From 1864 to 1867, the aggregate production of gold in the world was, according to the last mentioned authority, a yearly average of 188.4 millions of thalers, and of silver, 94.8 millions. In Europe, Russia not included, the production was, in 1863, 3,960 pounds of gold and 405,000 pounds of silver; in the Russian Empire, 46,500 pounds of gold and 40,000 of silver; in Mexico 12,000 pounds of gold and 1,250,000 pounds of silver; in South and Central America, 12,500 pounds of gold and 520,000 pounds of silver; in Africa, India and Lesser Asia, 30,000 pounds of gold and 40,000 pounds of silver—a total of 384,000 pounds of gold, and 2,905,000 pounds of silver. F.X. Neumann(861)(862) estimates that the whole world produced, in the years 1868-1870, annually, 192.8 million thalers of gold, and 94 million thalers of silver; and in 1873, of both metals, 291 million thalers. The question, whether in this second half of the nineteenth century, we are to have a revolution in prices similar to that which took place in the sixteenth century can be answered only hypothetically. The gold diggings now most productive will, probably, as we may judge from analogous cases in the past, be soon exhausted.(863) But it is entirely possible that, for a long series of years, other diggings will be found equally rich. It is almost certain that the restless activity of the English and of North Americans will not cease until they have exhausted the favors of nature.(864) Every improvement in agriculture, in the means of communication, and in the public security of the gold lands, makes the cost of production smaller. There are doubtless in other countries a great many _placers_ which need only to be touched with the finger of European civilization to produce gold in abundance.(865) It would, indeed, be necessary that this same civilization should make these same countries better markets for the precious metals by increasing their demand. So far as silver is concerned, there can be no question that America possesses mines unlimited in extent, and, as yet, almost untouched. “The time will come,” says Duport,(866) “a century sooner or later, when the production of silver will have no other limits than those put to it by the continual decline in the price of silver.” There seems, also, to be no lack of quicksilver, especially in California; and the cost of its production hitherto may be lessened very much by the labor of better workmen, machines and means of transportation.(867) All this supposes great progress of the mining countries in civilization in general; and yet, thus far, Mexico’s republican independence etc., as compared with the later years of the Spanish colonial system there, is a great retrogression. The conquest of Spanish America by the United States would give a vast impetus to economic improvement; and here, again, the increase of production would be attended by an increased demand.