PLAY n.
Motion; movement, regular or irregular; as, the play of a wheel or piston; hence, also, room for motion; free and easy action. "To give them play, front and rear." Milton. The joints are let exactly into one another, that they have no play between them. Moxon.
PNEUMATIC; PNEUMATICAL a.
r 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,…
PRESENT v.
To aim, point, or direct, as a weapon; as, to present a pistol or the point of a sword to the breast of another. Pesent arms (Mil.), the command in response to which the gun is carried perpendicularly in front of the center of the body, and held there with the left hand grasping it at the lower band, and the right hand…
PRESSURE n.
, Center, etc. -- Back pressure (Steam engine), pressure which resists the motion of the piston, as the pressure of exhaust steam which does not find free outlet. -- Fluid pressure, pressure like that exerted by a fluid. It is a thrust which is normal and equally intense in all directions around a point. Rankine. --…
RECIPROCATE v.
cating air. Dryden. Reciprocating engine, a steam, air, or gas engine, etc., in which the piston moves back and forth; -- in distinction from a rotary engine, in which the piston travels continuously in one direction in a circular path. -- Reciprocating motion (Mech.), motion alternately backward and forward, or up an…