Page:Elementary Principles in Statistical Mechanics (1902).djvu/96

72 of these anomalies is of course zero. The natural measure of such anomalies is the square root of their average square. Now identically. Accordingly In like manner,   Hence  Equation (206) shows that the value of $$d\overline\epsilon_q/d\Theta$$ can never be negative, and that the value of $$d^2\psi_q/d\Theta^2$$ or $$d\overline\eta_q/d\Theta$$ can never be positive.

To get an idea of the order of magnitude of these quantities, we may use the average kinetic energy as a term of comparison, this quantity being independent of the arbitrary constant involved in the definition of the potential energy. Since