APRJL 6 TH , 1907.

THE AUTOCAR B )ournal publisbc~ in tbe intcresto of tbe mecbnntcnll\2 propelle~ roa~ carriage.

EDITED BY H. WALTER STANER.

No. 598. VoL. XVIII . SATURDAY, APRIL 6TH, 1907.

[PRICE 3D.

TIIE AUTOCAR.

(Published Weekly).

- Registered as a newspaper for transmission in the United Kingdom.

Entered as second.class matter in the New York (N.Y. ) Post Office.

EDITORIAL OFFICE :

COVENTRY.

PUBLISHING OFFICES:

20, TUDOR STREET, LONDON, E.C., ENGLAND.

CONTENTS.

PAGE

NOTES , • , , , ,

477-478

USEFUL HINTS AND TIPS . • • • • • . •

. . 479

THE 30-35 H.P . SH,BIS·WELBECK CAR ( I LLUSTRATED) • .

480-483

A N EW SMALL CAR-THE NEW R OLLS-ROYCE WORKS • •

. . 483

A BRITISH M OTOR FUEL . . , . . . . . . . . . . 484-485 THE RENAULT PATENT AMENDED- MICH E LI N TYRES IN AMERICA • • 486 A BRITISH FORCE FEED LUBRICATOR ( ILLUSTRATED} . • . • 487 THE LADY MOTORIST . • • • • • • • • • 488-489 THE BELSIZE ENGINE L UBR ICATOR ( ILLUSTRATED) . • , . 489 S OME D ETAILS OF CARS ENTERED FOR THE GRAND PRIX AND COUPE DE

LA CoMMISSION SPORTlVE RACES . • , •

. . 490

A DANGER OF THE STREETS ( ILLUSTRATED)

, •

. • 490

THE HEEL OF ACHILLES. By G . STUART OGILVIE . • . . 49 1-492 CONTINENTAL NOTES AND NEWS : THE ~l ONACO :\lEETJNG-THE

FRENCH CRJTERIUM-THE PEKIN-PARIS RUN-THE AMERICAN I NVASION-ANOTHER SUCCESSFUL FLIGHT-THE l\1ULTJPLI CIT\' OF SHOWS • . . • · · · · 493 -494 BY AIRSHIP TO THE NORTH POLE • • • · 494 CORRESPONDENCE . . . . • , . . . , 495-500 THE DE DION FOUR-CYLINDER ENGINES ( ILLUSTRATED) • • 501 AMERICAN MOTOR NOTES . . , . 502 S OME QUERIES AND REPLIES . . . • , • . . • • 503 AN IMPROVED l\ .'I ECHAN ICA L TYRE PU:\IP ( I LLUSTRATED ) • . 504 THE NEXT MOTOR BOAT EXHIBITION • • 504 FLASHE'ii, . . • . . • . · • . • • · . . 505-507 THE STRENGTH AND STRUCTURE OF ALLOYS ( ILLUSTRATED ) 508-510 REVIEWS , • , • • . 510 CLUB DOINGS . • • . . . • • • . 511-512 AN AMERICAN C >.RBURETTE R ( ILL USTRATED) . • 512

"THE AUTOCAR " SUBSCRIPTION RATES: Br:tish I sles, 16s. Abroad (thin pu.per edition ), 22s. 8d. per annum.

/ Notes. The Fat Spark Again. The long respected fat or hot spark has been so much discredited of late that we think the lette r of Mr. T. Blackwood Murray which appeared in our issue of March 30th (page 457) dese rves special refer ence. In the course of his very interesting communication dealing with ex periments which he ha made Mr. ~Iurray says :

"The popular fallacy as to the advantage of a hot spark is , I think, explained by the fact th at it is extremely diffi cult to keep up a very high insulation standard in ignition circuits, particularly in th e plugs, a nd therefore tl} e more lively a magneto (or coil , as the case may be) employed to generate the igniting spark , th e better ma rg in there is to a llow for leaky circuits, and therefore the more certainl y is .regular ignition secured."

This is quite the best explanation of the apparently contradictory results obtained in the laboratory an:' on the road we ha\·e seen up to th e present time. In the laboratory exper iments the ignition equipment has been t~oroughly we ll installed, well a_djusted, and generally 111 perfec t order. In f~ct, 1t would ~ impossible to conduct accurate expenments unl ess this were the case. On the other hand, on the road many parts, if not the whole , of the ignition installation are subject to gradual deterioration , and certain parts, such as the pi ugs or th e contact maker , are particularly like ly to give trouble, owing to over-lubrication, and, as Mr. Murray points out, the lively spark will , so to speak, break down all opposition, whereas the one of lower rnltage, which would be entire ly satisfactory were eve rything in perfect order, would fail. There are many rough and ready instances of this. P erhaps there is no one better th an that of a faulty commutator with an ordinary accumulator and trembler coil ignitio n. The commutator may be faulty because it is worn, or the insulation may have been more or less damaged by becoming oil soddened after long use . Whatever be the cause , it will be found that the engine will run badly and misfire. It may even come to a stop altogether with four volts, but if one of the cells of the spare accumul ator be coupl ed up so as to put six volts through the coil the erstwhile unsatisfactory commutator will perform its work well , and the engine will fire with out a miss, provided always that th e co.ii will ca rry the higher volt ge. It al so fo ll ows th at as th e commutator f th er deteriorates the time will arrive when it will fuse to fun ction 1re ll e\·en with six volts . Repairers. Of all the men who serve motorists, the one who most deserves encouragement is the ski ! led and painstaking repairer. There a re many such men up and d01rn th e country, but the re a re still more who profess to repair motors and ye t are ab olute ly unsatisfactory and unfitted for the work . It seems an extraordinary thing that , without making any enquiries, motorists will place ca rs costing hundreds of pounds in the hands of almost a ny individual or firm who profess to be able to adjust or repair motor cars , though th ey may be almost incapable of effecting the simplest work. Provided the local rep airer is a really good mecha nic, we \\'Oul d personally rather have any ordinary job done by him th an by th e manufacturers. After a ll , th e manufacturer's mission is t o manufacture, just as th e repair er 's. is t o maintain and keep in order. The troubl e is th at there is no satisfactory system at present of finding out whether a man is a good repairer or not. It is true th at some manufacturers appoint rep::i.ire rs , bu t- th ey do not always know whether these repairers are qualified men; all th ey kn ow is they are agents for their particular car. Then aga in , there are offi c ial repairers to the Automobil e Club. These men are never appointed without ca re ful enquiri es by th e .C lub officials of members who reside in the localit y. but the fact remains th at some