The abundant formation of ammonia from decaying animal matter is evident to everyone, and depends upon the presence of moisture to a great extent. Chloride of ammonia is called sal-ammoniac, and the carbonate of ammonia crystallizes from the alkaline liquid produced by the distillation of certain animal matter. The compounds of ammonia are easily recognized by a certain sharp taste. They are highly valuable remedial agents, acting particularly upon the cutaneous system, and when taken internally, produce the effect of powerful sudorifics. Their volatility, and the facility with which they are expelled from other substances, render them of great importance in chemistry, and peculiarly fit them for the purposes of many chemical analyses. The ammonia compounds display a remarkable analogy to the corresponding combinations of potash and soda. The compounds of ammonia are highly important in their relation to the vegetable kingdom. It may be assumed that all the nitrogen of plants is derived from the ammonia which they absorb from the soil, and from the surrounding atmosphere.
Fig. 360.—Carré’s refrigerator (second action).
The similarity of ammonia to the metallic oxides has led to the conjecture that all its combinations contain a compound metallic body, which has received the name ammonium (NH4); but no one has yet succeeded in its preparation, although by peculiar processes it may be obtained in the form of an amalgam.
Ammonias, in which one or more atoms of hydrogen are replaced by basic radicals, are termed Amides, or Amines.
CHAPTER XXVIII.
NON-METALLIC ELEMENTS (continued).
CHLORINE—BROMINE—IODINE—FLUORINE—CARBON—SULPHUR—PHOSPHORUS—SILICON—BORON—TELLURIUM—ARSENIC.