Page:The New International Encyclopædia 1st ed. v. 18.djvu/220

* SILVER. 176 SILVER. yield of silver, are now worked mainly for other metals. The annual production of silver in the United States has increased steadily from an average of about 600 kilograms in 1834. to nearly 2,000,000 kilograms in 1892 — the aggregate reported pro- duction during this period being approximately 85,000,000 kg. Of this the famous Comstock lode in Xevada produced approximately 5,000,000 kg. during the period from 1859, the year of its discovery, until 1891 ; the value of the gold pro- duced with the silver at the Comstock mines amounted to more than $140,000,000 in value. Classified by States, the production of silver in the United States during 1900 was: Colorado, 20,3.36,712 ounces (derived chiefly from the lead, copper, and gold ores of Lake, Pitkin, Jlineral, Ouray, Clear Creek, and San Miguel counties) ; Montana, 17,300,000 ounces (chiefly from argen- tiferous copper ores of Butte) ; Utah, 9,569,183 ounces; Idaho, 6,100,000 ounces (from argentif- erous lead ores of the Coeur d'Alene district) ; Arizona, 1,750,000 ounces: California, 1,170,902 ounces ; other States, 3,335,000, making a total of 59,561,797 troy ounces. workable metals. For the production of silver and its use as money, see Money; Precious Metals. The world's production of silver and the ratio of silver to gold since 1492 are given in the fol- lowing table, compiled from statistics collected by Adolf Soetbeer and the United States Mint: World's Phodbction of Silveb The Pbodoction of Silver IN THE World in 1901 • COUNTRIES Ounces, troy Kilograms Commercial value, 58.95c. per oz. North .imerica: United States. .. 65,215.253 6.078.318 55,152.340 1.072.095 383.561 9.439.294 6.772.789 2,520,000 84.818 6,655,257 1,292.631 727,770 384.076 6.522.802 1.100.754 1.043,750 164,935 167.057 3.053.606 50.059 480.400 174.431 73.690 1,895,398 10,848,420 48,226 1,717,372.8 157,952.1 1,715.416.0 33.345.6 11.930.0 293,591.4 179.552.4 78.380.1 2.638.1 207,000.0 40,205.0 22,636.0 11,946 171,777.0 34,237.0 32.464.0 5.130.0 488.6 94,977 1,567 14,942 5,426 2.292.0 58.953.0 337,420.9 1,500.0 $32..549.342 2.993 668 32,512,304 Central America South America: 632,000 226,109 Bolivia 6,564,464 Chile 3,403,059 Colombia 1,485.540 50,000 Peru 3,923,274 Europe: Austria 762,006 429.020 226.413 Germany 3.435.540 648,904 Italy 683,209 97,229 Russia 92.585 Spain 2,000.301 29.510 283,196 Unit'd Kingdom Asia: Dutch B. Indies. 102,839 43.440 1.117,337 Australasia Other countries. 6,396,144 28.429 Total 168,391,730 5,237,129.4 599,714,862 It is difficult, if not impossible, to forecast with any reasonable degree of accuracy the fu- ture production of silver in the world. A large part of the output is obtained as a by-product in the treatment of certain copper, lead, and gold ores, consequently the total output of silver, to some extent, will go hand in hand with the increased or decreased output of these metals ; yet any very marked increase from these sources may cause the price of silver to decline to such an extent as to render unprofitable its direct ex- traction from ores that do not contain other period Mean annual product. kilograms Ratio of silver to gold, weight Ratio ot, gold to' silver. value 1493-1520 47.000 90.200 311,600 299,600 418,900 422,900 393,600 366,300 337,000 341,900 355,600 431,200 633,146 652.740 879.060 894,150 540,770 460,560 596,460 780,415 886,115 904,990 1,101,150 1,339.085 1,969.425 2.323.779 2.388,612 2,551,364 2,507,607 2,479,998 2,592,639 2,769,065 2,746,123 2.788,727 2,993.805 2,902,471 2,990,398 3,385.606 3.820.002 4,144,233 4,493,100 4.730.647 5,147,841 5,121,017 5.210.942 5.232.021 5.696.110 5.269,286 6.213.312 6,337.008 8.1 12.6 36.6 43.8 56.8 49.6 47.4 41.8 36.4 31.8 27.7 22.6 21.7 31.6 49.4 50.3 47.2 32.4 29.4 14.3 4.4 4.6 5.9 6.9 11.3 14.0 13.3 13.7 15.0 15.2 16.3 18.6 19.0 18.2 18.8 18.2 18.8 21.2 21.0 23.1 23,6 30.2 21.7 18.7 17.4 17.2 15.9 12.2 11.3 13.9 10.75 1521-1544 11.25 1545-1560 11.30 15C1-15S0 11.50 1581-1600 . . . 11.80 1601-1620 12.25 1621-1640 .. 14.00 145.0 1641-1660 1661-1080 . . .. 1 975 1681-1700 15.00 1701-1720 14.21 1721-1740 15.08 1741-1760 14.75 1761-1780 14.73 1781-1800 15.09 1801-1810.., 1811-1820 15.61 16.61 1821-1830 15 80 1831- 1840 15.75 1841-1S50 15.83 1851-1855 15.41 1866-1860 1861-1865 15.41 1866-1870 15.66 1871 1875 15.98 1876 17.88 1877 17 22 1878 17.94 1879 18.40 1880 18.05 1881 18.25 1882 18.20 18S3 18.64 1884 18.61 1885 19 40 1886 20.78 1887 21.10 1888 22 00 1889 22 10 1890 19.76 1891 20 92 1892 23 72 1893 26 49 1894 32.56 1895 31 60 1896 30.69 1897 34.20 1898 36.03 1899 34.36 1900 33.33 METALLURGY. The variety of processes for the extraction of silver from its ores is so great that only a gen- eral review of the most important is possible here. In all cases the silver is at last obtained in union with lead, zinc, copper, or mercury, or in solution from which it can be precipitated as metal or as sulphide or chloride, or el.se it is separated by electrolysis from its combinations. The methods of extraction thus fall into three main groups as follows: dry processes, com- bined dry and wet processes, and electrolytic processes. Dry Processes, The extraction of silver in the dry way is effected by converting the metal into a silver-lead alloy and then submitting this to an oxidizing melting in the cupellation fur- nace. The production of the silver-lead alloy depends upon the power which lead possesses of extracting silver from its ores or from various products containing it, the lead readily alloying
 * From The Mineral Industry, vol. x., 1902.