185.

Let us now calculate the entropy change of the system of oscillators which has taken place in the same time $dt$. According to [eqn:(173)] (173) the entropy at the time $t$ is $S=-kN{\sum }_1^{\infty }{w}_n\log w_n.$ Hence the entropy change in the time $dt$ is $dS=-kN{\sum }_1^{\infty }\log w_{n}d{w}_n,$ and, by taking account of [eqn:(343)] (343), we have: $dS=\frac{Nk𝖨dt}{4h\nu L}{\sum }_1^{\infty }(w_n-(1-\eta )w_{n-1})\log w_n.\mathrm{\backslash Label}[eqn](349)\text{upshape (349)}$