nnot wash your hands with plain
potash; but, when mixed with oil in the form of soap, it is soft as well
as cleansing, and is therefore much better adapted to the purpose.

Caustic potash, as we already observed, acts on the skin, and animal
fibre, in virtue of its attraction for water and oil, and converts all
animal matter into a kind of saponaceous jelly.

EMILY.

Are vegetables the only source from which potash can be derived?

MRS. B.

No: for though far most abundant in vegetables, it is by no means
confined to that class of bodies, being found also on the surface of the
earth, mixed with various minerals, especially with earths and stones,
whence it is supposed to be conveyed into vegetables by the roots of the
plant. It is also met with, though in very small quantities, in some
animal substances. The most common state of potash is that of
_carbonat_; I suppose you understand what that is?

EMILY.

I believe so; though I do not recollect that you ever mentioned the word
before. If I am not mistaken, it must be a compound salt, formed by the
union of carbonic acid with potash.

MRS. B.

Very true; you see how admirably the nomenclature of modern chemistry is
adapted to assist the memory; when you hear the name of a compound, you
necessarily learn what are its constituent parts; and when you are
acquainted with these constituents, you can immediately name the
compound which they form.

CAROLINE.

Pray, how were bodies arranged and distinguished before this
nomenclature was introduced?

MRS. B.

Chemistry was then a much more difficult study; for every substance had
an arbitrary name, which it derived either from the person who
discovered it, as _Glauber's salts_ for instance; or from some other
circumstance relative to it, though quite unconnected with its real
nature, as potash.

These names have been retained for some of the simple bodies; for as
this class is not numerous, and therefore can easily be remembered, it
has not been thought necessary to change them.

EMILY.

Yet I think it would have rendered the new nomenclature more complete to
have methodised the names of the elementary, as well as of the compound
bodies, though it could not have been done in the same manner. But the
names of the simple substances might have indicated their nature, or, at
least, some of their principal properties; and if, like the acids and
compound salts, all the simple bodies had a similar termination, the