<div class="htmlview paragraph">MARKING the completion of the investigation of engine acceleration in connection with a study of the economic volatility of motor fuels that has been under way since 1920, the paper is in the nature of a final progress-report and presents a summary of the results obtained. The earlier work done is reviewed briefly, following which the phase of the work that the paper covers, comparisons of fuel performance with downdraft and updraft induction-systems and with three separate carbureters connected by short pipes to the three intake ports of the engine, is described. Although the latter arrangement roughly represents cold carburetion, complete parallelism with the other series of tests is not possible since the three carbureters were not equipped with accelerating-charge pumps.</div> <div class="htmlview paragraph">The effect of the accelerating-charge pump was brought out in the discussion, a car so equipped traveling 160 ft. in 6 sec., while other cars of the same make but not fitted with the pump required 0.2 sec. more. Another point raised was the influence on acceleration exerted by the character of the interior surface of the manifolds. In reply, the author said that this factor had a great effect.</div>