Prep. By dissolving bone ash in hydrochloric acid, precipitating the solution with ammonia, and drying at a temperature not exceeding 212°.

Prop. & Comp. A white powder insoluble in water, but soluble without effervescence in dilute nitric acid. The solution continues clear when an excess of acetate of soda is added to it, but lets fall a white precipitate on the addition of oxalate of ammonia, and perchloride of iron (oxalate of lime and phosphate of iron being respectively formed). Composition (3 Ca O, PO). Ten grains dissolve without effervescence in dilute hydrochloric acid. The solution yields with ammonia a white precipitate (phosphate of lime), insoluble in boiling potash, and when washed and dried weighing ten grains: the absence of effervescence proves that no carbonate is present, and the weight of the precipitate shows that the salt is pure.

Off. Prep. (Contained in Pulvis Antimonialis.) Therapeutics. Scarcely given as a medicinal agent. Plaster of Paris. Appendix B. Native Sulphate of Lime (Ca O, So3). Deprived of water by heat. It is used for making a test solution.

Off. Prep. Solution of Sulphate of Lime. Appendix B. A saturated solution of sulphate of lime.