Magnitude is the degree of brightness of a star. In 1856, British astronomer Norman Pogson proposed a quantitative scale of stellar magnitudes, which was adopted by the astronomical community. He…
(Encyclopedia) soldersoldersŏdˈər [key], metal alloy used in the molten state as a metallic binder. The type of solder to be used is determined by the metals to be united. Soft solders are commonly…
(Encyclopedia) field, in physics, region throughout which a force may be exerted; examples are the gravitational, electric, and magnetic fields that surround, respectively, masses, electric charges,…
(Encyclopedia) fluoritefluoritefl&oomacr;ˈərīt [key] or fluorsparfluoritefl&oomacr;ˈərspär [key], mineral appearing in various colors, e.g., green, yellow-brown, rose, and red. Chemically, it…
(Encyclopedia) silicon carbide, chemical compound, SiC, that forms extremely hard, dark, iridescent crystals that are insoluble in water and other common solvents. Widely used as an abrasive, it is…
(Encyclopedia) nielloniellonēĕlˈō [key] [Ital. from Latin nigellus=blackish], black metallic alloy of sulfur, copper, silver, and usually lead, used as an inlay on engraved metal. The metal surface…
(Encyclopedia) ValentinusValentinusvăləntēˈnəs [key], fl. c.135–c.160, founder of the Valentinians, the most celebrated of the Gnostic sects (see Gnosticism) of the 2d cent. The little that is known…
(Encyclopedia) photometryphotometryfōtŏmˈətrē [key], branch of physics dealing with the measurement of the intensity of a source of light, such as an electric lamp, and with the intensity of light…
(Encyclopedia)
CE5
Blast furnace for production of iron
blast furnace, structure used chiefly in smelting. The principle involved in this means of extracting metals is that of the reduction of…
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