e name by which it has been so long known, that the modern
chemists have not yet succeeded in banishing it altogether; and it is
still sold under that name by druggists, though by scientific chemists
it is more properly called muriat of ammonia.

CAROLINE.

Both the popular and the common name should be inscribed on labels--this
would soon introduce the new nomenclature.

EMILY.

By what means can the ammonia be separated from the muriatic acid?

MRS. B.

By chemical attractions; but this operation is too complicated for you
to understand, till you are better acquainted with the agency of
affinities.

EMILY.

And when extracted from the salt, what kind of substance is ammonia?

MRS. B.

Its natural form, at the temperature of the atmosphere, when free from
combination, is that of gas; and in this state it is called _ammoniacal
gas_. But it mixes very readily with water, and can be thus obtained in
a liquid form.

CAROLINE.

You said that ammonia was more complicated in its composition than the
other alkalies; pray of what principles does it consist?

MRS. B.

It was discovered a few years since, by Berthollet, a celebrated French
chemist, that it consisted of about one part of hydrogen to four parts
of nitrogen. Having heated ammoniacal gas under a receiver, by causing
the electrical spark to pass repeatedly through it, he found that it
increased considerably in bulk, lost all its alkaline properties, and
was actually converted into hydrogen and nitrogen gases; and from the
latest and most accurate experiments, the proportions appear to be, one
volume of nitrogen gas to three of hydrogen gas.

CAROLINE.

Ammonia, therefore, has not, like the two other alkalies, a metallic
basis?

MRS. B.

It is believed it has, though it is extremely difficult to reconcile
that idea with what I have just stated of its chemical nature. But the
fact is, that although this supposed metallic basis of ammonia has never
been obtained distinct and separate, yet both Professor Berzelius, of
Stockholm, and Sir H. Davy, have succeeded in forming a combination of
mercury with the basis of ammonia, which has so much the appearance of
an amalgam, that it strongly corroborates the idea of ammonia having a
metallic basis.* But these theoretical points are full of difficulties
and doubts, and it would be useless to dwell any longer upon them.

Let us therefore return to the properties of volatile alkali. Ammoniacal
gas is co