Conversations on Chemistry, V. 1-2 / In Which the Elements of that Science Are Familiarly Explained and Illustrated by Experiments

by Mrs. Marcet

But pray tell me, can ammonia be procured from this Lybian salt only?

MRS. B.

So far from it, that it is contained in, and may be extracted from, all animal substances whatever. Hydrogen and nitrogen are two of the chief constituents of animal matter; it is therefore not surprising that they should occasionally meet and combine in those proportions that compose ammonia. But this alkali is more frequently generated by the spontaneous decomposition of animal substances; the hydrogen and nitrogen gases that arise from putrefied bodies combine, and form the volatile alkali.

Muriat of ammonia, instead of being exclusively brought from Lybia, as it originally was, is now chiefly prepared in Europe, by chemical processes. Ammonia, although principally extracted from this salt, can also be produced by a great variety of other substances. The horns of cattle, especially those of deer, yield it in abundance, and it is from this circumstance that a solution of ammonia in water has been called hartshorn. It may likewise be procured from wool, flesh, and bones; in a word, any animal substance whatever yields it by decomposition.

We shall now lay aside the alkalies, however important the subject may be, till we treat of their combination with acids. The next time we meet we shall examine the earths.

[*] This defence of the general theory, however plausible, is liable to some obvious objections. The phenomenon might perhaps be better accounted for by supposing that a solution of alkali in water has less capacity for heat than either water or alkali in their separate state.

[*] This amalgam is easily obtained, by placing a globule of mercury upon a piece of muriat, or carbonat of ammonia, and electrifying this globule by the Voltaic battery. The globule instantly begins to expand to three or four times its former size, and becomes much less fluid, though without losing its metallic lustre, a change which is ascribed to the metallic basis of ammonia uniting with the mercury. This is an extremely curious experiment.

[CONVERSATION XV.]
ON EARTHS.

MRS. B.