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Where to Buy your Supplies.
A.T. Speedometers in Grand Prix Races.
Wc have, from time to time, received from users of A.T. speedometers firsthand particulars of the satisfactory records which the instruments consistently, afford. Interesting testimony regarding the efficiency of these reconders under the most arduous conditions of service is forthcoming in that 50 per cent, of the cars which ran in the, recent Grand .Prix were fitted svith A.T. speedometers. This includes the successful Mercedes team. Also in the -United States, in the Grand Prix held at Indianapolis a little while back, the first, second, third and fourth cars home were each equipped with this well-known make of recorder.
A Journey-Recorder with a Silver Pencil.
On this page we have often described the different examples of well-known journey-recording devices on the market, these vary greatly in size. shape, weight,
stud price. A very compact form of recorder whin has recently been brought to our notice is the. Chronhodograph, which is being manufactured. by the thronhodograph Co., 17, Seaton Street, London, N.W. This instrument is of neat and well-made construction, the overall diameter being 4 ins, whilst the thickness is but 21 ins and the weight only e.„ lb. In this small space, it not only incorporates the recording disc with its mechanism. hut also a mile.ometer registering up to 100,000, the figures of which, as will be seen, are very clear,
This apparatus gives a complete survey of the Vorking of any vehicle to which it may be fitted. The duration of all stops is clearly shown, and the speed over any part of the journey is readily ascertained, as well as the total length of that journey. The instrument comprises a strong clock-movement, which, in place of the usual hands, is provided with a chemically-prepared paper disc marked off
into hours and their divisions. A teximeter-type drive from one of the front wheels is conveyed by flexible shafting to the interior of the instrument, where small bevel-gears connect. it. to a earn, -which operates, by suitable mechanism, a silver pencil
When the card is inserted, and the lid closed down, the silver pencil makes contact. with it, and, owing to the specially prepared surface, is able to mark the disc quite distinctly.
At present, the instrument is made in two types, the price of each being .t10; in the one type, the space between the pencil marks represents two miles, and in the other five miles ; for commercial vehicles, the former is the one most. snitable. The life of the pencil iasstated to be 20 years, and as all parts of the mechanism are of stout design, users of commercial vehicles will do well to obtain further particulars about the instrument from the Chronhodograph Co.
The Dinshah Engine Tester.
A novel engine-efficiency indicator, which we illustrate herewith, has recentlybeen brought to our notice; it. is named the Diushali and is marketed in this country by McDonald, Mostyn and Co., 186-188, Shaftesbury Avenue, London, W.C. The device consists of a polished wood box containing four vacuumtubes, which also embody four spark-gaps ; five wires are led from the instrument, of which four go to the sparking plug terminals or the h.t. leads as required, and the remaining one to " earth,''
To test an engine the leads are detached from the plugs and connected upto the instrument, then providing the ignition be in good order, each vacuum tube will show a blue spark on the left and a yellow flash on the right. If either sparks or flashes fail, or are irregular, something is wrong with the ignition, and the location of the fault can be ascertained by consulting the directions affixed to the cover of the instruments If the magneto and connections are perfect, the leads and the test-wires :ire connected to the plugs, and from the signals observed in the box faults in the sparking-plugs and carburetter can be readily detected, it is also pes.sible to note losses of compression in any cylinder.
The complete outfit i0priced at five guineas and should prove of great service in repair works and garages, especially where a large number of engines has to be examined.