For different concentrate solutions of several kinds of solute, the homogeneous nucleation temperature Th and the equilibrium melting points Tm were determined by using so-called emulsion method. The obtained Th and Tm for each solute dropped with concentration increasing, however, the relationship between both temperatures showed good linearity with different gradients depending on the kind of solute. That is, the relations could be expressed by an equation Th=aTm for each solute, of which the gradients a are considered to represent the degree of supercooling ability. The correlation between the a values for each solute and the chemical structure or hydrate characters was examined. As a result, the dynamic hydration number of solute was found to have a best correlation with the a value representing supercooling ability.
