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A traveler by some established conveyance, as a coach, steamboat, railroad train, etc. Passenger falcon (Zoöl.), a migratory hawk. Ainsworth. -- Passenger pigeon (Zoöl.), the common wild pigeon of North America (Ectopistes migratorius), so called on account of its extensive migrations.

ieces in the sea. -- Soft patch, a patch for covering a crack in a metallic vessel, as a steam boiler, consisting of soft material, as putty, covered and held in place by a plate bolted or riveted fast.

Spreading; forming a nearly right angle with the steam or branch; as, a patent leaf. Patent leather, a varnished or lacquered leather, used for boots and shoes, and in carriage and harness work. -- Patent office, a government bureau for the examination of inventions and the granting of patents. -- Patent right. (a) T…

Continuing more than two years; as, a perennial steam, or root, or plant.

ock.] (Mach.) A little faucet in a water pipe or pump, to let air out, or at the end of a steam cylinder, to drain it.

g 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 Sh…

the genera Pissodes, Hylobius, etc. -- Pine wool, a fiber obtained from pine needles by steaming them. It is prepared on a large scale in some of the Southern United States, and has many uses in the economic arts; -- called also pine- needle wool, and pine-wood wool.

y of wood, metal, earthenware, or the like: especially, one used as a conductor of water, steam, gas, etc.

r fitting within a cylindrical vessel along which it moves, back and forth. It is used in steam engines to receive motion from the steam, and in pumps to transmit motion to a fluid; also for other purposes. Piston head (Steam Eng.), that part of a piston which is made fast to the piston rod. -- Piston rod, a rod by wh…

low and enlarge a hole previously made, or to form a counterbore around it. -- Plug rod (Steam Eng.) , a rod attached to the beam for working the valves, as in the Cornish engine. -- Plug valve (Mech.), a tapering valve, which turns in a case like the plug of a faucet.

nd steadily; especially, to do something by repeated actions; to go back and forth; as, a steamer plies between certain ports. Ere half these authors be read (which will soon be with plying hard and daily). Milton. He was forced to ply in the streets as a porter. Addison. The heavy hammers and mallets plied. Longfellow…

A passageway in a machine, through which a fluid, as steam, water, etc., may pass, as from a valve to the interior of the cylinder of a steam engine; an opening in a valve seat, or valve face. Air port, Bridle port, etc. See under Air, Bridle, etc. -- Port bar (Naut.), a bar to secure the ports of a ship in a gale. -…

light and portable my pain seems now! Shak. Portable forge. See under Forge. -- Portable steam engine. See under Steam engine.

regarded as put forth or exerted; strength, force, or energy in action; as, the power of steam in moving an engine; the power of truth, or of argument, in producing conviction; the power of enthusiasm. "The power of fancy." Shak.

admission, as of steam, to the engine cylinder before the back stroke is completed, thus increasing the cushioning.

pressure, Center of pressure, etc. See under Atmospheric, 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 equall…

ned by chemical combination, and applied to produce changes in the volume and pressure of steam, air, or other fluids; and electricity, obtained by chemical action, and applied to produce alternation of magnetic force. (b) An engine, or machine, the object of which is to receive and modify force and motion as supplied…

The carrying over of water, with the steam, from the boiler, as into the cylinder. Priming of the tide. See Lag of the tide, under 2d Lag. -- Priming tube, a small pipe, filled with a combustible composition for firing cannon. -- Priming valve (Steam Eng.), a spring safety valve applied to the cylinder of a steam eng…

ive forward; to urge or press onward by force; to move, or cause to move; as, the wind or steam propels ships; balls are propelled by gunpowder.

A contrivance for propelling a steam vessel, usually consisting of a screw placed in the stern under water, and made to revolve by an engine; a propeller wheel.