CONDENSATION

, is the compressing or reducing of a body into a less bulk or space; by which means it is rendered more dense and compact.

Wolfius, and some other writers, restrain the use of the word condensation to the action of cold: that which is done by external application, they call compression.

Condensation however, in general, consists in bring- ing the parts closer to each other, and increasing their contact, whatever be the means by which it is effected: in opposition to rarefaction, which renders the body lighter and looser, by setting the parts farther asunder, and diminishing their contact, and of consequence their cohesion.

Air easily condenses, either by cold, or by pressure, but much more by the latter; but most of all by chemical process. Water condenses also both by cold and by pressure; but it suddenly expands by congelation: indeed almost all matter, both solids and fluids, has the same property of condensation by those means. See Compression. So also vapour is condensed, or converted into water, by distillation, or naturally in the clouds. The way in which vapour commonly condenses, is by the application of some cold substance. On touching it, the vapour parts with its heat which it had before absorbed: and on doing so, it immediately loses the proper characteristics of vapour, and becomes water. But though this be the most common and usual way in which we observe vapour to be condensed, nature certainly proceeds after another manner; since we often observe the vapours most plentifully condensed when the weather is really warmer than at other times.