of our attention, for its
striking properties. The acid, in this state of combination, contains a
still greater proportion of oxygen than when alone.

CAROLINE.

But how can the oxy-muriatic acid acquire an increase of oxygen by
combining with potash?

MRS. B.

It does not really acquire an additional quantity of oxygen, but it
loses some of the muriatic acid, which produces the same effect, as the
acid which remains is proportionably super-oxygenated.*

If this salt be mixed, and merely rubbed together with sulphur,
phosphorus, charcoal, or indeed any other combustible, it explodes
strongly.

[Footnote *: According to Sir H. Davy's new views, just explained,
oxy-muriat of potash is a compound of chlorine with oxyd of
potassium.]

CAROLINE.

Like gun-powder, I suppose, it is suddenly converted into elastic
fluids?

MRS. B.

Yes; but with this remarkable difference, that no increase of
temperature, any further than is produced by gentle friction, is
required in this instance. Can you tell me what gases are generated by
the detonation of this salt with charcoal?

EMILY.

Let me consider . . . . . The oxy-muriatic acid parts with its excess of
oxygen to the charcoal, by which means it is converted into muriatic
acid gas; whilst the charcoal, being burnt by the oxygen, is changed to
carbonic acid gas. --What becomes of the potash I cannot tell.

MRS. B.

That is a fixed product which remains in the vessel.

CAROLINE.

But since the potash does not enter into the new combinations, I do not
understand of what use it is in this operation. Would not the
oxy-muriatic acid and the charcoal produce the same effect without it?

MRS. B.

No; because there would not be that very great concentration of oxygen
which the combination with the potash produces, as I have just
explained.

I mean to show you this experiment, but I would advise you not to repeat
it alone; for if care be not taken to mix only very small quantities at
a time, the detonation will be extremely violent, and may be attended
with dangerous effects. You see I mix an exceedingly small quantity of
the salt with a little powdered charcoal, in this Wedgwood mortar, and
rub them together with the pestle--

CAROLINE.

Heavens! How can such a loud explosion be produced by so small a
quantity of matter?

MRS. B.

You must consider that an extremely small quantity of solid substance
may produce a very great volume of gases; and