{ Pneu*mat"ic, Pneu*mat"ic*al }, a. Adapted for containing compressed air; inflated with air; as, a pneumatic cushion; a pneumatic tire, a tire formed of an annular tube of flexible fabric, as India rubber, suitable for being inflated with air.

{ Pneu*mat"ic (?), Pneu*mat"ic*al (?), } a. [L. pneumaticus, Gr. &?;, fr. &?;, &?;, wind, air, &?; to blow, breathe; cf. OHG. fnehan: cf. F. pneumatique. Cf. Pneumonia.] 1. Consisting of, or resembling, air; having the properties of an elastic fluid; gaseous; opposed to dense or solid.

The pneumatical substance being, in some bodies, the native spirit of the body.

Bacon.

2. Of or pertaining to air, or to elastic fluids or their properties; pertaining to pneumatics; as, pneumatic experiments. "Pneumatical discoveries." Stewart.

3. Moved or worked by pressure or flow of air; as, a pneumatic instrument; a pneumatic engine.

4. (Biol.) Fitted to contain air; Having cavities filled with air; as, pneumatic cells; pneumatic bones.

Pneumatic action, or Pneumatic lever(Mus.), a contrivance for overcoming the resistance of the keys and other movable parts in an organ, by causing compressed air from the wind chest to move them. -- Pneumatic dispatch, a system of tubes, leading to various points, through which letters, packages, etc., are sent, by the flow and pressure of air. -- Pneumatic elevator, a hoisting machine worked by compressed air. -- Pneumatic pile, a tubular pile or cylinder of large diameter sunk by atmospheric pressure. -- Pneumatic pump, an air-exhausting or forcing pump. -- Pneumatic railway. See Atmospheric railway, under Atmospheric. -- Pneumatic syringe, a stout tube closed at one end, and provided with a piston, for showing that the heat produced by compressing a gas will ignite substances. -- Pneumatic trough, a trough, generally made of wood or sheet metal, having a perforated shelf, and used, when filled with water or mercury, for collecting gases in chemical operations. -- Pneumatic tube. See Pneumatic dispatch, above.

{ Pneu*mat"ic, Pneu*mat"ic*al }, a. Adapted for containing compressed air; inflated with air; as, a pneumatic cushion; a pneumatic tire, a tire formed of an annular tube of flexible fabric, as India rubber, suitable for being inflated with air.