rts, so that every name implies a knowledge of
the composition of the salt.

The three alkalies, the alkaline earths, and the metals, are called
_salifiable bases_ or _radicals_; and the acids, _salifying principles_.
The name of each salt is composed both of that of the acid and the
salifiable base; and it terminates in _at_ or _it_, according to the
degree of the oxygenation of the acid. Thus, for instance, all those
salts which are formed by the combination of the sulphuric acid with any
of the salifiable bases are called _sulphats_, and the name of the
radical is added for the specific distinction of the salt; if it be
potash, it will compose a _sulphat of potash_; if ammonia, _sulphat of
ammonia_, &c.

EMILY.

The crystals which we obtained from the combination of iron and
sulphuric acid were therefore _sulphat of iron_?

MRS. B.

Precisely; and those which we prepared by dissolving copper in nitric
acid, _nitrat of copper_, and so on. --But this is not all; if the salt
be formed by that class of acids which ends in _ous_, (which you know
indicates a less degree of oxygenation,) the termination of the name of
the salt will be in _it_, as _sulphit of potash_, _sulphit of
ammonia_, &c.

EMILY.

There must be an immense number of compound salts, since there is so
great a variety of salifiable radicals, as well as of salifying
principles.

MRS. B.

Their real number cannot be ascertained, since it increases every day.
But we must not proceed further in the investigation of the compound
salts, until we have completed the examination of the nature of the
ingredients of which they are composed.

The 4th law of chemical attraction is, that _a change of temperature
always takes place at the moment of combination_. This arises from the
extrication of the two electricities in the form of caloric, which takes
place when bodies unite; and also sometimes in part from a change of
capacity of the bodies for heat, which always takes place when the
combination is attended with an increase of density, but more especially
when the compound passes from the liquid to the solid form. I shall now
show you a striking instance of a change of temperature from chemical
union, merely by pouring some nitrous acid on this small quantity of oil
of turpentine--the oil will instantly combine with the oxygen of the
acid, and produce a considerable change of temperature.

CAROLINE.

What a blaze! The temperature of the oil and the a