Abstract. In addition to the hexagonal and monoclinic bismuth phosphate precipitates, whose structures are now known, a third crystalline phase has been found to appear in BiPO4 precipitates after (a) extremely long digestion in concentrated nitric acid; (b) oven drying at 800 degrees to 1000 degrees. Thought very small single crystals of the component have been isolated, nor crushed sample contained less than 30% of the beta-form. The cell size and symmetry of the crystal indicates that there ae two bismuth atoms in the cell, and there is no evidence that the compound is not BiPO4. It is suggested that this maty be a third form of BiPO4, stable over a short range of conditions, and tending to revert to the beta-form.

Abstract. An apparatus for measuring the thermal conductivities materials which are moderately good conductors of heat is described. Results obtained with a sample of pure Th are given on p. 10, 12, and 13.