Physical significance of entropy or of the second law

by Joseph Frederic Klein

For C. G. S. system, Entropy of any natural state, Eq. (28) is

For F. P. S. system, Entropy of any natural state, Eq. (28) is

To each of these may be added an arbitrary constant. In Eq. (20) we may substitute directly the equivalent of the product

found from Eq. (22), and then get for the entropy

of a monatomic gas in the state of thermal equilibrium,