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flame

(Encyclopedia)flame, phenomenon associated with the chemical reaction of a gas that has been heated above its kindling temperature with some other gas, usually atmospheric oxygen (see combustion). The heat and ligh...

silicate

(Encyclopedia)silicate, chemical compound containing silicon, oxygen, and one or more metals, e.g., aluminum, barium, beryllium, calcium, iron, magnesium, manganese, potassium, sodium, or zirconium. Silicates may b...

Bronze Age

(Encyclopedia)Bronze Age, period in the development of technology when metals were first used regularly in the manufacture of tools and weapons. Pure copper and bronze, an alloy of copper and tin, were used indiscr...

magnesium

(Encyclopedia)magnesium măgnēˈzēəm, –zhəm [key], metallic chemical element; symbol Mg; at. no. 12; at. wt. 24.3050; m.p. about 648.8℃; b.p. about 1,090℃; sp. gr. 1.738 at 20℃; valence +2. In 1808, Sir...

Nevada

(Encyclopedia)CE5 Nevada nəvădˈə, –vä– [key], far western state of the United States. It is bordered by Utah (E), Arizona (SE), California (SW, W), and Oregon and Idaho (N). In the 20th cent. the ...

metalwork

(Encyclopedia)metalwork. Copper, gold, and silver were probably fashioned into ornaments and amulets as early as the Neolithic period. Goldwork and silverwork have since employed the talents of leading artisans and...

tin

(Encyclopedia)tin, metallic chemical element; symbol Sn [Lat. stannum]; at. no. 50; at. wt. 118.710; m.p. 231.9681℃; b.p. 2,270℃; sp. gr. 5.75 (gray), 7.3 (white); valence +2 or +4. Tin exhibits allotropy; abov...

screen

(Encyclopedia)screen, in architecture, partition or enclosure not extending to the ceiling; usually a structure in stone, wood, or metal. It frequently serves to mark the boundaries of portions of churches and cath...

Continental System

(Encyclopedia)Continental System, scheme of action adopted by Napoleon I in his economic warfare with England from 1806 to 1812. Economic warfare had been carried on before 1806, but the system itself was initiated...

tungsten

(Encyclopedia)tungsten tŭngˈstən [key] [Swed.,=heavy stone], metallic chemical element; symbol W; at. no. 74; at. wt. 183.84; m.p. about 3,410℃; b.p. 5,660℃; sp. gr. 19.3 at 20℃; valence +2, +3, +4, +5, or...