_Carbonate of Potass._
QUALITIES. _Form_, crystals which are four-sided prisms with dihedral
summits, permanent in the air; _Taste_, slightly alkaline without
acrimony. CHEMICAL COMPOSITION. It is a _bi-carbonate_, consisting of
two proportionals of carbonic acid and one proportional of potass; and
in its crystalline form, it also contains water equal to one
proportional. SOLUBILITY. It is soluble in 4 parts of cold, and in ⅚ths
of its weight of boiling water, in which it is partially decomposed,
carbonic acid being emitted during the solution; it is quite insoluble
in alcohol. MED. USES. In cases where an alkali is indicated, this
preparation offers an agreeable and efficient remedy; and experience has
shewn that its additional proportion of carbonic acid does not in the
least invalidate its alkaline agency. In disordered states of the
digestive functions, alkalies frequently act with surprising effect; in
calculous affections their value has been already noticed (see _Liquor
Potassæ_), and the stomach appears to bear the protracted exhibition of
the carbonate of potass or soda, with more temper than it does that of
any other alkaline combination; and on account of the increased quantity
of carbonic acid which this salt contains, it is preferable for
effervescing draughts. (See _Acid. Citric._ and _Form. 123, 168_.)
INCOMPATIBLE SUBSTANCES. _Acids_ and _acidulous salts_; _borax_;
_muriate of ammonia_; _acetate of ammonia_; _alum_; _sulphate of
magnesia_; _lime water_; _nitrate of silver_; _ammoniated copper_;
_muriate of iron_; _sub-muriate and oxy-muriate of mercury_; _acetate of
lead_; _tartarized antimony_; _tartarized iron_; _the sulphates of
zinc_, _copper_, _iron_, &c. DOSE, grs. x to ʒss.