The gulf of Mexico, the bay of Honduras on the eastern side, the Pacific on the western, with the immense inlet or sea of California, afford to this rich and fertile viceroyalty the favourable opportunities for the most extensive commerce, were it not that it is greatly impeded by the want of numerous roads across the elevated land of the interior; these, however, are gradually opening; and in proportion as the Spaniards exert themselves in forming them, so will the commerce of Mexico increase in value above that of the neighbouring continental states, with whom, at present, it is, for this cause alone, unable to enter into competition. The distance in some parts of New Spain, from ocean to ocean is very inconsiderable; and some rivers which run from opposite sides of the same mountain approach so near, at their sources, to each other, as to offer to an enterprising people every facility for internal navigation; at present, the commerce of these colonies is tardily carried on from the coasts of the Pacific, to those of the Atlantic by means of mules, which travel in cavalcades along the roads crossing the chain, or by Indians carrying burdens on their backs.
The commerce of New Spain centres chiefly at the port of Acapulco in the Pacific, to which the vessels from Manilla bring the productions of the East Indies, which, with the commercial articles of the country itself, are transported over the mountains to Vera Cruz, the Atlantic port, from whence they proceed to the Havannah, and to Europe. We have related what the vegetable and animal kingdoms chiefly furnish towards this trade; it now remains to state the share which the mineral kingdom affords. New Spain is probably richer in productions of this nature than any other country of the world; but for want of the mechanical means which are so extensively employed in raising the metals of Europe, the produce of the Mexican mines, as well as of all those of the New World, is not so great as has been usually imagined, many of the richest veins having been abandoned (after enormous expences and labour employed in opening them), on account of water gaining on the operations of the miners. That useful and surprising instrument the steam-engine, requires to be introduced generally into the mining system of the Americans, before any great accumulations of the precious and useful metals can be had on that continent; then also will the terrible labour of those unfortunate people, who carry on their backs, in baskets, from the depths of these heated caverns, the ores which are there discovered, to the surface, be discontinued; the human race will sensibly increase, and the sterile wastes and thick forests will give way to the arts of agriculture.
The mining stations of gold and silver in New Spain amount to more than 450. They are divided into thirty-seven districts, each governed by a council of the mines. Humboldt supposes that near three thousand actual mines exist in these 450 stations. The principal and most valuable are those of the provinces of Guanaxuato, Zacatecas, San Luis Potosi, Mexico, Guadalaxara, Durango, Sonora, Valladolid, Oaxaca, Puebla, Vera Cruz, and Old California. The veins exist mostly in primitive and transition rocks, and the richest silver veins, which are single, run to an amazing breadth and length; the poorest are those in which the silver is dispersed in small and numerous ramifications. The best and most productive of the silver mines of New Spain, are situated at a height of from 5900 to 9840 feet above the level of the sea, and there are three which supply more than half as much again as all the rest put together; these are the mines of Guanaxuato, Catorce, and Zacatecas. The quantity of silver exported from New Spain to Europe and India, per annum, is about one million six hundred and fifty thousand pounds in weight. After the three above mentioned, the mines of Real del Monte, Tasco, and Zimapan in Mexico; Guarisamez, Batopilas, and Parral in Durango; Bolaños in Guadalaxara; Sombrerete and Fresnillo in Zacatecas and Ramos in San Luis Potosi, are those which afford the greatest quantity of ore.
Gold is generally procured in the sands of torrents by washings. It is produced abundantly in Sonora, where it is found in the alluvious grounds; in the sands of Hiaqui and in Pimeria, where grains of very large size have been discovered. It is also procured from the mines of Oaxaca in veins, as well as in most of the silver mines, mixed with the silver, crystallized, in plates, &c. The produce of gold in New Spain is stated to amount, in the most favourable seasons, to a million of piastres, or 218,333l. sterling; the produce of silver at twenty-two millions of piastres, is 4,812,500l. sterling.
Native silver is sometimes found in great masses in the mines of Batopilas, as well as in some others.
The mines of Guanaxuato, of which the most celebrated is the one named Valenciana, are said to produce double the quantity of gold and silver to that of the celebrated Potosi in South America. In this mine the great vein is twenty-two feet in breadth; and, as the chasm is entirely dry, it is easier worked than almost any other American mine. The pits extend to the breadth of 4900 feet, and the lowest is 1640 feet in depth. The undertaking employs upwards of 900 men in carrying the ores to the surface up the stairs on their backs, 1800 workmen in procuring and sorting the ore, with 400 women and children, carrying the minerals to the sorters; the total expences of the materials, workmen, overseers, &c., is above 187,500l. sterling per annum, and the net profit, during the same period, to the proprietors, after deductions of the kingʼs fifth, and all expences, is from 82,500l. to 123,759l. per annum.
The mine of Sombrerete in Zacatecas yielded in one year a profit of above 833,400l. sterling to its proprietor. In San Luis Potosi, the mine of La Purissima Catorce yields annually to its owners a profit of upwards of 43,700l. sterling. The others we have mentioned, as being the richest, yield immense revenues to their holders and to the government.
In these rich mines the miners and labourers contrive occasionally to steal the valuable metals. They, however, undergo a very rigorous search on leaving the pit; nevertheless, like the Indians in the diamond mines of Golconda, they frequently are adroit enough to secrete the ores, notwithstanding many of them go nearly naked. The greater part of the silver is procured by the means of mercury from the ores, smelting being not much used for want of fuel: the quantity of mercury used in the process of amalgamation is estimated at upwards of two millions one hundred pounds troy weight.
Copper, of which the ancient Mexicans made their tools, is found both native and in the mines of Valladolid; as well as in those of New Mexico.