The New Student's Reference Work/Copper

Copper. This appears to have been the first metal used by man, both in war and in the peaceful arts. Like and,  it is found native, sometimes in great masses, as on the south shore of , where blocks of many tons' weight have been obtained. The use of copper by ancient nations is well-known, through the many collections in museums of weapons and other objects of, that is, copper mixed with a small quantity of. The ancients obtained most of their copper from ; hence the name. Copper has a fine red color, takes a brilliant polish, and is nine times heavier than water. Next to silver it is the best conductor of heat and electricity. It is moderately hard and highly tenacious, though not so strong as. The largest masses of native copper are found in the mines of and in our own Lake Superior region. Copper is used in many ways. With other metals it makes, bronze and gun-metal; alone, it is used for boilers, cooking-vessels, pipes, wire, nails, spikes; in thin plates it is used for engraving and etching, and in strong rollers for calico-printing; as an electro-deposit it is used in copying engravings and pages of type for the printing-press. Copper is usually employed for lightning-conductors. Yellow metal, an alloy of copper, is used in sheathing the bottom of vessels. The is now the largest producer of copper. The richest mine in the world is at Calumet,, on Lake Superior. ,, and other parts of the Union also produce copper. The world's production of copper, in 1906, was 715,268 tons, the chief countries producing the metal, besides the United States, being, , , Australasia, , , and.