The Purchase Department.
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Where to Buy your Supplies.
The A.T. Magnetic Speedometer.
Makers and .users alike are always prepared to fit to their machines a reliable speedometer or log recorder which will give an accurate reading under all working conditions.
• The magnetic principle of speedometer constructioe has much to commend its use, providing it is designed and manufactured on practical lines. One of the well-known makers of this class of recorder is the A.T. Speedometer Co., Ltd., HO, Long Acre, London, W.C. There are few components in the A.T., the principal ones, apart from the drive, being the steel permanent magneto and the indicating body constructed of aluminium.
The actual working of the speedometer is very simple. A steel magnet with an attractor is coupled on to the driving cable and the latter when ;mused to revolve by the movement of the vehicle carries the magnet round with it. This magnet when rotating sets up eddy, currents -and thereby endeavours to revolve the indicating body, which is mounted on jewelled bearings. The latter, however, is restrained by a coiled spring, the strength of which is -correspondingly overcome by the eddy currents as the magnet gains in speed, thus drawing the indicator round the dial of the speedometer.
The faster the speed -of the ear and therefore of the magnet, the stronger the currents will be, and the indicating finger will be moved further round the dial. A special s feature of the A.T. is that the chief working parts are mounted on ball bearings, which enables the instrument to run with the minimum of noise and friction. The A.T. is unaffected by varying temperatures or climatic conditions, as a compensating device is fitted. E2 The actual drive of the A.T. is made up of a series of links, which are enclosed in a helical-pattern steel liner which in turn is encased by a metallic flexible easing. This forms a cleverly-designed and effective metal protection for the driving shaft.
The makers point out that the drive from the eardan shaft is more satisfactory than that taken from the front wheels, as, owing to the locking of the wheels, the cable is subjected to excessive strain and therefore does not last the same length of time as does the eardan shaft form of drive.
Carburine Spirit and Glico Supplies.
The Gas Lighting Improvement Co., Ltd., of Saliebury House, London Wall, EC., has issued an at tractive pamphlet giving particulars of its high-grade Carburine spirit and its special lubricating oils and greases for motor vehicles. The company is also marketing an excellent range of motor benzole. Its address in Scotland is 17, York Place, Edinburgh, and in Ireland its wholesale agency is held by William Preston and Co., Ltd., of Great Brunswick Street, Dublin. The company has adopted the trade description Glieo for many of its products, and this brand deservedly enjoys a high reputation with owners of commercial motors in all parts of the country.
A Rear-Light Indicator.
There have been a number of complaints from the police lately with regard to motorists' driving at night with a most inefficient rear light ; moreover, accidents have been reported, and those responsible have driven off without being identified on acettunt of such faulty lighting.
We have had brought to our notice recently a simple arrangement whereby the number-plate is illuminated from the interior of the casing; this renders it readily discernible at night.
A bull's-eye attached to each side of the easing enables the driver on turning round to see whether the light is burning. A single burner, as used in the ordinary rear light, is the only source of illumination, which serves for the purpose of lighting the numberplate, the rear light and the bull's-eye. This simple and useful invention should go a long way to solving the problem -of rear-light indicating.