So it has, indeed! And do the other alkalies produce a similar effect?

MRS. B.

Exactly the same. --We may now proceed to SODA, which, however
important, will detain us but a very short time; as in all its general
properties it very strongly resembles potash; indeed, so great is their
similitude, that they have been long confounded, and they can now
scarcely be distinguished, except by the difference of the salts which
they form with acids.

The great source of this alkali is the sea, where, combined with a
peculiar acid, it forms the salt with which the waters of the ocean are
so strongly impregnated.

EMILY.

Is not that the common table salt?

MRS. B.

The very same; but again we must postpone entering into the particulars
of this interesting combination, till we treat of the neutral salts.
Soda may be obtained from common salt; but the easiest and most usual
method of procuring it is by the combustion of marine plants, an
operation perfectly analogous to that by which potash is obtained from
vegetables.

EMILY.

From what does soda derive its name?

MRS. B.

From a plant called by us _soda_, and by the Arabs _kali_, which affords
it in great abundance. Kali has, indeed, given its name to the alkalies
in general.

CAROLINE.

Does soda form glass and soap in the same manner as potash?

MRS. B.

Yes, it does; it is of equal importance in the arts, and is even
preferred to potash for some purposes; but you will not be able to
distinguish their properties till we examine the compound salts which
they form with acids; we must therefore leave soda for the present, and
proceed to AMMONIA, or the VOLATILE ALKALI.

EMILY.

I long to hear something of this alkali; is it not of the same nature as
hartshorn?

MRS. B.

Yes, it is, as you will see by-and-bye. This alkali is seldom found in
nature in its pure state; it is most commonly extracted from a compound
salt, called _sal ammoniac_, which was formerly imported from _Ammonia_,
a region of Libya, from which both these salts and the alkali derive
their names. The crystals contained in this bottle are specimens of this
salt, which consists of a combination of ammonia and muriatic acid.

CAROLINE.

Then it should be called _muriat of ammonia_; for though I am ignorant
what muriatic acid is, yet I know that its combination with ammonia
cannot but be so called; and I am surprised to see sal ammoniac
inscribed on the label.

MRS. B.

That is th