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poison

(Encyclopedia)poison, any agent that may produce chemically an injurious or deadly effect when introduced into the body in sufficient quantity. Some poisons can be deadly in minute quantities, others only if relati...

cosmic rays

(Encyclopedia)cosmic rays, charged particles moving at nearly the speed of light reaching the earth from outer space. Primary cosmic rays consist mostly of protons (nuclei of hydrogen atoms), some alpha particles (...

antimony

(Encyclopedia)antimony ănˈtĭmōˌnē [key] [Lat. antimoneum], semimetallic chemical element; symbol Sb [Lat. stibium,=a mark]; at. no. 51; at. wt. 121.760; m.p. 630.74℃; b.p. 1,750℃; sp. gr. (metallic form) ...

hepatitis

(Encyclopedia)hepatitis hĕpˌətīˈtĭs [key], inflammation of the liver. There are many types of hepatitis. Causes include viruses, toxic chemicals, alcohol consumption, parasites and bacteria, and certain drugs...

glacial periods

(Encyclopedia)glacial periods, times during which large portions of the earth's surface were covered with thick glacial ice sheets. In the Pleistocene epoch, in the Carboniferous and Permian periods of the Paleozoi...

motor, electric

(Encyclopedia)CE5 Motor: In the AC motor, current fed to the conducting loop of wire causes it to rotate in the magnetic field, thus turning the shaft on which the loop is mounted. In the DC motor, the direction...

molybdenum

(Encyclopedia)molybdenum məlĭbˈdənəm [key] [Gr.,=leadlike], metallic chemical element; symbol Mo; at. no. 42; at. wt. 95.96; m.p. about 2,617℃; b.p. about 4,612℃; sp. gr. 10.22 at 20℃; valence +2, +3, +4...

manuscript

(Encyclopedia)manuscript, a handwritten work as distinguished from printing. The oldest manuscripts, those found in Egyptian tombs, were written on papyrus; the earliest dates from c.3500 b.c. parchment, which succ...

arsenic

(Encyclopedia)arsenic ärˈsənĭk [key], a semimetallic chemical element; symbol As; at. no. 33; at. wt. 74.92160; m.p. 817℃ (at 28 atmospheres pressure); sublimation point 613℃; sp. gr. (stable form) 5.73; va...

Turin

(Encyclopedia)Turin to͝orˈĭn, tyo͝orˈ–, tyo͝orĭnˈ [key], Ital. Torino, city (1991 pop. 962,507), capital of Piedmont and of Turin prov., NW Italy, at the confluence of the Po and Dora Riparia rivers. It i...