Very true; but you must recollect that charcoal, especially that which is used for common purposes, is not perfectly pure. It generally retains some remains of the various other component parts of vegetables, and hydrogen particularly, which accounts for the flame in question.
CAROLINE.
But what becomes of the carbon itself during its combustion?
MRS. B.
It gradually combines with the oxygen of the atmosphere, in the same way as sulphur and phosphorus, and, like those substances, it is converted into a peculiar acid, which flies off in a gaseous form. There is this difference, however, that the acid is not, in this instance, as in the two cases just mentioned, a mere condensable vapour, but a permanent elastic fluid, which always remains in the state of gas, under any pressure and at any temperature. The nature of this acid was first ascertained by Dr. Black, of Edinburgh; and, before the introduction of the new nomenclature, it was called fixed air. It is now distinguished by the more appropriate name of carbonic acid gas.
EMILY.
Carbon, then, can be volatilized by burning, though, by heat alone, no such effect is produced?
MRS. B.
Yes; but then it is no longer simple carbon, but an acid of which carbon forms the basis. In this state, carbon retains no more appearance of solidity or corporeal form, than the basis of any other gas. And you may, I think, from this instance, derive a more clear idea of the basis of the oxygen, hydrogen, and nitrogen gases, the existence of which, as real bodies, you seemed to doubt, because they were not to be obtained simply in a solid form.
EMILY.