Atmosphere, a term derived from the greek words vapour and sphere, whence it has been generally applied, to signify that surrounding mass of air which consists of aqueous and other vapours, the electric magnetic fluids, etc. but the altitude or extent of which never been accurately ascertained, under the article Air, p. 21, have already mentioned the general pro; of this surroundmedium ; hence we shall here observe, by way of supplement, discoveries of modern chemists, though still opd by Dr. Priestley, the at, but a compound body. Pure air, or of its three-fourths. The former is, on use red animals .1 animals, the life of creatures, when anima tion is accidently suspended, so that the late Dr. INGENHOUZ has justly termed it vital air; yet it is not for long.. Azote, or air, on the. ( unfit for supit is abso-le. Hence it must greater or ! proportion iocs noxious in our atmosphere, arise from the innumerable processes of combustion, putrefaction, and respiration, whether by nature or art, in all large and populous cities. For this reason, country-air much preferable, that certain invalids, especiaily pthisical and asthmatic persons, are obliged to retire from towns to a purer, or, at least, less vitiated region. Hence also, it will be understood, that sea-air must be infinitely more conducive to support the most important process of life ; as, by the constant agitation or commotion of the watery element, mephitic vapours are in a manner neutralized} though the azote enters into no combination with that fluid: upon a similar principle, it has been suggested (p. 23) to purify the foul air of pits and wells, before any person attempts to descend into them, by simply pouring in a few pailtais of water, whether boiling or cold. By the same method also, wine* casks, and other be fatal, influence. lent part of the con or carbonic in and therefore deserves no particular account in 'his place, as we propose to treat of it under the article of Brewing.