Search the Dictionary

A colorless, tasteless, odorless, gaseous element occurring in the free state in the atmosphere, of which it forms about 23 per cent by weight and about 21 per cent by volume, being slightly heavier than nitrogen. Symbol O. Atomic weight 15.96.

An instrument for ascertaining the amount of ozone in the atmosphere, or in any gaseous mixture. Faraday.

A lightning conductor erected, as in a vineyard, for drawing off the electricity in the atmosphere in order to prevent hailstorms. [France] Knight.

A high, bleak plateau or district, with stunted trees, and cold, damp atmosphere, as in the Andes, in South America.

, and of the physical movements or changes on the earth's surface, as the currents of the atmosphere and ocean, the secular variations in heat, moisture, magnetism, etc.; physical geography.

An instrument for measuring the tension of the aqueous vapor in the atmosphere, being essentially a wet and dry bulb hygrometer.

rized by wide separation of parts; of loose texture; not thick or dense; thin; as, a rare atmosphere at high elevations. Water is nineteen times lighter, and by consequence nineteen times rarer, than gold. Sir I. Newton.

n of a heavenly body from which it emanates, arising from its passage through the earth's atmosphere; -- hence distinguished as atmospheric refraction, or astronomical refraction.

tional. This high rotative velocity of the sun must cause an equatorial rise of the solar atmosphere. Siemens. Rotative engine, a steam engine in which the reciprocating motion of the piston is transformed into a continuous rotary motion, as by means of a connecting rod, a working beam and crank, or an oscillating cyli…

ve opening inward to admit air to a vessel in which the pressure is less than that of the atmosphere, to prevent collapse.

and which become visible by coming with planetary velocity into the upper regions of the atmosphere. At certain periods, as on the 13th of November and 10th of August, they appear for a few hours in great numbers, apparently diverging from some point in the heavens, such displays being known as meteoric showers, or st…

e vessel to another, over an intermediate elevation, by the action of the pressure of the atmosphere in forcing the liquid up the shorter branch of the pipe immersed in it, while the continued excess of weight of the liquid in the longer branch (when once filled) causes a continuous flow. The flow takes place only when…

Filled with smoke, or with a vapor resembling smoke; thick; as, a smoky atmosphere.

from Snift. Snifting valve, a small valve opening into the atmosphere from the cylinder or condenser of a steam engine, to allow the escape of air when the piston makes a stroke; -- so called from the noise made by its action.

gh steam, or High-pressure steam, steam of which the pressure greatly exceeds that of the atmosphere. -- Low steam, or Low-pressure steam, steam of which the pressure is less than, equal to, or not greatly above, that of the atmosphere. -- Saturated steam, steam at the temperature of the boiling point which correspon…

Not disturbed by noise or agitation; quiet; calm; as, a still evening; a still atmosphere. "When all the woods are still." Milton.

A violent disturbance of the atmosphere, attended by wind, rain, snow, hail, or thunder and lightning; hence, often, a heavy fall of rain, snow, or hail, whether accompanied with wind or not. We hear this fearful tempest sing, Yet seek no shelter to avoid the storm. Shak.

A sensitive kind of barometer, in which the pressure of the atmosphere, acting upon a liquid, as oil, in the lower portion of the instrument, compresses an elastic gas in the upper part.

The period of twelve hours. Atmospheric tides, tidal movements of the atmosphere similar to those of the ocean, and produced in the same manner by the attractive forces of the sun and moon. -- Inferior tide. See under Inferior, a. -- To work double tides. See under Work, v. t. -- Tide day, the interval between the o…

allowing the inclosed fluid to descend till it is counterbalanced by the pressure of the atmosphere, as in the barometer. Hutton.