The salts and preparations of potassium are most conveniently discussed in the following order:

1. Potsassae Carbonas

Potsassae Carbonas. Carbonate of Potash, K2CO3, with about 16 per cent. of water of crystallisation.

Source. - Obtained from wood ashes by lixiviation, evaporation, and crystallisation.

Characters. - A white crystalline, very deliquescent powder, of caustic alkaline taste. 20 gr. neutralise 17 gr. of citric acid, or 18 gr. of tartaric acid.

Impurities. - Sulphates and chlorides.

Dose. - 10 to 30 gr.

From Potassae Carbonas are made: a. Potassae Bicarbonas. - Bicarbonate of Potash.