We might, I think, use the comparison of two friends, who were very happy in each other’s society, till a third disunited them by the preference which one of them gave to the new-comer.
MRS. B.
Very well. I shall now show you how this takes place in chemistry.
Let us suppose that we wish to decompose the compound we have just formed by the combination of the two ingredients, copper and nitric acid; we may do this by presenting to it a piece of iron, for which the acid has a stronger attraction than for copper; the acid will, consequently, quit the copper to combine with the iron, and the copper will be what the chemists call precipitated, that is to say, it will be thrown down in its separate state, and reappear in its simple form.
In order to produce this effect, I shall dip the blade of this knife into the fluid, and, when I take it out, you will observe, that, instead of being wetted with a bluish liquid, like that contained in the glass, it will be covered with a thin coat of copper.
CAROLINE.
So it is really! but then is it not the copper, instead of the acid, that has combined with the iron blade?
MRS. B.
No; you are deceived by appearances: it is the acid which combines with the iron, and, in so doing, deposits or precipitates the copper on the surface of the blade.
EMILY.