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Marcs of silver Mean Produce of the Mines of New Spain, including the Mines of the northern part of New Biscay, and
those of Oaxaca, above 2,500,000
We shall afterwards compare the produce of the silver mines of Mexico, with that of the different mines of Europe. It will suffice in
this place to observe, that the two millions and
a half of marcs of silver annually exported from Vera Cruz, are equal to two thirds of the silver annually extracted from the nhole globe. The eight groups into which we have divided the mines of New Spain, occupy a surface of
12,000 square leagues, or a tenth of the whole
extent of the kingdom. When we look at the immense wealth of a very small number of mines, for example, the mine of Valenciana, and that of Rayas at Guanaxuato, or the principal veins (vetas madres) of Catorce, Zacatecas, and Real del Monte, we easily perceive that more than 1,400,000 mares of silver are produced in an extent of surface, not equal in size to that of the district of the mines of Freiberg. If the quantity of silver annually extracted from the mines of Mexico is ten times greater than what is furnished by all the mines of Europe, on the other hand, gold is not much more abundant in New Spain than in Hungary and Transylvania. These two last
countries annually throw into circulation nearly 5,200 marcs; and the gold delivered into the mint of Mexico, only amounts in ordinary years to 7000 marcs. We may reckon that in times of peace, when the want of mercury does not impede the process of amalgamation, the annual produce of New Spain is,
In Silver, 22 millions of Piastres.
The Mexican gold is for the most part extracted from alluvious grounds, by means of washing. These grounds are common in the province of Sonora, which as we have already observed", may be considered as the Choco of North America. A great deal of gold has been collected among the sands, with which the bottom of the valley of the Rio Hiaqui, to the east of the missions of Tarahumara, are covered. Farther to the north in Pimeria Alta, under, the 31° of latitude, grains of native gold (pepitas) have been found of the weight of from five to six pounds. In these desert regions, the incursions of the savage Indians, the excessive price of provisions, and the want of the necessary water for working, are all great obstacles to the extraction of gold.
Another part of the Mexican gold is extracted from the veins, which intersect the
• Vol. ii. p. 299.
mountains of primitive rock. The veins of native gold are most frequent in the province of Oaxaca, either in gneiss or micaceous slate (glimmerschiefer). This last rock is particularly rich in gold, in the celebrated mines of Rio San Antonio. These veins of which the gangue is lacteous quartz, are more than half a metre in thicknesst, but their richness is very unequal. They are frequently strangled, and the extraction of gold in the mines of Oaxaca, is in general by no means considera
ble. The same metal is to be found either
pure or mixed with silver ore, in the greatest number of veins which have been wrought in Mexico; and there is scarcely a single silver mine which does not also contain gold. Native gold is frequently found crystallized in octa hedra, lamina, or in a reticulated form, in the silver minerals of the mines of Willalpando and Rayas near Guanaxuato, in those of Sombrero (intendancy of Walladolid), Guarisamey to the west of Durango, and Mezquital in the province of Guadalaxara. The gold of Mezquital is looked upon as the purest, that is to say, as being least alloyed with silver, iron, and copper. The principal vein in the mine of Santa Cruz, at Villalpando, which I visited in the month of September, 1803, is intersected by a great number of small rotten
* 1.6 foot. Trans
veins, (hilos del desposorio) of exceeding richness. The argillaceous slime with which these small veins are filled, contains so great a quantity of gold disseminated in impalpable parcels, that the miners are compelled when they leave the mine nearly in a state of nakedness, to bathe themselves in large vessels, to prevent any of the auriferous clay from being carried off by them on their bodies. The silver mineral of Villalpando generally contains only two ounces of gold per load, (carga of 12 arrobas); but it frequently contains even eight or ten ounces per load, or 1 's ounces per quintal. It may be of use to mention here that at the Harz, the pyrites of Rammelsberg eontain only a 29 millionth part of gold, which is however extracted with profit". The District of the mines of Guanaxuato, has furnished according to the registers of the Provincial Treasuryt,
Marcs | Marcs Gold con-
* Brongniart, Mineralogie, T. ii. p. 345. t Estado de la Tresoreria principal de Real Hacienda de Guanazuato, del 21 de Novembre de 1799, (M.S.)
The result of this table is, that the silver extracted from the vein of Guanaxuato, contains from one to three thousand parts of its weight in gold.
Platina is erroneously stated to be found in the auriferous sands of Sonora. This metal has never yet been discovered to the north of the Isthmus of Panama, on the Continent of North America. Platina in grains is only found in two places of the known world; in Choco one of the provinces of the kingdom of New Granada, and near the shores of the South Sea, in the province of Barbacoas, between the 2° and 6° of north latitude. It is peculiar to alluvious grounds of a surface of 600 square leagues, the extent of which is scarcely equal to two of the departments of France. The Lavaderos, which at present yield the greatest quan- tity of platina, are those of Condoto, Santa Rita, or Viroviro, and Santa Lucia, and the Ravin (quebrada) of Iro, between the villages of Novita and Taddo. There are several lavaderos in Choco, (for instance, those of the districts of San Augustin, and Guaicama,) where no trace of platina is to be found. The price of this metal in grain on the spot is eight piastres, or 40 francs the pound, while at Paris it is generally from 130 to 150 francs. I shall examine in another place the quantity of platina, which in the present state of the mines of Choco, Ame