In our previous paper , it was pointed out that Tc is the temperature corresponding to x2 = 60~70%, a maximum value that a gas system enables to keep the thermal equilibrium by the heat exchange cycle. Here, Tc * is the theoretical temperature at x2 = 1. It corresponds to Pc* . However, in this paper, R•B is the heat delivered by, theoretically, complete liquefication of 1 mole gas.