CARBONATE OF POTASSIUM 177 



or more diluted doses gradually impair digestion and assimi- 

 lation, and destroy life by inanition. The antidotes are 

 diluted acids which form mild salts, and oils which produce 

 soaps the latter serving as demulcents, and in men and 

 dogs as auxiliary emetics. Irritation is also relieved by milk 

 and gruel. 



MEDICINAL USES. Diluted solution of caustic potash has 

 been used both internally and externally as an antidote for 

 the poison of snakes. Half a drachm, repeated twice daily, 

 has been prescribed for sheep affected with vesical and 

 urethral calculi ; but the carbonate is milder and equally 

 effectual. It is occasionally added to cough mixtures when 

 bronchial secretion is scanty and tenacious. 



Caustic potash is used for eradicating warts and fungous 

 growths, and cauterising poisoned wounds. On account of 

 its deliquescence and liability to spread, it must, however, 

 be applied cautiously, and any excess of alkali neutralised 

 by subsequent washing with a weak acid. Mixed with one- 

 third lime, and moistened with alcohol, constituting Vienna 

 paste, it is less deliquescent and more manageable. 



POTASSIUM CARBONATE. Potassii Carbonas. Carbonate of 



Potash. K 2 C0 3 . 

 POTASSIUM BICARBONATE. Potassii Bicarbonas. Potassium 



Hydrogen Carbonate. KHCO 3 . 



Potassium carbonates are got by several processes (1) the 

 American pot or wood ashes, in their partially purified 

 condition of pearl ashes, contain about eighty per cent, 

 of potassium carbonate, with twenty per cent, of potassium 

 sulphate and chloride, w r hich, being less soluble, are got 

 rid of by dissolving the pearl ashes, with brisk agitation, 

 in an equal weight of water, pouring off the solution, and 

 evaporating it to dryness. (2) From the sulphate they 

 are obtained by a process similar to that followed in making 

 sodium carbonate. (3) A pure carbonate is got by burning 

 potassium tartrate with charcoal. 



The carbonate occurs in crystals, as a crystalline powder, 

 but more generally in grains. It is white, opaque, and 

 inodorous, with a strong alkaline taste, and an alkaline 



M 



