able acids be the same, it should form
but one acid; it may indeed combine with different proportions of
oxygen, but the nature of the acid must be the same.

MRS. B.

The only difference that exists in the basis of vegetable acids, is the
various proportions of hydrogen and carbon from which they are severally
composed. But this is enough to produce a number of acids apparently
very dissimilar. That they do not, however, differ essentially, is
proved by their susceptibility of being converted into each other, by
the addition or subtraction of a portion of hydrogen or of carbon. The
names of these acids are,

The _Acetic_
_Oxalic_
_Tartarous_
_Citric_
_Malic_ Acids, of double bases, being of vegetable origin.
_Gallic_
_Mucous_
_Benzoic_
_Succinic_
_Camphoric_
_Suberic_

The 3d class of acids consists of those which have triple radicals, and
are therefore of a still more compound nature. This class comprehends
the animal acids, which are,

The _Lactic_
_Prussic_
_Formic_ Acids, of triple bases, or animal acids.
_Bombic_
_Sebacic_
_Zoonic_
_Lithic_

I have given you this summary account or enumeration of the acids, as
you may find it more satisfactory to have at once an outline or a
general notion of the extent of the subject; but we shall now confine
ourselves to the first class, which requires our more immediate
attention; and defer the few remarks which we shall have to make on the
others, till we treat of the chemistry of the animal and vegetable
kingdoms.

The acids of simple and known radicals are all capable of being
decomposed by combustible bodies, to which they yield their oxygen. If,
for instance, I pour a drop of sulphuric acid on this piece of iron, it
will produce a spot of rust, you know what that is?

CAROLINE.

Yes; it is an oxyd, formed by the oxygen of the acid combining with the
iron.

MRS. B.

In this case you see the sulphur deposits the oxygen by which it was
acidified on the metal. And again, if we pour some acid on a compound
combustible substance, (we shall try it on this piece of wood,) it will
combine with one or more of the constituents of that substance, and
occasion a decomposition.

EMILY.

It has changed the colour of the wood to black. How is that?

MRS. B.

The oxygen deposited by the acid has burnt it; you know that wood in
burning becomes black before it is reduced to ashes. Whether i