Pneu·mat·ic Pneu·mat·ic·al a.
 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.”
 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.

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 Rail·road Rail·way n.
 1. A road or way consisting of one or more parallel series of iron or steel rails, patterned and adjusted to be tracks for the wheels of vehicles, and suitably supported on a bed or substructure.
 Note: ☞ The modern railroad is a development and adaptation of the older tramway.
 2. The road, track, etc., with all the lands, buildings, rolling stock, franchises, etc., pertaining to them and constituting one property; as, a certain railroad has been put into the hands of a receiver.
 Note: ☞ Railway is the commoner word in England; railroad the commoner word in the United States.
 Note: ☞ In the following and similar phrases railroad and railway are used interchangeably: --
 Atmospheric railway, Elevated railway, etc. See under Atmospheric, Elevated, etc.
 Cable railway. See Cable road, under Cable.
 Ferry railway, a submerged track on which an elevated platform runs, for carrying a train of cars across a water course.
 Gravity railway, a railway, in a hilly country, on which the cars run by gravity down gentle slopes for long distances after having been hauled up steep inclines to an elevated point by stationary engines.
 Railway brake, a brake used in stopping railway cars or locomotives.
 Railway car, a large, heavy vehicle with flanged wheels fitted for running on a railway. [U.S.]
 Railway carriage, a railway passenger car. [Eng.]
 Railway scale, a platform scale bearing a track which forms part of the line of a railway, for weighing loaded cars.
 Railway slide. See Transfer table, under Transfer.
 Railway spine Med., an abnormal condition due to severe concussion of the spinal cord, such as occurs in railroad accidents. It is characterized by ataxia and other disturbances of muscular function, sensory disorders, pain in the back, impairment of general health, and cerebral disturbance, -- the symptoms often not developing till some months after the injury.
 Underground railroad Underground railway. (a) A railroad or railway running through a tunnel, as beneath the streets of a city. (b) Formerly, a system of cooperation among certain active antislavery people in the United States prior to 1866, by which fugitive slaves were secretly helped to reach Canada.
 Note: [In the latter sense railroad, and not railway, was usually used.] “Their house was a principal entrepôt of the underground railroad.” --W. D. Howells.

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 At·mos·pher·ic At·mos·pher·ic·al a.
 1. Of or pertaining to the atmosphere; of the nature of, or resembling, the atmosphere; as, atmospheric air; the atmospheric envelope of the earth.
 2. Existing or occurring in the atmosphere.
    The lower atmospheric current.   --Darwin.
 3. Caused, or operated on, by the atmosphere; as, an atmospheric effect; an atmospheric engine.
 4. Dependent on the atmosphere. [R.]
    In am so atmospherical a creature.   --Pope.
 Atmospheric engine, a steam engine whose piston descends by the pressure of the atmosphere, when the steam which raised it is condensed within the cylinder. --Tomlinson.
 Atmospheric line Steam Engin., the equilibrium line of an indicator card. Steam is expanded “down to the atmosphere” when its pressure is equal to that of the atmosphere. (See Indicator card.)
 Atmospheric pressure, the pressure exerted by the atmosphere, not merely downwards, but in every direction. In amounts to about 14.7 Ibs. on each square inch.
 Atmospheric railway, one in which pneumatic power, obtained from compressed air or the creation of a vacuum, is the propelling force.
 Atmospheric tides. See under Tide.

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