Comment on the Proposed Magnetic Cooling ofHe3

We examine a recent proposal by Goldstein for producing very low temperatures by freezing ${\mathrm{He}}^3$ in the presence of magnetic fields. We conclude that the highly isotropic nature of solid ${\mathrm{He}}^3$ will completely suppress the particular cooling mechanism envisaged, but a related magnetothermal effect should be observable. At readily accessible temperatures this effect will be small, but below about 1 mK a potentially useful amount of magnetic cooling is predicted. The field required for the maximum cooling is about 70 kOe.