Air, n.

The fluid which we breathe. Air is inodorous, invisible, insipid, colorless, elastic, possessed of gravity, easily moved, rarefied, and condensed.

Atmospheric air is a compound fluid, consisting of oxygen gas, and nitrogen or azote; the proportion of each is stated by chimists differently; some experiments making the oxygen a twenty-eighth part of a hundred; others, not more than a twenty-third, or something less. The latter is probably the true proportion.

Oxygen gas is called vital air. The body of air surrounding the earth is called the atmosphere. The specific gravity of air is to that of water, nearly as 1 to 828. Air is necessary to life; being inhaled into the lungs, the oxygenous part is separated from the azotic, and it is supposed to furnish the body with heat and animation. It is the medium of sounds and necessary to combustion.