ins to boil; in a few minutes bubbles will appear, which take fire
and detonate as they issue from the water.

CAROLINE.

There is one--and another. How curious it is! --But I do not understand
how this is produced.

MRS. B.

It is the consequence of a display of affinities too complicated,
I fear, to be made perfectly intelligible to you at present.

In a few words, the reciprocal action of the potash, phosphorus,
caloric, and water are such, that some of the water is decomposed, and
the hydrogen gas thereby formed carries off some minute particles of
phosphorus, with which it forms phosphoretted hydrogen gas, a compound
which spontaneously takes fire at almost any temperature.

EMILY.

What is that circular ring of smoke which slowly rises from each bubble
after its detonation?

MRS. B.

It consists of water and phosphoric acid in vapour, which are produced
by the combustion of hydrogen and phosphorus.

CONVERSATION IX.

ON CARBON.

CAROLINE.

To-day, Mrs. B., I believe we are to learn the nature and properties of
CARBON. This substance is quite new to me; I never heard it mentioned
before.

MRS. B.

Not so new as you imagine; for carbon is nothing more than charcoal in a
state of purity, that is to say, unmixed with any foreign ingredients.

CAROLINE.

But charcoal is made by art, Mrs. B., and a body consisting of one
simple substance cannot be fabricated?

MRS. B.

You again confound the idea, of making a simple body, with that of
separating it from a compound. The chemical processes by which a simple
body is obtained in a state of purity, consist in _unmaking_ the
compound in which it is contained, in order to separate from it the
simple substance in question. The method by which charcoal is usually
obtained, is, indeed, commonly called _making_ it; but, upon
examination, you will find this process to consist simply in separating
it from other substances with which it is found combined in nature.

Carbon forms a considerable part of the solid matter of all organised
bodies; but it is most abundant in the vegetable creation, and it is
chiefly obtained from wood. When the oil and water (which are other
constituents of vegetable matter) are evaporated, the black, porous,
brittle substance that remains, is charcoal.

CAROLINE.

But if heat be applied to the wood in order to evaporate the oil and
water, will not the temperature of the charcoal be raised so as to make
it burn; and