, this _weaker acid_, as it is called, is capable of
separating both the vitriolic and the nitrous acids from the phlogiston
with which they are combined.

On the other hand, the solution of metals in the different acids seems
to shew, that the nitrous acid forms a closer union with phlogiston than
the other two; because the air which is formed by the nitrous acid is
not inflammable, like that which is produced by the oil of vitriol, or
the spirit of salt. Also, the same weight of iron does not yield half
the quantity of nitrous air that it does of inflammable.

The great diminution of nitrous air by phlogiston is not easily
accounted for, unless we suppose that its superabundant acid, uniting
more intimately with the phlogiston, constitutes a species of _sulphur_
that is not easily perceived or catched; though, in the process with
iron, and also in that with liver of sulphur, part of the redundant
phlogiston forms such an union with the acid as gives it a kind of
inflammability.

It appears to me to be very probable, that the spirit of nitre might be
exhibited in the form of _air_, if it were possible to find any fluid by
which it could be confined; but it unites with quicksilver as well as
with water, so that when, by boiling the spirit of nitre, the fumes are
driven through the glass tube, fig. 8, they instantly seize upon the
quicksilver through which they are to be conveyed, and uniting with it,
form a substance that stops up the tube: a circumstance which has more
than once exposed me to very disagreeable accidents, in consequence of
the bursting of the phials.

I do not know any inquiry more promising than the investigation of the
properties of _nitre_, the _nitrous acid_, and _nitrous air_. Some of
the most wonderful phenomena in nature are connected with them, and the
subject seems to be fully within our reach.

Sec. 2. _Speculations arising from the consideration of the similarity of
the ELECTRIC MATTER and PHLOGISTON._

There is nothing in the history of philosophy more striking than the
rapid progress of _electricity_. Nothing ever appeared more trifling
than the first effects which were observed of this agent in nature, as
the attraction and repulsion of straws, and other light substances. It
excited more attention by the flashes of _light_ which it exhibited. We
were more seriously alarmed at the electrical _shock_, and the effects
of the electrical _battery_; and we were astonished to the highest