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spinel

(Encyclopedia)spinel, magnesium aluminum oxide, MgAl2O4, a mineral crystallizing in the isometric system, usually as octahedrons. It occurs as an accessory mineral in basic igneous rocks, in aluminum-rich metamorph...

Sierra Maestra

(Encyclopedia)Sierra Maestra syāˈrä mäāˈsträ [key], rugged mountain range, SE Cuba, rising abruptly from the coast. Consisting of connecting ranges with local names, the Sierra Maestra is the highest system ...

Shoshone project

(Encyclopedia)Shoshone project, NW Wyo., near the Mont. line and in the Shoshone River basin. Developed by the U.S. Bureau of Reclamation, it irrigates a large portion of land and has four divisions. The project is...

cryptosporidium

(Encyclopedia)cryptosporidium krĭpˌtōspərĭdˈēəm [key], genus of protozoans having at least four species; they are waterborne parasites that cause the disease cryptosporidiosis. One of the species appears to...

Chang Chih-tung

(Encyclopedia)Chang Chih-tung jängˈ jûrˈ-do͝ongˈ [key], 1837–1909, Chinese Ch'ing dynasty statesman and educational reformer. He occupied the high post of governor-general for over two decades, first of Gua...

Henry, Joseph

(Encyclopedia)Henry, Joseph, 1797–1878, American physicist, b. Albany, N.Y., educated at Albany Academy. He taught (1826–32) mathematics and natural philosophy at Albany Academy and was professor of natural phi...

Gaucher's disease

(Encyclopedia)Gaucher's disease gōshāzˈ [key], rare genetic disease involving a deficiency of an enzyme, glucocerebrosidase, which normally breaks down certain body glycolipids (i.e., lipids (fats) that have a s...

Lorentz, Hendrik Antoon

(Encyclopedia)Lorentz, Hendrik Antoon hĕnˈdrək änˈtōn lōˈrĕnts [key], 1853–1928, Dutch physicist, a pioneer in formulating the relations between electricity, magnetism, and light. He was one of the first...

Mammoth Cave National Park

(Encyclopedia)Mammoth Cave National Park, 52,830 acres (21,396 hectares), central Kentucky, authorized 1926, est. 1941. Located in a hilly, forested region, it offers numerous outdoor activities. It is the site of ...

treaty port

(Encyclopedia)treaty port, port opened to foreign trade by a treaty. The term is usually confined to ports in those countries that formerly strongly objected to foreign trade or attempted altogether to exclude it. ...