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linseed oil

(Encyclopedia)linseed oil, amber-colored, fatty oil extracted from the cotyledons and inner coats of the linseed. The raw oil extracted from the seeds by hydraulic pressure is pale in color and practically without ...

safety valve

(Encyclopedia)safety valve, device attached to a boiler or other vessel for automatically relieving the pressure of steam before it becomes great enough to cause bursting. The common spring-loaded type is held clos...

gas laws

(Encyclopedia)gas laws, physical laws describing the behavior of a gas under various conditions of pressure, volume, and temperature. Experimental results indicate that all real gases behave in approximately the sa...

Lebedev, Pyotr Nikolaevich

(Encyclopedia)Lebedev, Pyotr Nikolaevich pyôˈtə nyĭkəlīˈəvĭch lāˈbyədyəf [key], 1866–1912, Russian physicist. The most noted Russian physicist of his time, he studied at Strasbourg and Berlin and was...

artesian well

(Encyclopedia)artesian well, deep drilled well through which water is forced upward under pressure. The water in an artesian well flows from an aquifer, which is a layer of very porous rock or sediment, usually san...

hydrotherapy

(Encyclopedia)hydrotherapy, use of water in the treatment of illness or injury. Although the medicinal and hygienic value of water was recognized by the early Greeks, hydrotherapy attained its widest use in the 18t...

pumice

(Encyclopedia)pumice pŭmˈĭs [key], volcanic glass formed by the solidification of lava that is permeated with gas bubbles. Usually found at the surface of a lava flow, it is colorless or light gray and has the g...

cyclone

(Encyclopedia)cyclone, atmospheric pressure distribution in which there is a low central pressure relative to the surrounding pressure. The resulting pressure gradient, combined with the Coriolis effect, causes air...

Hales, Stephen

(Encyclopedia)Hales, Stephen, 1677–1761, English physiologist and clergyman. From 1709 he was perpetual curate of Teddington. His experimental studies in animal and plant physiology contributed greatly to the pro...

temperature inversion

(Encyclopedia)temperature inversion, condition in which the temperature of the atmosphere increases with altitude in contrast to the normal decrease with altitude. When temperature inversion occurs, cold air underl...