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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...

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. ...

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...

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...

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...

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...

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...