This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol2", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
This is made by mixing heated solutions of chloride of calcium and carbonate of soda. Chloride of sodium forms, remaining in solution; and carbonate of lime is precipitated. A soft white powder is thus obtained, which may be employed for the same purposes as chalk, but has, so far as I am aware, no advantage over it in efficiency, to counterbalance its greater costliness.