ittle to remember; it
makes a very insignificant figure in comparison to oxygen, although it
composes a much larger portion of the atmosphere.

MRS. B.

Perhaps this insignificance you complain of may arise from the compound
nature of nitrogen, for though I have hitherto considered it as a simple
body, because it is not known in any natural process to be decomposed,
yet from some experiments of Sir H. Davy, there appears to be reason for
suspecting that nitrogen is a compound body, as we shall see afterwards.
But even in its simple state, it will not appear so insignificant when
you are better acquainted with it; for though it seems to perform but a
passive part in the atmosphere, and has no very striking properties,
when considered in its separate state, yet you will see by-and-bye what
a very important agent it becomes, when combined with other bodies. But
no more of this at present; we must reserve it for its proper place.

CONVERSATION VII.

ON HYDROGEN.

CAROLINE.

The next simple bodies we come to are CHLORINE and IODINE. Pray what
kinds of substances are these; are they also invisible?

MRS. B.

No; for chlorine, in the state of gas, has a distinct greenish colour,
and is therefore visible; and iodine, in the same state, has a beautiful
claret-red colour. The knowledge of these two bodies, however, and the
explanation of their properties, imply various considerations, which you
would not yet be able to understand; we shall therefore defer their
examination to some future conversation, and we shall pass on to the
next simple substance, HYDROGEN, which we cannot, any more than oxygen,
obtain in a visible or palpable form. We are acquainted with it only in
its gaseous state, as we are with oxygen and nitrogen.

CAROLINE.

But in its gaseous state it cannot be called a simple substance, since
it is combined with heat and electricity?

MRS. B.

True, my dear; but as we do not know in nature of any substance which is
not more or less combined with caloric and electricity, we are apt to
say that a substance is in its pure state when combined with those
agents only.

Hydrogen was formerly called _inflammable air_, as it is extremely
combustible, and burns with a great flame. Since the invention of the
new nomenclature, it has obtained the name of hydrogen, which is derived
from two Greek words, the meaning of which is, _to produce water_.

EMILY.

And how does hydrogen produce water?

MRS.