The heat capacity of pure ${\mathrm{He}}^3$ has been measured using a difference method from 6 to 50 m°K at 0.28 atm and from 4 to 30 m°K at 27.0 atm. In neither case is the ratio of heat capacity to temperature constant over the range of temperature of the measurements. Moreover, the high- and low-pressure heat capacities seem to have qualitatively different temperature dependences. The raw heat-capacity data down to a temperature [on the magnetic temperature scale valid for powdered cerium magnesium nitrate (CMN) in the form of a right circular cylinder with diameter equal to height] of 2 m°K at 0.28 atm and 4 m°K at 27.0 atm show no evidence for anomalous behavior. As a by-product of the measurements the heat capacity of the CMN cooling salt was also obtained.

• Received 27 January 1966

DOI:https://doi.org/10.1103/PhysRev.147.111