On the Theory of Fusion

Although equilibrium between two phases is in general determined by both phases, fusion stands somewhat apart in that a crystal cannot be overheated. As a type of the simplest possible crystal, the exact equation of state of frozen argon has been developed here. It has been found that the pressure as function of the volume at a given temperature has a minimum, which means the breakdown of the crystal under these conditions. The temperature at which this minimum occurs at zero pressure is interpreted as the melting point. It has been found in accordance with experiment that a positive pressure is necessary for the existence of crystalline helium but the numerical agreement is bad.