I shall
presently explain.

EMILY.

Is this acid susceptible of different degrees of oxygenation?

MRS. B.

Yes, for though we cannot deoxygenate this acid, yet we may add oxygen
to it.

CAROLINE.

Why, then, is not the least degree of oxygenation of the acid called the
_muriatous_, and the higher degree the _muriatic_ acid?

MRS. B.

Because, instead of becoming, like other acids, more dense, and more
acid by an addition of oxygen, it is rendered on the contrary more
volatile, more pungent, but less acid, and less absorbable by water.
These circumstances, therefore, seem to indicate the propriety of making
an exception to the nomenclature. The highest degree of oxygenation of
this acid has been distinguished by the additional epithet of
_oxygenated_, or, for the sake of brevity, _oxy_, so that it is called
the _oxygenated_, or _oxy-muriatic acid_. This likewise exists in a
gaseous form, at the temperature of the atmosphere; it is also
susceptible of being absorbed by water, and can be congealed, or
solidified, by a certain degree of cold.

EMILY.

And how do you obtain the oxy-muriatic acid?

MRS. B.

In various ways; but it may be most conveniently obtained by distilling
liquid muriatic acid over oxyd of manganese, which supplies the acid
with the additional oxygen. One part of the acid being put into a
retort, with two parts of the oxyd of manganese, and the heat of a lamp
applied, the gas is soon disengaged, and may be received over water, as
it is but sparingly absorbed by it. --I have collected some in this
jar--

CAROLINE.

It is not invisible, like the generality of gases; for it is of a
yellowish colour.

MRS. B.

The muriatic acid extinguishes flame, whilst, on the contrary, the
oxy-muriatic makes the flame larger, and gives it a dark red colour. Can
you account for this difference in the two acids?

EMILY.

Yes, I think so; the muriatic acid will not supply the flame with the
oxygen necessary for its support; but when this acid is further
oxygenated, it will part with its additional quantity of oxygen, and in
this way support combustion.

MRS. B.

That is exactly the case; indeed the oxygen added to the muriatic acid,
adheres so slightly to it, that it is separated by mere exposure to the
sun's rays. This acid is decomposed also by combustible bodies, many of
which it burns, and actually inflames, without any previous increase of
temperature.

CAROLINE.

That is extraordin