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.

    18/768 (page 6)
    sively products of the vegetable system ; and as the vege- table acids are placed under the class of vegetable sub- stances, these bodies are, on the same principle, to be re- ferred to that class. CHAP. I. OF AMMONIA. This alkali, obtained by indirect processes, was known to the older chemists only in its combination with water, forming the liquid which, from its volatility compared with the other alkalis, was denominated Volatile Alkali. Dr Priestley first shewed, that a gas can be procured from this liquor by a moderate heat, and that the pure alkali is a permanently elastic fluid : it is therefore called Ammo- nia or Ammoniacal gas, and its solution in water is call- ed Liquid Ammonia. In the progress of pneumatic chemistry, several facts were observed, proving the composition of ammonia. Priestley found, that on taking the electric spark in the gas, or on transmitting it through an ignited earthen tube, the volume is much enlarged, and its properties are chang- ed ; it is no longer absorbed by water, and is highly in- flammable. By heating certain metallic oxides in the am. moniacal gas, he further found, that they were reduced to the metallic state; a little water was produced, and the residual gas was nitrogen. Berthollet, guided by the ex- periments of Priestley and Scheele, was led by them to institute others, in which ammonia was decomposed : and, from the whole, he first inferred that it is a compound of