Physical significance of entropy or of the second law

by Joseph Frederic Klein

(in the C.G.S. system) is a universal constant, function

is the law of distribution of the particles and their velocity elements and

is a sort of fictitious elementary region in a six-dimensional space. From its derivation and definition the value given for entropy

in Eq. (33) depends only on the state of the body at the instant in question and does not at all depend on its history preceding this instant.

The difference between the value of

for the final state (say, as given for a gas by Eq. 20) and the value of