en consider them in their combinations with
each other.

Excepting the more general agents of nature, heat, light, and
electricity, it would seem that the simple form of bodies is that of a
metal.

CAROLINE.

You astonish me! I thought the metals were only one class of minerals,
and that there were besides, earths, stones, rocks, acids, alkalies,
vapours, fluids, and the whole of the animal and vegetable kingdoms.

MRS. B.

You have made a tolerably good enumeration, though I fear not arranged
in the most scientific order. All these bodies, however, it is now
strongly believed, may be ultimately resolved into metallic substances.
Your surprise at this circumstance is not singular, as the decomposition
of some of them, which has been but lately accomplished, has excited the
wonder of the whole philosophical world.

But to return to the list of simple bodies--these being usually found in
combination with oxygen, I shall class them according to their
properties when so combined. This will, I think, facilitate their future
investigation.

EMILY.

Pray what is oxygen?

MRS. B.

A simple body; at least one that is supposed to be so, as it has never
been decomposed. It is always found united with the negative
electricity. It will be one of the first of the elementary bodies whose
properties I shall explain to you, and, as you will soon perceive, it is
one of the most important in nature; but it would be irrelevant to enter
upon this subject at present. We must now confine our attention to the
enumeration and classification of the simple bodies in general. They may
be arranged as follows:

CLASS I.

_Comprehending the imponderable agents, viz._

HEAT or CALORIC,
LIGHT,
ELECTRICITY.

CLASS II.

_Comprehending agents capable of uniting with inflammable bodies, and in
most instances of effecting their combustion._

OXYGEN,
CHLORINE,
IODINE.*

[Footnote *: It has been questioned by some eminent chemists,
whether these two last agents should not be classed among the
inflammable bodies, as they are capable of combining with oxygen,
as well as with inflammable bodies. But they seem to be more
distinctly characterised by their property of supporting
combustion than by any other quality.]

CLASS III.

_Comprehending bodies capable of uniting with oxygen, and, forming with
it various compounds. This class may be divided as follows:_

DIVISION 1.

HYDROGEN, _forming