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herbicide

(Encyclopedia)herbicide hrˈbəsīdˌ [key], chemical compound that kills plants or inhibits their normal growth. A herbicide in a particular formulation and application can be described as selective or nonselectiv...

rheostat

(Encyclopedia)rheostat rēˈəstătˌ [key], device whose resistance to electric current depends on the position of some mechanical element or control in the device. Typically a rheostat consists of a resistance el...

malachite

(Encyclopedia)malachite mălˈəkīt [key], a mineral, the green basic carbonate of copper occurring in crystals of the monoclinic system or (more usually) in masses. It is translucent or opaque; the luster is silk...

Organization for the Prohibition of Chemical Weapons

(Encyclopedia)Organization for the Prohibition of Chemical Weapons (OPCW), international body (est. 1997) responsible for the implementation of the Chemical Weapons Convention (CWC), which aims at the destruction o...

strontium

(Encyclopedia)strontium strŏnˈshēəm [key] [from Strontian, a Scottish town], a metallic chemical element; symbol Sr; at. no. 38; at. wt. 87.62; m.p. 769℃; b.p. 1,384℃; sp. gr. 2.6 at 20℃; valence +2. Stro...

Black Country

(Encyclopedia)Black Country, highly industrialized region, historically mostly in Staffordshire but partly in Worcestershire and Warwickshire, W central England. It includes Dudley, Rowley Regis (see Warley), Tipto...

Heinze, Frederick Augustus

(Encyclopedia)Heinze, Frederick Augustus hīnˈzē [key], 1869–1914, American copper magnate, b. Brooklyn, N.Y. He went in 1889 to Butte, Mont., as engineer for a mining company. In 1893 he organized the Montana ...

Sheffield plate

(Encyclopedia)Sheffield plate, metalware of copper, silver-plated by fusion, originated at Sheffield, England. This process of plating was discovered c.1742 by a Sheffield cutler, Thomas Boulsover, who found while ...

German silver

(Encyclopedia)German silver, name for various alloys of copper, zinc, and nickel, sometimes also containing lead and tin. They were originally named for their silver-white color, but use of the term silver is now p...

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...