e liquor, having a considerably smaller specific
gravity than water, or even spirit of wine.--A.

[6] It would have been more satisfactory if the Author had specified the
degrees of the thermometer at which these heights of the mercury in the
barometer are produced.

[7] Vide Memoirs of the French Academy, anno 1780, p. 335.--A.

CHAP. II.

_General Views relative to the Formation and Composition of our
Atmosphere._

These views which I have taken of the formation of elastic aeriform
fluids or gasses, throw great light upon the original formation of the
atmospheres of the planets, and particularly that of our earth. We
readily conceive, that it must necessarily consist of a mixture of the
following substances: _First_, Of all bodies that are susceptible of
evaporation, or, more strictly speaking, which are capable of retaining
the state of aeriform elasticity in the temperature of our atmosphere,
and under a pressure equal to that of a column of twenty-eight inches of
quicksilver in the barometer; and, _secondly_, Of all substances,
whether liquid or solid, which are capable of being dissolved by this
mixture of different gasses.

The better to determine our ideas relating to this subject, which has
not hitherto been sufficiently considered, let us, for a moment,
conceive what change would take place in the various substances which
compose our earth, if its temperature were suddenly altered. If, for
instance, we were suddenly transported into the region of the planet
Mercury, where probably the common temperature is much superior to that
of boiling water, the water of the earth, and all the other fluids which
are susceptible of the gasseous state, at a temperature near to that of
boiling water, even quicksilver itself, would become rarified; and all
these substances would be changed into permanent aeriform fluids or
gasses, which would become part of the new atmosphere. These new species
of airs or gasses would mix with those already existing, and certain
reciprocal decompositions and new combinations would take place, until
such time as all the elective attractions or affinities subsisting
amongst all these new and old gasseous substances had operated fully;
after which, the elementary principles composing these gasses, being
saturated, would remain at rest. We must attend to this, however, that,
even in the above hypothetical situation, certain bounds would occur to
the evaporation of these substances,