Elements of chemistry, in two volumes / by John Murray.

  • Murray, John.
Date:
1828
Catalogue details

Licence: Public Domain Mark

Credit: Elements of chemistry, in two volumes / by John Murray. Source: Wellcome Collection.

    29/768 (page 17)
    The sesqui-carbonate of ammonia being volatilized, is condensed on the sides of the receiver in the form of a crust. Sometimes it is obtained by another process in solution in water. Equal parts of muriate of ammonia and of carbonate of potash are put into a retort with two parts of water, and heat is applied ; a double decompo- sition likewise takes place in this case, the muriatic acid uniting with the potash, and the carbonic acid with the ammonia; the carbonate of ammonia passes over with the aqueous vapour, which, when condensed, is sufficient to dissolve it. Sesqui-carbonate of ammonia is also ob- tained in large quantity in the decomposition of animal matter by heat. It is thus procured from bones, and forms the impure product which has been named Salt of Hartshorn. The composition of these products varies so much, that, according to their analysis by Davy, the quantity of am- monia is from 20 to 50 in 100 parts. In general, the sesqui-carbonate consists of one equivalent and a half of acid, with one of ammonia and one of water. The num- bers will be found in the Table at the end of this chap- ter. Sesqui-carbonate of ammonia is very soluble in water ; at 60° it requires only twice its weight, and at 212° less than its own weight is sufficient for its solution. ' Its sa- turated solution deposit.es crystals, the figure of which appears to be octohedral. Exposed to a very moderate heat it is volatilized, but is easily condensed, and its de- composition on the sides of the vessel is of a regular dentri- tical form. It effloresces on exposure to the air, and its odour becomes weaker, from the loss of part of its am- monia ; and it even at last becomes a bi-carbonate. This salt is used in medicine as a stimulant and diaphoretic, and as a stimulating perfume. The bi-carbonate is com- paratively mild. VOL. II. B