SILVER.

In 1880 the United States produced 30,300,000 ounces of silver, valued at $34,700,000. The production has gradually increased until in 1914 the total amount produced, the largest ever recorded, was 72,400,000 ounces, valued at $40,000,000. The silver production of the world is estimated as about 225,000,000 fine ounces, of which the United States produces one-third. Practically three-fourths of the world's silver production is derived from North America, about 14 per cent from Europe, and the remainder mainly from Australia and Asia. The imports of silver in 1914 contained in foreign ore and base bullion amounted to approximately $26,000,000, while exports for the same period amounted to $51,600,000. The majority of the exports were to Europe, China, and India. The United States produces so much more silver than the domestic arts and sciences can assimilate that the price is largely regulated by the foreign demand. There is every reason to believe that the United States will continue to retain its position as the largest producer of silver and have a large surplus for exports. Twenty-five States produced silver in 1914. Nevada produced 15,900,000 ounces, mainly from the siliceous ores of the Tonopah district; Idaho 12,600,000 ounces, mainly from the Coeur d'Alene lead and lead-silver ore; Montana, 12,500,000 ounces, mainly from Butte copper ores; Utah, 11,700,000 ounces, mainly from copper and lead ores; Colorado, 8,804,400 ounces, mainly from siliceous and lead ores; and Arizona, 4,439,500 ounces, mainly from siliceous and copper ores. Almost 40 per cent of the silver produced in the United States is derived from siliceous (quartz) or dry ores, 21 per cent from copper ores, 28 per cent from lead ores, and 10 per cent from leadzinc ores. High prices for copper and lead will have a tendency to increase the yield of silver which is recovered as a by-product.

The cyanide process applied to Tonopah ores and to those of other districts has permitted the treatment of lower-grade ores which otherwise could not profitably have been shipped to smelters. In 1911 about 14 per cent of the United States silver was recovered by cyanidation and in 1914 over 22 per cent. Experiments are being conducted under the direction of the department for perfecting details and cheapening the cost of treatment to make the process more widely applicable.

Vast quantities of low-grade complex ores carrying silver with lead, copper, or zinc are now unworked in the metal-mining States of the West because of the lack of processes by which the metals can be recovered at a profit. Investigations are in progress under the direction of the department to determine the extent of these ores and the possibility of developing processes for treating them profitably, thus greatly enlarging the available supply of silver-bearing ores.

PLATINUM.

In 1914 the United States produced 570 ounces of crude or 525 ounces of refined platinum from placer sands and 110 ounces from deep mines. In 1880 the total output was 100 ounces of crude platinum from placers. In all 3,430 ounces of refined platinum were recovered in 1914 from the electrolytic refining of gold bullion, platinum sands, and copper matte, of which probably 2,500 ounces came from domestic sources.

During 1914 about 70,000 ounces of platinum, having a value of $2,908,000, were imported into the United States. This was about 42 per cent below the 1913 imports and indicates the extent to which the world is dependent on Russia for platinum. The United States has never been an exporter of platinum. Russia produces about 90 per cent of the platinum of the world, and Colombia, South America, the next largest producer, about 6 per cent.

Within the last year English capitalists have given considerable attention to the Colombian platinum fields on the Condote, San Juan, and Atrato Rivers, in the Choco district, and some American capital is turning in that direction. With the Panama Canal an accomplished fact, and the many platinum refineries on our eastern seaboard, it does not seem reasonable that much of the crude platinum from Colombia will be taken to Europe for refining. The development of Colombian fields would be a boon to this country.

The placer fields of northern California and southwestern Oregon constitute the largest source of crude platinum in the United States, and it seems probable that they will continue to prove our most reliable source of this metal, because, as has been repeatedly shown, the quantity of platinum ordinarily found in veins is too small to be of commercial value. However, in the United States we have at least three places where enough platinum occurs in the rocks to offer possibilities for production. These are the Rambler mine in Albany County, Wyo.; the Boss mine and near-by properties in the Yellow Pine district, Clark County, Nev.; and the Great Eastern mine, about 25 miles northeast of Moapa, Clark County, Nev.

The platinum recovered by gold and copper refiners occurs in the original ores in such minute quantities that it is rarely determined in assaying. Only the immense tonnages of gold, copper, and silver ores treated annually render the platinum content of importance. Our output of this by-product platinum, as it may well be called, depends entirely on the production of the other metals, particularly copper, with which platinum seems to be most often associated.

Probably one of the most important uses of platinum in this country at the present time is in the manufacture of "fuming" sul

phuric acid and sulphur trioxide, materials that are practically indispensable to the makers of high explosives and aniline colors. It is not possible to estimate the quantity of platinum tied up in the manufacture of sulphur trioxide, but the loss of platinum in the industry undoubtedly is very small. Should the price of platinum prohibit its use, sulphuric acid manufacturers could still make the fuming acid by substituting iron oxide for platinum.

In former years platinum was considered essential in electrical work where it is now replaced by "nichrome" and other alloys or metallic molybdenum and tungsten. In dental work, platinum plating gives as satisfactory results as the pure platinum formerly much used.

Probably our greatest economic waste of platinum at present is its increasing use as a setting for precious stones, but platinum settings may go out of style at any time and the platinum come back into the market. A large quantity of platinum is also tied up in the form of utensils in the various chemical laboratories throughout the United States.

Our domestic supply of platinum is entirely inadequate to meet present uses, but if these uses were cut to the essentials, it is believed that the United States could be independent of the world for some time. The western placer miners are realizing the practicability of saving the platinum as well as the gold, and new devices on gold dredges are saving much more of the platinum than those used heretofore. Further improvements seem likely.

The waste of such a valuable metal as platinum is very small, once the metal is on the market. It may be overlooked in placer mining, but in metallurgy it is not, as is shown by the large recoveries made by gold and copper refiners. The amount of scrap platinum handled during 1914, amounting to 40,500 ounces-more than 16 times our domestic production-shows the economy practiced in the use of this metal. Sweepings from jewelry manufacturing and dental establishments and scraps from every conceivable source that might contain platinum are refined and the metal recovered.

At the present time the United States Geological Survey and the Federal Bureau of Mines are cooperating in a general study of the placer deposits of the United States. This study is giving new information as to the places where platinum occurs and the best methods for its recovery.

QUICKSILVER (MERCURY).

The annual production of quicksilver in the United States is approximately 20,000 flasks of 75 pounds each, a total of 1,500,000 pounds, representing a total value of $800,000. During 1914 the

United States imported 615,000 pounds, largely from Italy, Austria, and England. The exports amounted to 108,000 pounds, mostly to South America, Canada, and France.

The chief producing districts in the United States are in California, that State yielding over two-thirds of the entire output. Texas, Nevada, and Arizona are small producers. Quicksilver is also found in Alaska, Washington, Oregon, and Utah, but many of these deposits have not been thoroughly prospected and developed.

The principal uses of quicksilver are in the manufacture of fulminate, in making electric appliances and in the milling of gold and silver ores. The quantity of quicksilver used for the latter purpose is much less than formerly because of the growing use of the cyanide process. Consequently more quicksilver is available for use in the manufacture of explosive caps and electrical appliances. More than 30 per cent of the gold mined in the United States is recovered by cyanidation, and only about 21 per cent by amalgamation, the total amount of quicksilver used for the purpose amounting to only 700 or 800 flasks a year.

The United States supply of quicksilver is ample for domestic use under normal conditions, and the increased use of wet processes for the extraction of gold leaves still more of the original supply available for other purposes.

BASE METALS.

IRON ORE AND PIG IRON.

In 1880 about 7,000,000 long tons of iron ore, valued at $17,500,000, were mined in the United States, as compared with 60,000,000 tons in 1913, valued at about $130,000,000. The production of pig iron increased in the same period from less than 4,000,000 tons to more than 30,000,000 tons, the value of which in 1913 exceeded $458,000,000. The United States leads the world in the production of these commodities, iron ore and pig iron, and produces annually about 40 per cent of the world's supply of iron. This is shown graphically in fig. 2.

Comparatively little iron ore is imported into the United Statesless than one-half of 1 per cent of the quantity annually mined. Moreover, the exports of iron ore from the United States nearly offset the imports, so that the United States is self-sufficient so far as the production of iron ore is concerned. Such ore as is imported comes mainly from Cuba, Sweden, Newfoundland, Canada, Spain, and Chile. It is possible to import high-grade iron ores, such as are received from the above countries, for use along the Atlantic seaboard when ocean freights are low and there is no tariff on the ore. Even under these favorable conditions, however, foreign ore rarely gets beyond the tidewater furnaces.

The United States is abundantly supplied with iron ore, yet there are excellent arguments in favor of encouraging imports of ore from Cuba and South America. Iron ore forms the basis of the largest manufacturing industry in the United States. The profits to both labor and capital are made from the manufacture and sale of iron and steel products rather than from iron ore mining, therefore, so long as the United States can utilize the cheap ores from Latin America and export to those countries as well as to Europe the fabricated iron and steel goods, there is reason to favor the continuance of these conditions. Moreover, since there is little good coal near the largest deposits of iron ore in South America it may never be feasible to establish the manufacture of iron there. The iron ore of that continent will find a market either in Europe or in the

TONS 30,966,152

19,004,022 10,481,917 5,227,378 4,474,757 2,335,170 2,318,767 1,015,118 2,203,588 FIG. 2.-World's production of pig iron in 1913.

United States, therefore, whatever is commercially available to the United States should serve a double purpose if sold here, viz., in increasing trade between the United States and South America and in conserving the ore supplies of the United States.

So far as exports of either iron ore or pig iron from the United States are concerned there is little reason for their encouragement. Twenty-eight States are regular producers of iron ore and several others contain deposits of potential value.

The States in which iron ore occur may be conveniently grouped into six geographic divisions, namely:

1. Northeastern States.-Massachusetts, Connecticut, New York, New Jersey, Pennsylvania, and Ohio.

2. Southeastern States.-Maryland, the Virginias, Kentucky, Tennessee, North Carolina, Georgia, and Alabama.

3. Lake Superior States.-Michigan, Wisconsin, and Minnesota. 4. Mississippi Valley States.-Iowa, Mississippi, Missouri, Arkansas, and Texas.