4. (Biol.)
Defn: 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.
PNEUMATICITY
Pneu`ma*tic"i*ty, n. (Biol.)
Defn: The state of being pneumatic, or of having a cavity or cavities filled with air; as, the pneumaticity of the bones of birds.
PNEUMATICS
Pneu*mat"ics, n. Etym: [Cf. F. pneumatique.]
1. That branch of science which treats of the mechanical properties of air and other elastic fluids, as of their weight, pressure, elasticity, etc. See Mechanics.
2. (Philos. & Theol.)
Defn: The scientific study or knowledge of spiritual beings and their relations to God, angels, and men.
PNEUMATO-
Pneu"ma*to-.
Defn: A combining form from Gr. wind, air, breath, respiration; as, pneumatograph, pneumatology.