and I think the peaks inthis art are approached as the amount ofaccurate detail in work of this kind isaccomplished.

In Fig. 2 . is shown what modernprinters can do in reducing an ordinaryissue of a weekly periodical to 1 }-in. x 24 -inEach tiny page is readable and is anaccurate miniature of the " real thing." .

" Endeavour " BarqueThe next model I have taken from my

wzy:CItt.H2140e

SPF,,i4BRYMAY MACH

Fig. 4.-A steam plant for a motor boat.

own collection of ships. It is the famousEndeavour Barque of Captain Cook, 1/1200thactual size, which makes it 1 inch long !The detail work on this small ship has beenmost accurately carried out. (See Fig, 7.)

Also by the same craftsman, Mr. GeorgeSell of London, is the infinitesimal 3 -mastedsailing ship, shown in Fig. 3. It is only

Fig. 3.-A threemasted sailing shipwhich is only 4 in.long, installed in a

watch case.

half an inch long, and square -rig ged withhum in hair. It is the property of a keen

Figs. 5, 6, and 7.-(Left) Miniaturedeckfittings.(Above)A model speed boatwhich is only 8 in.long. (Right) Amodel of the famous`Endeavour' Barque.

connoisseur of models, Mr. Cyril Derry ofLondon, and he carries it in his watch case(N.B.-the works having been removed !),and here it is shown compared with a penny.Working Models

Now for something that works ! Fig. 1shows probably one of the most uniqueworking models ever constructed-a modelof a model !

Some readers may remember that Mr.F. J. Camm described in this publication ayear or so ago how to make a fin. scalesingle cylinder traction engine from castingsby Bassett-Lowke.

Mr. George Southby of Willesden hasmade a miniature model from thisscale model, and here you see it mountedon four match boxes. Some details may notbe amiss. The cylinder bore is only Andsand the strk ke A -in. It has reversing gearand runs well forward or backward, and thesteam cock is correctly made with taperplug, washer and nut. The steering gear isa working job, as also is the hand brake,and the engine can be thrown in or out ofgear as desired. Mr. Southby runs thetractor on compressed air as steam is apt tospoil a tiny engine, and the most naturalspeed is 7 to 8 feet per minute.Miniature Speed Boat

Fig. 6 shows a speed boat by the samecareful model maker. This is only 84 incheslong, and has a single acting slide valveengine, bore h -in., stroke A, which actuallypropels the boat along at 3 miles an hour.

Before we leave working models, let us


look at the working steam plant for amodel motor boat shown in Fig. 4. Itssize can be gauged frpm the match box,and it is fired with sohd methylated spirit,runs for 3 minutes and has a workingdisplacement lubricator

" Queen Mary "Modern show -case models of giant liners

are full of small masterpieces of detail.You will see on the stern view of the QueenMary, Fig. 5, a group of deck fittings to ascale of 1 -in. to the foot, which neededmuch care and thought on the modelmaker's part before they were produced.

Last but not least I would say that theinteriors of ship models sometimes call forminute craftsmanship. Fig. 8 shows a

Fig. 8.-A portion of a dining saloon on a British liner.

portion of a dining saloon on a Britishliner, about 7 inches long and 11 incheshigh. Each of the chairs, and there are overfifty of them made by hand, are scarcelyan inch high. It is an interesting fact, too,to note that the small flowers in the vases

on the tables, though only 1 in. long arereal !

These pictures just show a few examplesthat have come to my notice recently, and Ihope they may give you some idea of theexquisite work of miniature modelling.

PETROL -DRIVEN MODEL By. C. E. B.

AEROPLANES

LAST month we showed a land biplanewith the engine installed. Its maindimensions are :

Span, 3 ft. 41 in. ; chord, q in. ; length,3 ft. Its all -up weight is only 3 lb. It hasa pleasantly flat glide after the power is off.

I do feel, however, that people who expectto obtain exactly the same ease of startingand coarse handling that larger engineswill stand will never get the best out of thelittle fellows.

For anyone who is prepared to treatdelicately, mixture, control, etc., the littlefellows will give great satisfaction. Inother words, although they are sufficientlyrobustly built to stand just as hard knocks,they are not so good for the hard -fisted man.

A very small biplane flying boat was alsoshown last month with a similar type hull tomy large 8 -ft. span record -holding flying boat.The glide is so flat that this little boat hasmade a number of landings on its hull overgrass without any damage. The boatslithers over the grass on landing.

This is rather tempting Providence,however, and the boat is being put awayuntil its water tests can be carried out.It ought to be mentioned that this littleboat has detachable wings, tailplane finand tail -boom. It packs up into a smallbundle in a few seconds.

Large ModelsAlthough I have made a considerable

number of little petrol models that can becalled satisfactory flying models, my lastbeing a 3 -ft. 6 -in. low -wing model, I thinkI prefer the large model of about 8 -ft. span.The little fellows are delightful to carryand pack up, but the big model flies moresteadily and looks more purposeful in theair to me. I prefer its steadier and morefloating type of glide. Large engines are,of course, easier to start as a rule, as theyare naturally less temperamental and have

Fig. l.-The

writer's8 ft. span

simpletype

low -Wingmodel.

a greater reserve of power. Nevertheless,I would not be without my little models.I also realise that the lure of producing areally tiny model is too great for manypeople. They so often fall for it as theirfirst model. I shall always advise starting

ion the larger and easier model first wherethere is greater latitude for mistakes inweight paring and engine operation.Something between a 6 -ft. and 8 -ft. span.Having obtained experience on the largermodel with an engine of 6 c.c. or 9 c.c.,then conies the time for the little highlyportable model.

The low -wing petrol model is oftenlooked upon as a dangerous type of modelthat is likely to be unstable, and damageitself, and I have so often heard the absurdremark that low wings will not glide.Actually, properly designed low wingsglide beautifully, both rubber and petrolmodels. It should be obvious thatthey are easier to get to glide after power isoff than a high wing, because the thrustline can easily be arranged so that itpasses through the centre of resistance ofthe main plane, and so does not tend topull the nose up or down around thecentre of resistance when the engine isfiring. Stability on a low -wing model isquite easily obtained if a really generousdihedral is used, and the fuselage is builta bit longer than normal, so that the tail-plane and fin run the disturbed air asmuch as possible from the mainplane.The positioning of the thrust line isimportant. Also weight should be keptlow. Fig. 1 shows an 8 -ft. span taperedwing, low -wing model that I built almostentirely of balsa wood. The main sparsin the wing are of 1 -in. by 1 -in. spruce-all other spars are balsa. It can be seenthat the wing is detachable and held up to acut -away portion in the bottom of thefuselage by elastic bands to wire hooks

that protrude from the fuselage side.These bands can be seen in the smallblack marks on the fuselage side in thephotograph. The wing fixing is thereforehardly noticeable on this model and yetwill give if it hits anything it should not.The wing itself has a nearly straightleading edge and the trailing edge broughtforward to the tips to make the taper.This has been proved to be the mostlaterally stable type of tapered wing shapein full-size research. The wing is alsomade in two halves and is detachable inthe centre for ease of carrying.

Tailplane and FinBoth the tailplane and fin are detachable

and also held on by rubber bands thatscarcely show. The fuselage is made up oftwo sides of sheet balsa wood withlongerons and uprights of 1 -in. by 1 -in.balsa. Cross pieces are then added andthe top and bottom are then also coveredwith *-in. sheet balsa. A turtle deckingis added, also made of sheet balsa withformers of balsa. A small cabin can beseen on top. This contains the timeswitch to control duration of flight. Themain dimensions of this model are-Wing :8 -ft. span, 16 -in. chord at root, 10 -in. chord10 in. from tips. Length overall: 5 ft.41 in. Tail : 3 ft. 4 in. span, chord 14 in.at roots, 7 in. at tips. Undercarriagetrack : 26f in.

The engine is a 9 c.c. " Brown Junior "and is interesting because it is one of thevery first engines of this make that cameinto this country several years ago. It hasnever been taken down for decarbonisationor repair. The only modification has beenthe fitting of platinum ignition points.A mixture of one part heavy motor -cycleoil to 3 parts petrol is always used.Although it is oily and throws oil about, theengine certainly has worn well and still hasa hefty power output. I have flown thismodel on the new Ohlsson engine whichis 9 c.c. and a beautiful engine. Itsstarting is a delight and its power- outputexcellent. It also looks as if it will last.

I have described this low -wing model,as I think readers will be interested in itbecause the low -wing is a change from thealmost universal high -wing model, andbecause it is such a stable model ineveryway.

It is a delightfully slow -flying model and .

its glide is pretty to watch.


AN IMPULSE STARTER FORMODEL PETROL ENGINESTHE failure of model petrol motors to

start readily arises, most frequently,from the necessity of having to

prime the engine or to adjust the car-buretter to provide a richer mixture inorder to achieve the object.

In these conditions unless a start isimmediately effected the engine rapidly" juices up." When this has happened itnecessitates the drying out of the crank-case, etc., before operations can be recom-menced. Apart from this the wet mixturethus produced tends to destroy the oil -sealbetween the piston and cylinder whichconsiderably reduces the compressionnormally obtainable.

No Priming NecessaryUpon the assumption that the ignition

system functions perfectly it should bepossible to start the engine with certaintywithout prior priming and with the car-buretter set at its correct running position.In order to accomplish this it is, however,necessary to cause the engine to turnmomentarily at approximately runningspeed. While this may prove an easymatter, with the aid of a cord, where the

This device is quite simpleto make although it in-volves a certain amount

of lathe work

By W. H. DELLERmaterial that is to hand, in which case manyof the leading dimensions will be governedby those of the tube employed.

The right-hand or rear cap is made frombrass or mild steel. This is shouldereddown to fit inside the tube, being securedby three screws passing through clearanceholes into tapped ones in the, cap. Thecentre hole is drilled and reamed to permitthe hook -ended spindle to run freely in itand the mouth of the hole is counter -bored to receive a special split thrust -washer. It will be noticed that thiswasher fits into a groove which is turned inthe shaft before the hook is bent. Theouter end of this shaft is provided, with asquare and thread to engage and secure the

THRUST COLLAR CATCH SLOTSPRING

FLEXIBLE SHAFTSWEATED TO ENDS

/ ft ff

iligaer //

BALL RACE

MODIFIEDPROP. NUT TO

ENGAGE STARTER

g

@1

CATCH PIN

TUBECATCH HOUSING

L.

I

SKEIN OF RUBBER

engine is mounted in a boat, it is apparentthat where the method of starting is viathe prop. some other form of mechanicalaid is required in order to +impart therequisite speed to the crankshaft.

Where the engine provides the methodof propulsion .for a model aeroplane thedevice employed for the purpose underconsideration needs to be of reasonablysmall dimensions and easily portable. Thecontrivance illustrated fulfils these require-ments and has the advantage of being self-contained.

Constructional DetailsAs will be seen by reference to the sketch

shown in half section, which by the way isreproduced approximately half full-size,'the main part of the device is housed in aplain metal tube. This, in order to afforda better grip while the rubber is beingwound up, may be knurled on the outsideas indicated. The tube as shown is 1} in.diameter x 1/16 in. walls, but no generaldimensions are given as there is no reasonwhy the starter should not be made from

'AV?:

Cr,

a 5/32 in. diameter silver steel pin tightly.This pin is intended to engage with asliding catch which releases the drivingforce when required.

The CatchA 3/16 in. slot cut longitudinally in the

top of the tube forms a guide for the catchwhich is made from a 3/16 in. hexagonheaded steel bolt. It is advisable to filea square on the underside of the bolt headto fit this slot. A terminal nut fitted overa plain washer on the shank of the boltforms an operating knob: For the purposeof returning the catch to the back end ofthe slot it is backed up by a small spring.This is guided by a pin fitted into the bolthead tightly and guided in a clearance holedrilled, and counter -bored slightly to re-ceive the spring, in the top of the cap. 'Atthe front end of the flexible shaft a shoul-dered thimble is fitted with a cross pin toengage with the clop cut in the face of themodified prop. nut as shown in a separatesketch. .

A piece of shaft from an old speedometercable will provide the flexible shaft referredto. This will, however, require thoroughly

;PLIT THRUSTWASHER

KNURLED GRIP SPRINGANCHOR

Showing the construction of thedevice.

handle. Before bending the portion ofthe rod forming the hook it is tapered downas shown. The thrust washer is turned tofit the counterbore in the end cap and boredto clear the bottom of the groove in theshaft. To permit assembly the washer iscut across the centre line into two pieces.A washer and split pin on the inside of thecap prevents this assembly from comingadrift. -

Some form of check action needs to befitted to the winding spindle and the springclutch shown provides a simple solution.A tail on the end of the spring is anchoredby means of a small clip or saddle to theend plate.

Front End PlateThe front end plate is bossed and bored

to receive a small ball race. A thrustbrace is really what is required although anordinary race will serve for the purpose inthis instance. At this end the hookended shaft is similar to that at the oppositeend, the difference being that a thrustcollar is fitted by means of a pin to buttagainst the face of the inner race -ring andthe front end drilled to receive the shortflexible shaft. The front spindle is alsodrilled and reamed with a cross hole to take

SPRINGCLUTCH

Ldegreasing before the sweating operationsare attempted.

Rubber StrandsA fair amount of rubber strand is required

in the skein fitted over the hooks, but theactual amount will depend upon the sizeof the engine to be started. As drawn, theends of the hooks are approximately twoinches apart; the centres being made shortpurposely.

In use the rubber is wound up by makingabout half a dozen turns of the handle andafter engaging the end of the starter in thedog -ended nut on the propeller the enginestarted by releasing the catch pin, by

- pushing the knob forward.Although the device as described involves

a certain amount of simple lathe workthose who have not the facilities necessaryand to whom it may appeal can make it ina less elaborate but at the same time per-haps more cumbersome form. The tubewhen omitted is replaced by a wooden baseand the end caps by brackets attached tothe base. The other fittings can, of course,follow the lines more or less of thosedescribed.

84 NEWNES PRAO ICA.1._ MECHANICS November, 1938 November, 1938 NEWNES PRACTICAL MECHANICS 85

Maurice Reeve.

IN commencing the study of any instru-ment we must distinguish betweenthe musical and the mechanical, the

practical and the theoretical, the artisticand the technical. The latter is nothing butthe servant of the former, but if the wholeis to function perfectly, the servant mustbe very efficient !

We have three mechanical sides to thequestion :-

(a) The score.(b) The instrument.(c) The fingers with which we play

the instrument.It is the last of these three points with

which we are mainly concerned here, but

TREBLE NOTES

The PianoMAURICE REEVE,

an accurateknowledge ofthe scoreis absolutelyessential,to themusician aswell as thepianist.

It is the jobof the fingersto be able toexecute whatthe eye per-ceives on thepaper, whichis our presentobjective ofstudy. All thefinger dex-terity in theworld wouldbe wasted ifthe markingsand indica-tions con-tained on anywell - writtenand editedscore werenot under -toad. It ishe thorough

comprehen-sion of thesewhich makesthe job of the

fingers so difficult and their development totheir maximum of efficiency so necessary.Therefore an explanation of all that ascore contains must come first.

Some knowledge of the instrument weare using will also be necessary.

Every note is represented in two places,and must be sought in both, simultaneously,before the fingers can perform their ulti-mate task :-

(a) On the score.(b) On the keyboard.

A third representation should bedeveloped as soon as possible-the abilityto hear notes in our minds before soundingthem. The other two are inescapable for

THE FAMOUS

A New Method of LearningPIANIST,

MR. REEVE

every single note we set ourselves to play.Therefore, we have to develop the facultyof finding them with lightning rapidity andunfailing accuracy firstly on the paper withthe eye, and secondly on the keyboard withthe fingers: A semiquaver played atallegro speed is a very minute fraction oftime-there would be several to eachsecond !-and this is what has to beaccomplished if we wish to perform thefeat successfully. When we open the pagesof, say, a Beethoven Scnata, and con-template the tens of thousands of noteseach of which has to be played with exactcorrectness both as regards its pitch and itsvalue, and then the whole:work brought tolife by the fingers giving it an interpretationand an artistic consciousness, it will bequickly realised that the task of the fingersin co-ordinating these various elements-the acquiring of a " technique " that willdo justice to the music-is big indeed.

This treatise on the elements of pianofortetechnique divides the whole study into itsseveral parts with rather greater separate-ness than the majority of tutors. Theobject is to present in the clearest possibleway the various " ingredients " both of amusical work and the technical equipmentnecessary to play it satisfactorily. Theseare followed by the advice on the acquiringof the technique with which we ultimatelyweld the parts into a satisfactory per-formance. The subject naturally divideeitself into three main groups :-

(1) Sound(2) Time(3) Technical development

which enables us to unite the elementsmaking up a musical work. The principlesunderlining a musical and artistic renderingof a score will form the conclusion. Althoughfirst in practice, this last point must takeback place for the moment as it is impossibleto give life and meaning to the musicuntil :--

(a) We understand how it is written*, and(b) Until our fingers can carry out orders.The student, as a performer, is con-

fronted with three tasks, all of which work*In its bare elements the various branches of musical

study necessary for its complete understanding-harmony, form, etc , are not dealt with here.

8-AL

BASS NOTES_L

_ - - 7Wiz! -- ;,

; ; , ;

i3tiFc)030:qq4cDP4PcI? bDcD

I 11 [II 1.1'111 1111iA B C D E F G A B C D E F A B C D E F A B C D E F A B C D E F

mcDOcABcpE

Iii Iii11G. A B C D E F A B C D E F A

BC

B C

The keyboard lay -out

ALSO

TEACHES YOU HOW TO PLAY THE PIANO BY A NEW AND MODERN METHOD.REGULARLY BROADCASTS FROM THE B. B .C.

simultaneously in practice, but which mustbe very thoroughly understood as separateentities.

(1) Sound, which embraces the pitch ofindividual notes and the combination ofvarious notes into intervals and chords,keys and key relationship, scale andarpeggio sequences, etc., etc. ; everything,in fact, which is ultimately embraced inthe words HARMONY and MELODY.

(2) Time, including rhythm, accent,phrase construction, which lead, eventuallyto the FORM and STYLE of the composi-tion we play.

These two elements go equally to makeup a musical work. They are one andindivisible, and must always be togetherin the student's mind during every note hereads.

These concern him as a musician,whether pianist or anything else. Solelyas a pianist, however, it can be said withoutfear of exaggeration that the art of fingering,by which we mean the fingers we use foreach note and the way we use them, is ofsuch capital importance, that it can well beconsidered as the third element confrontingus.

In it is bound up the entire business oflearning how to play the piano. Withoutthe most careful use and manipulation ofthe fingers we can neither give expressionto our musical personalities through theworks which we choose to play, norcan we even correctly execute the meresttrivialities of the mechanical or con-structional side of the art. It is by far thebest plan to read this side of one's studiesin with the rest, thus making a habit ofcorrect fingering. After a short while, itceases to worry us overmuch, our forgersmove over the notes in front of us with everincreasing ease and accuracy, and ourminds are thus left freer and freer toconcentrate on the purely musical side ofour studies.

Having decided to combine three ele-ments into our reading, we will study themseparately first.

SoundMusical sounds are shown as NOTES

written on a STAVE, the notes being placedboth on and between the lines.

Almost all piano scores are written ontwo staves, one for each hand, joined by aBRACE.

Notes written off the stave are put onLEDGER LINES.

Before notes can be named we must fix

A stave

A trace

Ledger Lines

The G Clef

The F Clef

Middle C is the notewhich divides the two

hands

BEERIO 'S INSTRUCTIONS TO CARL CZERNY FOR THE TEACHING

OF HIS NEPHEW CARL VAN BEETHOVEN. .

:-In regard to his playing for you. I beg that not

until he has acquired a correct fingering and can playin time and can read the notes with reasonable correctness,you direct his attention to the matter of interpretation ;and thereafter not to stop him because of trifling mistakes,but to point them out after he has finished the piece.Although I have given but few lessons I have alwaysfollowed this method, it soon makes musicians which, at theleast, is one of the first purposes of art, and gives the mini-mum of weariness to both master and pupil.

CLEFS, which are the signs that determinethe absolute pitch of the notes. Only twoclefs concern the piano student, the G ortreble and the F, or bass.

Middle C is the note which divides thetwo hands on the score and the first ledgerline above the base clef and the first belowthe treble clef represent this note.

The hands can use either stave, as ismost convenient.

The Names of the Notes.The white notes are seven in number,

named A to G as in the alphabet andrepeated over throughout the length ofthekeyboard, from left to right.

The black notes, in alternate groups oftwo and three, are also named after thesame letters of the alphabet, but with theprefix of sharp # or flat b.

Sharps and flats are used to raise or lowernotes. The sharp raises it one semitone; thedouble sharp- X -, two semitones. Theflat lowers it one semitone and the doubleflat [7[7 two semitones.

The NATURAL, t4 is used to lower byone semitone a note that has been pre-viously sharpened, and, similarly, to raiseto its natural pitch a note which haspreviously been flattened.

To make a double sharpened note into asingle sharp it must revert to its natural

C D E

to Play Itstate and be re -sharpened andsimilarly when flattened lab.

The double natural, 1111 cancels a doublesharp or double flat, that is, it restorestheni to their normal pitch.

Semi-tone.-One note to the next one-white or black.

Tone-One note to the NEXT BUT ONE.It will now be seen that the keyboard

divides itself into groups of TWELVEnotes, seven white and five black. It isfrom these twelve notes that we get ourkeys, twelve major and twelve minor.From each note to the next of the svanename is called an OCTAVE.

The last note of one octave is the first ofthe next. Thus from A to A is an octaveand the one A is called the octave of theother.The Progression of the Notes

When we say that a piece is in such andsuch a key-C major or B minor-we meanthat the piece is solely or mainly founded onthe major or minor scale which starts fromthe note specified. There are only twomodes but many keys.

SCALE.-Major (greater) as applied tointervals, chords and scales. The majorscales-keys-are formed by the followingsequence of intervals, commencing on anynote :

Tone, tone, semitone, tone, tone, tone;semitone. Whatever note is started fromgives its name to the scale or key.

Thus we get the key of C major. Thesame sequence of intervals, starting on G,

T0NE

The major scales.

C MAJOR

dJ ll

Ami

0NE

TONE

S TE 0M N

E

caJ

C MINOR, TONIC MINORKEY SIGNATURE OF

J

EFLAT RELATIVE MAJOR

AUGMENTED SECOND

An enharmonic representation of C minor scale.

A MINOR (RELATIVE)

#41i

AUGMENTEDSECONDC MAJOR

J(x

r rI 2 3 4 5 6 7 8

The relative minor of a major commences on the sixth note of the scale, the seventhnote being changed by raising it one semitone.

84 NEWNES PRAO ICA.1._ MECHANICS November, 1938 November, 1938 NEWNES PRACTICAL MECHANICS 85

Maurice Reeve.

IN commencing the study of any instru-ment we must distinguish betweenthe musical and the mechanical, the

practical and the theoretical, the artisticand the technical. The latter is nothing butthe servant of the former, but if the wholeis to function perfectly, the servant mustbe very efficient !

We have three mechanical sides to thequestion :-

(a) The score.(b) The instrument.(c) The fingers with which we play

the instrument.It is the last of these three points with

which we are mainly concerned here, but

TREBLE NOTES

The PianoMAURICE REEVE,

an accurateknowledge ofthe scoreis absolutelyessential,to themusician aswell as thepianist.

It is the jobof the fingersto be able toexecute whatthe eye per-ceives on thepaper, whichis our presentobjective ofstudy. All thefinger dex-terity in theworld wouldbe wasted ifthe markingsand indica-tions con-tained on anywell - writtenand editedscore werenot under -toad. It ishe thorough

comprehen-sion of thesewhich makesthe job of the

fingers so difficult and their development totheir maximum of efficiency so necessary.Therefore an explanation of all that ascore contains must come first.

Some knowledge of the instrument weare using will also be necessary.

Every note is represented in two places,and must be sought in both, simultaneously,before the fingers can perform their ulti-mate task :-

(a) On the score.(b) On the keyboard.

A third representation should bedeveloped as soon as possible-the abilityto hear notes in our minds before soundingthem. The other two are inescapable for

THE FAMOUS

A New Method of LearningPIANIST,

MR. REEVE

every single note we set ourselves to play.Therefore, we have to develop the facultyof finding them with lightning rapidity andunfailing accuracy firstly on the paper withthe eye, and secondly on the keyboard withthe fingers: A semiquaver played atallegro speed is a very minute fraction oftime-there would be several to eachsecond !-and this is what has to beaccomplished if we wish to perform thefeat successfully. When we open the pagesof, say, a Beethoven Scnata, and con-template the tens of thousands of noteseach of which has to be played with exactcorrectness both as regards its pitch and itsvalue, and then the whole:work brought tolife by the fingers giving it an interpretationand an artistic consciousness, it will bequickly realised that the task of the fingersin co-ordinating these various elements-the acquiring of a " technique " that willdo justice to the music-is big indeed.

This treatise on the elements of pianofortetechnique divides the whole study into itsseveral parts with rather greater separate-ness than the majority of tutors. Theobject is to present in the clearest possibleway the various " ingredients " both of amusical work and the technical equipmentnecessary to play it satisfactorily. Theseare followed by the advice on the acquiringof the technique with which we ultimatelyweld the parts into a satisfactory per-formance. The subject naturally divideeitself into three main groups :-

(1) Sound(2) Time(3) Technical development

which enables us to unite the elementsmaking up a musical work. The principlesunderlining a musical and artistic renderingof a score will form the conclusion. Althoughfirst in practice, this last point must takeback place for the moment as it is impossibleto give life and meaning to the musicuntil :--

(a) We understand how it is written*, and(b) Until our fingers can carry out orders.The student, as a performer, is con-

fronted with three tasks, all of which work*In its bare elements the various branches of musical

study necessary for its complete understanding-harmony, form, etc , are not dealt with here.

8-AL

BASS NOTES_L

_ - - 7Wiz! -- ;,

; ; , ;

i3tiFc)030:qq4cDP4PcI? bDcD

I 11 [II 1.1'111 1111iA B C D E F G A B C D E F A B C D E F A B C D E F A B C D E F

mcDOcABcpE

Iii Iii11G. A B C D E F A B C D E F A

BC

B C

The keyboard lay -out

ALSO

TEACHES YOU HOW TO PLAY THE PIANO BY A NEW AND MODERN METHOD.REGULARLY BROADCASTS FROM THE B. B .C.

simultaneously in practice, but which mustbe very thoroughly understood as separateentities.

(1) Sound, which embraces the pitch ofindividual notes and the combination ofvarious notes into intervals and chords,keys and key relationship, scale andarpeggio sequences, etc., etc. ; everything,in fact, which is ultimately embraced inthe words HARMONY and MELODY.

(2) Time, including rhythm, accent,phrase construction, which lead, eventuallyto the FORM and STYLE of the composi-tion we play.

These two elements go equally to makeup a musical work. They are one andindivisible, and must always be togetherin the student's mind during every note hereads.

These concern him as a musician,whether pianist or anything else. Solelyas a pianist, however, it can be said withoutfear of exaggeration that the art of fingering,by which we mean the fingers we use foreach note and the way we use them, is ofsuch capital importance, that it can well beconsidered as the third element confrontingus.

In it is bound up the entire business oflearning how to play the piano. Withoutthe most careful use and manipulation ofthe fingers we can neither give expressionto our musical personalities through theworks which we choose to play, norcan we even correctly execute the meresttrivialities of the mechanical or con-structional side of the art. It is by far thebest plan to read this side of one's studiesin with the rest, thus making a habit ofcorrect fingering. After a short while, itceases to worry us overmuch, our forgersmove over the notes in front of us with everincreasing ease and accuracy, and ourminds are thus left freer and freer toconcentrate on the purely musical side ofour studies.

Having decided to combine three ele-ments into our reading, we will study themseparately first.

SoundMusical sounds are shown as NOTES

written on a STAVE, the notes being placedboth on and between the lines.

Almost all piano scores are written ontwo staves, one for each hand, joined by aBRACE.

Notes written off the stave are put onLEDGER LINES.

Before notes can be named we must fix

A stave

A trace

Ledger Lines

The G Clef

The F Clef

Middle C is the notewhich divides the two

hands

BEERIO 'S INSTRUCTIONS TO CARL CZERNY FOR THE TEACHING

OF HIS NEPHEW CARL VAN BEETHOVEN. .

:-In regard to his playing for you. I beg that not

until he has acquired a correct fingering and can playin time and can read the notes with reasonable correctness,you direct his attention to the matter of interpretation ;and thereafter not to stop him because of trifling mistakes,but to point them out after he has finished the piece.Although I have given but few lessons I have alwaysfollowed this method, it soon makes musicians which, at theleast, is one of the first purposes of art, and gives the mini-mum of weariness to both master and pupil.

CLEFS, which are the signs that determinethe absolute pitch of the notes. Only twoclefs concern the piano student, the G ortreble and the F, or bass.

Middle C is the note which divides thetwo hands on the score and the first ledgerline above the base clef and the first belowthe treble clef represent this note.

The hands can use either stave, as ismost convenient.

The Names of the Notes.The white notes are seven in number,

named A to G as in the alphabet andrepeated over throughout the length ofthekeyboard, from left to right.

The black notes, in alternate groups oftwo and three, are also named after thesame letters of the alphabet, but with theprefix of sharp # or flat b.

Sharps and flats are used to raise or lowernotes. The sharp raises it one semitone; thedouble sharp- X -, two semitones. Theflat lowers it one semitone and the doubleflat [7[7 two semitones.

The NATURAL, t4 is used to lower byone semitone a note that has been pre-viously sharpened, and, similarly, to raiseto its natural pitch a note which haspreviously been flattened.

To make a double sharpened note into asingle sharp it must revert to its natural

C D E

to Play Itstate and be re -sharpened andsimilarly when flattened lab.

The double natural, 1111 cancels a doublesharp or double flat, that is, it restorestheni to their normal pitch.

Semi-tone.-One note to the next one-white or black.

Tone-One note to the NEXT BUT ONE.It will now be seen that the keyboard

divides itself into groups of TWELVEnotes, seven white and five black. It isfrom these twelve notes that we get ourkeys, twelve major and twelve minor.From each note to the next of the svanename is called an OCTAVE.

The last note of one octave is the first ofthe next. Thus from A to A is an octaveand the one A is called the octave of theother.The Progression of the Notes

When we say that a piece is in such andsuch a key-C major or B minor-we meanthat the piece is solely or mainly founded onthe major or minor scale which starts fromthe note specified. There are only twomodes but many keys.

SCALE.-Major (greater) as applied tointervals, chords and scales. The majorscales-keys-are formed by the followingsequence of intervals, commencing on anynote :

Tone, tone, semitone, tone, tone, tone;semitone. Whatever note is started fromgives its name to the scale or key.

Thus we get the key of C major. Thesame sequence of intervals, starting on G,

T0NE

The major scales.

C MAJOR

dJ ll

Ami

0NE

TONE

S TE 0M N

E

caJ

C MINOR, TONIC MINORKEY SIGNATURE OF

J

EFLAT RELATIVE MAJOR

AUGMENTED SECOND

An enharmonic representation of C minor scale.

A MINOR (RELATIVE)

#41i

AUGMENTEDSECONDC MAJOR

J(x

r rI 2 3 4 5 6 7 8

The relative minor of a major commences on the sixth note of the scale, the seventhnote being changed by raising it one semitone.


PERFECT 5T."OCTAVE

How arpeggios are formed.

C.MAJOR

a J J

C MINOR MAJOR THIRDMAJOR SIXTH

6J J

JJ

-o- e.'MINOR THIRD

MINOR SIXTH

results in the key of G, and when beginningon B flat, the key of B flat, etc.

MINOR (Smaller).-Takes its namefrom the smaller intervals between thefirst and third and the first and sixth notes.

Keys are related to each other and aresaid to be most closely related when thereare fewest notes altered. Then the twonearest " relations " are a major and itsrelative minor, and any major and itsdominant major, there being only one notealtered : one note being sufficient com-pletely to change the key or tonality.

The relative minor of a major commenceson the sixth note of the scale. From that

r

(Left) Two noteshave to be changedto turn a major into'ts tonic minor scale,the third and thesixth, both beinglowered ont semitone.

variety in both rhythm and expression,three, or any odd number of notes can beplayed to the same value. But this isalways notified thus :-

This gives us, ascending, a sequence thesame, with the one exception of the thirdnote, as the tonic major, A; and, descending,it is identical to the relative major, C.It is a very beautiful mode, and either theascending or the descending sequence canbe used on its own. These are known asthe DIATONIC scales-scales in whichTONES predominate.

ARPEGGIOS are formed from the 'chords of the major and minor keys with thenotes played separately.

They consist of the 1st, 3rd, 5th and 8th,or 1st repeated, notes of the scale-thesame in both major and minor: and are

4 different notation descending from that ascending.

then said to be in the ROOT position.CHROMATIC scales are formed by

progressing in semitones, or, in other words,using all the notes one after the other.

The sharps and flats placed at thePERFECT beginning of a stave are called the KEY

SIGNATURE. Those occurring during thecourse of a score, ACCIDENTALS.-Anaccidental lasts for the duration of a bar

r

Chromatic scales.

point, only the seventh note is changed, byraising it one semitone-sharpening. Whenthe minor scale begins on the same note asany given major scale, it is referred to asthe TONIC minor-tonic being the namegiven in harmony to the first note of anyscale.

It will be seen that two notes have to bechanged to turn a major into its tonicminor scale, the third and the sixth, bothbeing lowered one semitone-flattened.

Melodic MinorThe harmonic minor, with its augmented

second, was found to be a drawback, con-sequently the melodic variety was invented,with its adherence to tones and semitones.But it introduces a further element inas-much as it gives a different notation descend-ing from that ascending.

a

Semibreve. Minim. Crotchet.

JoJ JE,..1

only; if not cancelled before, the bar lineautomatically does so.

TimeNote Values and Rests.-As well as

having a sound, or pitch, a note mustpossess a definite value.- Thus the twoelements, heretofore mentioned, are in-extricably linked and should never be readone at a time, as is so frequently done.

Next to each note is its equivalent inRESTS. The value of each succeedingnote or rest is one half of the preceeding one.

Quavers and smaller fractions are alsogrouped together.

A dot by the side of a note or restincreases its value by one half.

Although note values are based on therule of " twice one make two," this ruleis not immutable, and for the purposes of

ei

Quaver. Semiquaver. Dem'semiquaver.

Three, or any odd number of notes, can be playedto the same valise for purposes of rhythm.

Diagram of rule for counting notevalues :-0 semibreve.

r

minim-one han.

crotchet-quarter of semibreve, halfof minim.

quaver-one eighth.

semiquaver-onp sixteenth.

demisemiquaver-one thirty-second.

semidemisemiquaver-one sixty-fourth.

There are -larger and smaller fractions inthe same ratio.

RhythmFor the purposes of giving form, balance

and coherence to a musical work, it has to begiven a rhythm-the division of the scoreinto bars and a fixed value to each bar,

Dividing the scoreinto bars.

together with accenting, phrasing andgrouping pf the notes and bars must beunderstood. There are three kinds of time-duple, quadruple and triple. Each ofthese can be both simple and compound.

The numbers at the commencement of awork are known as the " time signature,"and denote the time and rhythm in whichthe piece is to be played. The lower figuretells the kind of note and the upper thenumber of those notes there are in each bar.

Four is a crotchet, one-fourth of a semi-breve-a whole note. Duple time has twobeats in a bar. Quadruple-" commontime "-four beats. Triple, three beats.

Phrasing-Refers to the proper articula-tion and accentuation of musical thoughts(of periods and their sub -divisions, phases,sections, etc.); it is in music what stops andthe raising and lowering of the voice are inspeaking and reading, and accents are vitalparts in.a complete interpretation of a pieceof music. The student should cultivate thehabit of reading their various markings onthe score as he goes along through a piece,rather than try to add them in after havingread the notes first.

There are three kinds of accent :-( 1) Metrical-giving regularly recurring

emphasis-such as the well-knownrhythm of a Valse or March.

(2) Rhythmical-which is, unlike the

Ur Quavers and smaller frac ions grouped together.

November, 1938 NEWNES PRACTICAL MECHANICS '87

Metrical, unfettered, and embraces wholesentences and periods. In short, thewords " metrical " and " rhythmical 'are used to distinguish the fixed, mechan-ical bar -accent, from the free, poeticmotive -accent.

(3) Pathetic.-Is not dictated by rule,as 1, or intelligence, as 2, but by bothcombined with taste, feeling and imagina-tion.Having thoroughly mastered those

portions of the rudiments and theory ofmusic necessary for the perfect understand-ing of a score, we can approach the mainpart of our studies with far greater assur-ance and composure than would otherwisehave been the case-the training ofthe fingersproperly to execute the score and thensatisfactorily present the work for heiring.Upon the ability of the fingers to :-

(a) Play every note without the leastfaltering or possibility of striking awrong one;

(b) To give every note its exact value,i.e., to pass from note to note within thespecified measure of crotchet, quaver,etc., thus assuring the perfect rhythmand balance of the piece; and

(c) To infuse the whole performancewith poetic and artistic feeling, light andshade, variety of tone colour, the correcttempi, etc., etc.

depends the measure of your success asa pianist.

TechniqueThe absolute foundation of pianoforte

technique, and the primary ingredient,first, last, and all the time, is the ability ofthe fingers to make a perfect join betweenevery two notes. This can be said withoutany fear of contradiction, although .manyother ingedients are necessary in order to dopoetic justice to the music we set out toplay. But correct finger work is the root,or the soil, from which all the other productsspring.

Two things are necessary-both of themmuch more easily said than done ! Firstly,we have to bring the five extremely un-equal fingers into line. Their great ine-qualities of length, strength and dexteritymust be levelled up as far as possible. And,secondly, they must be trained to proceedfrom note to note by their own unaidedegort (I refer, of course, to legato passagesof single or double notes). When variety ofexpression calls for different qualities oftone and touch, an extension of one'sstudies to cover these phases of techniquebecomes necessary. But legato fingerwork,in all shades of tone, still remains the firstrequisite of good piano playing.

This discussion only concerns the pro-duction of a pure finger action, from whichthe higher, and later, branches of pianotechnique can grow, at a more or less evengrade of tone. The development of tonecolour-the ability of the fingers to producevarious shades of loud or soft tone forgiving variety of expression to the music,depends on the weight with which onestrikes the keys, and the height from whichone strikes them, too. Also the co-operationof wrist and arm. But this is only referredto here more as information and cannot beentered into at any length.

But even from the earliest stage, anexamination of " what happens inside " thepiano when one plays a note should bemade. The chain of causes from the momentone presses a note down in order to producesound, to the production of the sound itself,is an important item to get to know. Thetouch of pianos varies tremendously accord-ing to their size and age, and it might takefifteen or twenty times the weight toproduce a given tone quality on one instru-

ment than it does on another. It is always agreat handicap to a player, on frequentlyfinding himself at different instruments,to have to adjust his technical equipmentto the needs of the moment-unlike aviolinist, who, presumably, always carrieshis own instrument about with him.

This slight digression will serve toemphasise the importance of the instrumentand its action on the player's fingerworkand the results his fingers produce.

After the first note of a sequence has beenstruck, three acts should be simultaneouslyperformed at every subsequent note in thesequence :-

(a) The note is struck, and sustained.(b) The finger that is to play the note

after that is raised from the knuckleto its highest extent, in preparationfor the playing of that note, and

(c) The previous note is released and thatfinger, also, raised to its highestextent.

The player's posi-tion at the pianomust necessarilyvary considerablyaccording to his orher physique, age,etc. But it can belaid down that ashort to averageperson should sitwell into the key-board with theweight of their bodythrown forward togive the maximumcontrol and powerto the fingers andarms. The seatshould be of aheight to enablethe forearm andwrists to be absol-utely parallel withthe ground.

With taller per-sons the length oftheir arms and legswill compel themto sit farther awayfrom the instrumentwithout their losingany control oftheir manipulation

sary for the different phases of techniquecalled upon by all work of imagination midmusical value-staccato, double notes,octaves, non -legato passages, chords,martellato, etc., etc.; by far the finestexercises for all general purposes are themajor and minor scales and their arpeggios.They are also very easily adaptable toseveral of the aforementioned technicalrequirements. Furthermore, they are in-valuable as ear training and for a develop-ment of a sense of key distinction-such anecessary item of one's equipment. And,lastly, their fingering forms the basis for thefingering of all scale and arpeggio notesequences in piano music-surely a fairproportion of the whole of one's task as apianist !

If all scales are practised with " C major "fingering, they form exercises of the higheststandard and greatest value. In fact, theymake of the piano a veritable gymnasiumfor the fingers !

DUPLE TIMESIMPLE COMPOUND

2= TWO MINIMS r r IN A BAR

4= TWO CROTCHETS r r IN A BAR

ti= TWO QUAVERS ri r INA BAR

6_TWO DOTTED .0 R SIX

4-MINIMS r r CROTCHETS

6_TWO DOTTED OR SIX

8- CROTCHETS ITQUAVERS

6_TWO DOTTED. OR SIX16 QUAVERSp 'p'SEMIQUAVERS

QUADRUPLE TIME

4oRC=FOUR CROTCHETS INABAR12,_FOUR DOTTED CROTCHETS

8 -OR TWFIVE QUAVERS

TRIPLE TIME

3 -IHREE MINIMS IN A BAR2-3_

THREE CROTCHETS INABAR4-3- THREE QUAVERS IN A BAR8-

9_ THREE DOTTED4 MINIMS INA BAR

9_ THREE DOTTED8- CROTCHETS INA BAR

9_ THREE DOTTED16 QUAVERS INA BAR

of it; there is no need to feel uncom-fortable in any way, and on no accountshould the legs feel cramped or hamperedin their usage of the pedals.

This is the correct way to practise, andto gain the maximum of finger dexterity,and response to the most exacting music.Naturally, it only produces one kind ofresult. As many results are required duringthe performance of a piece, this action isbeing constantly varied and adapted toever-changing needs. But after training onthese lines plus speciality exercises, the handsbecome readily adaptable to these demands.

In raising the fingers in this manner, allstiffening in the wrists and arms must bemost carefully avoided. Some stiffening, ortiring, is unavoidable for some time. Thisis counteracted by frequent pauses forrelaxation without releasing the note beingplayed at the moment.

Advantage should be taken, on all notesof long value, tied notes, pauses, etc., ofletting the hand and arm completely relaxby sinking into the note-only for a briefmoment, as the preparation for the nextnote must not be delayed too long.

The observance of rests, too, is not onlyof the greatest importance aesthetically;but as further " breathing spaces," orchances for relaxation.

Although speciality exercises are neces-

The construction of scales is dealt withunder " sound."

Positions of the HandsThe hand should be placed with the thumb

well over the keys. This gives greatest poiseand balance, and, consequently the maximumfreedom and agility-responsiveness of thefingers. It is most important that the thumbshould at all times be well over the keyboardand ready for instant use. In addition to thereasons mentioned above, its use may beindispensable in all intervals or chords of aspan of five notes and over, and, in singlenote sequences, it is our sole means of" climbing " up and down the keyboardand maintaining that continuous legato-joining of the notes-emphasised elsewhere,instead of having to proceed by means ofkangaroo hops and leaps !

It is a good plan, when placing the handson the keyboard preparatory to playing, toimagine the keys to be loose and that youare going to pick them up like money offa counter or counters off a table. Youwouldn't try to pick your change up withfour fingers, leaving the thumb a lonespectator; doing nothing. The tips of allfive fingers would touch the surface and" close in " over whatever money orcounters happened to be there.

(to be continued'


(Left). The model of Euston showing the modern train in the foreground, nearing completion. (Right). Model of the original train leaving Euston Station.

EUSTON STATION 100 YEARS AGOAs most readers will be aware this

year of 1938 marks the Centenaryof the opening of the first long-

distance main line railway, namely thatbetween London and Birmingham. Thestation which formed the metropolitanterminus of the line was completed in timefor the departure of the first through trainon September 17th, 1838. To mark thisCentenary the successors to the Londonand Birmingham Company, later theLondon and North Western Railway andnow the London, Midland and Scottish,celebrated the occasion by holding anexhibition at Euston. A portion of thisexhibition was centred in the shareholders'meeting room beyond the Great Hall.It was opened by Lord Stamp on Mondaythe 19th of September and continued forthe inspection of the public until Sundaythe 25th.

A prominent and picturesque item, whichserved perhaps as the principal centre ofinterest, was a model of Euston Station asit was one hundred years ago. This modelprovides an excellent example of thecraftsmanship of two well-known Companiesof model makers who associated themselvesin fulfilling in a most excellent manner therequirements of Mr. G. H. Loftus Allen,chief of the Publicity Department of theL.M.S.R.The model consists of two portions,one representing the year 1838 and theother this year of grace 1938. The historicalklection is the work of Twining Models Ltd.,whilst the present day is represented by asplendid example of the products of Bassett-Lewke Ltd.

Various SectionsDealing with the sections of the model in

chronological order, the model shows at theleft-hand end, to a scale of in. to 1 foot,the world famous Doric Portico flanked bythree of the four lodges with their entrancegates between them. The accompanyingphotographs will show that Euston origin-ally had two comparatively short bays in theroof covering the arrival and departureplatforms, and that one side of one of thebays was supported by the building whichcontained booking offices and waitingrooms.

The platforms extended to a considerablelength beyond the station roof and near

E. W. Twining.......Details Of A Model WhichWas A Prominent FeatureOf The L.M.S.'s Exhibition

Recently Held At Euston

the departure platform is modelled anexact replica of the London and Birminghamtrain as shown in Osborne's original mapof the railway. This train consists of aBury 2-2-0 type locomotive with insidebar frames, 5 ft. 6 ins. driving -wheels and aboiler having a domed firebox covered withcopper cleading. Behind the tender thereis shown two first-class carriages, thena carriage truck carrying a road vehicle,which was of a new type one hundred yearsago, and was known as a brougham, then asecond-class open carriage and lastlythe mail coach, which also carried first-class passengers.

At the right-hand end of the modelthere is an overbridge, since removed,- withWriothesley Street crossing it. Betweenthe station and the retaining wall of theapproach to the bridge is the carriage shedwhere coaches were stored and also repaired.

A FeatureThe feature about the model which

perhaps more than anything gives it interestand life is the large number of model humanfigures, nearly one hundred in all, in correctcostume of the period. The brilliant colour-ing of some of the ladies' dresses addsgreatly to the picturesque effect. Theengine driver and fireman are posed on theengine and tender and brakesmen areriding in the seats provided for themupon the roofs of the carriages. All thecoaches have a reasonable complement ofpassengers, many of them lookinginterestedly out of the windows. Thecharming feature of these little " people "is that they are all apparently doing some-thing with a definite object in life and havenot the appearance of being mere dummies.

Some difficulty was experienced indiscovering the correct colours for thecoaches, but it was finally found that onehundred years ago some of the first-classcarriages had their lower panels paintedgreen 'of a similar shade to the lagging ofthe boilers and tenders of the engines. Othercoaches were red as were also the mailcoaches, whilst the second-class " opens "were all varnished oak. Besides thebrougham on the carriage truck, which hasyellow panels, there is another on theapproach road with a dapple grey horse inthe shafts. This gentleman's carriage haspanels of blue.

The permanent way, upon which theold train stands, is almost exactly afacsimile in miniature of the original.The rails are of a light pattern carried inchairs without wooden keys. These, chairsare spiked down to imitation stone sleepersarranged diamond fashion.Modern Equipment

Turning our attention to the modernequipment, the track is of full weightbullhead rail on wooden sleepers properlyballasted and laid upon a shelf forming anintegral part of the model at a considerablylower level. At each end there is a correctlyshaped eliptical arch with a tunnel front inblue brick and between the tunnel fronts

'is a long retaining wall with buttresses.The train which runs upon this is made upof six coaches hauled by a " Royal Scot 'locomotive and represents a typical expresswhich performs the journey betweenEuston and Birmingham in under two hours.Near the entrance to the tunnel at the right-hand end is a signal of the two colourtrafficlight type.

In addition to the model of EustonStation there was an excellent display ofother models in the same room includinga 1 inch to the foot model of the " PrincessRoyal " made by Messrs. Bassett-LowkeLtd., for the Johannesburg Exhibition,and also two 1 inch to the foot scale model -coaches with a portion of the roof removedshowing the interior-one a first-classkitchen car and the other a first-classdining car. These were also the work ofBassett-Lowke Ltd., ,and attracted muchattention from connoisseurs of good scalemodels.


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MODEL AFROTOPICSCurrent News from the World of Model Aviation

An Engine Testing PlantTHE design of model petrol engines is

showing rapid progress. The somewhattemperamental nature of these small enginesis aggravated as the cubic capacity getssmaller, and now that we are down to 3 c.c.,2 c.c., and 1 c.c., the chief problem is to getthe engines to start. Most of them have nota wide range of speed. None of them havetick -over, and hence a fairly high crankshaftspeed is necessary in order to start them.To get, over this difficulty, several torquestarters have been put on the market, andelsewhere in this issue we explain how tomake one.

Many of .the engines which have beendesigned have been produced by hit andmiss methods, but I am glad to know thatmany firms are now treating the matterseriously, and are installing testing plantsso that they can analyse results. One ofmy readers, Mr. A. E. Browne, of Chiswick,has made an ingenious engine testing stand.He writes : "The stand was built to testsmall petrol engines and props from 6 c.c.to 10 c.c. It gives a recording for staticthrust, engine temperature at differentspeeds, carb. suction, exhaust back pressure,

Electron EngineMountings sup-plied by Kanga

Models.

amps. consumed on starting and running,speed r.p.m. is recorded on a speed indi-cator and rechecked on a Hasler time andr.p.m. clock. The following may interestyou. On the tests of a Baby Cycloneengine, fitted with a prop supplied by theCyclone people, ,one hour test gave thefollowing

21 lb. thrust at 4,650 revs. ; engine temp.,65 degrees cent. ; I amp. consumed at abovespeed, 4f amp. to start; back pressure, 1ounce, 1 gram, which, according to informa-tion I have secured suggests wrongly de-signed exhaust pipe ; carb. suction is 1 oz.11 grams. I have tried a larger and smallerair intake to get greater speed, but find thatthe one supplied is best. 4,670 is the highestspeed I have had from this engine, which

has run on and off forabout 16 hours. I don'tmind saying that thisengine has been putthrough its paces. Ihave not treated it atall gently, rev'ing from400 revs. up and downflat out. I must say herethat I used only Valvo-line oil. I tried anotherwell-known brand whichconformed to the SAE70 degrees specification,but found the enginetemperature going up.So I got in touch withthe Valvoline Co. andthey supplied me withsome Valvoline SAE.70,as specified by the enginemakers. I ran the enginein with 3 parts Shell, 1part Valvoline, but I gotbest results from 5 partsShell, 1 part Valvoline.

You will remember mewriting to you last yearfor information on thebest way to constructthis stand, but you didnot seemto holdout muchhope of me being able to do it. Itwas the same with other people I wroteto; it seems to me that they just stickthe engine in a vice and as long as it

runs it's O.K., but they don'tseem to find out what the enginecan do. I am not a technicianby any means, but I thought itcould be done and you see foryourself the results. My ideais to use this stand for the demon-

stration of model -engines. I may tellyou that the cost has been very high.You must remember I had no data to workto. My readings have been checked by twogentlemen in the aircraft world whosenames I cannot repeat here,but should this information bepublished I should like themto know that it was throughyour help and advice that thistest stand came to be built."

Engine MountingsI IGHT engine mountingsI- in electron are made intwo sizes and supplied byKanga Models, Ltd., 1,Colonnade Passage, NewStreet, Birmingham. I show

a sketch of them on this page.They are so designed that theengine will knock off in theevent of a crash. There is aspigot behind the mountingwhich fits into a hole cut inthe first bulkhead of thefuselage. As supplied theyare rough castings and needto be cleaned up, and a file isall that is necessary for thispurpose.

An Engine Testing Stand made byMr. A. E. Browne.

Records PassedC. W. Needham (O1P1 hand -launched),

71.4 sec.P. M. H. Lewis (R.O.W. Flying Boat),

33 sec.A. C. Minion (Biplane R.O.G.), 4 min. 57

sec.A. B. Rainey (Ornithopter hand -

launched), 20 sec.C. W. Needham (O1P1), 1 min. 26.2 sec.C. W. Needham (O1P1), 1 min. 27.25 sec.

1939 Wakefield CompetitionTHE S.M.A.E. have decided that altera

tions will not be made to the rules fornext year's Wakefield Competition, but that

The Hallam 10 c.c. Engine.

92 NEWNES PRACTICAL MECHANICS

alterations and amendments to the organi-sation side will be discussed.Results of the Biplane Cup

Average PluggeSec. Pts.

1. H. Holbrook (Lanes.) ... 135.73 672. C. S. Rushbrooke (Lanes.) 133.16 663. A. Tindall (Lanes.) ... 132.33 654. H. Jones (Dartford) ... 124.83 645. R.A.H.Johnson (Halifax) 116.66 636. P. L. Smith (Lanes.) ... 100.16 62

Speed Contest Results M.p.h.I. C. Lucas (Brighton) ... ... 34.375R. Brown (Blackheath) ... .- 31.375H. L. Rogers (Nthn. Heights) Broken Motor.

There were only three entries.

Farrow Shield Result1. Luton and District ..2. Halifax M.A.C.3. Bristol & W.M.A.04. Dartford M.F.C. 5. Lanes. M.A.S.6. Birmingham M.A.C.

Points804.5630.3606.4525.6524.9518.2

An attractive model madeBobbins for ElasticM ODEL aeroplanes were well repre-

sented at the recent Model EngineerExhibition, and a great deal of the toil hasbeen taken out of model making by the

November, 1938

Another view of Mr. Wareham's model Hawker Hurricane-the first prize winner in our recent contest.

supply of correct fittings such as bearing,thrust washers, accurately cut wood, ribsections, etc. One of the troubles withelastic driven models has been the tendencyfor the elastic to climb round the hook, andif the hook is not of the closed variety theelastic when wound comes off and often doesconsiderable damage, especially to balsamodels. I noticed on one stand some smallbobbins which enable the skein to be made

by The Model Aerodrome.up complete, and then to be dropped on tothe hooks at the rear and propeller shaft.

There is a tendency amongst clubmen toadopt the plaiting system with elasticskeins. That is to say, the skein is made up

twice the length between the hooks and itis then twisted and doubled and placed onthe rear hook. The skein is then stretchedwhilst winding, and it is claimed that thereis less risk of bunching of the rubber at eachend of the skein and that more turns canbe placed on it.

The Hallam 10 c.c. EngineTHE Hallam 10 c.c. in. bore 1 in. stroke

engine will meet the requirements ofthose who require ample power to lift modelaeroplanes from 5 to 8 pounds in weight,and is obtainable complete. ready to run, orin sets of castings with fully detailed printand materials.

The engine is 4f in. high, overall, If in.between bearers and 2i in. wide over sidebrackets, 51 in. long from end of tank topropeller nut. The cylinder and crankcaseare in one casting with transfer passagecored out. The ends are recessed into thecrankcase and secured by 3 one -eighththrough bolts and steel liner and cast ironpiston are employed with gudgeon pincompletely shrouded. The suction tank ismachined from a casting and bolted directto the rear end of crankcase. Exhaustmanifold provides easy attachment for i-in.exhaust pipe. The engine drives a 15 in.propeller 9 in. pitch, with blade area of20 sq. in. and gives static thrust of 3i lb. at3,400 r.p.m. ; maximum r.p.m. with flywheel15,000.

The set of eleven castings, print, nutsscrews and materials cost 17s. 6d. The majoroperation of boring the crankcase requiresa lathe that will swing 3i by 2 in. All otheroperations can be accomplished with a 2 in.centre. Boring and facing the crankcasecosts 5s. The finished engine complete withpropeller, coil condenser, on test standcosts £5.

At our Model Hawker Hurricane Contest at Brooklands. The fudges, and an Inspection.


STARGAZING FOR AMATEURSTHERE will be a' partial eclipse of the

Sun on the 21st; but since it will nottake place until about midnight

(G.M.T.) it will not be visible from theseislands. The maximum phase of theeclipse will be observable from Alaska.There will, however, be an even morestriking spectacle to be seen from thiscountry on the evening of the 7th, when thefull Moon will be totally eclipsed by theshadow of the Earth.. Our satellite will riseat sunset and begin to be slightly dimmedby the penumbra, or " false shade," at7.39 p.m. At 8.41 p.m. the Moon willenter the umbra or true shadow and be

ii y N. de NullyA GUIDE FOR NOV.

will occupy an hour and twenty-threeminutes, the maximum possible beingabout two hours and the minimum anythingdown to a grazing contact. This particulareclipse will commence in a darkening skywith the Moon well up in the south-east. Anaked -eye view is perhaps the most

Diagrammatic drawing of a total lunar eclipse showing the moon passing through the earth's shadow.Note the fainter penumbra on each side of the earth.

entirely immersed by 9.45 p.m. Totalitywill last until 11.8 p.m., after which theeclipsing veil will commence to draw offand the disc will be clear again at twelveminutes past midnight. By 1.15 a.m.(morning of the 8th) even the faint penum-bra will have disappeared and normalbrilliancy have been restored. It is to behoped that the weather will be fine.Features of a Lunar Eclipse

A total eclipse of the Moon is one of themost weirdly impressive sights in Nature.The tint of the darkened disc is usuallycoppery; but the predominant hue dependsupon the state of our atmosphere during theprogress of the phenomenon. If the air isabnormally transparent, the colour may bealmost blood -red. If loaded with dust, hazeor heavy clouds, the tinge will probablybe leaden -grey; and this has been known tobe deep enough to blot out the Moonaltogether ! The usual dull illumination ofthe obscured disc, even during totality(except on the rare occasions of completeobliteration), is due to the glow from animmense ring of refracted sunlight thatsurrounds the black body of the interposingEarth as seen from the Moon. To LunariansSituated within the limits of the broad trackof the Earth's shadow-if there are anysuch beings-the appearance presented willbe that of a total eclipse of the Sun lastingfor nearly an hour and a half; whereas themaximum length of such a spectacle viewedfrom our world can barely exceed sevenminutes. In spite of this abnormal pro-longation, the delicate solar corona wouldalmost certainly be overpowered by theradiance of the rosy encircling terrestrialaureole. The length of a lunar eclipse isregulated by the width of the section of theumbra traversed. This varies according tothe distance that our satellite may be fromus and we ourselves from the Sun at the time.On the forthcoming occasion the passage

impressive; but a binocular, 'or telescopeusing an eyepiece of sufficiently low powerto include the whole face of the Moon, willenable the steady progress of the shadow to

0N

5:0

:14 "-o

0

0C.

be more closely followed as it slowly creepsover craters, mountain ranges and vastplains. It is estimated that when the directrays of the " midday " sun are cut off, thetemperature on the Moon's surface dropsfrom 250 degrees fahr. above to 180 degreesbelow freezing.

The PlanetsMercury will not be perceptible this

month and Mars continues a " ifforningstar." Venus is now less than 30 millionmiles distant, but is becoming increasinglydifficult to discern as it drifts farther intothe brighter regions of twilight. Atpresent the planet sets at 5 o4slock but maybe glimpsed with binoculars immediatelyafter sunset during the first week of themonth. It will be in " inferior conjunction,"and at its closest to us as it passes betweenthe Earth and the Sun on the 20th; thoughof course it will then be lost in the glare ofdaylight. Jupiter is low in the south andsets at midnight. Transits of one or other ofits principal satellites may be found inprogress at 7.15 p.m. on the 7th (the eveningof the lunar eclipse), 18th, 29th and 30th.On the 29th, at the same hour, there willbe but two " moons " visible through smalltelescopes; of the missing pair one will beon the disc and the other hidden in eclipse.Later on, at 8.41 p.m., there will be anapparent further reduction to a single" moon " for a couple of minutes. Thisrather exceptional minimum will be worthwatching for if clouds are absent. Thediscovery of two more minute satellites isreported from Mt. Wilson Observatory.increasing the number to eleven. Saturnrises slightly before sunset and will be

NOZI8OH I -112 -.ION

13

'8. TrAt,Taurus

Gets.'

P sces

SOUTH HORIZON

Z0N

4i9SGIta.4i

Fr

Ss X0 eRu 5 RI t7-.)

Laswi; g

R.," 0se

LsThe

stars inNovember.

The shadedband indicates

thedoudytrackofthe Milky Way. To

use the chart turn itround until the section of

the horizon facing the ob-server is at,the bottom. Thecentre represents the zenith.

94 NEWNES PRACTICAL MECHANICS November, I93&

fairly high in the south by about 10 o'clock,arriving at that aspect half an hour latereach night. Its ring system is temporarily atrifle less open than a few weeks ago, but it isstill an attractive object in instruments ofadequate aperture.1

Once again there is a possibility of seeingsome remnants of the long -lost famousNovember Leonid meteors, on the nights-or perhaps early mornings-of the 15th,16th and 17th. The Moon will be absent so,if the 'sky is clear, at least a dozen or morecelestial rockets should be forthcoming.Nevertheless, hopeful watchers must beprepared for disappointment. The radiantpoint in the constellation Leo (the Lion)will rise in. the north-east shortly before11 o'clock.

Among the stars in mid -evening (twohours earlier than indicated by the starchart) the little group Lyra (the Harp),embracing brilliant Vega, the quadruplestar Epsilon Lyrae and the remarkableRing Nebula, is high in the west. Overhead,the Milky Way arches the heavens, with theconstellations Auriga, Perseus, Cassiopeia

and Cygnus embedded in its pearly track.Due south, half -way between the horizonand the zenith, stands the Square of Pegasuslinked to straggling Andromeda-celebratedfor its great spiral nebula. Almost on thesouthern horizon shines the giant red sun,Fomalhaut, in Piscis Australis, while tothe south-east glitters the beautiful Pleiadescluster, and the ruddy star, Aldebaran, onthe verge of that more scattered group. theHyades. In the east stately Orion, with itsconspicuous " belt," and the brilliant star,Rigel, is coming into view. It will soondominate the, winter firmament, aided byflashing Sirius and Procyon in Canis Majorand Canis Minor. All the foregoing featureshave already been described and illustratedin past numbers of this magazine. Theinformation -there given, as well as the seriesof twelve star charts (of which the one inthis issue is the last) embracing the entirecircuit of the heavens, will serve equallywell for future years.

NotesExperiments made in Germany tend to

show that the ordinary form of Newtonianreflecting telescope, if used in conjunctionwith a " Barlow " lens, is more suitable forplanetary photography than the Cassegraintype generally employed in the big obser-vatories for that purpose. It is also statedthat the best kind of camera lens for " snap-ping " shooting stars is one giving a field of30 to 40 degrees in good focus, and ofaperture ratio F/4.5, with focal lengths offrom four to ten inches. Plates, not films,are recommended.

What is there between the stars? It hasfor long been supposed that the interveningvoid, though physically empty, is pervadedby a mysterious medium vaguely styled the" aether." But, for the past forty years, ithas been becoming more and more evidentthat interstellar space contains a small,though negligible, quantity of such matteras ionized calcium, sodium, potassium,titanium and perhaps also dust. It isconsequently thought probable that theseimpalpable particles may account for thefaint luminosity of the sky even on thedarkest nights.

Gold-And the Philosopher's StoneThe Quest of the Alchemists

THE Philosopher's Stone or " GrandAlkahest," as it was known, wasthat nebulous " something " which

the alchemists were convinced would,once found, transmute the baser metalsinto the king of all metals, and make themrich beyond the dreams, of avarice. Up toabout thirty or forty years ago these oldalchemical ideas and the weird formulaeof such men as Paracelsus, Ramond Lully,and van Helmont were looked upon aschildish and utterly futile delusions, butrecent investigation and advances inscience have proved that while the methodswere all wrong, the basic idea was right fortransmutation is not only possible, but hasactually been accomplished. It is interestingto note, in passing, that not only hasthe old lure persisted, but some of theancient phraseology has survived, for theorigin, of the quest was alleged to have beenin Egypt, and under the instruction ofthe Egyptian god Thoth-or Hermes-and the ancient alchemists sealed crucibles,alembics and retorts with the seal ofHermes. To -day we speak of vessels orcontainers being " hermetically sealed,"but we do not stop to think of the originof the term.

The alchemical theory was that allnatural substances were originally of onesubstance, and that the varied forms ofnature existing were due to a multitude ofinfluences acting on this substance in amyriad different ways. In view of thefact that the modern atomic theory ispractically the same, we have a veryinteresting parallel. The idea is fo obtainby purification, distillation; etc., thenearest possible approach to this originalsubstance, or " prima materia," as theytermed it, and then to treat it with themysterious and elusive elixir or philosopher'sstone, when, they believed, gold wouldtake the place of the raw material. Mucharduous labour and years of unremittingeffort were spent in the search, while thetwo most favoured materials were mercuryand sulphur, possibly because they were,visually, the nearest approach to silverand gold.

Right down to the time of van Helmont-

who died in 1644-claims were made in allseriousness by students who really believedthey had performed the great transmutation,but from that time until quite recentyears the beliefs of alchemy were shelvedwith fairy tales and superstitions.

The Alchemists Were RightNow, however, the dream of those Old

enthusiasts has come true, and trans-mutation is an accomplished fact, thoughnot in the sense they looked for, becausethey strove with the idea of making largequantities of gold for gain, while thescientists of our day labour to effect thechange for the purpose of obtaining moreinsight into the atomic theory of matter.

In the case of radio -active matter,transmutation is going on all the time,but this is Nature's own work and cannotbe duplicated. Man has, nevertheless,transmuted several of the elements byartificial rearrangement of their atomicstructure, and it is most intriguing to notethat one of the latest successes-by M.Nagaoka, the Japanese physicist-is withmercury, just as the alchemists predicted;surely an amazing coincidence ? Nagaoka'sprocess is interesting and comparativelysimple.

He simply passed a high -frequency spark,from an induction coil, across a gap witha tungsten wire at one side and a surfaceof mercury at the other, but the spark wasfour feet long and of enormous potential,which continued for some hours. To keepthe terminal voltage high the mercury wascovered by an oil film, and, at the conclusionof the process, the mercury and oil remainedas a pasty, dough -like mass, which con-tained minute quantities of gold.

The " royal ' metal has also beenproduced, accidentally, in mercury vapourlamps which have been run on too high avoltage, traces of gold being found in theblack deposit formed in the lamps. Upto now no really 'sound reason has beenadvanced for this discovery. It almostseems as though, ere long, the transmutationof many more elements will be possible, butthere is no call for us to get excited, asNature has a way of ordaining that the

processes necessary make the cost ofproduction far greater than the intrinsiovalue of the material obtained.

'It is only becauSe of its relative scarcitythat gold has value greater than other metalsand if it were cheap some other rare andsuitable basis of exchange would be forth-coming. In a sense this would be all tothe good, for gold has many values apartfrom currency. Its amazing malleabilityenables foil to be produced as thin as.00001 mm. in thickness, while the factthat gold and oxygen cannot combinedirectly under any circumstances accountsfor its being absolutely untarnishable.

Jewellers' white -gold is gold with 25 percent. of platinum, while 12 per cent. ofpalladium gives a still whiter alloy. Thirty orforty per cent. of silver gives green gold,a singularly beautiful metal, while 20per cent. of that common metal, aluminium,gives an alloy of a superb purple colour,but -it is, unfortunately, much too brittlefor use in jewellery.

A World of ColdIt is not to alchemy or modern chemistry

that we may look for the greatest potentialgold mine, but to astronomy, for somevery strange facts have come to lightrecently, which make it quite within thebounds of possibility that we have, closeto us, a planet, or rather two planets, madeof solid gold !

The neighbour in question is Eros, thelittle asteroid which, apart from our ownmoon, is our nearest celestial relative.For a long time this tiny body was regardedas one sphere, but has now been provedto consist of two, ' each eight miles indiameter, revolving once every five and ahalf hours and ten miles apart, but tiedtogether by the invisible string of gravity.

Now, astronomy is able, by a simpleformula, to estimate the mass of anyheavenly body or bodies, and investigationshows that while the volume of the Earthis 500,000,000 times that of Eros, its massis only 177,000,000 times as much. Inother words, Eros is proportionately threetimes as heavy as Earth, though our planetis the heaviest of all others.


Ingenious new features make TRIXTwin Railways more realistic -and more irresistibly fascinatingthan ever . . .

" Just like the real thing ! " That's howmodel railway enthusiasts describe TrixEquipment. And that is and always hasbeen the aim of Trix inventors anddesigners. This year's models embodystill more new features which can add torealism and make model railway workingmore fascinating then ever. Yet, althoughimprovements are constantly being intro-duced-they do not make earlier equip-ment obsolete or unsuitable. Every newfeature is carefully designed to fit in withand bring Trix equipment up to date.

THE LATEST IMPROVEMENTS:

100 per cent. Remote Control, includingremote control uncoupling.

Scale Models, designed by Bassett-Lowke, of" Pacific " type 4-6-2 Locos : " Flying Scotsman"and " Princess " class.

Remote Control Uncoupling of Engine onany point of the track-an exclusive Trix feature.

Remote Control Signals with light.

Super Controller, giving greater flexibilityand sensitivity of control.

zap TRIXGet Catalogue, price 2d.,

from Toy Shops and Storeseverywhere.

TWIN RAILWAYIf any difficulty, write :TR IX LTD 45-47 Clerkenwell Road, London, E.C.I


EVERYTHING FOR MODELS!t. NIODEL RAILWAYS from gauge "00" to

9i in., new reprint just out containing 6D.many reductions in price. A.12. Post free

2. NEW BOOKLET on GAUGE " 0 "RAILWAYS only. A most attractive D.

production. GR.12. (ready November) ".3. SEGTION B.12. In two books.

. Stationary Engines, Boilers and 3D.Fittings. Post free.

z. Castings, Materials, Drawings 3D.and Parts. Post free.

4. MODEL SHIPS and Ship Fittings. Bas- AD.sett Lowke's complete range. S .1 2.Post free

5. GAUGE "00." Bassett-Lowke's latestbooklet on the " TWIN TRAIN " 10.Table Railway. TT. x 2. Post free . . . . 4".

USEFUL BOOKS-Laying Model PermanentWay, 2d. How to Build a Traction Engine, 3d.Waterline Booklet of Ship Sets, id. How to SailYour Model Yacht, 4d. The T.T.R. (gauge"00") Permanent Way Manual, x/3. TheT.T.R. Many -Way Station Sets, 1/-.

THE SIZE ofYOUR RAILWAY

must depend on the space you have to spare for it-but "QUALITY," the mostimportant factor of your model hobby, CAN ALWAYS BE YOURS in whatevergauge you choose if you rely on BASSETT-LOWKE!With this famous firm you can be sure of the most helpful advice on starting a

railway-laying track, for electric, steam or clockwork traction, choosing theright locomotives and rolling stock for it, and adding the finishing touches ofstations, engine sheds, signals, and platform accessories.You can call at either of their branches-in London or Manchester-or write fortheir fully descriptive catalogues to Head Office at Northampton.They have many new models ready for this Christmas, not only for model railwaysof all gauges, but of stationary engines, boilers, and model ships of every type.

Illustrations showyou a gauge "0"Iloyal Scot" andTWIN TRAINModels in gauge"00," comparedwith the sizeof the young

enthusiasts.

BASSETT-LOWKE LTD., NORTHAMPTONLONDON : 112, High Holborn, W.C.I. MANCHESTER : 28, Corporation Street.

DE LUXE MODELWith 8 Accessories

£5.10.0

The Tool of1001 USES

HANDEEELECTRIC HAND TOOL

Made in U.S.A.

Just plug in and you

are ready to:GRIND, DRILL, POL-ISH, CARVE, SAND,

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FOREST RD.South Yardley

BIRMINGHAMCATALOGUE ON REQUEST

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PLATING PostOUTFIT Free

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the result. Brighten up your home, plate your taps, door handles, fittings,etc., without removing. Do your own Electro-Plating, besides beautifyingyour home, it becomes a fascinating pastime and is so easy to use, and ispeimanent.Packed in neat case with full instructions, Post free 6/9, fromCONN! C PRODUCTS LTD., Dept. P .M . I , 19 Campbell Road, West Croydc nand from all the Principal Stores.

THE GRAYSON 31" LATHE

NOW

£11

We regret that due to the continued high costs of rawmaterials, we have at last been compelled to advancethe price of our 31 in. lathe to the above figure. Evenat this price it represents THE FINEST VALUE.3 in. MODEL REMAINS THE SAME. FROM IS -10-0.

Write for Free Descriptive Leaflets.WE HAVE A SPECIAL DEPT. FOR EXPORT ORDERSE. GRAY & SON, LTD., 18-20 Clerkenwell Road,

London, E.C.1.


"PRACTICAL MECHANICS" WI ELESS SUPPLEMENT

A 1 -WATT BATTERY -OPERATEDAMPLIFIER

A Simple, Compact and Very EfficientAmplifier for Pick -Up and MicrophoneWork when Electricity Supplies are

not Available

By 4 Experimenter "

OWING to amplifiers being so oftenassociated with high -power outputs,it has become common to think of

them as being essentially mains operated,therefore, in view of this and the numberof requests received for a battery -operatedoutfit, the unit mentioned above has beendesigned.

The first consideration with any battery -operated apparatus is current consumption.The second, at least so far as amplifiers areconcerned, is the output obtainable. Bear-ing in mind the fact that these two require-ments are very closely related to each other,and that dry H.T. batteries are likely tobe the source of. anode current supply,limits to suit both factors had to be selected,and it soon becomes apparent that it isabsurd to think in terms of 4, 5, or 6 wattsoutput, as so many constructors woulddesire.

If one can eliminate the question ofdry H.T. batteries. by, say, using large -capacity H.T. accumulators, or, for examplea Milnes Unit, then the output can beraised considerably, but, even so, onecannot soar to the large outputs obtainablefrom some of the mains -operated " power "amplifiers.

So many pick-up enthusiasts appear tohave the impression that unless an amplifiercan deliver, say, 5 watts of undistortedoutput, it is not worth considering forrecord reproduction. It is a matter of

&RUTCONTROLNo./

Fig. 1.-The amplifier, withall parts in position ready

for wiring.

personal taste, but, bearing in mind thatone is usually concerned with using theequipment in a room of average size, it issuggested that such power is out of allproportions.

From the reproduction point of view,by which I mean judging aurally, I main-tain that an output system capable ofhandling 2 watts is more pleasing, when itis fully loaded, than a 5- or 8 -watt outfitwith the volume turned down to the sameoutput. However, whatever the pros andcons of the case may be, it is always wiseto remember that the ear is not too criticalas regards intensity of sound when con-sidered from the point of view of watts.For example, it would take a very experi-enced ear to differentiate between 3 and 5watts output, therefore I have selected ahappy medium, remembering other limita-tions and decided on an output of 21 watts.

The CircuitThe valve sequence is one L.L.2 which

lA1 tN,..20NE CONTROL ANDON/OPP 5'w.

2-541'

/A/PL/7-CoNTAFOLNo 2

254"

Fig. 2.-Panel layout or drilling diagram.

4.//

has an amplification factor of 30 feedinginto two pentodes, P.P.225's, arranged inquiescent push-pull, the coupling beingprovided by a Varley Q.P.P. transformertype D.P.36 which is parallel fed to allowthe utmost inductance to be obtained fromthe primary winding to ensure a good bassresponse.

The normal output of one P.P.225 with135 volts on the anode and auxiliary grid,and with its grid biased 12 volts negative,is 1,000 milliwatts, or 1 watt, therefore,with two in the above output circuit, it issafe to estimate that at least 21 watts willbe obtained, providing the anode and biasvoltages are correctly adjusted.

The current consumption of the L.L.2with 135 volts on its anode, is approximately3 mA's, while each P.P.225, under normalworking conditions, will draw as much as18 mA in the anode circuit and 2 mA inthe auxiliary grid circuit. These figures,at first sight, seem rather drastic for batteryoperation, but one must not overlook thefact that with Q.P.P. output the twoP.P.225's are so heavily biased that theirstanding current becomes very low andlarge current surges only take place duringthe handling of powerful passages in theinput signal.

It is impossible to go into the whys andwherefores of Q.P.P. operation in thisarticle, but it will suffice to say that thewhole secret of satisfactory output, anddistortion -free reproduction, is the correctadjustment of the grid bias with relationto the actual anode potentials.

The output from a normal pick-up willprovide adequate input for the outputvalves as the L.L.2 has a fairly highmagnification factor, while the couplingtransformer has -a ratio of 1 : 9. So faras microphones are concerned, a lotdepends on the type and their actualefficiency, and with a high sensitivity modela satisfactory output will be obtained; butwith others having a lower output, such as

- high quality transverse current and movingcoil types, it will be advisable to providea simple " head " amplifier in the form of,


50,0 0 0 CI20,000 CI

5 MF D.

INPUT

L1.2.TuNGSRAM

RI 1 MFD

A.

O

HT.+,

Rg

PP 2251 ITUNGSRAM

GB. --1

Rg.

a

a

3 POINTSWITCH ON R3

OH:T:1.130-450T+

-0SCREENS

KT;

OUTPUTTRANS -FORMER

GB.+

t> Lot.0 LT.+

Fig. 3.-Theoretical circuit of the 24 -watt battery amplifier.

say, a good straight H.F. pentode resistance -capacity coupled to the L.L.2.Input Controls

Two variable controls are provided toallow two inputs to be controlled and"vmixed " before being fed into the gridcircuit of the L.L.2, thus allowing twopick-ups or one pick-up and a " mike "to be used according to individual require.ments. This item is always very handyas it increases the uses of the amplifierconsiderably apart from giving the operatorgreater scope so far as results or effectsare concerned.

The third control R.3 is a combinedpotentiometer and switch, the potentio-meter section being used as a tone controlwhile the switch is wired to cut off allbatteries. It will be noted that the tonecontrol is really a low -note booster or high -note cut-off, but the values have beenselected to provide a most satisfactoryvariation in the tonal response and it willbe found very useful for the elimination ofrecord surface noise or needle scratch. Itmust be appreciated, when considering thisarrangement, that the natural characteris-tics of the amplifier are on the high side, soany additional form of high -note booster isnot required ; in fact, it would be detrimental.Layout

It will be seen, from the illustrations,that a small simple chassis has been usedto bold all components, as this allows aclean top deck to be obtained and facilitateswiring. It will be quite an easy matter tobuild a compact cabinet round the chassisor, if a more professional appearanceis required, to make a cover to fit into thetop of the chassis out of stout perforatedzinc.

LIST OF COMPONENTSOne 50,000 -ohm 1 -watt resistance, Erie.One 20,000 -ohm 1 -watt resistance, Erie.Two 50,000 -ohm half -watt resistances, Erie.One 1-megohm half -watt resistance, Erie.One 4 mfd. fixed condenser, type 50, T.C.C.Two .1 mfd. fixed condenser, type 250,

T.C.C.One .02 mfd. fixed condenser, type 300,

T.C.C.Two .001 mfd. fixed condenser, type 300,

T.C.C.One 4 -pin valveholder, chassis type, Clix.Two 5 -pin valveholders, chassis type, Clix.One 25,000 ohm potentiometer, with three.

point switch, Erie.Two .5-megohnt potentiometers, Erie.Two socket strips,.P.I.J., Clix.One Q.P.P. transformer, type 36, Varley.One L.L.2 valve, Tungsram.Two P.P.225 valves, Tungsram.Wooden chassis, screws, wire and Systoflex.

GE,2

GES:1

The transformer is placed so that thegrid leads to the two output valves areshort and direct, the resistances Rg beingincluded to prevent, in conjunction withthe two fixed condensers Ca between eachanode and the negative line, parasiticoscillations which are sometimes generatedin symmetrical push-pull circuits.

The anode circuit of the L.L.2 is de -coupled by means of a resistance anda condenser to eliminate any possibleinstability through battery coupling, butthe anodes of the P.P.225's receive theirH.T..via the output or speaker transformer.No output transformer is included inthe amplifier as the majority of modernmoving -coil speakers are fitted with amulti -ratio transformer which usuallyallows satisfactory matching to besecured.

Particular attention must be given tothe connecting wires associated with thetwo input controls. As these potentio-meters are in direct contact with the inputgrid, it is essential to cover all connectingwires with metallised braiding.

Cokte.oN/O,FSw:ce To/vz-CoNrRoz..

2 3

0{)GB L.F.

TRANS.'?.:

A

HTh

7

o0 0

N.U. P Li

1054(ScReeiv) H.7:4-tirommz-,

(e) -IWO°'

2t2000OHMS'SO. 000 OHMS illi cL

CI 68-2 cp',..Ola N7:*

4 MFD..

(iii_(..q-REEP,

.

I. ® f I/ Br

HT.- ..e 0*.litigo

,, gi imEs ill ts4fr,....02 MFD. MED

oil50.0cho OHM a 2 a

MEG

Fig. 4.-The wiring diagrams.

-5 MA -6-


we a gimps firrwrisrvai.wit V

Yrrrmewl RS 41111111111.1 OM. 11.

.1 in. to the fool model with the sea added, showing the realism apparent when set in its natural surroundings.

MODELLING THE "DOMINIONMONARCH"

Tic., cities of the -1 in. to the foot model.

A bow view of the in. to the foot model.

WE show on this page photographs of the modelling of the DominionMonarch, which, when she is completed in February next, will bethe largest quadruple -screw motorship ever to be built in England,

and the most powerful in the world. Messrs. Bassett-Lowke, Ltd., ofNorthampton, were entrusted with the making of several DominionMonarch models both to 1/vin. scale and 1/2 -in. scale, and even before the shipwas launched (in July) from the Wallsend-on-Tyne yard of Messrs. Swan,Hunter and Wigham Richardson, the builders, there was a large 1/4 -in.scale model of the ship on view in the New Zealand Pavilion of the BritishEmpire Exhibition at Glasgow-as long ago, in fact, as May last.

The ship has been built for Messrs. Shaw Savill and Albion Co., Ltd.,to inaugurate a new route for passenger traffic to New Zealand, and oneof the new models of the ship will be on show shortly in the London office,in Leadenhall Street, of her owners.

The Dominion Monarch will sail from London and will call at Teneriffe,Cape Town, Durban, Fremantle, Melbourne, Sydney and New Zealand,a voyage occupying about 35 days. Thus the mother country will belinked up with three of her greatest Dominions and a new direct con-nection established between South Africa and New Zealand.

With one raked mast placed forward and two stream -lined funnels, astriking 'and pleasing profile is obtained and the general appearance ofthe ship is enhanced by the owners' well-known colours of black, buffand white.

Putting the finishing touches to a 16 ft. long model of the "Dominion Monarch."

100 NEWNES PRACTICAL MECHAN,CS November, 1938

INTRODUCINGELECTRO- HIGH -POWERPLATING OUTFIT MICROSCOPE

WHEN one thinks of electro-platingarticles at home, one generally assumes

that expensive apparatus will be necessary.This is not so, as it is now possible to obtaina complete electro-plating outfit for thereasonable price of 6s. 9d. By following thesimple instructions enclosed with each kit,you will be amazed at the ease with whichyou can plate such articles as taps, doorknobs, fittings, etc. The outfit is not a toybut apparatus that has been scientificallydevised by experts [206].

SELF -HEATINGSOLDERING IRON

WE show on this page the latest typeof soldering iron which is self heating.

It is known as the " Soldo " and can beused in any conditions that may arise,especially where it is not possible to obtainheat by the ordinary method. To heat theiron place a mox-intense heat tablet insidethe special container in the head of theiron, and ignite the tablet by means of afusee. In a few seconds the iron will be atsoldering heat. The iron should be used inconjunction with " Soldo " patent tinningcompound. The complete soldering outfitcontaining 1 iron, 10 mox-intense heattablets and one box of fusees costs 15s.Extra mox tablets can be obtained at 3s.for 10 including a box of fusees '12071

A HUMIDITYINDICATORKNOWN as the Certo Humidity In-

dicator, a device has appeared on themarket which indicates the amount ofdampness in the atmosphere. It can beused for health purposes by indicatingdampness in a room, also dampness in abed if placed between the sheets. Theinstrument can be used as a weatherindicator providing it is hung in a positionwhere it comes into contact with theoutside air. When the pointer movestowards damp it indicates approachingrain and when it moves to dry, fair weather.This is due to the fact that damp windsare forerunners of rain and dry ones arenot. It is obtainable in red, blue, blackand walnut and costs 7s. 6d. [208].

A humidity indicator which has a number of uses.

ON this page is shown the " Omag "high -power microscope which is ex-

tremely useful where an expensive labora-tory apparatus would be superfluous anda pocket lens insufficient. It is fitted witha sliding eyepiece which gives magnificationsfrom 20 to 35 times and has finger-tipcontrol for fine focusing. It is illuminatedand takes a No. 8 dry cell. A feature isthat the internal reflecting system givesthe object under view a plastic appearance.It is sold complete with a dry cell in a boxand costs 50s. [209].

The " Sold° " self -heating soldering iron showing thefuel container in the bit.

FORDRAUGHTSMENTWO useful gadgets for draughtsmen

are the quick -opening drawing pen andthe " Polyflex " adjustable curve. The penhas a pocket knife action enabling it to beinstantly opened for cleaning without thenecessity for releasing screws, etc. Madethroughout in stainless steel in two sizes,6 in. and 44 in., it costs 8s. with round ivoryhandle, 8s. 6d. with square ivory handleand 7s. with round ebonite handle.

The adjustable curve consists of a rubbercovered, triple steel spring, rigidly attachedat one end to asquare steel bar, theother end being se-cured, by means of aroller, to a slidewhich may be clamp-ed at any position onthe square bar. Thebar is divided andfigured, so that anyparticular setting ofthe curve can benoted and repeatedat will. The con-struction of the curveand the method ofadjusting can be seenfrom the illustration.It costs 10s. [210].

A high -power micro-scope which gives amagnification from

20 to 35 times.

The address of the makers ofany device described below willbe sent on application to theEditor, "Practical Mechanics,"Tower House, SouthamptonStreet, Strand, W.C.2. Pleasequote number at end of para-

graph.

A DISTILLERDISTILLED water has a number of

practical uses in the household, and adevice known as the ." Autostil " has nowappeared on the market which will give anunlimited supply of guaranteed chemicallypure distilled water. It is electricallyoperated and entirely automatic in action,and only requires filling with tap water.It is quite easy to instal and with elec-tricity at 4d. a unit, distilled water can beproduced at apprdximately 3d. a gallon.The " Autostil " distilling plant is of robustconstruction, has a number of outstandingfeatures, and is sold complete and readyfor attachment to the mains. Its outputis one pint of distilled water per hour,consumption 500/600 watts, and works off200/250 volts A.C. /D.C. The plant measures2 ft. x 1 ft. 8 in. x 10f in. and weighs 164 lb.The standard model costs £7 10e., and thenon -automatic model £6 10s. [211].

The " Polyflex" adjustable curve.

"AERONAUTICS"HAVE you seen Aeronautics" George

Newnes new Part Work for all whoare interested in flying.? Written by expertpilots, engineers and designers, it presents,in simple language, all there is to knowabout flying-the theory and practice, air-manship on the ground, aerial communica-tions and operations, servicing and upkeep,military flying, and in fact it covers all theaspects of modern aircraft. An aerodromedata sheet is included in every part through-out the work, which will be completed inabout 32 weekly parts. The work, which isprofusely illustrated with photographs,drawings, plans, tables, data, etc., shouldbe invaluable to all civil air guards, andeveryone interested in flying. Parts 1 and2 are now on sale everywhere-price ls. Od.each part [212].

A new quick -opening drawing pen which has a pocketknife action.


Be sure YOU have it!The famous All -British

TILLEY LANTERN(Burns ordinary Paraffin)

Light of 300 c.p. for 6 hours for Id.Mechanics and owners of small work-shops, lathe sheds, observatories, etc.,will find it invaluable for work afterdark, either in or outdoors. Holdsenough oil for 10 hours' use on onefilling. Can be placed anywhere withabsolute safety. Easy to light. Wind andrain proof. Strongly made in stoutbrass, No parts to rust, corrode or getout of order. For dependability youcannot do better than get the All -British Tilley Storm Lantern.Price 36'..

Remit 36 - or can be sent C.O.D.Post and Charges Paid.

TILLEY LAMP CO. (Dept. P.M.), HENDON, N.W.4

HOME STUDY FOREXAMINATIONS

University Correspondence College, founded1887, prepares students for London UniversityMatriculation, Intermediate, and Degreeexams.; also for Oxford or Cambridge SchoolCertificate, Civil Service, R.S.A., Book-keeping,etc. The College has a resident staff of Tutors,specialists in their subjects. Over 1,000U.C.C. students pass London Universityexaminations each year. 5,029 matriculatedduring the ten years 1928-1937.

FREE GUIDES to London Universityand other exams. (mention exam.) may be

obtained post free from the Registrar,

UNIVERSITYCORRESPONDENCE COLLEGE62 Burlington House, Cambridge

ENGINEER'SGuide to SuccessThis Great Guide shows how to study at homewith The T.I.G.B. for a well -paid post. Containsthe widest choice of engineering courses in theworld-over 200-including MECHANICAL,CIVIL, ELECTRICAL, AUTOMOBILE,AERONAUTICAL, RADIO, TELEVISION,CHEMICAL, etc.-alone gives the Regulationsfor Qualifications such as A.M.I.Mech.E.,A.M.Inst.C.E., A.M.I.E.E., C. & G., G.P.O.,etc.-contains remarkable tributes from Engin-eering Institutions and eminent technical mento the successful tuition methods of TheT.I.G.B.-and details latest successes ofT.I.G.B. students in all fields. Training untilsuccessful guaranteed for the one fee. Writefor Free copy TO -DAY.THE TECHNOLOGICAL INSTITUTE

OF GREAT BRITAIN,218 Temple Bar House, London, E.C.4Founded 1917. 20,000 Successes.

The GLUE thatneveryives way . .

CASCO' - the ideal adhesivefor model toys, etc.

'CASCO' is a new type of glue of amazingstrength. No heating is required-just mixthe powder with cold water. 'CASCO'sets by chemical action like cement-thusit is waterproof and heatproof, and with-stands the hardest knocks. Obtainable fromironmongers, woodworkers' supply stores,oil and paint shops in handy tins from 6d.

FREE SAMPLEJust send P.C. to Dept.P.M.i, LEICESTERLOVELL & CO., LTD.,34-18 Nile Street, LondonN.i, for sample and copyof the 'CASCO' GluingGuide.

vAscaCOLD WATER GLUE

DENNIS sat SMITHMODEL ENGINEERS' TOOLS SUPPLIES

ELECTRIC MOTOR TOOL

63/ -for A.C. or D.C. currents

Complete with Enclosed Switch, Cable and Plug.Full Particulars on Request.

SETS OF MILLING CUTTERS or GRINDINGPOINTS Made up in Wood Block. To any Value.

Assortments from 7;6 upwards.SPECIAL OFFER FULLY MACHINED VEE

BLOCKS AND CRAMPPer pair, with

9Cramp,1

set Blocks only I ,8ePost .0 Extra.

DENNIS & SMITH, 83 Goswell Rd., London, E.C.ITel.: Clerkenwell 4457. "felc!.2,r;inis : Fertitor Barb, London

The SOLDO Self -HeatingSOLDERING IRON No External Heat Required. Ready for Use in 30 seconds. Remains Hot for 5 mins.

Ideal for UseOut of Doors.

PRICE

15/ -COMPLETEExtra Tablets

for 10

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WHEELS FOR MOD

Fig. 26.-Foundry pattern for a locomotive wheel.

THE method followed by most modelengineers when making patternsfor their locomotive models is to

plane up a flat piece of mahogany or otherwood, mount it in the lathe, turn it toshape and afterwards pierce it for spokeswith a fretsaw, finishing with chisels,gouges and glasspaper. Such a procedureis perhaps good enough for small wheels,if they are to be sent to the foundry atonce, but for large patterns, or even smallones which are likely to be wanted againafter a lapse of time, the -method is unreli-able, because wood, when cut to such aform, in unstable. Shrinkage is almostcertain to take place and they will becomeoval, and possibly warp. If it is desired tocut small patterns from the solid, it willbe much the safest plan to use the veryhest plywood which can be bought ; gluingup several thicknesses, if necessary, andmaking sure that all the laminations of eachthickness are thoroughly well glued. Un-fortunately, in plywood, when cut intosmall pieces, there is often,an insufficiencyof glue and the consequence is that thelaminations come apart. .

Another good plan when making smallwheel patterns is to buy some straight -grained mahogany veneer, the thickestobtainable, and make one's own plywood,by gluing piece after piece of veneertogether, each with the grain running in adifferent direction, until the requisitethickness for turning the pattern is obtained.All superfluous glue should be squeezedout and the plywood, thus made, shouldbe dried under considerable pressure;

" Handyman "

The Fifth Article of a ShortSeries Dealing with theConstruction of WheelsSuitable for every Type of

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after which it can be treated as ordinarywood except that the finishing of spokeswill have to be done chiefly with filesand glasspaper.

Built-up PatternsLarge wheel patterns, that is to say, for

locomotives of 1 in. scale and upwards,should, in all cases, be built up and one ofthe best forms of construction which canbe adopted is that shown in Fig. 26. Hereit will be seen that each spoke is a separatepiece of wood, straight in the grain, mitredat the hub so that all the spokes meet atthe exact centre of the wheel.

At the rim the spokes butt against aring, b, which can be of as many segmentsas may be thought desirable. On a ten -spoke bogie or tender wheel the numberof segments may be five, each one thereforewill cover two spokes. Short fellowes, c,fill in the spaces between the squaredends of the spokes and covering the sidesof both fellowes and rim segments there willbe two rings of thinner wood, a, a. Tocover the mitring of the spokes at the hubtwo discs, d, d, are glued on.

The turning of the pattern in the latheshould be done after building up and thefinal shaping of the inner faces of the fellowestowards the hub should be done afterthe turning is finished. The surfaces tobe turned will, of course, be the backs andfronts of hub and rim and the flange andtread of the tyre.Loco. Driving Wheels

The foregoing will apply to the making

Fig. 27.-(Left),A railway car-

riage wheel.

No. 28.-(Right),A railway wagon

wheel.

of patterns for all engines and tenderwheels, but the driving and coupled wheelswill require the addition of cranks andbalances. The cranks will be the same sizeand shape for both driving and coupledwheels and so can be made a part of, and bebuilt into, the wheel by modifying theinner ends of the spokes and adding theusual pear shape instead of the discs, d, d.When we come to the question of balances,however, the case is different. On anycoupled engine the coupled wheel balancesare of different size from those on the drivingwheels and all in a different position inrelation to the cranks ; so, in order toavoid the necessity for making two (orperhaps more) wheel patterns, the simplestway will be to make two balances eachdivided longitudinally, and of such formthat they will be notched out to fit overthe spokes in any position on the wheel.Two balances will be needed because thatfor the driving will be larger than the onefor the coupled wheel.

Of course, the pattern will have to gotwice to the foundry. After the first wheels,say the driving, are cast, the balanceis changed and the pattern sent againfor casting the coupled wheels.

Machining the WheelsWhen the castings are received they

are held either in the chuck or on thefaceplate of the lathe with the back faceoutwards and the back is machined. Theyare then reversed on the faceplate and thetread, flange and face of the tyre turned,also the face of the crank. In' the same

104 NEWNES PRACTICAL MECHANICS November, 1'138

operation the hub is first drilled and thenbored out, with a boring tool in the sliderest for the axle.

All the wheels of the same diametershould be bored dead to a uniform sizeand this size should be settled by a cylindri-cal gauge, like a mandrel, with a slight taperat the end to allow of entry into the boredhole. The axle ends will be turned to oneor two ten thousandths of an inch largerthan the bore and when the wheels areready they are forced on to the axles,either in "a screw -press or a very large vice.

The axles should have been turnedbetween centres, and, when the wheels areon, the axles are again so placed in thelathe. A very light cut is then taken overthe tread and flange of the tyre to ensuretheir absolute truth, finally finishing offwith emery cloth.

Railway Carriage WheelsFig. 27 shows the standard, wooden

centred, wheel in front elevation and at Ain cross section. This latter shows themodified construction which can be adoptedwhilst retaining the wood. The hub andtyre can be of cast iron, the two ringsthrough which the rivets pass can be ofeither steel or brass. Such a wheel builtup in this manner looks well with oakcentres, left unpainted, but varnished.

If the model -maker considers that thebuilding of many wheels, such as this,involves too much labour, the only wayis to cast them wholly in metal, and awooden foundry pattern is shown in crosssection at B. The pattern can either havethe rivets put in, so that they reproducein the castings, or, in order to get sharperand .cleaner form to the heads, the castingscan be drilled and rivets knocked in.

Railway Wagon WheelsFig. 28 shows a practically unmodified

form of wheel for four-wheel wagons.Obviously, as there is no other way ofreproducing this than by building it up,the open type of spoke can only be copiedin large scale wheels, Small wheels will becast with solid spokes.

In the model shown the hub, of brassor gunmetal, is slotted by saw cuttingright across and the two ends of eachpair of spokes are soldered into each slot,the slots beyond the spokes being filledin with solder.

The triangular outline of two half -spokes is obtained by bending strip brassin a suitable jig, carefully made to measure-ment from a drawing. The tyre can be ofcast iron and this should be bored outto fit t'ghtly over the skeleton spokes.

In the drawingA is a half eleva-tion, B a sectiontaken parallel withthe face and inline with the faceof the spokes andC is a cross section.The rivets shownin A and B shouldpass through thering,a, and so secure

'the spokes to thetyre.

From the railwaywe will go back tothe road and treat,first, on wheels forlight vehicles suchas private motor-cars and light vans. Fig. 29.-These are of three A discprincipal types : the wheel.disc wheel, thepressed and weldedsteel -spoked wheel, and the wire -spokedwheel. We will deal with them in theorder mentioned.

The Disc WheelFig. 29 shows in cross section and front

elevation a disc which makes, perhaps, oneof the prettiest wheels of this type on theroad. It is that fitted to the Rover " 9 "car. Either one of three methods may beadopted in modelling this. Perhaps themost simple is to make a pattern and getcastings off in brass or aluminium; anotheris to mount two pieces of thick metal-brass or aluminium would be best-in thelathe and turn a pair of moulds; then castall the wheels required in type -metal. Athird way is to turn all the rims from acylindrical casting, or else spin them fromshort rings cut from copper tubing andstamp, or rather press, the centre discsfrom annealed sheet copper by first makinga pair of dies-very similar to castingmoulds-in cast iron or mild steel. The discswould be soldered on to the hubs, whichwould be either cast or turned from brassrod, and soldered also into the rims. Ifthe discs are not soldered to the hubsproper studs and nuts can be fitted, as infull-sized practice, so as to make all thewheels of the car interchangeable.

Steel -spoked WheelsThe full-sized wheel, shown in Fig. 30,

is made by welding two steel stampingstogether, the weld being made on the centre-line of every opening between the spokesand in a plane parallel with the faces of the

Fig. 30.-Asteel -spoked

wheel.

wheel. The simplest, and perhaps only,practicable way to reproduce this typeis to make a foundry pattern and getcastings off in brass or aluminium.

The Wire WheelThe wire -spoked, built up, wheel presents,

at first sight, what appears to be a terriblytedious job; and so it would be if we werecompelled to make five, or it may be six,wheels for one miniature car by buildingthem exactly like the prototypes ; that isto say, by forming heads at one end of thespokes, screwing the other end and makingand tapping nipples. To build six wheels288 spokes and the same number of nippleswould be required.

As several model cars had to be built,some years ago, the writer devised acomparatively simple way of reproducingthe wire wheel, and the drawings heregiven show how the job was done.

Briefly, the principle adopted was this :instead of any one spoke terminating inthe hub it was merely laid in a groove inthe hub and continued onward to form asecond spoke; the spokes therefore wereput in in pairs. At the rims they weresoldered into fine saw -cuts. The hubs,which were made for the cars referred to,were not of the same shape as here shown,but the drawings now given indicate anup-to-date pattern.

(to be continued)

WATCH REPAIRING ANDADJUSTING

(continued from page 62)try the clearance. Some balances carry anumber of timing washers-very smallWashers placed under some of the balancescrews to bring the watch to time-andoccasionally a Washer hangs below the rimof the balance, an unsuspecting evil. Donot attempt to file away the washer.Reduce the thickness of the pallet bridgeif there is still insufficient clearance.

The clearance between the pallets and theunderside of the pallet bridge should also beclosely examined. With most modernwatches the upper pallet pivot should riseso short that there is hardly any clearance,and I have often seen bright marks on thepallet arms made by contact with thepallet bridge. This contact is caused bythe jewel hole being set too high. Toprevent this friction file off the corner of thebridge from the underside and reduce thegeneral thickness. File carefully, for shouldthe jewel setting be disturbed, the bridgewill be ruined. Fig. 4 shows a section ofthe pallets and pallet bridge.


THE NEW PATENT ACT0N August 1st, 1938, there came into

force certain amendments of thePatents and Designs Acts 1907-

1932 which may prove of interest to allconcerned in the protection of inventionsand designs.

The amendments made in the originalActs with respect to Patents, affect moreparticularly the right of an inventor to bementioned as such in any patent grantedfor an invention, on the Complete Specifi-cation and in the Register of Patents.

The duration of the term of a Patent isalso affected.

The actual deviser of an invention or partof an invention may now have his namementioned in the Patent, but the mentionof the deviser does not confer or derogatefrom any rights under the Patent.

It is possible for a Patent to be grantedto a person who is not actually the inventorof the invention, for instance, a Patent canbe granted on a communication from abroador under the terms of the InternationalConvention for the Protection of Industrialproperty without the name of the actualinventor appearing, and the object of thepresent amendment of the Act is to allowthe actual inventor to be named with theattendant honour and glory attaching tothe actual inventorship of an invention.

Duration of a PatentThe duration of a Patent granted after

August 1st, 1938, instead of being 16 yearsfrom its date (i.e. the date of applicationfor Patent) is for a term beginning on thedate of the Patent and ending at theexpiration of 16 years from the date onwhich the specification accepted as acomplete specification is treated by theComptroller as having been left.

Other minor amendments have been madewhich are not specifically referred to above,for instance, fees hitherto payable for thelate filing of certified copies in connectionwith Convention applications, bothPatents and Designs, have been done awaywith and fees reduced for the late entry ofsubsequent proprietors, notices of mort-gages, licences or documents in the Registerof Patents, and the Register of Designs.

The new Trade Mark Act which cameinto force on July 27th, 1938, makes manydrastic alterations in the law affecting theregistration of Trade Marks.

Trade MarksWhen the Register of Trade Marks was

first established in 1876 by virtue of the" Trade Marks Registration Act, 1875 "(38 & 39 Vict., Ch. 91), a classification ofgoods in respect of which Trade Marks hadto be registered, was prepared. Thisclassification extended to 50 separateclasses, and up till the present time has notbeen altered or amended, but under a newAct a new classification has been preparedwhich will doubtless in the near future en-tirely supersede the old classification, infact all applications for registrations ofTrade Marks filed after the July 27th,1938, will be made under this new classifi-cation, which now comprises only 34classes. Many of the old classes have be-come unwieldy, particularly for instanceClass 42, which covered substances used asfood or ingredients in food, and Class 50,the miscellaneous class. Under the newclassification the miscellaneous class hasbeen done away with, and articles of food

By A. Milwardare subdivided into four separate classes.

On the other hand the 13 textile classesin the old classification have been reducedto 5 classes in the new classification.

There is provision in the new Act forbringing Trade Marks registered under theold classification into the new classification,which in certain cases appears to beadvantageous.

An Important ItemOne of the most important sections of the

new Act is in respect of the assignment ofregistered Trade Marks, hitherto a TradeMark when registered could only be assignedand transmitted in connection with thegoodwill of the business concerned in thegoods, for which it had been registered, andwas determinable with that goodwill.Now, however, a registered Trade Mark isassignable and transmissible either inconnection with the goodwill of a businessor not.

Further a registered Trade Mark can beassigned in respect of all the goods inrespect of which it is registered, or onlysome of them. This section applies notonly to marks registered in the future, butalso to marks already registered.

Hitherto Trade Marks have been regis-tered for' a first period of 14 years, andcapable of being renewed from time to timefor like periods of 14 years, whereas in futurethe registration of a Trade Mark shall befirstly for a period may berenewed as hitherto from time to time forfurther periods of 14 years.

Under the old Act, a Trade Mark to beregistered under part B of the Register, hadto be bona fide used for a term of not lessthan two years before the date of appli-cation for registration, whereas under thenew Act this proviso is omitted.

Under the new Act it is possible for aperson other than the owner of a registeredTrade Mark to be registered as a registereduser of the Trade Mark in respect of all or anyof the goods in respect of which it is regis-tered (not, however, in respect of a defensiveTrade Mark) either with or without con-ditions or restrictions. The application forregistration as a registered user must bemade jointly by the owner of the mark, andthe proposed registered user. The Regis-trar has power to refuse such an applicationif in his opinion the grant would be contraryto the public interest. A registered userhas no assignable or transmissible right tothe use of the mark.

A series of Trade Marks may be coveredby one registration provided that theseveral marks are for the same descriptionof goods in any one class, and resemble oneanother in material particulars so as not tosubstantially affect the identity of theTrade Mark.

Removing a Trade MarkUnder the new Act provisions for removing

a Trade Mark from the Register for non-use have been strengthened. Under theold Act, non -user of a registered TradeMark for five years preceding the appli-cation for removal of the mark had to beproved, whereas in the present Act it will besufficient to prove in order to remove aTrade Mark from the Register, (1) that

where a Trade Mark has been registeredwithout any bona fide intention to use themark, and in fact where there has been nobona fide use of the mark up to one monthfrom the date of the application for removalfrom the Register; and (2) that up to onemonth before the application for removala continuous period of five years or longerhad elapsed in which there had been nobona fide use of the mark.

In order to prevent the unjustifiable useof a Trade Mark which has become wellknown for certain goods being used byanother trader in respect of other goods, anew- form of protection is made availableby the present Act and known as a " Defen-sive Trade Mark."

Where a registered Trade Mark consistingof one or more invented words has becomeso well known in connection with the goodsin respect of which it has been registeredand used, that its use in relation to othergoods not covered by the registration norused by the proprietor of the mark mightbe taken as indicating some connectionwith the owner of the mark, it is possiblefor the latter to register the original markas a Defensive Mark in respect of any othergoods. Such Defensive Trade Marks areregistered as associated Trade Marks, i.e.assignable and transmissible as a wholeonly, and are not liable to be removed fromthe Register on the ground of non-use.

If a registered Trade Mark consists of orcontains one or more words which, throughuse, . becomes solely identified with ordescriptive of a particular article or sub-stance, i.e. the said word (or words) becomesthe only known name in the trade for thatparticular article or substance, then theregistered proprietor of such a Trade Markhas no longer any exclusive right to the useof such descriptive word or words.

It has frequently happened that a word isinvented, registered as a Trade Mark, andused in connection with a particular articleor substance which forms the subject matterof a Patent, so that the only practical nameor description for such a patented articleor substance is the Trade Mark; in such acase, after a period of two years from thelapse of the Patent, the proprietor of theTrade Mark has no longer any exclusiveuse of such a Trade Mark.

Further, no word which is. the commonlyused and accepted name for any chemicalsubstance can be registered as a TradeMark in respect of a chemical substance orpreparation, or if already registered as aTrade Mark, may be removed from theRegister.

It is possible under the new Act toregister a Trade Mark which the applicantdoes not use or propose to use, provided thesaid mark is intended for use by a companyor corporation to be constituted, andprovided an undertaking is given to assign,and the mark is actually assigned, to saidcompany within a stipulated period.

A new section (37) of the Act deals morefully with " certification " Trade Marks,and is in place of the old section (62) dealingwith special Trade Marks whereby anyassociation or person undertakes to certifythe origin, quality, accuracy, or othercharacteristic of any goods by a particularmark. A certification Trade Mark is regis-terable only under part A of the Register,and is registerable only by any person orpersons not carrying on any trade in thegoods of the kind certified.

106 NEWNES PRACTICAL MECHANICSAIP

November, 1938

ALL THE LATEST WELDING METHODS]iLAINED

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THE WATC II VARER AT THE BENCH.-By Donald de Carle. 244 pages, 138illustrations. Sir Isaac Pitman & Sons,Ltd., London. 8s. 6d. net.

This is the third edition of an extremelypractical work intended for the watch-maker, the student and all interested in thewatch trade. There have been very manybooks written on watches and clocks, few ofthem, however, are of a practical nature,and most of them deal with obsoletemethods which do not apply to modernwatches which are now chiefly mass pro-duced. This present volume, however, dealswith modern methods. It explains thearrangement of the workshop, filing, turn-ing, polishing, hardening and tempering,drilling, examining the movement, themain spring and barrel, the train, the leverescapement, the balance and balance spring,types of movements, escapements,.chrono-graphs, repeaters and other complicatedwatches, watch cleaning, pivoting, wheelcutting, etc. It is an ideal book for thosewho wish to know how to repair a watch inthe correct way, how to understand itsprinciples, and most important of all howto make the watch keep accurate time.The illustrations are an important featureof the work and are in line and half -tone.The book is well indexed.

AUTOMATIC TELEPHONY.-By C. W.Wilman. 208 pages, 103 illustrations.Technical Press, Ltd., London. 10s. 6d.

This is a revised second edition of a bookwhich is an attempt to deal in an elemen-tary manner with the principles of auto-matic telephony. The author in theprefaceuses the archaic expression : "The art ofautomatic telephony." It is not an art;it is a practice or a science, and I deprecatethe consistent application of the word art(the art of eating, the art of talking, the arta writing, the art of swimming, the art' oftypewriting, etc.); authors of technicalbooks please note. The present book isbased upon lectures given by the author tostudents at the Coventry Municipal Techni-cal Institute, preparing for the automaticsection of the final examination in tele-phony of the City and Guilds of LondonInstitute. The book deals with remote con-trol of switches, trunking principles, sub-scribers' equipment, relays and their time -elements,. impulsing conditions, selectormechanisms, traffic, line switches and linefinders, group and final selectors, selectorcircuits, inter -change connections, the direc-tor system, small exchanges, party lines,etc. An index is included. The book is ofan elementary character and gives a veryclear explanation to non -technical peopleof the Subject of which it treats.

AIRPLANE STRUCTURES.-By Niles &Newell. 2 vols., 452 pages and 178pages fully illustrated. Chapman &Hall, Ltd., London. 25s. and 13s. 6d.respectively.

The authors of these two volumes are re-spectively Professors ofAeronautic Engineer-ing at the Leland Stanford Laboratory andAssociate Professor of Aeronautical Struc-tural Engineering at the Massachusetts Insti-tute of Technology. The present volumesare second editions. The purpose of thevolumes is to meet needs of instructorsgiving courses in aeroplane construction,and describes the application of the funda-mental principles to practical work, and itis also intended as a text book. They are,of course, highly technical volumes dealingwith stresses and strains, and this aspect ofaeronautics is most exhaustively andauthoritatively dealt with. The volumesdeal with design procedure, the specifica-

BOOKS illothREADING

tion, selection of a power plant, perform-ance computations, weight control, designof wings, balance computation, location ofwings, the wind -tunnel model, the Mock-up,detailed design, the forces acting on anaeroplane, loading conditions, flying andlanding conditions, wing and tail flutter,reactions, shears, moments and influencelines, the laws of statics, reactions, bendingmoments, beam deflections, design ofbeams, torsion, truss analysis, graphical

-methods, design of simple ties and columns,deflections, etc. The books are very well pro-duced, nicely bound, fully illustrated, andan ideal work for the student as well as forthe experienced designer. Throughout thework suitable problems are included togetherwith answers. They are books which I warmlyrecommend to all those interested in thedesign of aeroplanes. They are well indexed.

YOUR MIND AND MINE.-By R. B.Cattell. 314 pages, fully illustrated.Scientific Book Club, London. Price2s. 6d.

This most interesting volume is an accountof psychology for the inquiring layman andthe prospective student, written by thepsychologist to the City of Leicester Educa-tion Authority. It, is an inquiry into theworking of the brain, and the contents dealwith the search for mind in the nervoussystem, intelligence, creative mind and theabilities of man, the natural history ofintelligence, passion and impulse, Freud'sExploration of the Borderland of Madness,dreams and laughter, love life and lunacy,victims of the will to power, the completearchitecture of character, the mind out ofgear, order in diversity, psychological tyees,wonders of the body -mind relationship,applied psychology in the school, the fac-tory, the police court and the Houses ofParliament. This is, indeed, a remarkablegroup of subjects and it is most fascinat-ingly dealt with, the text being illustratedby numerous drawings in line and half-tone. The book is written in simple lan-guage. It is a book which every teachershould read, for then it would not be pos-sible to have backward pupils. It enablesthe teacher to analyse the minds of eachpupil, and to adopt the appropriate treat-ment. The man in the street, also, shouldread this book for it will tell him how torectify backwardness and other humanfailings. An index is included.

SCIENTIFIC RIDDLES.-By Professor J.Arthur Thomson, M.A., LL.D. 384pages. Scientific Book Club, London.Price 2s. 6d.

The author reminds us that naturebristles with marks of interrogation andthat it is one of the joys of life to discoverthe answers to them. The solving of oneriddle often discloses others, and the follow-ing list of subjects show the scientificriddles discussed in the book : How did lifebegin, Characteristics of living creatures,What is Protoplasm? What are Chro-mosoms, What is a Nerve Impulse, Why dowe Fall Asleep, Suspended Animation, AreAnimals Afraid, Why do we Laugh andCry? What is the Meaning of Colour?Hormones and Enzynes, How do we CatchColds? Why does our Hair turn Grey?Why Must we Die ? Problems of Natural

History, Riddles of the Countryside,Cuckoo Puzzles, The Cat's Nine Lives, Isthere Natural Wireless ? Do Animals Think?Is Telepathy a Fact? Crystal -gazing, Whydo we Dream? Does the Past Die? Whencecame Man? The book is fascinatinglywritten in everyday language and as thechapters are complete in themselves thebook may be opened at any particular chap-ter and read with great interest.

THE Am AND ITS MYSTERIES.-By C.M. Botley. 296 pages, illustrated inline and half -tone. George Bell &Sons, Ltd., London. 8s. 6d. net.

This is a popular book intended to gietr,athose who live in an air minded age aninsight into the mysteries of the air. It isnot a book on aeroplanes, but on air. Theway of the wind, cloudland, the drops thatwater the earth, the thunderstorm,weather, climate, the atmosphere and light,the realm of sound, the highways of the air,towards the unknown regions. It is not atext -book but a popular exposition of thesesubjects, which can be read by the non-technical. The book is indexed.

SCHOOL CRAFTWORK IN WOOD.-ByEdward W. Luker. 152 pages. TheTechnical Press, Ltd., London. Price7s. 6d. net.

The author states that this book isintended for craft teacher -students in train-ing, for those preparing for examinationsand for teachers. It deals with practicallessons in woodwork, timber, tools, design,solid geometry, isometric and oblique pro-jection, and includes a great number ofdesigns and exercises in joints, etc.

A " SOAPSAVER "Save -on -Soap Disc

AN ingenious and reliable little appliancewhich will save money on your soap

bill, and which has many other uses besides,has recently appeared on the market. Ascan be seen from the sketch the device ismade in round and oval shapes to tit alltypes of soap. The inside has severallittle spikes which pierce the soap and holdit firmly. The outside is finished with aslightly raised and roughened surfacewhich enables the " soapsaver " to obtaina grip on wet and slippery surfaces. Thedevice prevents soap wasting when left ina wet toilet basin, and the smallest piecesof soap can be used right to the end withoutbreaking.. The " soapsaver," which costs3d., alto makes a good substitute fcr pumio

°stone.

The " soapsaver," an ingenious devicethat will save money on your soap bill.

108 NEWNES PRACTICAL MECHANICS November, i938

1, QUERIESle'?\ ENQUIRIES

POTASSIUM FULMINATE" DOTASSIUM fulminate is used in the

I preparation of fulminic acid. Can youtell me how this is made ? " (P. S., Liver-pool.)

FEE fulminic acid is obtained by theI action of sulphuric acid (in excess) on a

solution of potassium fulminate. The freeacid is extracted with ether. Potassiumfulminate is formed by the action ofpotassium amalgam on mercury fulminatesolution.

A STAIN ON CLOTHES

"HOW can the yellow stain of trinitro-

phenol be bleached ? A small quan-tity got on to my trousers, and when theywere cleaned at the cleaners, the latter failedto remove the stain." (A. T., Harrow.)I N practice, this stain is practically non -

removable. Chemical workers who acquirethis stain usually employ an acidified pasteof bleaching powder in an endeavour toremove it, but even this powerful agentis not always successful. Sodium hydro -sulphite (not hyposulphite) solution is some-times used in the treatment of these stains.

CATALYSTS" DEFERRING to the article in Practical

IN Mechanics ' on catalysts, surely thecontact process is obsolete. Is not ironmixed with molybdenum used in the Haberprocess, and not uranium ? " (A. L.,Walsall.)

FRfrom being obsolete, the contact

process for the manufacture of sulphuricacid, whereby sulphur dioxide is combinedwith oxygen to form sulphur trioxide bypassage over a heated catalyst, has dis-placed almost completely the older " cham-ber " process for the production of this acid.

Various catalysing metals are used in theHaber process of atmospheric nitrogenfixation. Besides uranium, which was oneof the first to be used, may be mentionedplatinum, osmium, molybdenum, iron oxide,nickel and, of course, mixtures of these.

THE PROFESSOR

A stamped addressed envelope, three pennystamps, and the query coupon from the currentissue, which appears on page 112, must be enclosedwith every letter containing a query. Every queryand drawing which is sent must bear the name and}ddress of the sender. Sand your queries to theEditor, PRACTICAL MECHANICS, Geo. Newnes,Ltd., Tower House, Southampton Street, Strand,

London, W.C.2.

MAKING CHLOROFORM

"CAN you tell me how to make chloro-

form from methane ? " (E. M.,Brighton.)rHLOROFORM is formed when methane

is mixed with chlorine in sunlight.Methyl chloride, methylene dichloride andcarbon tetrachloride are also formed in thisreaction (which is not a practical one forlaboratory purposes) and the small amountof chloroform formed would require separat-ing from these other products.

If you wish to make chloroform, keep tothe well-known bleaching powder methoddescribed in any practical textbook oforganic chemistry.

SODIUM AND DRY ICE" I UNDERSTAND that sodium will not

I react with water at temperatures above-98 C. Can you explain why sodium reactswith dry ice and why action ceases at-98 C ? " (S. L., Glamorgan.)SODIUM reacts with dry ice because the

heat of combination melts the icelocally, and thus enables the reaction tospeed up. As reacting substances are cooledthey (usually) become progressively lessreactive until, eventually, a temperature isreached at which the mutual influence ofthe two substances ceases. It is a sort (If" critical temperature of reactivity," belowwhich no mutual reaction or interactioncan take place.

MERCURY FULMINATE"U OW is mercury fulminate made ? I

I I dissolved Hg in HNO3, added alcohol andcollected and dried ppt., but could not getit to detonate by heat." (E. K., Wolver-hampton.)

YOU must allow us to decline from givingyou information concerning the practical

preparation of mercury fulminate. Thepreparation of all fulminates is an exceed-ingly dangerous task unless carried out byexpert hands, and if you persist in attempt-ing to make this chemical you will, sooneror later, have a bad explosion in whichyou may suffer severe injury.

REMOVING RED INK" DLUE inks can be removed by the KMnO4

and hydrogen peroxide method, buthow is red ink removed ? " (S. C., Bristol.)

ORDINARY red ink is best- removedby wiping it over with a soft rag

charged with an acidified solution ofbleaching powder.

WHAT WOULD HAPPEN ?" IF a mixture of sodium peroxide and

aluminium powder were placed in atin in which a small hole had been boredand the tin thrown into a pond, would aviolent detonation take place ? " (E. M.,Watford.)I N the instance you quote, there would

not be any detonation. The tin wouldsink to the .bottom of the pond and youwould see nothing more of it. Actually,the water would combine with the sodiumperoxide to form caustic soda and hydrogenperoxide :-

Na202 2H20 = 2NaOH -1- H2O2Heat would be evolved in the reaction, butthis heat would quickly be dissipated inthe cold water of the pond.

STIMULATING MUSCLES" I REQUIRE a drug which will stimulate

the muscles of the body. I have triedcaffeine, but it was not very effective. Istheobromine any use ? " (E. T., Sheffield.)QUININE sulphate dissolved in dilute%DC phosphoric acid and taken a tea-spoonful at a time is probably the "drug"you are seeking. Caffeine is quite a goodstimulant, but all other similar drugs aredangerous and should be avoided. Theo -bromine is useless for your purpose.

THERMITE BOMBS" f UNDERSTAND that a liquid has been

I discovered which will put out thermitebombs. I know that its identity is secret,but can you give me any hint as to its com-position ? " (T. T., Devon.)

WE have never heard of such anextinguishing liquid and our practical

experience is that a thermite conflagration,once properly started, is unextinguishable.However, the hypothetical liquid which you

RATHER FISHY


mention may be some organic halogencompound, say a chlorine compound which,on being heated, will release chlorine and sotend to " blanket " the fire.

MAKING CARBONS" U OW are gas carbons formed into

I special shapes, such as for coredarc carbons, etc. ?

" How could I deposit a thin coating ofpure carbon (in the form of gas carbonpreferably, but this is not essential) uponsheet metal, the carbon to be in goodelectrical contact with the metal, and im-pervious to liquids and gasses ? " (E. D. S.,Montgomeryshire.)

CARBONS for arc lamps are producedfrom specially selected grades of gas

carbon which is finely ground, mixed witha little graphite to act as a binder andthen moulded in long cylindrical moulds.The carbon mixture is rammed into themoulds by means of a drop hammer, afterwhich it is hydraulically compressed. Inan alternative process, the carbon mixtureis hydraulically compressed and then forcedthrough a nozzle, in virtue of which process,long rods of the carbon are obtained. Theseare then cut into convenient lengths.Finally, the carbons are baked in specialovens in order to consolidate their com-position and to render them more enduring.After this process, the carbons are shaped,sorted and packed. .

Cored carbons are produced by similarmeans. In the first place, the carbon" rods " are " hollow moulded " instead ofbeing made solid. After the baking treat-ment, the core mixture is rammed into thehollow carbOns and compressed by care-fully controlled hydraulic pressure.

We fear that you will find it very difficultto deposit a firm and enduring layer of gascarbon upon a sheet of metal. The onlyway is to make up a suitable carbon " mix-ture," say one containing 95 per cent. offine -powdered gas carbon, and 5 per cent.of graphite. Mix this into a paste withglue solution. Coat the paste on to themetal surface and allow it to set, understrong pressure, if possible. At this stage,the carbon layer will not be a good con-ductor, owing to the insulating propertiesof the admixed glue. However, on heatingthe carbon -coated sheet of metal to thecharring point of the glue, the latter willbe resolved into carbon and the conductivityof the carbon layer will increase.

The minimum amount of glue should beused since, upon heating, the glue will tendto swell up, thus interfering with thehomogenity of the carbon layer.

We feel bound to say, however, that,even in the best of circumstances, thecarbon coating of a metal plate preparedin the above manner will tend to flake off.In order to secure permanent attachment,some form of hydraulic pressure is essential,for carbon cannot be deposited electro-lytically.

An exceeding thin and fairly tenaciouscoating of carbon may be laid on a metalsurface merely by roughening up the metalwith sandpaper and then by rubbing amixture of finely powdered carbon andgraphite over it. The carbon will be ingood electrical contact, but the layer of itwill, not be thick enough to be imperviousto liquids and gases.

DISSOLVING RUBBER" I S it possible to dissolve rubber ? If so,

what chemical is necessary, and howis it done ? Would it be practicable todissolve ordinary rubber motor tubes andapply the liquid on cloth to make it water-proof and give it a rubber facing and also

to keep it flexible ? Any information wouldbe appreciated.

" Is there any chemical which wouldsecurely join two pieces of celluloid ? "(R. D. T., Berwick -on -Tweed.)

NATURAL rubber dissolves with fairreadiness in a variety of organic

solvents, among which may be mentionedtoluene, xylene, carbon bisulphide, coal -tarnaphtha, carbon tetrachloride, ethylene -dichloride and trichlorethylene.

We would advise you to use a solutionof ordinary naphtha for your solutionexperiments, bearing always in mind thefact that this liquid is inflammable

Inner tubes can be dissolved by shred-ding them and by soaking the shreds innaphtha for two or three days. During thistime, the rubber softens, and it is thereaftereasily dissolved by vigorous stirring. Duringthis final solution stage, the solution shouldbe warmed by standing the vessel contain-ing it in a larger vessel of hot water.

After satisfactory solution of the rubberhas been obtained, the liquid should befiltered through several folds of fine clothand stored in tightly corked bottles.

Fabrics may be " rubberised " by the useof this solution, but the process is at thebest a messy one when conducted on thesmall scale, and the rubberised fabrics arenearly always permanently tacky.. However,for the sake of interest, the process isworthy of a trial.

Celluloid cement is the best substancefor joining celluloid. It is made by dis-solving clean scrap celluloid in amyl acetateuntil a liquid of the consistency of thinvarnish is obtained. Both the pieces ofcelluloid which are to be joined are smearedover with the above cement, placed togetherand then placed under light pressure for afew hours. By this means a fairly strongand permanent joint will be effected.

When dissolving the scrap celluloid inthe amyl acetate, allow the celluloid tosoak in the liquid for a few hours, duringwhich time it will soften considerably.Then Complete the solution of the celluloidby vigorous shaking.

CHEMISTRY AT HOME" I WISH to study chemistry at home.

I Therefore would you please advise meas to the best way to start, what plan Ishould follow and what books and apparatusI may need? I should. particularly like tostudy chemical analysis." (T. S., Kent.)IT is not easy to study chemistry seriously

on one's own, for the study requiresmuch systematic work, accompanied byregular practical experimentation.

If, therefore, you can attend some part-time class in your nearest technical insti-tute, we should strongly advise you to doso, even if it is only for a short time, forsuch instruction will go far to enable youto realise the general extent of your chosensubject.

Assuming, however, that this is impos-sible, and that you have no previous know-ledge of chemistry, we would advise youto obtain a good elementary textbook ofinorganic chemistry, as, for instance,Parrish's " Introduction to InorganicChemistry " `Longman). Read this throughin a general sort of way and then, afterpurchasing the necessary pieces of apparatusand chemicals from one or other of theadvertisers in " Practical Mechanics," fitup a small workbench and carry out theexperiments in conjunction with yourreading, making sure that you fully under-stand the nature and import of each experi-ment before you proceed to a new one.

Afterwards, you can proceed to a moreadvanced textbook of inorganic chemistry,

ARE YOU AFRAID TOFACE THE TRUTH

ABOUT YOURSELF ?THERE are occasions in the life of every

man when he realises how miserably he.has fallen below what others have expectedof him and what he had dreamed for him. -self. The "big" man faces the truth, anddoes something about it. The "little" manfinds an excuse for his failure and doesnothing. What are your answers when youask yourself questions like these?

Am I not drifting along aimlessly ?What, after all, is my purpose in life ?Am I trusting too much to chance to bring

me success ?What is my greatest weak point ?Is it lick of will, poor memory, mental

laziness, mind -wandering, or what ?Am I " licked " by life, am I a " quitter ? "What can I do to " find " myself ? "

Take up Pelmaniqn now !

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A course of Pelmanism brings out the mindslatent powers, and develops them to thehighest point of efficiency. It banishes suchweaknesses and defects as :-

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If, therefore, you wish to make the fullest useof the powers now lying latent or only semi -developed in your mind, you should send to -dayfor a free copy of this most interesting book.

Write or call to -day to :

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such as Newtit's " Inorganic Chemistry "(Longmans). You can also fake up thestudy of Organic Chemistry-the chemistryof the carbon compounds-by beginningwith a book such as Perkin and Kipping's" Organic Chemistry " (Chambers).

Chemical analysis is not a subject whichcan be learned solely from books. In orderto pursue this subject, you must have awell-equipped laboratory, and it is here,we think, that you will really need toattend a course of practical instruction ata _technical institute if you wish to becomereally proficient in this branch of chemistry.

An inquiry to the Institute of Chemistry,30 Russell Square, London, W.C.1, wouldreveal whether or not there are any suitableteaching institutes in your district. Thisbody would also inform you whether thereare any private teachers of chemistry inyour neighbourhood.

REPLIES IN BRIEF

G. T. (Surrey).-This machine is hardlylarge enough for serious work. Rotaryelectrodes and the bars can be used, but thistransformer is not big enough for this work.You should be able to weld the 16 -gaugesheet quite well. Strip the secondary,count the turns per volt, and re -wind toget a maximum, as explained, of 5 volts.Re -wind with rip .5 in. x .2 in.

J. H. (Tonbridge).-Your best plan is touse a well -made type of mat contact. Wehave known some of these last for manyyears without any trouble, but get a goodone. A photo -cell is expensive, but thecheapest is the electric eye as advertisedin our issue.

G. A. (Kingston Vale).-The trouble isthat your machine requires new contactsand probably a new condenser. You canfit new platinum contacts yourself, but acondenser may have to be bought fromthe makers.

You cannot make a spark coil to do thiswork; you see the voltage of the mainsis too high for a primary winding. Weadvise you in this case to fit new contactsand not to try and make a coil.

H. B. (Nr. Gloucester).-Your best plan isto connect the meter in circuit the otherway round, then it will read discharge.However, if connected in a discharge circuitit should read correctly. The ammeter ismost probably stuck, and we cannot saywhat is wrong with it without an examina-tion, but advise you to check up theconnections and clean the pivots, etc.

j. A. (Dewsbury).-We advise you tomake both the lamp and reflector movableand to use the 500 -watt lamp. The largerlens will be better. You can use the headlamp as a spot, but you will find that itdoes not give sufficient light for generalillumination.

Your enclosed sketches are quite good.

F. C. (Surrey).-Your idea is not entirelynew and there has been quite a discussionon the subject in the Press lately. Wecannot see that a six -volt battery will lastmonths. Perhaps a week but no longerif the apparatus is some form of inductioncoil. We would advise you to experimentwith an ignition coil on about 2 volts. Usea small pen with bare wire and dry stakes.Connect one lead from the coil to the wireand earth the other. The wire will notkeep the animals in if for instance they arescared and rush at it..

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November, 1938 NEWNES PRACTICAL MECHANICS i I i

SYNTHETIC RESIN MOULDINGS(Continued from page 76)

this also. These two flanges projectingfrom the mould body are used for openingthe mould. The top plate is now markedout in pitched diameter circles (PDC) tothe required sizes. These sizes are notimportant with the exception of notingthat the thin part of the wall is sufficient towithstand the great internal pressure whichis necessary for moulding. No set rule islaid down, but it is generally safe when thiswall is of a thickness which is not less thanone half the outer diameter of the mouldedobject. Each of the circles is now dividedup into three equal spaces at staggeredintervals of 60, the outer circle defines theposition for the locating pegs, and theinner circles the centres for the mouldinginserts. The plate and bolster are nowclamped together, and the three holesdrilled and reamered, which will acceptthe location pegs, a tight fit in the plate anda nice slide fit in the bottom bolster. Thesepegs are usually lathe turned from caststeel, and approximately .015 in. is left onthe diameter, which is ground off afterhardening. One peg is made larger thanthe other two to ensure that the mould isalways assembled in the same position.

When the pegs have been fitted satis-factorily, so that the plate can be put on andtaken off without undue effort, it is clampedtogether again, and three holes which in thiscase would be in. diameter drilled andreamered right through both top and bottommembers, this then represents a datumline for each "mould bore. The bottombolster is now mounted on the lathe faceplate, and each hole opened out to a sizewhich will accept the cast steel insert, andthis will be ground to suit. Two fairlysmall holes will be noticed in the bolster-these are to knock the cast steel insertout if need be, and should on no accountbe omitted. The inside moulding surfaceof the inserts are then highly polished byrotating at high speed, and a surfaceproduced first with emery cloth dipped inparaffin, and finally rouge powder on a stick.Tie plungers are turned with a spigot onthe top end, which will be in. diameter,and a sliding fit in the hole alreadyin the top plate. This centralises them,and also maintains direct relationshipwith the bottom force on assembly. Beforebeing hardened, holes are drilled and tappedto accept three cheese -headed screwswhich are also counter -bored in the topplate, so that the heads are just below thesurface. The ejector, which is shown onthe sketch, forms the bottom of the cup,and must be a good fit in the cast steelinsert, otherwise the moulding materialwill be forced down between. To minimisethe possibility of this occurring a taper of1 is made on the head part, the mouldingpressure then having the effect of effectuallyclosing the surfaces against leakage.

The material used for mould -makingvaries considerably with the design of thearticle to be moulded-for this cup mould afairly low grade. of cast steel could be usedfor those components forming the mouldingmembers, as there are no abrupt protrusionswhich would be liable to warp or crack inthe hardening process, and moreover themachining operations are mostly turning,which is considered the cheapest process,but should the making of these partsinclude a lot of milling machine work wheresharp defined protuberations occur, thenthe very best quality cast steel is advisableto minimise the risk of scrapping a part inthe heat treatment, which would greatlyincrease, the cost and time of production.

Ashtray MouldThe cigarette ashtray mould (Fig. 5) is a

single impression mould of fairly simpledesign, which would be loaded with Bakelitepowder when in operation to ensure an easyand uninterrupted flow immediately fluxingoccurs. Although it appears simpler, thanthe cup mould, the cost would be greater,as it is mostly milling machine work. Theprocedure would follow very much the samelines as the cup mould, the three holes forthe location pegs being bored first to act asa guide for further machining.

The ejector studs form the three half -round sunken slpts as well as pushing thejob out, and to avoid them twisting, it willbe noted on the sketch that the shanks arerectangular. Both forces are fairly difficultto produce, and require a lot of highlyskilled milling to reproduce the equallyspaced flats which will be noticed on theexternal circumference.

The polishing will be a tedious process,having to be mostly accomplished by hand.A very simple handy tool for this work canbe made from a piece of mild steel with asaw cut in the end, into which a strip ofgood quality emery cloth can be inserted,and then drawn back along the remainder(Fig. 6). This instrument will be foundextremely handy in getting into awkwardcorners.Impression Knob Mould

This is a simple form of plunger typemould for producing wireless cabinetcontrol knobs, and although there aremany designers adverse to this method, thelower force or cast -steel inserts were madeup of two parts to facilitate machining.The flutes were produced on a slottingmachine, although failing this, they couldhave been filed by an experienced toolmaker.The mould did not give as much trouble aswas anticipated, excepting for occasionallyhaving to " stripped down,"flash cleaned away from the butt faces ofthe inserts. The top insert acted as theplunger, and protruded above the mouldwhen loaded and before being placedbetween the press platens. To strip aftermoulding, the tool was placed on metalparallels under a fly press, and the completetop and bottom inserts were pushed rightthrough and then pulled apart by hand to

- withdraw the component.Pins were fitted by drilling and reamering

holes slightly over the centre line to facilitateassembly, which will be noted on the sketch.(Fig. 7.)

THE P.M. LIST OF BLUEPRINTSI-. J. CAMM S

PETROL -DRIVEN MODEL MONOPLANE7s. 6d. per set of four sheets, full-size.

The "PRACTICAL MECHANICS" £20 CAR(Designed by F. J. CAMM.)

10s. 6d. per set of four sheets.

" PRACTICAL MECHANICS " MASTERBATTERY CLOCK

Blueprint Is.

The "PRACTICAL MECHANICS"OUTBOARD SPEEDBOAT7s. 6d. per set of three sheets.

A MODEL AUTOGYROFull-size blueprint, Is.

SUPER -DURATION BIPLANEFull-size blueprint, Is.

TheP.M. "PETREL" MODEL MONOPLANE

Complete set, 5s.

The I-c.c. TWO-STROKE PETROL ENGINEComplete set, 5s.

The above blueprints are obtainable post free fromMessrs.G.Newnes Ltd .,Tower House, Strand, WC2

ENTHRALLINGHOBBIESMAKE MONEY with a

GilbertMETAL

CASTINGSet

Earn money while enjoying anabsorbing pastime. A Gilbert MetalCasting Outfit enables you to makelead soldiers, metal toys, badges,medals. Supply them to friends.You'll make pounds. Simple to use,the outfits include moulds, metal.tools, paints, etc. Non -electric andElectric models. Entertaining andprofitable.

No. 1.Non -Electric 5 -No. 2.Non -Electric 10,6No. 3.Electric ... 10/6No. 5.Electric ... 21/ -No. 7. Electric.Makes hollowtoys ... 30/ -

Spell -binding Discoveries withMICRO -CHEMISTRY

70013

Weird secrets are evealed by the microscope inGilbert Micro-Chemi try Outfits. Amazing discoveriesand new knowledge await you. Outfits includemicroscopes which magnify up to 200 times; alsochemicals for experiments and the Polaroid whichreveals beauties not usually seen in microscopy.

No. 5 Outfit, 12'6 No. 7 Outfit, 21 -

SPECIAL OFFER

GILBERTELECTRIC

BENCH DRILLA boon to amateurmechanical This precision -built bench drill is robustand reliable. Runs at1,750 r.p.m. Drills woodor metal. Also does counter-sinking and routing. Ad-justable motor and drillingtable. Takes drills up toI in. Operates on A.C.house current. 100/110 or200/250 volts. Completewith switch, chuck andflex. Reduced from Eft,.

75/- to 711Also. Electric Lathe, 501-

rf any difficulty in obtaining Gilbert Outfitslocally, send cash with order to us.

Money refunded at once if not satisfied.

rommionma-ammo ni

TO -DAY' The A. C. GILBERT CO. I109 Kingsway, London, W.C.2.

Please send me, absolutely FREE, the four-colourCatalogue of Gilbert Outfits.

Post Coupon

II Name

IIAddress

PRINT IN CAPITAL LETTERS.

Elm smi Ism isms mai Ems mu ems

I12 NEWNES PRACTICAL MECHANICS November 1938

BUY, EXCHANGE OR SELLPHOTOGRAPHY (Continued)

"PANTOGRAPHS " make large accurate draw-ings from stnall photographs, etc., easily. 1/..-Cooke,33 Hawthorn Road, Levenshulme, Manchester.PHOTOGRAPHIC MATERIALS. Plates, Films,

Mounts, Chemicals, etc. Interesting money -savinglists and samples free.-" Kimber's," 105 Queens Road,Brighton.

TOOLS

Special large purchase -1.1" Split Circular Dies,guaranteed quality, usual price 10d. to 1/3 each.Sizes in stock, r, -iv, s92", fe,B.S.F., also Brass Tube Thread, Cycle Thread, andModel Engineer 40 Thread; also in 0, 1, 2, 3, 4, 5, 6BA. Thread. Offered at the low price of 6d. each, 5/6per doz. Also Taps to suit, guaranteed, 6d. to 10d.quality clearing at 3/- doz., 4d. each; all B.A. sizes andothers to a" diam.; also 191" and -a"' 6d. each. Alsobest Adjustable Tap Wrenches to a", 9d.; Die -Stocks,9d.-Below.

12 only, Ball -Bearing Double -ended Grinding Headsto take j" bore wheels, practically new, 15/- each.Six only, Stands for same fitted with rise and fall slidesuitable for converting to surface or special toolgrinder, bargain 10/- each.-Below.

300 Sete 1" Circular Dies, i" 1°a" I", V', Whit.,B.S.F., Brass Thread, also American S.A.E. Threadfor Yankee Cars; clear at 2/9 set of Five; also beatquality Taps to suit any above sets, 2/9 set of Five.Adjustable Tap Wrenches to 4" 1/9 each; r Die -Stocks, 1/9 each. Guaranteed.-Below.

3,000 High Speed Twist Drills, if" to 162", actualvalue from 5d. to 8d. each. Bargain 2/- doz.-Below.

Finest Quality Tool Steel, Round, Bright, I" to I"diam., 4 lb., 2/6; larger sizes, 8 lb., 4/-. Costs 2/- lb.- -Below.

1/9 any lot. Wonderful Value.-Below.One Gross Bright Steel Hex. Bolts with Nuts.Dozen Assorted Files, 4" to 6".Six Assorted Files, 6" to 12".Three Assorted Files, 12" to 14".Six Assorded Grinding Wheels, 2" to 24" diam.Dozen Twist Drills, to a" diam. Best quality.Grinding Wheels, Carborundum, about 6" by 1"

mile, 1' Lyle.Three Hex. Die Nuts, Cycle Thread, -136", I", lag%Three Slitting Saws, 21' diem., lia" to ji." thick.Four M.M. Dies, diam.Dozen Assorted Taps./," Square Tool Holder, with H.S. Tool.2 Doz. Hack -saw Blades, 9", 10", or 12".Two H.S. Tap Fluting Cutters, ir diam.-Below.29 any lot.-Below.0 to a Drill Chuck, Mors; Taper or half -inch Straight

Dozen Drills, to %".One each, j", i", 1" Whit. Taper Taps.18 Assorted Flexible Shaft Grinding Wheels, }" to 1"

4 - any lot.16 Lengths Silver Steel, -/" to Round.Dozen Superfine Swiss Files.2 Dozen Files, 1" to 10".Taper, 2nd and Plug Taps, Whit., r , I".Set Hex. Die -Nuts, a", I", j", 1", Whit. or B.S.F.400 Dozen Tool-makers' Needle Files. An absolute

necessity for small work. Clearing at 2/9 per dozen;assorted shapes.-Below.

600 Morse Taper SI , 1-2, 1/6; 2-3, 1/10 ; 3-4, 2/6.Best quality, ground finish. British made.-Below.

1,000 Fine Emery Wheels, 2" to 4" diam. r hole, jr"to a" thick, slightly used, but quite serviceable, 1/6per dozen.-Below.

Super Quality High -Speed End Mills, Right hand,for use in Lathe. Straight Shank, }", 2/-; at", 2/9;aetual value nearly treble. Also ja". Best QualityCarbon Steel, 1/9 each.-Below.

Genuine Carborundum Wheels, 9" diam., 1" hole,1" wide, 6/-; la", 6/6; la", 7/6; 2", 10/- each; 7" diam.,a" hole, a" to a" wide, 2/6 each. All suitable for generaltool use. Also Rough Wheels, 1 hole la" wide; 8",3/6; 7", 3/-; 6", 2/3.-Below.

Please Note. --£1 orders and above only are postpaid; small orders please allow for postage.-SteelBars, carriage forward.-Below.

J. BURKE, 30 TRIPPET LANE. SHEFFIELD.

An Absorbing /lobbyBUILDING A STUART MODEL ISAN ENGROSSING PASTIME, ANDTHE RESULT A CONTINUOUS

PLEASURE

We Illustrate:

STUARTNO. 10.High Speed

Steam Engine.

Bore r.Stroke r.Each set is quitecomplete-drawings andinstructions areincluded.

If you have a lathe-The rough castings

If not-' Fully machined set

Ditto, with all holes drilledand tapped - - -

8/6

18/6

25/ -

This and many other Stuart engines arefully described in the 72 -page CATA-

LOGUE No. 3, 6d. post free.

STUART TURNER LTD. -HENLEY - ON - THAMES

l tic I lalyti" Nipper- Acro Petrol Engine

MINIATURE PETROL ENGINES . . . for Aero-planes and Speed Boats. 1 c.c. 3 and 6.

Easily made from our Castings, 12/6 per set.Complete Engines ready to run, £3 IS.

SEND 3d. FOR PARTICULARS

J. HALLAM & SON, Limn Poole, Dorset

Price63 - 3 -0

MachineYes 11, -

///Z, PROTRUDING EARSORO, a simple modern method setsthem In position immediately.Invisible-Comfortable-Harm-less, used any time by adults andchildren. Endorsed by physiciansand users as the best method forcorrecting this disfigurement.Write for free booklet and testi-monials to-

M. TRILETY (R 158)45 Hatton Garden. London. E.C.I.

The ' ADEPT' Bench Hand ShaperLength of stroke of ram, 3i ins.; Length o:

cross travel of elide, 3 Ins; Size o1 Tabie4} Ins. - 4 ins.; Rise and fall of 'raid,'2 ins.; Vertical feed of tool slide,Maximum distance between tool and table,3 tag.; Weight, 18 lb. Also the 'Adept'

No. 211.11. Shaper, 61 -in. stroke.Price £6-9-6.

Manufactured byF. W. PORTASS

SELLERS STREET, SHEFFIELD

TOOLS-Continued

GRAYSON'S Glass -boring Outfits and Tube.Cutters avoid risk.-Below. -

DRILLS, 1 aps, Dies, Files, Chisels and Punches.Beet quality at keenest prices.-Grayson &, Company,300 Campo Lane. Sheffield.

MYFORD LATHE SPECIALISTS. Cash or nodeposit terms from 10/- monthly. Immediate deliveriesanywhere. List free. - Nuttalls, 20, Albert Street,Mansfield.

BRAND NEW POWER TOOLS of quality.10 in. Bandsaws, 54/-. Jigsaws, 22/6. Wood PlaningMachines, 80/-. Bench Drills, 11/-. Circular Saws,from 25/-. 3 in. S.C. Tootroom Lathes, from £4 180.New 1 in. Chromium Plated Micrometers, 12/6. ElectricDrills, 32/6. Grinders, Spray Plants, Guns, Air Com-pressors, etc.-John P. Steel, Clyde St. Mills, Bingley.

MUSICAL INSTRUMENTSBAND GUIDE. Hints on the Bugle, Drum, Flute,

Staff Parade formation, etc. Free, post paid.-Potter's (Manufacturers), West Street, London, W.C.2.

SITUATIONS VACANTG.P.O. ENGINEERING DEPT. (no experience

required). Commencing £3/13/0 per week. Age 18-23.Excellent prospects. Free details of Entrance Exam.from B.I.E.T. (Dept. 579). 17-19 Stratford Place,London; W.1.

DRAUGHTSMAN. Numerous vacancies availablein Electrical, Mechanical, Structural and otherBranches of Engineering; Building; G.P.O. etc. for menage 17-40. Exp. unnecessary if willing to learn.. Detailsof openings, salaries, etc. FREE from N.I.E. Wept.372), Staple Inn Bldgs. W.C.1.

WATCHMAKINGWATCH & CLOCK REPAIRERS. Send 3d. for

complete list of material and tools. Blakiston Sr Co.,Ainsdale, Southport.

WIRELESSHEAR AMERICA, AUSTRALIA, JAPAN. New

Receivers with valves, from 19/6. Numerous testi.montals. List free.-W. J. Buckle, 63 AvenueApproach, Bury St. Edmunds.,

MISCELLANEOUSCASTING MOULDS FOR LEAD SOLDIERS,

animals and novelties. Sample mould, 2/9. Catalogue,stamp.-Industries, 2 Waidegrove Park, Twickenham.

A LARGE STOCK OF SEARCHLIGHTS, Saleor Hire.-London Electric Firm, Croydon.

CATAPULTS. - Improved pattern. Scientificunbreakable frame, giving unerring accuracy and longlife to the rubber. Superior elastic, easily replaced.Very powerful. 2/3 post free.-Cox, 17 Oakham Road,Harborne, Birmingham.

USED MODEL RAILWAYSPERFECT BARGAINS, EQUAL TO NEW. SEND4}d. FOR OUR CATALOGUE AND SAVE MONEYGEORGES', I I, FRIARS STREET, IPSWICH

OUR ADVICE BUREAU

COUPONThis coupon is available until November 30, 1933,

.and must be attached to all letters containing 1

queries, together with 3 penny stamps. A stamped -addressed envelope must also be enclosed.PRACTICAL MECHANICS, NOV., 1938.

BUY, EXCHANGE OR SELLAdvertisements are accepted for these columns at 3d. per word (minimum 12 words at 3s.-advertisements of less than 12 words arecharged at the minimum rate of 3s.) subject to a discount of 21% for 6 consecutive monthly insertions or 5% for 12 consecutive monthlyinsertions. TERMS:-Cash with order. Cheques, Postal Orders, etc., should be made payable to George Newnes, Ltd. The Proprietorsreserve the right to refuse or withdraw advertisements at their discretion. All advertisements must be received on or before the 5th of themonth 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.

CANOESBOAT AND CANOE. Kits from 25/-. All types

completed craft. Winter Reductions. List stamp.Trade.-Metacraft (P), Christchurch, Hants.

CINEMATOGRAPHYART CINE FILMS. Exclusive 9.5 and 16 -mm.

Free Films to Cine Camera or Projector buyers. Allmakes. State wants.-P. M. Dane, 64, Stanley Street,Liverpool 1.

CINEMATOGRAPH FILMS. Standard Sizefrom 68. 100 feet. Machines, Accessories. SampleFilms 1/- and 2/6 post free. Catalogues free.-"Filmeries," 67 Lancaster Road, Leytonstone, E.11.

ELECTRICALA.C. & D.C. MOTORS, Dynamos, Converters,

Transformers, Chargers, Supplies and Repairs.-Easco, 18pm, Brixton Road, S.W.9.

3/4 -h.p. A.G. MOTORS. REPULSION orCAPACITOR, All voltages, £2/2/6 each. D.C. £11216.-Johnson Engineering, 86 Great Portland Street,

SUPER A.C. MOTORS. Brand New, 1/10 h.p.30/-; 1/4 h.p., 38/6; * h.p., 38/6; h.p., 55/-; largersizes. Electric Tools, Machines, Pumps, Compressors,etc.-John P. Steel, Clyde Street Mills, Bingley.

ENGINEERINGA BALL -BEARING ANNOUNCEMENT. Minia-ture Ball -Races, 134 mm. to 30 mm. o/d. Sample ofthe smallest standard ball -race in the world, undere in. overall, 2/6 post free. Send 2d. stamp for lists.Dept. P., MINIATURE BEARINGS, LTD., 3 DukeStreet, St. James's, S.W.1.

PORTASS LATHES3" MOTOR DRIVEN MODELS

B.G.S.C. LATHE£11 . 15 . 0

USUAL PRICE £14.16.0.B.T.H. motor with re-

duction gears, iron stand,flywheel belts. Terms. Nointerest charged. Stampplease. 311n. lathes from£4.10.0.

AMAZING OFFERUSUAL PRICE £6.16.0.

t £3.15.0 MaS.""S

V Crate 2,6. Taxes 121in. bet.cen. To take 18in. extra15/-. Compound Rest extra

ackine 15/6. Money returned if10 - you are not delighted.

PORTASS LATHES, BUTTERMERE Rd., SHEFFIELD

JUBILEEWORM DRIVEHOSE CLIPSThe long -life clipwith

the ever -tight gripThe Best Known

For Radiator Joints,Air, Oil, and WaterHose Joints.We guarantee a Tight

Jointrocked by all Garages

and Accessory Dealers.

L. ROBINSON & CO.,25 London Chambers,GILLINGHAM, KENT.

LITERATURELARGEST STOCKS. Imported American books,

magazines, every subject. Samples and catalogue2/6.-G. A. Final, 15, Nashleigh Hill, Chesham.

METAL WORKMAKE METAL TOYS. Easy, profitable with

' Success " Moulds. List Free. Complete trial mouldIs. 6d.-Lee's, 1 Birkin Avenue, Nottingham.

MODEL ENGINESAERO ENGINE SETS.-Baby aero castin4s as

low as 5/9. Tiptop yz h.p. sets, water or air-cooled 9/9.Charging dynamos, ball -bearing enclosed, from Samps., 15/-. Boat propellers, tubes, fittings. Castingsmade in any metal. Instructive, interesting catalogue3d. Write-Butler's, Profit -Sharing Works, WadeStreet, Littleover, Derby.

MODELSTABLE TOP PHOTOGRAPHIC MODELLING.

Make, use and supply the right material. 2/8 illus-trated.-Architrave, 2 Jeffreys Place, London, N.W.1.

easily the Best SolderingFluid Obtainable." Th is state-ment by a regular user of" BAKER'S " expresses thegeneral opinion of the Motorand Engineering Trades.Sold in 6d., 1/- and 1/6 tins,

also in bulk.

SIP Wm. BURNETT CO. (CHEMICALS) LIMITEDGREAT WEST PO AD ISLE WOAIT14:MIMFSE1

WEBLEY AIR PISTOLSMarvellouslyaccurate fortarget practice.No licence required to porches.:or use at homeSenior 45/ -, Mark 1 32/6Junior 21/-, Webley Air Rifle 95/Write for List. WEBLEY & SCOTT LTD.106 WEAMAN STREET, BIRMINGHAM,

INVENTORS

1

General Advice tree. POST FREE 6d.VALUABLE GUIDE

CHATWIN & CO. Est. 1880

Regd. Patent, Design and Trade Mark Agents forall countries.

253 DI Gray's Inn Road, Lont.on, W.C.I.

MAKE MORE MONEYto £6 weekly can be earned at house in a wonder-

ful business of your own. No matter where you liveyou can commence to make money in your spare orwhole tone. No rink, canvassing or experiencerequired. A wonderful opportunity for anyonewishing to add pounds to their income. Particulars,stamp.BALLARD, York Hems, 12 Hambrooe Road,

LONDON, S.E.25.

MODELS (Continued)SLIGHTLY USED TRIX RAILWAY GOODS,

list lid. Georges', 11, Friars Street, Ipswich.

PATENTS

REGINALD W. BARKER & CO. (Established1886), 56 Ludgate Hill, London, E.C.4.-Patent andTrade Mark Booklets Gratis.

PATENTS AND INVENTIONSWE SUCCESSFULLY SELL inventions, patented

and unpatented. Write for proof, and tell us what youhave for sale.-Chartered Institute of AmericanInventors, Dept. 104, Washington, D.C., U.S.A.

AMERICA. Sell your patents through " INVEN-TION," leading U.S.A. monthly. Specimen copy 2/3,annually, 25/- from British Agents, INTERNATIONALENGINEERING CONCESSIONAIRES, LTD., 3Duke Street, St. James's, S.W.1.

PHOTOGRAPHYE500worth, good, cheap Photo Materials, Films,

Plates, Cards, Papers, Chemicals, Catalogueand 4 Samples free.-Hackett's Works, July Road,Liverpool 6.

DON"T TAKE RISKS. Good developers meargood results. Our reliable stock developers keep twelvemonths after mixing. Satisfaction certain to amateursand professionals. Best developers ever put on themarket. Makes two pints strong developer. 6d. each,6 for 2/3, 12 for 4/-. Post tree.-Hackett's WorksJuly Road, Liverpool 6.

"DOUBLE 0"MODEL RAILWAYS

The small gauge with the big appeal

A layout in "00" takes only ONE QUARTER thespace of the same design in "0" gauge. Youcan have a real Model Railway in a small room.We have the most extensive range of modelsand specialise in this gauge. Send 6d. in stampslor our new 198-9 Catalogue. Ask for FREESAMPLE of scale model Permanent Way.

GEORGE E. MELLOR5, Brewis Road, Rhos -on -Sea

NORTH WALES

" MYFORD "BEST VALUE-INEXPENSIVE

DESIGNED AND MANUFACTURED ON THEFINEST ENGINEERING PRINCIPLES.

Bench -Treadle- Motorised Lathes & Accessories.Send P.C. for free illustrated list (your tool merchants'

address would be appreciated).MYFORD ENG. Co., Ltd., Beeston,Nottm.

All applications respecting Advertising in this Pulorcation should be addressed to the ADVERTISEMENT MANAGER, GEORGE NEWNES LTD..Tower House, Southampton Street, Strand, London, W.C.2. Telephone : Temple Bar 4363.

fi

GEE...I would like tchave real HE-MANmuscles !

So would I, but iftakes a long while

toff 9

Prove inthe,rst 7days YOUcan have aBodylikemme

-CHARLES ATLASHolder of the title "The World's Most

Perfectly Developed Man."DON'T get the idea that it takes a lot of time and hardwork for you to get smashing strength and powerful

muscles ! And don't think you need a room full of apparatus.Both these ideas are all rot-and I have PROVED it ! AllI need is 7 days to prove what I can do for you ! And Idon't need any gadgets either. I don't believe in artificialmethods that may strain your vital organs for life !

DYNAMIC TENSION IS ALL I NEEDAbove you see an actual photo of how I look to -day. No muscles have been

"painted" on. This is the camera's honest proof of what I did for MY body. NowI'm ready to prove what my secret of Dynamic Tension can do for YOURS. I usedto be a physical wreck, a 7 -stone weakling, flat -chested, arms and legs like broom-sticks. I was worried; I studied myself. Then I found a new way to build myselfup-a way that was simple, natural, quick and sure ! Dynamic Tension is what Icalled it. In a short time I had the body that has won for me the title of"The World's Most Perfectly Developed Man."

This Secret Has Helped ThousandsThousands of others now know from their own personal experience what Dynamic

Tension has done for them. They were just as frail and puny as I once was. Nowthey are life-sized examples of what a man can and ought to be. My interestingbook, filled with pictures, tells my story-and theirs.

48 -Page Book FREEThis coupon brings you my free book, which tells all about it. No cost or obligation

I just want to give you proof that I can do for you what I have done for so manyothers; give you broad, powerful shoulders, biceps that bulge with smashingstrength, a chest which stands out solid and muscular, and an evenly developedbody that will make others look like dwarfs next to you. Post this coupon TO -DAY.Address-CHARLES ATLAS, (Dept. 10/L), 2, Dean Street, London, W.I.

somi

CHARLES ATLAS, (Dept. 10/L), 2 Dean St., London W.1I want the proof that your system of Dynamic Tension will make a New Man o.

me. Send me your book, "Everlasting Health and Strength," FREE, and details 01your amazing 7 -DAY TRIAL OFFER.

NamePlease print or write plainlyAddress

SPECIAL SALE

BING MINIATURE RAILWAY PARTS

Do not miss this opportunity of procuring these bargains inMiniature Railway Equipment. Stocks are limited and cannot

be repeated. BUY NOW.Clockwork Electric

Tank Locomotives 4'9 8,6Passenger Coaches 8d. 8d.Signals .. 8d. 8d.Level Crossing Gates 1/- 1/6Turntables . 6/-Tunnels .. 10d. 10d.Straight Rails doz. 6d. 5;-Curved Rails fig 3/6 5/-Points .. each 1/9X Crossings 6d.

All prices plus postage.

AEROPLANE KITSMake a real flying model 12 -in. wing span of the AERONCA, BOEING PI2E,CURTISS, PURSUIT, HELL DIVER, LOCKHEED VEGA, MONOCOUPE,PUSS MOTH STINSON RELIANT, TAYLOR CUB, VULTEE VIA, WACO.

Price 1 Od. each. Postage 3d.SEND 6d. FOR BOND'S 1933 CATALOGUE. Its 202 pages will interest you.

BOND'S 0' EUSTON ROAD LTD.357, Euston Road, London, N.W.I.

Phone LUSton 5441-2 Est. 1887

lommommimm111111110111111111111

TRADEOn R Power Tools

7

BAND SAWS- Wizard " Band Saws are excep-

tionally well made, and will appealto those whose needs do not requirea machine of large capacity. A mostuseful tool for the practical mechanic.Made in two sizes, 9" and 12"

PRICES

9" (illustrated) ... £5 3 612" ... £148U

Pease write for illustratedoriced catalogue

No. I37C.

WIZARDMACHINERY CO.

13, VICTORIA STREETLONDON, S.W.ITelephone - Abbey 3018

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U :CAL...teach you not only how to draw what is wanted, but how to make buyers want what you draw. Many of our students who originally took up Commercial Art as a hobby have since