a pneumatic machine or syringe for compressing air, by means of which ten or more atmospheres, or ten times as much air as exists in a given space under the ordinary pressure of the atmosphere, may be forced into that space.

The syringe consists of a brass cylinder in which there is a moveable piston which forces the air into a receiver; and a valve prevents the air from escaping. The receiver or vessel in which the air is condensed should be made very strong, to bear the increased force of the air; for which reason vessels of this sort are generally made of brass, and the orifice is fitted with a female screw to receive the male screw at the end of the condenser. See Pneumatics. The term is also applied to vessels in which aqueous or spirituous vapours are reduced to a more dense state, either by the injection of cold water, as in the condenser of a steam-engine; or, when this is inapplicable, as in the distillation of spirituous liquors, by surrounding the condenser with cold water, which is perpetually renewed, and is applied over a large surface of the condensing vessel. See Distillation, Steam-Engine, &c.