ids and oxyds.

MRS. B.

Acids were, in fact, oxyds, which, by the addition of a sufficient
quantity of oxygen, have been converted into acids. For acidification,
you must observe, always implies previous oxydation, as a body must have
combined with the quantity of oxygen requisite to constitute it an oxyd,
before it can combine with the greater quantity that is necessary to
render it an acid.

CAROLINE.

Are all oxyds capable of being converted into acids?

MRS. B.

Very far from it; it is only certain substances which will enter into
that peculiar kind of union with oxygen that produces acids, and the
number of these is proportionally very small; but all burnt bodies may
be considered as belonging either to the class of oxyds, or to that of
acids. At a future period, we shall enter more at large into this
subject. At present, I have but one circumstance further to point out to
your observation respecting acids: it is, that most of them are
susceptible of two degrees of acidification, according to the different
quantities of oxygen with which their basis combines.

EMILY.

And how are these two degrees of acidification distinguished?

MRS. B.

By the peculiar properties which result from them. The acid we have just
made is the first or weakest degree of acidification, and is called
_sulphureous acid_; if it were fully saturated with oxygen, it would be
called _sulphuric acid_. You must therefore remember, that in this, as
in all acids, the first degree of acidification is expressed by the
termination in _ous_; the stronger, by the termination in _ic_.

CAROLINE.

And how is the sulphuric acid made?

MRS. B.

By burning sulphur in pure oxygen gas, and thus rendering its combustion
much more complete. I have provided some oxygen gas for this purpose; it
is in that bottle, but we must first decant the gas into the glass
receiver which stands on the shelf in the bath, and is full of water.

CAROLINE.

Pray, let me try to do it, Mrs. B.

MRS. B.

It requires some little dexterity--hold the bottle completely under
water, and do not turn the mouth upwards, till it is immediately under
the aperture in the shelf, through which the gas is to pass into the
receiver, and then turn it up gradually. --Very well, you have only let
a few bubbles escape, and that must be expected at a first trial. --Now
I shall put this piece of sulphur into the receiver, through the opening
at the top, and introduce along wit