The quantity of these metals which is brought to market is very trifling, as they are not much sought after; as is also the case with iron, which exists in various parts of New Spain in great abundance, and under every form. Lead is chiefly found in New Leon, and New Santander; and in Mexico, antimony, zinc, and arsenic. Mercury is procured in Mexico and Guanaxuato, particularly at Chica, Celaya, and Zimapan: but the mines are insufficiently worked, the mercury for amalgamation coming entirely through Spain to the northern colonies of Spanish America. Coal exists in New Mexico; and salt is yielded from the lakes of the Mexican plains; diamonds, topazes, emeralds, and other gems; asphalt, amber, jasper, alabaster, and the magnet, are produced in New Spain. The affairs of the mining interest are directed by a council-general; on this council, which has a president, the thirty-seven districts depend. The mines are wholly the property of individuals; their councils are only erected to judge of the affairs relating to the payment of the duties, and to the general ordering of the undertakings. At Mexico there is a college of mining, where young men are educated by the government, to instruct them in all the branches of science necessary to be attained, in order that the mines may be worked in the best manner. The council-general receives a tithe on all metals, and with this, the salaries of the members, the expences of the college, and advances to undertakers, are paid. RIVERS.--New Spain does not contain such extensive and majestic rivers as are to be found in her sister colonies of the south; nevertheless some of the streams are by no means inconsiderable; the _Rio Bravo del Norte_, and the _Rio Colorado_, roll a vast body of water to the Atlantic and Pacific oceans. The Rio Bravo rises in the Sierra Verde, near the northern boundaries of the kingdom; this noble river, after various intricate windings, and watering a tract of country, inhabited principally by the aborigines, loses itself in the Gulf of Mexico, having performed a course of nearly two thousand miles; which immense length of river is obstructed by cataracts in the mountainous country of the interior, and by bars of sand in the flat and marshy lands towards the sea coast; canoes navigate, however, a surprising distance up the stream. The Rio Colorado rises in the same mountains, and nearly in the same latitude; but on the opposite side to the sources of the Rio del Norte, and running through a country either waste or inhabited only by the Indians, empties itself into the upper extremity of the Gulf of California, by a large estuary, after a course of a thousand miles; canoes navigate this river for three hundred miles from its mouth. The other rivers of New Spain which are of the greatest importance, are the Mexicana, Arighitas, Flores, Trinidad, Colorado de Texas, Medina or San Josef, Magdalena or Rio Guadalupe, the Nueces, the Gila near the Great Colorado, and almost equalling it