Pneumatic

1. Consisting of, or resembling, air; having the properties of an elastic fluid; gaseous; opposed to dense or solid.
2. Of or pertaining to air, or to elastic fluids or their properties; pertaining to pneumatics; as, pneumatic experiments.
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.
5. 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.
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.