The longitudinal and shear wave velocities of 10 Mc/s ultrasonic waves have been measured in polycrystalline specimens of zirconium and tungsten at temperatures between 14° and 300°k and the elastic constants calculated from these measurements. The difference between the specific heats at constant pressure and at constant volume in these metals at various temperatures has been calculated by means of the thermodynamic relation involving the bulk modulus of the metal; this difference is used in the examination of a suggested method of obtaining the γ values, and hence the electronic specific heats of metals.