The heat capacity of terbium metal was measured between 0.25 and 1.0 deg K. The high temperature data can be expressed as C = 28R x 10/sup -3/T/sup 2/ cal/ mole-deg. The data are compared with a Schottky formula for the heat capacity, assuming equal spacing between the nuclear hyperfine levels with an over-all spacing of beta = 0.45/ deg K, correspondlng to the high temperature expression above. The agreement is within experimental error except at the very lowest temperatures obtained. The effective field at the nucleus of the terbium atom can be calculated and is found to be H/sub eff/= 4 x 10/sup 6/ gauss. (auth)