Fermat-Ostwald principle

Fermat's principle of least time and Ostwald's law of intermediate stages are postulates concerning the physical processes that deal with light and heat energy flows, respectively. A comparative analysis of these processes shows that there is a close analogy between them. This suggests that the principle of least time can be applied to phase transitions of first kind concerned Ostwald's law. This supposition has been proven using the Maxwell-Boltzmann distribution law and an assumed correlation between two parameters of solids (heat conductivity and activation energy of molecules). Thus, a modification of Fermat's principle is obtained, which can be named Fermat-Ostwald principle.