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Dyson, Sir Frank Watson

(Encyclopedia)Dyson, Sir Frank Watson dīˈsən [key], 1868–1939, English astronomer, b. Ashby-de-la-Zouch, grad. Cambridge. He was astronomer royal of Scotland (1905–10) and of England (from 1910). As director...

ureter

(Encyclopedia)ureter yo͝orēˈtər [key], thick-walled tube that conveys urine from the kidney to the urinary bladder. It is approximately 10 in. (25.4 cm) long, with the upper half located in the abdomen and the ...

Rochelle salt

(Encyclopedia)Rochelle salt, colorless to blue-white orthorhombic crystalline salt with a saline, cooling taste. It is also called Seignette salt after Pierre Seignette, an apothecary of La Rochelle, France, who wa...

terrestrial planet

(Encyclopedia)terrestrial planet, the earth or a planet that resembles the earth in its physical characteristics. The terrestrial planets in the solar system are the earth, Mercury, Venus, and Mars. These planets a...

Earle, Ralph

(Encyclopedia)Earle or Earl, Ralph, 1751–1801, American portrait and landscape painter, b. Worcester co., Mass. He is purported to have painted four scenes of the battle of Lexington as an eyewitness, but is best...

barite

(Encyclopedia)barite bərīˈtēz [key] [New Lat., from barium], or heavy spar, a white, yellow, blue, red, or colorless mineral. It is a sulfate of barium, BaSO4, found in nature as tabular crystals or in granular...

lubrication

(Encyclopedia)lubrication, introduction of a substance between the contact surfaces of moving parts to reduce friction and to dissipate heat. A lubricant may be oil, grease, graphite, or any substance—gas, liquid...

dark energy

(Encyclopedia)dark energy, repulsive force that opposes the self-attraction of matter (see gravitation) and causes the expansion of the universe to accelerate. The search for dark energy was triggered by the discov...

isopleth

(Encyclopedia)isopleth īˈsəplĕthˌ [key], line drawn on a map through all points of equal value of some measurable quantity. In many meteorologic, oceanographic, or geologic studies some physical or chemical pr...

arteriosclerosis

(Encyclopedia)arteriosclerosis ärtĭrˌēōsklərōˈsis [key], general term for a condition characterized by thickening, hardening, and loss of elasticity of the walls of the blood vessels. These changes are freq...
 

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