ts it more weakly than it does the acid, and
because the acid and air cannot both be joined to the same body at the
same time.

I also imagined, that, when the calcarious earths are exposed to the
action of a violent fire, and are thereby converted into quick-lime,
they suffer no other change in their composition than the loss of a
small quantity of water and of their fixed air. The remarkable acrimony
which we perceive in them after this process, was not supposed to
proceed from any additional matter received in the fire, but seemed to
be an essential property of the pure earth, depending on an attraction
for those several substances which it then became capable of corroding
or dissolving, which attraction had been insensible as long as the air
adhered to the earth, but discovered itself upon the separation.

This supposition was founded upon an observation of the most frequent
consequences of combining bodies in chemistry. Commonly when we join two
bodies together, their acrimony or attraction for other substances
becomes immediately either less perceivable or entirely insensible;
altho' it was sufficiently strong and remarkable before their union, and
may be rendered evident again by disjoining them. A neutral salt, which
is composed of an acid and alkali, does not possess the acrimony of
either of its constituent parts. It can easily be separated from water,
has little or no effect upon metals, is incapable of being joined to
inflammable bodies, and of corroding and dissolving animals and
vegetables; so that the attraction both of the acid and alkali for these
several substances seems to be suspended till they are again separated
from one another.

Crude lime was therefore considered as a peculiar acrid earth rendered
mild by its union with fixed air: and quick-lime as the same earth, in
which, by having separated the air, we discover that acrimony or
attraction for water, for animal, vegetable, and for inflammable
substances.

That the calcarious earths really lose a large quantity of air when they
are burnt to quick-lime, seems sufficiently proved by an experiment of
Mr. _Margraaf_,[6] an exceedingly accurate and judicious Chemist. He
subjected eight ounces of _osteocolla_ to distillation in an earthen
retort, finishing his process with the most violent fire of a
reverberatory, and caught in the receiver only two drams of water, which
by its smell and properties shewed itself to be slightly alkaline. He
does