atmospherical : Idioms & Phrases

• a steam engine whose piston descends by the pressure of the atmosphere, when the steam which raised it is condensed within the cylinder. Tomlinson.

Webster 1913

• (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.)

Webster 1913

• noun the pressure exerted by the atmosphere
  pressure; air pressure.
  

WordNet

• the pressure exerted by the atmosphere, not merely downwards, but in every direction. In amounts to about 14.7 Ibs. on each square inch.

Webster 1913

• one in which pneumatic power, obtained from compressed air or the creation of a vacuum, is the propelling force.

Webster 1913

• . See under Tide.

Webster 1913