Mining and Pro Duction Silver Metallurgy

Production.

The most ancient silver mines of importance known to history were those in Asia Minor and on islands in the Aegean Sea. The deposits of silver-lead ore at Hissarlik in the Troad were worked probably as early as 2500 B.c. and lasted for many centuries, and the Greek mines at Laurium, also of silver lead, were known in 100o B.C. The Romans obtained most of their silver from Spain, but in the middle ages the supplies which had previously been plentiful became scarce, as production was small and the stocks gradually disappeared. The scarcity came to an end with the discovery of America, which has given the rest of the world a large and ever increasing supply of silver. The following estimates of production are those given in the Annual Reports of the Director of the United States Mint. The statistics for the period 1493-1885 were compiled by Dr. Adolf Soetbeer, and from 1886 onward the estimates were made by the United States Mint. Between 1493 and 1520 the average annual production of the world was 1,511,00o oz. troy of fine silver. The output then rose until in 1545-60 the annual average was 10,018,000 oz., but a lull followed up to about the year 1700, during which production was almost stationary. In the period 1701-10 the average was 11,432,500 oz. per annum and the production then rose gradually until in 1801–io it was oz. per annum. The Wars of Independence of the Spanish colonies of America disorganized the mining industry, and production fell so that in 1821-30 the aver age was only 14,807,000 oz. Thereafter the rise was almost con tinuous until in 1900 it was 173,591,000 oz.

The annual production of the world from mines since 1901 is given below in units of i,000 oz. fine.

About two-thirds of the world's supply is derived from Mexico and the United States. The Mexican mines first sent supplies to Europe in the 16th century and during the years 1781-1800 yielded two-thirds of the world's production. After a period of less activity owing to civil war, Mexico was again the leading pro ducer in 1924-27. The United States became a large producer about 1860, and was first among the countries during most of the next 4o years. Its production was 116,019 oz. in 186o; 1,546,920 oz. in 1861; 22,254,002 oz. in 1872 and 54,647,00o oz. in 1900, but

the production is no longer increasing. Canada produced little until late in the i9th century, but South America has sent supplies to Europe since the discovery of the Potosi mines in Peru in 1533. In Europe, Germany and Spain are the most important producers. The German mines were worked in the loth century and at the beginning of the i6th century the production was over 400,000 oz. annually. In 1905 the output was 12,535,238 OZ. but declined later. In Spain the mines were neglected in the i6th century ow ing to the plentiful supplies from America, but production was revived in the i9th century. The output in Asia is chiefly from India and Japan. Australia became noticeable after the dis coveries at Broken Hill, New South Wales, where 36,6o8 oz. were produced in 1885 and 7,727,877 oz. in 1890. The silver in Africa is mainly derived from the gold bullion of the Transvaal.

The production by countries is given in the Report of the direc tor of the United States Mint as follows, in units of i,000 oz. fine.

The silver produced in the world is in great part exported to India and China. The net amounts sent to these countries, taken together, averaged about 87,000,000 oz. per annum in the years 1910-24 according to the figures published by the London dealers in bullion. The Report of the Director of the United States Mint gives the following figures of coinages and consumption, in thousands of fine ounces.

tion of the ores of silver; W. Gowland, Metallurgy of the Non Ferrous Metals (1914), and D. M. Liddell, Handbook of Non-Ferrous Metallurgy contain technical accounts of the metallurgy of silver; see also Annual Reports of the Director of the Mint (Washington, 188o, foll.) ; and B. White, Silver: Its History and Romance (Igi7), a popular treatise. (T. K. R.; X.) (Elaeagnus argentea), a North American shrub of the oleaster family (Elaeagnaceae), found from Quebec to Hudson bay and British Columbia, south to Minnesota and Utah. It grows from 6 to 12 ft. high, with silvery-scurfy leaves and numerous fragrant flowers, pale yellow within and silvery without, borne in the leaf-axils, and round-ovoid, olive-like silvery fruit, with a mealy edible fleshy portion enclosing a grooved nut.