ALTHOUGH no radical change in design has been noticed in motorcars during the last ten years, performance has improved out of all recognition. More efficient carburation and better cylinder-head design has accounted for a good deal of this improvement, but the chief cause has been the general raising of compression ratios. This in turn has only been made possible because fuels are now available which minimise the ” knocking” and ” pinking” inevitably resulting when normal straight petrol is used with high compression engines.

For racing, where extremely high compression ratios are necessary to obtain the greatest possible power-output, alcohol fuels have for many years been widely used. For general use alternative methods of raising the anti-knock value, or octane rating as it is called, of petrol have been the inclusion of a 20 percentage of benzol, or a very small percentage of tetra-ethyl lead fluid. Without discussing here the relative advantages possessed by these three methods of improving the anti-knock value of motor spirit, it is sufficient to say that alcohol-blends have the approval of most people who have studied the ,question, particularly from the point

of view of the sport car owner, whose machine is affected materially by the quality of the fuel used. At present there are two alcohol-blend fuels on the market. Cleveland-Discol

is the product of the Petroleum Storage and Finance Corporation Ltd., and is made in association with the Distillers Co. Ltd., the largest manufacturers of alcohol in the United Kingdom.

Cleveland Discol will shortly be on sale all over England, Scotland and Wales. The Cleveland petrol pumps are now numerically the third strongest in the country and the organisation is based on ten coastal bulk depots at Preston, Ellesmere Port, Avonmouth, Newport, Lymington, Shoreham, Barking, Goole, Sunderland and Thameshaven. Cleve

land-Discol will be sold at the current No. 1 price of Is. 6d. per gallon. Koolmotor Alcohol Blend has been on sale in England since the early part of

1932, and there are now some hundreds of Koolmotor pumps situated in 27 different counties of England. It sells at the usual price of Is. 6d. per gallon.

Koolmotor possesses to the fullest degree the advantages of an alcohol fuel. That is to say, it has a very high octane rating, or anti-knock value, and by reascn of the lower temperature of vaporised.

alcohol fuel as compared with straight petrol, due to the high latent heat, it is particularly useful for small-bore high compression sports cars, where a cool mixture is essential.

The manufacturers of Koolmotor Alcohol Blend are the Cities Service Oil Co. Ltd., and the alcohol used in its production is manufactured at Dagenham by Messrs. Solvent Products, Ltd., who are associated with the United Molasses Company and the 1,istillers Group.

It has probably occurred to the reader that it is remarkable that these two concerns are able to market alcohol fuel at a price no clearer than ordinary petrol, when alcohol used for drinking purposes is subject to a tax of over *.6 per gallon. This is accounted for by the exemption from any tax of alcohol used for mechanical purposes, even the 8d. per gallon tax on petrol, the idea being to foster as much as possible the use of home-produced fuels. Thus for every gallon of alcohol fuel manufactured, only 75% of it (the alcohol content is roughly 25%) is subject to the 8d. petrol tax. And so, although alcohol is expensive to manufacture, this cost is counterbalanced by the saving on petrol tax, and the companies mentioned above are able to sell their fuel at a competitive price.