Volume 1: 1771 Edition of the Encyclopedia Britannica!
Air
Air, a thin transparent fluid which encompasses the globe of the earth to a
considerable height. For the weight, pressure, elasticity, etc. of air,
see Pneumatics.
Air, in medicine, one of the six non-naturals, and as essential to the life
of animals as food, or any of the ordinary evacuations.
Air, in mythology, was adored by the heathens under the names of Jupiter and
Juno; the form is representing the superior and finer part of the atmosphere,
and the latter the inferior and grosser part. The augurs also drew
presages from the clouds, thunder, lightning, etc.
Air, in painting, etc. denotes the manner and very life of action; or it is
that which expresses the disposition of the agent.It is sometimes also used
in a somewhat synonymous sense with gesture or attitude.
Air, in music, denotes the melody proper for songs, odes, and the like;
being usually quick and lively.Sometimes it is used for the songs
themselves, called by the Romans aera, from which the modern term air is
derived.