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Ohm, Georg Simon

(Encyclopedia)Ohm, Georg Simon gāˈôrkh zēˈmôn ōm [key], 1787–1854, German physicist. He was professor at Munich from 1852. His study of electric current led to his formulation of the law now known as Ohm's...

vacuum cleaner

(Encyclopedia)vacuum cleaner, mechanical device using a draft of air to remove dust, loose dirt, or other particulate matter from dry surfaces. It is especially useful on highly textured surfaces, such as carpets a...

Halloween

(Encyclopedia)Halloween säˈwĭn [key], the beginning of winter and the Celtic new year. Spirits, or fairies, were said to roam the earth on this evening, playing tricks on human beings to mark the season of dimin...

pistachio

(Encyclopedia)pistachio pĭstăshˈēō, pĭstäˈshēō [key], tree or shrub (of the genus Pistacia) of the family Anacardiaceae (sumac family). The species that yields the pistachio nut of commerce is P. vera, na...

Heaney, Seamus

(Encyclopedia)Heaney, Seamus (Seamus Justin Heaney) shāˈməs, hēˈnē [key], 1939–2013, Irish poet, one of the finest contemporary English poets, b. Londonderry (now Derry), Northern Ireland, grad. Queen's Uni...

ammonium chloride

(Encyclopedia)ammonium chloride əmōˈnēəm klôrˈīd [key], chemical compound, NH4Cl, a white or colorless, odorless, water-soluble, cubic crystalline salt with a biting taste, commonly known as sal ammoniac. I...

Rock Springs

(Encyclopedia)Rock Springs, city (1990 pop. 19,050), alt. c.6,270 ft (1,910 m), Sweetwater co., SW Wyo., on Bitter Creek; inc. 1888. It is a cattle and sheep shipping point and the center of large natural trona min...

scalar

(Encyclopedia)scalar, quantity or number possessing only sign and magnitude, e.g., the real numbers (see number), in contrast to vectors and tensors; scalars obey the rules of elementary algebra. Many physical quan...

barley

(Encyclopedia)barley, annual cereal plant (Hordeum vulgare and sometimes other species) of the family Poaceae (grass family), cultivated by humans probably as early as any cereal. It was known to the ancient Greeks...

Harvey, George Brinton McClellan

(Encyclopedia)Harvey, George Brinton McClellan, 1864–1928, American journalist and diplomat, b. Peacham, Caledonia co., Vt. After a career in journalism and insurance, he became involved in the construction and a...