Prep. Made by saturating bitartrate of potash with carbonate of soda, when the basic equivalent of water is replaced by one of soda, and carbonic acid given off.

Prop. & Comp. Four or six-sided prisms, generally occurring in half crystals, neutral in reaction, entirely soluble in cold water, tasting like common salt. When sulphuric acid is added to a strong solution, bitartrate of potash is precipitated. Nitrate of silver and chloride of barium throw down no precipitate, or only such as is dissolved by water. Heated with sulphuric acid it blackens and evolves inflammable gas. It imparts a yellow colour to flame. Composition (Na O, KO, C8 H4 O10 + 8 HO). Forty-seven grains heated to redness till gases cease to be evolved, leave an alkaline residue, which requires for neutralization 30 measures of the volumetric solution of oxalic acid.

Therapeutics. A mild saline purgative, in large doses; in smaller ones, diuretic; and producing an alkaline condition of the fluids in the same way as tartrate of potash: it is employed under exactly similar circumstances.

Dose. As a purgative, 120 gr. to 1/2 oz.; as a diuretic, 30 gr. to 60 gr.

Soap and Valerianate of Soda will be treated of under the heads of Olive Oil and Valerian.