This section is from the book "Materia Medica Pharmacy, Pharmacology And Therapeutics", by W. Hale White. Also available from Amazon: Materia Medica Pharmacy, Pharmacology And Therapeutics..
Pearlash, which is a product of the lixiviation of wood ashes, is treated with water, which dissolves little but potassium carbonate, and the solution is evaporated.
A white, granular powder, odorless, having a very strong alkaline taste; very deliquescent. Solubility. - In 1.1 parts of water, and in 0.65 part of boiling water; insoluble in alcohol.
Sulphates, chlorides, nitrates, cyanides, earthy and metallic matters.
Potassium Carbonate is used in preparing Mistura Ferri Composita, Pilulae Ferri Carbonatis (in which Ferrous Carbonate is formed), and Potassa Sulphurata.
Dose, 5 to 30 gr.; .30 to 2.00 gm.
These are the same as those of potash; but the carbonate is less caustic.