With respect to the silver-mines, it is stated, on competent authority, that the northern States of Mexico are very rich in silver; but there is scarcely any population, and that consisting mostly of Red Indians who will not work. When this district becomes a territory of the United States—as seems almost certain, this silver will, no doubt, be worked. We may make three periods in the history of Mexican silver-mining. Before the Conquest, the Aztecs worked the silver-ore at Tasco and other places; and were very familiar with silver, though they did not value it much. Under the Spaniards, the working of silver became the prominent industry of the country; and, until the Mexican Independence, the production steadily increased. The Spaniards invented amalgamation by the _patio_-process, a most, important improvement. Then came above twenty years of confusion, when little was done. But when the Republic had fairly got under way, and the country was in some measure open to foreigners, Europe, especially England, in hot haste to take advantage of the opportunity, sent over engineers and machinery, and great sums of money, much of which was quite wasted, to the hopeless ruin of a great part of the adventurers. The improvements and the machinery remained, however; and the mines passed into other hands. Of late years the companies have been doing very well, and now export nearly as much silver as during the latter years of the Spanish government—nearly, but not quite. The financial history of the Real del Monte Company is worth putting down. The original English company spent nearly one million sterling on it, without getting any dividend. They sold it to two or three Mexicans for about twenty-seven thousand pounds, and the Mexicans spent eighty thousand more on it, and then began to make profits. The annual profit is now some £200,000. I have said that the modern Mexican Indian has but little idea of arithmetic. This was not the case with his ancestors, who had a curious notation, serving for the highest numbers. The Indians of the present day use the old Aztec numerals, and from these there is something to be learnt.