IN econometric models of the business cycle,one of the most difficult problems is the occurrence of relaxation phenomena, or what Georgescu-Roegen has termed phase-periodicity. 1 An actual system appears to behave according to one rule of behavior during a certain phase of the fluctuations, and then according to an entirely different rule during another phase. This is precisely the sticky thing about the bottleneck problem in an inflation and about the excess capacity problem for a depression. This paper reports on some research into the excess capacity problem made possible through using Whirlwind I, a high-speed, electronic computer.