ary, indeed! I hope you mean to indulge us with some
of these experiments?

MRS. B.

I have prepared several glass jars of oxy-muriatic acid gas for that
purpose. In the first we shall introduce some Dutch gold leaf. --Do you
observe that it takes fire?

EMILY.

Yes, indeed it does--how wonderful it is! It became immediately red hot,
but was soon smothered in a thick vapour.

CAROLINE.

What a disagreeable smell!

MRS. B.

We shall try the same experiment with phosphorus in another jar of this
acid. --You had better keep your handkerchief to your nose when I open
it--now let us drop into it this little piece of phosphorus--

CAROLINE.

It burns really; and almost as brilliantly as in oxygen gas! But, what
is most extraordinary, these combustions take place without the metal or
phosphorus being previously lighted, or even in the least heated.

MRS. B.

All these curious effects are owing to the very great facility with
which this acid yields oxygen to such bodies as are strongly disposed to
combine with it. It appears extraordinary indeed to see bodies, and
metals in particular, melted down and inflamed, by a gas without any
increase of temperature, either of the gas, or of the combustible. The
phenomenon, however, is, you see, well accounted for.

EMILY.

Why did you burn a piece of Dutch gold leaf rather than a piece of any
other metal?

MRS. B.

Because, in the first place, it is a composition of metals (consisting
chiefly of copper) which burns readily; and I use a thin metallic leaf
in preference to a lump of metal, because it offers to the action of the
gas but a small quantity of matter under a large surface. Filings, or
shavings, would answer the purpose nearly as well; but a lump of metal,
though the surface would oxydate with great rapidity, would not take
fire. Pure gold is not inflamed by oxy-muriatic acid gas, but it is
rapidly oxydated, and dissolved by it; indeed, this acid is the only one
that will dissolve gold.

EMILY.

This, I suppose, is what is commonly called _aqua regia_, which you know
is the only thing that will act upon gold.

MRS. B.

That is not exactly the case either; for aqua regia is composed of a
mixture of muriatic acid and nitric acid. --But, in fact, the result of
this mixture is the formation of oxy-muriatic acid, as the muriatic acid
oxygenates itself at the expence of the nitric; this mixture, therefore,
though it bears the name of _nitro-muriatic acid_