<div class="htmlview paragraph">THE ordinary governor used on trucks and tractors is essentially a one-speed device. It gives good results at one speed, but at higher speeds “hunting” develops and at lower speeds governing is less accurate. This is because the spring must be stiff enough for maximum speed, and hence four times stiffer than it should be for half speed.</div> <div class="htmlview paragraph">The paper shows by calculations and curves the best results that can possibly be obtained; also, curves from a test showing what results are actually obtained with one well-known governor. Two new types of governor are described; in which the position of the spring is varied for different speeds. Theoretical curves also are presented and the results of tests, indicating that the new types produce the same character of curve at 800 as at 1600 r.p.m.</div>