What is "pneumatic pile"

Pile \Pile\, n. [AS. p[=i]l arrow, stake, L. pilum javelin; but cf. also L. pila pillar.]

1. A large stake, or piece of timber, pointed and driven into the earth, as at the bottom of a river, or in a harbor where the ground is soft, for the support of a building, a pier, or other superstructure, or to form a cofferdam, etc.

   Note: Tubular iron piles are now much used.

2. [Cf. F. pile.] (Her.) One of the ordinaries or subordinaries having the form of a wedge, usually placed palewise, with the broadest end uppermost.

   Pile bridge, a bridge of which the roadway is supported on piles.

   Pile cap, a beam resting upon and connecting the heads of piles.

   Pile driver, or Pile engine, an apparatus for driving down piles, consisting usually of a high frame, with suitable appliances for raising to a height (by animal or steam power, the explosion of gunpowder, etc.) a heavy mass of iron, which falls upon the pile.

   Pile dwelling. See Lake dwelling, under Lake.

   Pile plank (Hydraul. Eng.), a thick plank used as a pile in sheet piling. See Sheet piling, under Piling.

   Pneumatic pile. See under Pneumatic.

   Screw pile, one with a screw at the lower end, and sunk by rotation aided by pressure.

Pneumatic \Pneu*mat"ic\, Pneumatical \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.

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.