2, may be found by adding to the heat required for the change of temperature at constant volume, sdo, or at constant pressure, Sdo, the heat absorbed in isothermal expansion as given by relations (4).
We thus obtain the expressions dH = sdo +0 (dp I dO) dv = Sd0 - o (dv/do) dp..
The change of energy at constant volume is simply sdo, the change at constant temperature is (odp/de - p)dv, which may be written dE/de (v const) =s, dE/dv (0 const) =odp/do - p .
The energy E and the total heat F are functions of the temperature only, by equations (9) and (I I), and their variations take the form dE = sdO, d F = Sd0.
The value of the angular coefficient d(pv)/dp is evidently (b - c), which expresses the defect of the actual volume v from the ideal volume Re/p. Differentiating equation (17) at constant pressure to find dv/do, and observing that dcldO= - nc/O, we find by substitution in (is) the following simple expression for the cooling effect do/dp in terms of c and b, Sdo/dp= (n+I)c - b..