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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...

Toltec

(Encyclopedia)Toltec tŏlˈtĕk [key], ancient civilization of Mexico. The name in Nahuatl means “master builders.” The Toltec formed a warrior aristocracy that gained ascendancy in the Valley of Mexico c.a.d. ...

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...

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 ...

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...

furnace

(Encyclopedia)furnace, enclosed space for the burning of fuel. There are many kinds of furnaces, the type depending upon the fuel and the use to which the heat produced within it is put. Most familiar are the furna...

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...

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...

Western Australia

(Encyclopedia)Western Australia, state (2016 pop. 2,474,410), 975,920 sq mi (2,527,633 sq km), Australia, comprising the entire western part of the continent. It is bounded on the N, W, and S by the Indian Ocean. P...