PROGRESS OF THE PRECIOUS METAL INDUSTRY IN THE UNITED STATES SINCE 1880.
By S. F. Emmons.
A review of the conditions governing the production of gold and silver in the United States during the past decade is more difficult to make, and, at the best, necessarily more incomplete than that of any other of our mining products, for the reason that the United States Geological Survey was not allowed by Congress to include these metals in its annual investigation of the mineral resources of our country. The * Bureau of the Mint, which furnishes the most reliable data as to the aggregate production of these metals, is not so organized as to be able * to segregate these products by mining districts, or even by States, in a complete and accurate manner, nor to furnish such 'technical data as are necessary for an intelligent study of the underlying causes which have governed the variations in the product of these metals.
The reports of the Tenth and Eleventh Censuses show more or less completely the conditions of the mining industry of these metals for the respective years of which they treat, but dp not include the interme- diate period, nor has the latter Census attempted to continue the geological sketches of the most important mining districts which was inaugurated by the former.
While, therefore, it is manifestly impossible with the available data to give more than the most general outlines of the progress of these* industries, the qu-estion as to the relative future output of gold and silver is one of such paramount importance at the present time that it seems advisable to make an attempt to trace' the causes of their variation in the past decade as well as the imperfection of the data will. admit.
Gold is the only important metal that is found in great measure in the native or metallic state, and comparatively free from other metallic combinations. Silver, on the other hand, is almost universally found in nature more or less intimately combined with baser metals from which it must be separated by a relatively expensive process in order to be reduced to the metallic state. Gold, again, is largely produced from placer deposits detrital gravels and sands resulting from the disintegration of gold-bearing rocks and veins in which atmospheric agents have concentrated and prepared it for man's use, so that it can be extracted by simple processes requiring but little technical skill or 46