Abstract
The classical formulation of homogeneous nucleation theory has been tested in the methylcyclohexane‐perfluoromethylcyclohexane liquid‐liquid gap miscibility system. The theory was found to be invalid for temperatures above 35°C. The discrepancy between theory and experiment (critical undercoolings are predicted which are less than those observed) can not be explained by simple modifications of the theory. These results confirm the discrepancy found by Sundquist and Oriani.