A mercury delay line memory system for electronic computers, capable of operating at pulse repetition rates of several megacycles per second, has been developed. The high repetition rate results in a saving in space and a reduction in access time. Numerous improvements in techniques have made the high repetition rate possible. The use of the pulse envelope system of representing data has effectively doubled the possible pulse rate; the use of crystal gating circuits has made possible the control of signals at high pulse rates; and a multichannel memory using a single pool of mercury has simplified the mechanical construction, reduced the size, and made temperature control much easier. The memory system described makes possible a significant increase in the over-all speed of an electronic computer.