Copper

Collier's New Encyclopedia (1921)

a dyad metallic element; symbol, Cu.; at. wt. 63.5; sp. gr., 8.95; melting point, 1,091° C. Copper is a red malleable, ductile metal, occurring in a native state on the S. shore of Lake Superior. It also occurs to a greater extent as copper pyrites of a brass yellow color as peacock ore, characterized by its iridescent colors, in the Butte mines, Montana; as gray copper ore, a sulphide, in Cornwall and Freiberg; as indigo copper, so called from its color, in Chile; as malachite, or green carbonate, in Si' beria and Australia; and as azurite or blue carbonate in Burra Burra, Australia. Copper forms several alloys. Brass is an alloy of two-thirds copper and onethird zin zinc; bronze, gun-metal, and bellmetal are alloys of copper with tin. Copper forms two series of compounds, the cuprous and cupric salts. Copper arsenite, or Scheele's green, is used as a pigment for wall papers; it is very poi- Copper salts are detected by sonous. giving in an acid solution a black precipitate with H₂S. All salts of copper are poisonous. Verdigris is an acetate of copper, often formed by cooking food in copper vessels. Production.-Since the census year 1880 the United States has risen to the rank of the largest copper producer in the world, outstripping by far any other country. The production of copper in the United States in 1919 was 1,310,- 541,529 pounds. The production in 1918 was 1,908,533,595 pounds. The largest production was from Arizona, which contributed 536,513,368 pounds. Michigan 35 pounds, and was second with 201,716,335 Montana third with 176,189,873 pounds. The production of Utah was 148,057,450 pounds. Other States producing over 50,000,000 pounds were New Mexico and Alaska produced 56,534,992 Nevada. pounds. The total value of the production in 1919 was $243,761,000, compared with a value in 1918 of $471,408,000. The imports of copper ore in 1919 amounted to 49,716,511 pounds. There were imported 263,220,449 pounds of unrefined black copper, and copper in bars, pigs, or other forms. The exports of copper in 1919 amounted to 516,627,775 pounds. History. Copper has been known since prehistoric times. There may have been a copper age before that of bronze. The latter compound metal, an alloy of copper and tin, was known long before brass had been made. The word copper occurs once in the Old Testament (Ezra viii: 27), but what is in many places called brass should have been rendered copper. Copper was in use in ancient Assyria. The classical nations were familiar with it, The Greeks brought it from Cyprus, the mines being at Tamassus, near Fama- Copper mines were first opened Co gosta. in England A. D. 1189, but not very successfully till A. D. 1689.