<div class="htmlview paragraph"><b>U</b>SING analogies based on our everyday experience with hydraulic phenomena, Mr. Deimel gives here a simple explanation of the operation of an increasingly important mechanism - the hydraulic transmission.</div> <div class="htmlview paragraph">The author then discusses the various problems involved in adopting hydraulic transmissions - both the hydraulic coupling and the torque converter - to motor vehicles; for best performance can be obtained only if the transmission is tailored to the engine and the conditions under which the vehicle operates.</div> <div class="htmlview paragraph">Finally, he describes a special arrangement for testing hydraulic transmissions, because the accuracy required is much higher than that needed in testing engines.</div> <div class="htmlview paragraph"> <div class="graphic-wrapper"><img class="article-image" src="450152_fig0001.jpg" alt="No Caption Available"/></div> </div>