rived of its caloric. The same,
however, has not been found necessary with respect to water reduced to
the state of vapour by an additional dose of caloric; since those
persons who do not make a particular study of objects of this kind, are
still ignorant that water, when in a temperature only a little above the
boiling heat, is changed into an elastic aeriform fluid, susceptible,
like all other gasses, of being received and contained in vessels, and
preserving its gasseous form so long as it remains at the temperature of
80 deg. (212 deg.), and under a pressure not exceeding 28 inches of the
mercurial barometer. As this phenomenon has not been generally observed,
no language has used a particular term for expressing water in this
state[10]; and the same thing occurs with all fluids, and all
substances, which do not evaporate in the common temperature, and under
the usual pressure of our atmosphere.

For similar reasons, names have not been given to the liquid or concrete
states of most of the aeriform fluids: These were not known to arise
from the combination of caloric with certain bases; and, as they had not
been seen either in the liquid or solid states, their existence, under
these forms, was even unknown to natural philosophers.

We have not pretended to make any alteration upon such terms as are
sanctified by ancient custom; and, therefore, continue to use the words
_water_ and _ice_ in their common acceptation: We likewise retain the
word _air_, to express that collection of elastic fluids which composes
our atmosphere; but we have not thought it necessary to preserve the
same respect for modern terms, adopted by latter philosophers, having
considered ourselves as at liberty to reject such as appeared liable to
occasion erroneous ideas of the substances they are meant to express,
and either to substitute new terms, or to employ the old ones, after
modifying them in such a manner as to convey more determinate ideas. New
words have been drawn, chiefly from the Greek language, in such a manner
as to make their etymology convey some idea of what was meant to be
represented; and these we have always endeavoured to make short, and of
such a nature as to be changeable into adjectives and verbs.

Following these principles, we have, after Mr Macquer's example,
retained the term _gas_, employed by Vanhelmont, having arranged the
numerous class of elastic aeriform fluids under that name, excepting
only atmospheric air.