TABLE PAGE I. The Production of Copper, 15 II. North American Production of Copper, 17 III. Influence of Impurities on the Electrical Conductivity of Copper, 23 IV. Analysis of Various Commercial Coppers, 44 V. Development in Size of the Reverberatory Furnace, 89 VI. Daily Reports. Reverberatory Furnaces, 102 VII. Daily Assay Report. Reverberatory Furnaces, 103 VIII. Monthly Report. Reverberatory Furnaces, 104 IX. Effect on Coke Consumption of Increased Sulphur in the Furnace Charge, 120 X. Blast-Furnace Charge Calculations, 151 XI. Typical Charging Tables at Pyritic Smelter, 187 XII. Changes in Composition during Bessemerising, 206 COPPER SMELTING. LECTURE I. History of Copper — Development of the Copper Industry — Progress of Smelting Practice — Price and Cost of Production of Copper — Copper Statistics. =The History of Copper.=—Copper was probably the earliest metal commonly employed by mankind. It occurs in the native condition in various parts of the world, and the natural product thus required no metallurgical treatment prior to use. Its malleability and the property of being readily toughened by simple mechanical treatment were also factors which account for the discovery of its general usefulness in such primitive times. Although silver and gold were possibly known even earlier, these metals appear to have been employed chiefly for ornamental purposes, and as tokens, rather than for general service. The alloy of copper and tin, known as bronze, was the first metallic combination in common use by man; its employment was so characteristic in prehistoric times, that archæologists assign to one of the epochs the name of the Bronze Age. As is well known, archæological time is marked by a series of ages, in which the use, first of stone, then of bronze, and ultimately of iron for the manufacture of tools and implements, indicate the development of industrial culture. The dates which can be assigned to those periods vary with the locality; the races in the more Northerly latitudes being later in their development. In our own country, the Stone Ages may be said to date from 3000 B.C. down to 1000 B.C., and the Early and Late Bronze Ages from 1000 B.C. to 500 B.C., and from 500 B.C. to the commencement of the present era, respectively.