) is almost the same value, 85~88 J/(K•mol) , , for various kinds of liquids at their boiling points. Although it is based on the Gibbs potential ∆G = 0, ∆𝐻 𝑣 ∅ and Tb are measured independently. Hence, ∆S 𝑣 may be comparable to the data in Tab. 1-4. Tab. 5 shows the results. As shown in Tab. 5, Trouton's entropy is only found in some long-chain alkanes, benzene, and toluene. An interesting observation is that the entropy of small molecules calculated from Gibbs's potential is almost two-fold the entropy calculated in this paper. For example, this paper gives the entropy of 36.7 J/(K•mol) to Ar, whereas Trouton's entropy is 74.9 J/(K•mol). Gibbs's potential suggests the minimum ΔG at equilibrium. It is correct, but it doesn't mean ΔG=0. The second law of thermodynamics implies that the spontaneous process is irreversible. Indeed, the exothermic heat of liquefaction is not equal to the endothermal heat of evaporation. Since the surroundings must keep the isolation of an isolated system, it pays more energy than the exhausted energy from an isolated system. Similarly, it may be inferred that Walden's entropy of fusion should also have been overestimated.