order to exclude the atmospherical air; the gas is then introduced
through the water, which you see it displaces, for it will not mix with
it in any quantity, unless strongly agitated, or allowed to stand over
it for some time. The bottle is now about half full of carbonic acid
gas, and the other half is still occupied by the water. By corking the
bottle, and then violently shaking it, in this way, I can mix the gas
and water together. --Now will you taste it?

EMILY.

It has a distinct acid taste.

CAROLINE.

Yes, it is sensibly sour, and appears full of little bubbles.

MRS. B.

It possesses likewise all the other properties of acids, but, of course,
in a less degree than the pure carbonic acid gas, as it is so much
diluted by water.

This is a kind of artificial Seltzer water. By analysing that which is
produced by nature, it was found to contain scarcely any thing more than
common water impregnated with a certain proportion of carbonic acid gas.
We are, therefore, able to imitate it, by mixing those proportions of
water and carbonic acid. Here, my dear, is an instance, in which, by a
chemical process, we can exactly copy the operations of nature; for the
artificial Seltzer waters can be made in every respect similar to those
of nature; in one point, indeed, the former have an advantage, since
they may be prepared stronger, or weaker, as occasion requires.

CAROLINE.

I thought I had tasted such water before. But what renders it so brisk
and sparkling?

MRS. B.

This sparkling, or effervescence, as it is called, is always occasioned
by the action of an elastic fluid escaping from a liquid; in the
artifical Seltzer water, it is produced by the carbonic acid, which
being lighter than the water in which it was strongly condensed, flies
off with great rapidity the instant the bottle is uncorked; this makes
it necessary to drink it immediately. The bubbling that took place in
this bottle was but trifling, as the water was but very slightly
impregnated with carbonic acid. It requires a particular apparatus to
prepare the gaseous artificial mineral waters.

EMILY.

If, then, a bottle of Seltzer water remains for any length of time
uncorked, I suppose it returns to the state of common water?

MRS. B.

The whole of the carbonic acid gas, or very nearly so, will soon
disappear; but there is likewise in Seltzer water a very small quantity
of soda, and of a few other saline or earthy ingredients, which wil