Hysteresis and elastic after-working in the condensed films

Hysteresis and elastic after-working in the condensed films. As a rule, if the compression on the films is reduced, they expand nearly along the original curve of compression, with but little time-lag. In the neighbourhood of the transition temperature of the urea derivatives, however, a decided difference between the curve of compression and of decompression was found (/). 

Signs of elastic afterworking have been observed in a number of cases, though never so pronounced as in the above two. There seems to be a slight delay in reaching equilibrium in the films of myristic acid, especially in the transition region between the expanded and condensed states. A closer investigation of this phenomenon is needed. 

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