Contribution of Nuclear Magnetism to the Isochoric Pressure of bcc Solid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$

Isochoric pressure measurements have been made in bcc solid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ from the melting point down to 29 mK in magnetic fields up to 8.0 T and for molar volumes of 23.834, 24.163, and 24.371 ml/mole. The measurements show that the pressure at high magnetic fields is thermodynamically inconsistent with reported values for the Weiss temperature deduced from nuclear magnetic susceptibility. Furthermore, the Weiss temperature deduced from our data at 24.25 ml/mole is in disagreement with that used in the theory of Roger, Hetherington, and Delrieu.