COPPER. A metallic element known to the ancients. It is mentioned in the Bible, al though the term there used is believed to include also brass and bronze. The prehistoric inhab itants of North America worked the native cop per deposits of the Lake Superior region. Specimens of metal-work of pure copper have been excavated at the ruins of Troy. Deposits of copper ore on the island of Cyprus were early mined and smelted by the Greeks, and, according to Homer. the combatants in the Trojan War had no other armor than that made of bronze, which is a /11 ixture of copper, tin, and zinc. The P,omans learned of it from the deposits in Cyprus, and it was originally called by them ws eyprium, Cyprian brass, a term which was subsequently shortened into cyffintn, and then cuprum. It was regarded as the metal specially sacred to Venus, and in the writings of alchemists it is designated by the symbol known as the looking glass of that goddess. Paracelsus and other early chemists believed that when iron precipi tates metallic copper from solutions of its salts, a transmutation of iron into copper takes place, and it was not until the seventeenth century that chemists recognized the elementary char acter of copper. Copper is found, either native or combined, in the following minerals: cuprite the red oxide) : tenorite (the black oxide) ; 01a/twit(' (sulphide) ; malachite (the green cop per carbonate) ; azurite (the blue copper carbon ate) ; chalcopyrite (copper and iron sulphide) ; borniie (black copper and iron sulphide). In addition to these, copper is found in many min erals of a more complex composition, such as ataca in i e, boltrnonitc, enargitc, tetrahcdritc, etc. It is also found in sea-water and in mineral waters, in seaweed, in the blood of various animals, in eggs, in flowers, in plants that live in soil containing copper, ete. Minerals contain ing copper have a wide distribution, Inn the chief sources of the world's supply are the United States, Spain. Germany, Japan, Australia, Mex ico, and Chile. Among these countries which together are responsible for 90 per cent. of the output, the United States stands far in the lead, contributing at present about 55 per cent., while Spain ranks second with little more than 10 per cent. of the total. The world's production of cop per increased from 269,615 long tons in 1890 to 487,993 long tons in 1000 The distribution of the output in the latter year is shown in the following table compiled for The Mineral In dustry: Copper-mining has long been carried on in the United States; deposits were worked in Con necticut, New Jersey, and Pennsylvania in the early part of the eighteenth century, and there are records of ore-shipments to England as early as 1731. The beginning of the industry in its
present importance, however. may be said to date from the opening of the Lake Superior dis trict in 1844. At this time the output of the whole country was inconsiderable, but increasing steadily as new mines were developed; it reached 10,000 long tons in 1S07 and 27.000 tons in 1880. Then, with the extension of railway facilities in the West, the rich deposits of Montana and Arizona became accessible for exploitation and quickly assumed a prominent place in the list of producers. The Lake Superior copper-mining district on the Upper Peninsula of Michigan is for its unique character as well as for its great commercial importance. The ore is native copper, carrying some silver, but with only small amounts of other impurities. It occurs as a cement, binding together or replacing the pebbles of a conglomerate, as a filling in an amyg,daloidal diabase, and as irregular masses in veins. The last-named deposits have yielded immense masses of copper, but, as the veins are irregular and of variable tenor, they cannot be worked at a profit when copper prices are low. The productive mines, at the present time. are located in the conglomerate or in the diabase. These deposits yield an ore averaging from six tenths to four per cent. copper. With the lower limit, which is reached in the Atlantic mine. the operations must lie conducted on a large scale and at a minimum of cost to yield a profit. The bo•nite, chalcopyrite. chalcocite, and other sul phides, carrying silver and some gold, occur as fissure veins in granite. Enormous quantities of ore averaging as high as 40 per cent. copper were discovered in some of the mines and resulted in the rapid development of the district. With depth there has been a gradual decrease in values, and the average at the present time is probably less than 5 per cent. The Anaconda Company for several years maintained an output of over 100,000,000 ponnds, and still ranks as the largest producer of copper in the world. Next in impor tance to the Lake Superior and Montana dis tricts are those in Arizona at Bisbee, Clifton, and Globe. The ores, here, are carbonates, oxides, and native copper. Their occurrence is limited to Carboniferous limestone and porphyry. The mining companies have the advantage of working a rich and easily smelted ore, but this is offset by the lack of water as well as of cheap fuel and transportation facilities. Besides the foregoing there are less important districts in California, Colorado, Utah, New Mexico, Tennessee, and Vermont.