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European Monetary System

(Encyclopedia)European Monetary System, arrangement by which most nations of the European Union (EU) linked their currencies to prevent large fluctuations relative to one another. It was organized in 1979 to stabil...

formula weight

(Encyclopedia)formula weight, in chemistry, a quantity computed by multiplying the atomic weight (in atomic mass units) of each element in a formula by the number of atoms of that element present in the formula, an...

pinworm

(Encyclopedia)pinworm, roundworm, Enterobius vermicularis, worldwide in distribution and the most common source of worm infestation of humans in the United States. Children are more commonly infested than adults. A...

Ch'in, dynasty of China (221–206 b.c.)

(Encyclopedia)Ch'in chĭn [key], dynasty of China, which ruled from 221 b.c. to 206 b.c. The word China is derived from Ch'in, the first dynasty to unify the country by conquering the warring feudal states of the l...

Barnard, Henry

(Encyclopedia)Barnard, Henry, 1811–1900, American educator, b. Hartford, Conn., grad. Yale, 1830. He studied law and was admitted to the bar in 1835. As a member (1837–39) of the Connecticut legislature, he ori...

W and Z particles

(Encyclopedia)W and Z particles, elementary particles that mediate, or carry, the fundamental force associated with weak interactions. The discovery of the W and Z particles at CERN near Geneva, Switzerland, in the...

Stas, Jean Servais

(Encyclopedia)Stas, Jean Servais zhäNˈ sĕrvāˈ stäs [key], 1813–91, Belgian chemist. He was assistant to J. B. A. Dumas and professor (1840–65) at the École royale militaire, Brussels. He is noted for his...

centrifuge

(Encyclopedia)centrifuge sĕnˈtrəfyo͞oj [key], device using centrifugal force to separate two or more substances of different density, e.g., two liquids or a liquid and a solid. The centrifuge consists of a fixe...

krypton

(Encyclopedia)krypton krĭpˈtŏn [key] [Gr.,=hidden], gaseous chemical element; symbol Kr; at. no. 36; at. wt. 83.798; m.p. −156.6℃; b.p. −152.3℃; density 3.73 grams per liter at STP; valence usually 0. Kr...

Meyer, Julius Lothar

(Encyclopedia)Meyer, Julius Lothar, 1830–95, German chemist. He taught at Breslau, Karlsruhe, and Tübingen (from 1876) and is known especially for his work in the development of the periodic law, for which, with...