Atmosphere

at′mo-sfēr, n. the gaseous envelope that surrounds the earth or any of the heavenly bodies: any gaseous medium: a conventional unit of atmospheric pre ure: ( fig. ) any surrounding influence.— adjs. Atmospher′ic , -al , of or depending on the atmosphere.— adv. Atmospher′ically .— Atmospheric engine , a variety of steam-engine in which the steam is admitted only to the under side of the piston; Atmospheric hammer , a hammer driven by means of compre ed air; Atmospheric railway , a railway where the motive-power is derived from the pre ure of the atmosphere acting on a piston working in an iron tube of uniform bore. [Gr. atmos , air, sphaira , a sphere.]