ANDES. This immense American mountain chain is one of the richest mineral storehouses on the globe. Pumice-stone is found to a great extent in many of the volcanoes of the Andes ; and volcanic-tuff, which is a stone more or less compact, made up of fragments of hard lava, cinders, and ashes, agglutinated together, covers immense tracts on the flanks of the Andes and on the table-lands. Stone of every description is met with—a storehouse of material ready for the time when menu factures and the arts of civilized life shall find a home in these regions. But it is in metals that the Andes are so especially rich. These mountains have been celebrated for their mines of metal since our earliest know ledge of America. Gold, silver, mercury, pla tina, copper, and tin, are met with. Gold is found in the form of grains and small rounded lumps, scattered through alluvial soils, which have been derived from the disintegration of rocks containing the metal, and most proba bly in the form of slender veins. The places chosen for digging into that auriferous soil are called lavaderos, because the gravel, sand, and earth, undergo repeated washings to sepa rate the heavy particles of gold. The most considerable gold mines are at Petorea, Co quimbo, Copiapo, Pataz, Huailas, Curirnayo, Zorata, Antioquia, Choco, and Barbacoas.
Silver is more abundant in the Peruvian than in the China]] Andes. The richest mines are those of Pasco, in 11° S. let., which have been worked since the year 1630. Here, as well as in other situations in Peru, the greatest part of the silver is obtained from an ore called in the countrypacos, which is an intimate mixture of minute particles of native silver with brown oxide of iron. The mines of Chota are also very productive. They are situated in the mountain of Gualgayoc, at an elevation of 13,300 feet, where the thermometer in sum mer descends every night to the freezing point. The ore lies immediately beneath the surface. But the most celebrated are the silver mines ofPotosi, in a lofty mountain. This mountain
is perforated in all directions, and it is said that there are not less than 5000 excavations in it, some of them within 120 feet of the top, which is 16,000 feet above the sea-level.
Mercury, in the form of cinnabar or sill phuret of the metal, is met with at Azogue and other parts of the Andes ; but the most celebrated, those of Guancavclica, were over whelmed by incautious mining in 1789. Pla tine is met with in small quantities in Colom bia. Copper and tin are found in the Chilian Andes.
In respect to the commerce of the Andes, little has yet been effected. The passes be tween the lofty peaks are few in number ; and the routes by which the gold and other mining produce reach the ports of shipment are most inefficient. The distance to the Atlantic is in most cases too great to admit of the transfer in this direction : the Pacific ports are for the most part, selected.
In a recent number of the Join•nal of the Franklin Institute, a description is given of a small steam-boat just built at New York for the Andes region. It is 55 feet keel, 12 feet beam, and 5 feet depth of hold. It is to be propelled by two high-pressure engines, of 10-horse power each ; with iron paddle-wheels 10 feet in diameter. It is built in separate pieces, all carefully marked and fitted ; and for the convenience of carriage, no piece ex ceeds 3501bs. weight. It is to be taken by ship to Lima, and the pieces transported on the backs of mules to Lake Titicata, one of the highest lakes on the surface of the globe, in the midst of the Andes. The lake is 140 miles long, and the shores are well timbered; and it is expected that much traffic and com merce will ensue from the establishment of steam navigation there. The pieces of the vessel will be fitted together on the shores of the lake ; and if the enterprise succeeds, a larger steamer will be sent out in a similar manner. The surface of Lake Titicata is no less than 12,795 feet above the level of the Pacific ; and some parts are nearly 1000 feet deep.