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cobalt, chemical element

(Encyclopedia)cobalt, metallic chemical element; symbol Co; at. no. 27; at. wt. 58.9332; m.p. 1,495℃; b.p. about 2,870℃; sp. gr. 8.9 at 20℃; valence +2 or +3. Cobalt is a silver-white, lustrous, hard, brittle...

Qaddafi, Muammar al-

(Encyclopedia)Qaddafi, Muammar al- mo͞oäm-märˈ äl-käd-däˈfē [key], 1942–2011, Libyan army officer and dictator. He graduated from the Univ. of Libya in 1963 and became an army officer in 1965. In 1969 he...

Munch, Edvard

(Encyclopedia)Munch, Edvard ĕdˈvärt mo͝ongk [key], 1863–1944, Norwegian painter and graphic artist. He studied in Oslo and under Bonnat in Paris, traveled in Europe, and lived in Berlin from 1892 to 1908. He ...

Hunan

(Encyclopedia)Hunan ho͞oˈnänˈ [key] [south of the lake], province, c.80,000 sq mi (207,254 sq km), S ce...

Colombo

(Encyclopedia)Colombo kəlŭmˈbō [key], largest city (2021 est. metro area pop. 619,000) and former capi...

chromium

(Encyclopedia)chromium krōˈmēəm [key] [Gr.,=color], metallic chemical element; symbol Cr; at. no. 24; at. wt. 51.9961; m.p. about 1,857℃; b.p. 2,672℃; sp. gr. about 7.2 at 20℃; valence +2, +3, +6. Chromiu...

coast protection

(Encyclopedia)coast protection, methods used to protect coastal lands from erosion. Beaches can exist only where a delicate dynamic equilibrium exists between the amount of sand supplied to the beach and the inevit...

diamond

(Encyclopedia)diamond, mineral, one of two crystalline forms of the element carbon (see allotropy), the hardest natural substance known, used as a gem and in industry. The discoveries of 1870–71 in South Africa...

island

(Encyclopedia)island, relatively small body of land surrounded entirely by water. (As the oceans form a continuous mass of water on the earth's surface, all continents are islands in the strict sense of the word.) ...

dredging

(Encyclopedia)dredging, process of excavating materials underwater. It is used to deepen waterways, harbors, and docks and for mining alluvial mineral deposits, including tin, gold, and diamonds. The Dutch at an ea...