redients which may be occasionally blended with
them: the veins and colours of marbles, for instance, proceed from a
mixture of metallic substances; silex and alumine also frequently enter
into these combinations. The various carbonats, therefore, that I have
enumerated, cannot be considered as pure unadulterated neutral salts,
although they certainly belong to that class of bodies.

CONVERSATION XIX.

ON THE BORACIC, FLUORIC, MURIATIC, AND OXYGENATED MURIATIC ACIDS; AND ON
MURIATS. --ON IODINE AND IODIC ACID.

MRS. B.

We now come to the three remaining acids with simple bases, the compound
nature of which, though long suspected, has been but recently proved.
The chief of these is the muriatic; but I shall first describe the two
others, as their bases have been obtained more distinctly than that of
the muriatic acid.

You may recollect I mentioned the BORACIC ACID. This is found very
sparingly in some parts of Europe, but for the use of manufactures we
have always received it from the remote country of Thibet, where it is
found in some lakes, combined with soda. It is easily separated from the
soda by sulphuric acid, and appears in the form of shining scales, as
you see here.

CAROLINE.

I am glad to meet with an acid which we need not be afraid to touch; for
I perceive, from your keeping it in a piece of paper, that it is more
innocent than our late acquaintance, the sulphuric and nitric acids.

MRS. B.

Certainly; but being more inert, you will not find its properties so
interesting. However, its decomposition, and the brilliant spectacle it
affords when its basis again unites with oxygen, atones for its want of
other striking qualities.

Sir H. Davy succeeded in decomposing the boracic acid, (which had till
then been considered as undecompoundable,) by various methods. On
exposing this acid to the Voltaic battery, the positive wire gave out
oxygen, and on the negative wire was deposited a black substance, in
appearance resembling charcoal. This was the basis of the acid, which
Sir H. Davy has called _Boracium_, or _Boron_.

The same substance was obtained in more considerable quantities, by
exposing the acid to a great heat in an iron gun-barrel.

A third method of decomposing the boracic acid consisted in burning
potassium in contact with it in vacuo. The potassium attracts the oxygen
from the acid, and leaves its basis in a separate state.

The recomposition of this acid I shall show you,