extent, and left a fortune to his children, which has only been equalled in Mexico, by that of the Count de la Valenciana. The level of Moran traverses the vein of la Biscaina, in the San Ramon shaft, at a depth of 210 metres*, below the level of the surface, on which the baritels à chevaux are placed. The profit of the proprietor has been annually diminishing since 1774. In place of cutting galleries of investigation, to discover the vein on a great extent, they continued their sinking operations to a depth of 97 metres below the level. At that depth, the vein preserved its great wealth in sulphuret of silver, mixed with native silver, but the abundance of water increased to such a degree, that 28 baritels, each of which required more than 40 horses, were not sufficient to draw it off. In 1783, the weekly expence amounted to 45,000 francs. After the death of the old Count de Regla, the works were suspended till 1791, when they ventured to re-establish all the baritels. The expence of these machines which drew up the water, not by means of pumps, but by bags suspended by ropes, then amounted to more than 750,000 francs per annum.§ At length they reached * 688 feet. Trans. 1875 Sterling. Trans. the deepest point of the mine, which according to my measurements* is only 324 metrest above the level of the lake of Zumpango; but the ores which they extracted did not compensate the expence of the process, and the mine was again abandoned in 1801. It is surprising that they never thought of substituting to this wretched plan of drawing off the water by bags, proper pump apparatus, put in motion by horse baritels, by hydraulical wheels, or by machines moved by a column of water (colonne d'eau). A level begun at Pachuca, or lower down towards Gazave in the valley of Mexico, would have exhausted the mine of Biscaina at the pit of San Ramon, for a depth of 370 metres. The same object could be attained at less expence, by following the project of M. D'Elhuyar, in placing the mouth of a new level near Omitlan, in the road which leads from Moran, to the place of amalgamation at Regla. This * I found the absolute height of the lake of Zumpango, 2284 metres (7492 feet. Trans.); the pit of San Ramon 2815 metres (9233 feet. Trans.); now the deepest point of the mine of Biscaina is 307 metres (1006 feet. Trans.) below the upper mouth of the pit. I insert these results here, because in the country it is generally believed, that the works of the Real del Monte have already reached the level of the salt lake of Tezeuco. last level before reaching 3800 metres* in length, would cut the vein of Biscaina. The very wise plan which the Count de Regľa at present follows is, to leave off the clearing of the old works, and to investigate the mineral repository, in points where it has never yet been worked (in unverfahrenem felde). In studying at Real del Monte, the surface and undulations of the ground, we observe that the vein of Biscaina has furnished for three centuries its greatest riches on a single point, that is to say, in a natural deepening (enfoncement) contained between the shafts of Dolores, Joya, San Cayetano, Santa Teresa, and Gaudalupe. The shaft from which the greatest quantity of silver ores has been extracted, is that of Santa Teresa. To the east and west of this central point, the vein is contracted for a distance of more than 400 metres. It preserves its primitive direction, but becomes destitute of metals, and reduced to an almost imperceptible vein. For a long time it was believed that the vein of Biscaina was insensibly lost in the rock; but they discovered in 1798 very rich metals, at a distance of more than 500 metrest, to the east and west of the centre of the old works. They then * 12,466 feet. Trans. 1640 feet. Trans. sunk the shafts San Ramon and San Pedro; and they discovered that the vein resumed its old power, and that an immense field was opened to new undertakings. When I visited the mines in the month of May 1803, the San Ramon shaft was only then 30 metres in depth; and it will be nearly 240 metrest to the bottom of the level of Moran, which is itself still distant 45 metres from the point which corresponds to the intersection of the new shaft, and the roof of the level. In its present state, the mine of the Count de Regla, annually yields more than from 50 to 60,000 marcs of silver.§ The vein of Biscaina contains in the points of the principal mines, milk-quartz, which frequently passes into splintery hornstone, amethyst, carbonate of lime, a little sulphate of barytes, sulphuret of silver mixed with native silver, and sometimes prismatic black silver (sprödglaserz), deep-red silver, silver, galena and iron and copper pyrites. The same silver ores are found near the surface of the ground in a state of decomposition, and mixed with oxide of iron, like the pacos of Peru. Near the San Pedro shaft, the pyrites are some * 98 feet. Trans. † 787 feet. Trans. 147 feet. Trans. § From 32,815 to 39,378 lb, Troy. Trans. 222 POLITICAL ESSAY ON THE [BOOK IV. times richer in silver than the sulphuret of silver. The mines of Moran, formerly of great celebrity, have been abandoned for 40 years, on account of the abundance of water which they could not draw off. In this district of mines, which is in the vicinity of that of Real del Monte, near the mouth of the great level of Biscaina, there was placed in 1801 a machine à colonne d'eau, of which the cylinder is 26 centimetres in height, and 16 in diameter.* This machine the first of the kind ever constructed in America, is much superior to those of the mines of Hungary. It was executed agreeably to the calculations and plans of M.del Rio, professor of mineralogy in Mexico, who has visited the most celebrated mines of Europe, and who possesses at once the most solid and various acquisitions. The merit of the execution is due to M. Lachausée, a Brabant artist of great talents, who has also fitted up for the school of mines of Mexico, a very remarkable collection of models, for the use of students of mechanics and hydrodynamics.t It is to be regretted that this fine machine, in which the regulator of the suckers † is put in * 10.23 by 6.29 inches. Trans. † See Vol. i. p. 216. ‡ Delius, des mines de Schemnitz, edition of M. Schreiber, § 591. |