alled fixed or fixable air by the
chemists who first discovered it; they did not then know whether it was
air resembling that of the atmosphere, or some other elastic fluid,
vitiated and corrupted by combustion; but since it is now ascertained to
be an acid, formed like all others by the oxygenation of its peculiar
base, it is obvious that the name of fixed air is quite ineligible[11].

By burning charcoal in the apparatus mentioned p. 60, Mr de la Place and
I found that one lib. of charcoal melted 96 libs. 6 oz. of ice;
that, during the combustion, 2 libs. 9 oz. 1 gros. 10 grs. of
oxygen were absorbed, and that 3 libs. 9 oz. 1 gros. 10 grs. of
acid gas were formed. This gas weighs 0.695 parts of a grain for each
cubical inch, in the common standard temperature and pressure mentioned
above, so that 34,242 cubical inches of acid gas are produced by the
combustion of one pound of charcoal.

I might multiply these experiments, and show by a numerous succession of
facts, that all acids are formed by the combustion of certain
substances; but I am prevented from doing so in place, by the plan
which I have laid down, of proceeding only from facts already
ascertained, to such as are unknown, and of drawing my examples only
from circumstances already explained. In the mean time, however, the
three examples above cited may suffice for giving a clear and accurate
conception of the manner in which acids are formed. By these it may be
clearly seen, that oxygen is an element common to them all, which
constitutes their acidity; and that they differ from each other,
according to the nature of the oxygenated or acidified substance. We
must therefore, in every acid, carefully distinguish between the
acidifiable, base, which Mr de Morveau calls the radical, and the
acidifiing principle or oxygen.

FOOTNOTES:

[11] It may be proper to remark, though here omitted by the author,
that, in conformity with the general principles of the new nomenclature,
this acid is by Mr Lavoisier and his coleagues called the carbonic acid,
and when in the aeriform state carbonic acid gas. E.

CHAP. VI.

_Of the Nomenclature of Acids in general, and particularly of those
drawn from Nitre and Sea-Salt._

It becomes extremely easy, from the principles laid down in the
preceding chapter, to establish a systematic nomenclature for the acids:
The word _acid_, being used as a generic term, each acid falls to be
distinguished in language, as in natur