nd carbon, which they derive from vegetables,
constitute their volatile products.

CAROLINE.

Pray is not _coke_, (which I have heard is much used in some
manufactures,) also a bituminous substance?

MRS. B.

No; it is a kind of fuel artificially prepared from coals. It consists
of coals reduced to a substance analogous to charcoal, by the
evaporation of their bituminous parts. Coke, therefore, is composed of
carbon, with some earthy and saline ingredients.

_Succin_, or _yellow amber_, is a bitumen which the ancients called
_electrum_, from whence the word electricity is derived, as that
substance is peculiarly, and was once supposed to be exclusively,
electric. It is found either deeply buried in the bowels of the earth,
or floating on the sea, and is supposed to be a resinous body which has
been acted on by sulphuric acid, as its analysis shows it to consist of
ah oil and an acid. The oil is called _oil of amber_, the acid the
_succinic_.

EMILY.

That oil I have sometimes used in painting, as it is reckoned to change
less than the other kinds of oils.

MRS. B.

The last class of vegetable substances that have changed their nature
are _fossil-wood_, _peat_, and _turf_. These are composed of wood and
roots of shrubs, that are partly decomposed by being exposed to moisture
under ground, and yet, in some measure, preserve their form and organic
appearance. The peat, or black earth of the moors, retains but few
vestiges of the roots to which it owes its richness and combustibility,
these substances being in the course of time reduced to the state of
vegetable earth. But in turf the roots of plants are still discernible,
and it equally answers the purpose of fuel. It is the combustible used
by the poor in heathy countries, which supply it abundantly.

It is too late this morning to enter upon the history of vegetation. We
shall reserve this subject, therefore, for our next interview, when I
expect that it will furnish us with ample matter for another
conversation.

CONVERSATION XXII.

HISTORY OF VEGETATION.

MRS. B.

The VEGETABLE KINGDOM may be considered as the link which unites the
mineral and animal creation into one common chain of beings; for it is
through the means of vegetation alone that mineral substances are
introduced into the animal system, since, generally speaking, it is from
vegetables that all animals ultimately derive their sustenance.

CAROLINE.

I do not understand that;