nt there
are only the muriatic and the fluoric acids, which have not had their
bases distinctly separated.

CAROLINE.

We have heard of a great variety of acids; pray how many are there in
all?

MRS. B.

I believe there are reckoned at present thirty-four, and their number is
constantly increasing, as the science improves; but the most important,
and those to which we shall almost entirely confine our attention, are
but few. I shall, however, give you a general view of the whole; and
then we shall more particularly examine those that are the most
essential.

This class of bodies was formerly divided into mineral, vegetable, and
animal acids, according to the substances from which they were commonly
obtained.

CAROLINE.

That, I should think, must have been an excellent arrangement; why was
it altered?

MRS. B.

Because in many cases it produced confusion. In which class, for
instance, would you place carbonic acid?

CAROLINE.

Now I see the difficulty. I should be at a loss where to place it, as
you have told us that it exists in the animal, vegetable, and mineral
kingdoms.

EMILY.

There would be the same objection with respect to phosphoric acid,
which, though obtained chiefly from bones, can also, you said, be found
in small quantities in stones, and likewise in some plants.

MRS. B.

You see, therefore, the propriety of changing this mode of
classification. These objections do not exist in the present
nomenclature; for the composition and nature of each individual acid is
in some degree pointed out, instead of the class of bodies from which it
is extracted; and, with regard to the more general division of acids,
they are classed under these three heads:

First, Acids of known or supposed simple bases, which are formed by the
union of these bases with oxygen. They are the following:

The _Sulphuric_
_Carbonic_
_Nitric_
_Phosphoric_
_Arsenical_ Acids, of known and simple bases.
_Tungstenic_
_Molybdenic_
_Boracic_
_Fluoric_
_Muriatic_

This class comprehends the most anciently known and most important
acids. The sulphuric, nitric, and muriatic were formerly, and are still
frequently, called _mineral acids_.

2dly, Acids that have double or binary radicals, and which consequently
consist of triple combinations. These are the vegetable acids, whose
common radical is a compound of hydrogen and carbon.

CAROLINE.

But if the basis of all the veget