• Sir,

Pre-supposing that a certain firm, having unlimited resources and full technical abilit y. designs and produces two cars of the highest efficiency (for Gramr Prix purposes), one a 6-cylinder 1/-litre, and the other a 6-cylinder 6-litre, will the larger engine develop as many b.h.p. per litre as the smaller ?

As this hypothetical case is stated so as to settle a query in my mind, to which I have never had a satisfactory answer, it should be assumed that the firm in question has aimed solely at obtaining the utmost power-development in each case. I am, Yours, etc.,

Belfast. J. F. W. GA LLA1,10 HER. [Expert readers will probably be better able to answer Mr. Gallaugher’s query than we, but, generally, a small engine can he made to give greater b.h.p. per litre than a big one because its lighter moving parts permit of higher r.p.m., the stresses set up by high piston speed are less, and its combustion chambers can be made a better shape. The fact that both engines are sixes does not completely undermine these facts.—En.] 5 • Sir,

Considering MOTOR SPORT to be the main contact between the distant past when one could breathe all week-end the gloriOus stench of Castro! “R,” and the somewhat problematical future when one will be able to listen to an approaching exhaust throb without wondering whether it will suddenly cease and blow us skywards, I am writing to ask whether any of your readers could help me in my search for a “San Sebastian” Salmson engine—or, at least, a Grand Prix ” Special ” of the same breed ?

I should also appreciate information regarding any of the latter engines which have been blown.

Wishing you continued success, and with great admiration for the way in which you carry on in such difficult circumstances. I am, Yours, etc., A.T.A. DAvm G. S. CorrEn (Ft./Capt.) [Letters will be forwarded.—En.]