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foliated gypsum.- At Sierra de Pinos near
A great part of the silver annually produced
* Among the varietes of galena, particularly rich insilver, and of very fine grain, may be specified those of the new mine of Talpan, in the Cerro de las Vegas, belonging to the district of Hostotipaquillo. This galena, which sometimes passes into compact antimonial sulphuret of lead (bleischweif is accompanied with much copper pyrites, and carbonate of lime.
A very considerable quantity of silver is produced from the~smelting of iron pyrites (gemeiner schwefizl/vies) of which New Spain sometimes exhibits varieties richer than the glaserz itselfl It has been found in the Real del Monte, on the vein of Biscaina, near the pit of San" Pedro, the quintal of which contained even so much as three marcs of silver. At Sombrerete, the great abundance of pyrites disseminated in the red silver ore, is a great obstacle to the process of amalgamation.
We have described the ores which produce the Mexican silver, and it remains for us to examine into the mean riches of these minerals, considering them as all mixed together. It is a very common prejudice in Europe, that great masses -of native silver are extremely common in Mexico and Peru, and that in general the mineralised silver ores destined to amalgamation or smelting, contain more ounces, or more marcs of silver to the quintal, than the poor ores of Saxony and Hungary. Full of this prejudice, I was doubly surprised on my arrival in the Cordilleras to find that the number of poor mines greatly surpasses those of the mines to which in Europe we give the name of rich. A traveller who visits the famous mine of Valenciana in Mexico, -after having examined the
and Schemnitz, can scarcely conceive how a vein which, for a great part of its extent contains the sulphuret of silver disseminated in the gangue in almost imperceptible particles, can regularly supply thirty thousand marcs per_ month, a quantity of silver equal to the half of what is annually furnished by all the mines of Saxony. It is no doubt true that blocks of native silver (papas de plata) of an enormous weight, havebeen extracted from the mines of Batopilas in Mexico and Guantahajo in Peru; but when we study attentively the history of the principal mines of Europe, we find that the veins of Kongsberg in Norway, Schneeberg in Saxony, and the famous metallic repository of Schlangenberg in Siberia, have produced masses of much more considerable bulk. We are not in general to judge from the size of the blocks, of the wealth of Ikthe mines of different countries. France does not altogether produce more than 8000 marcs of silver an!-' nually; and yet there are veins in that country (those of .Sainte-Marie-aux-Mines) from which amorphous masses of native silver have been extracted, of the weight of 30 kilogrammes. *
It appears that at the period of the formation of veins in every climate, the distribution of
silver has been very unequal; sometimes con-
one point, while the neighbouring parts are
Although the New Continent, however, has
The result of the investigations made by Don‘ Fausto d’Elhuyar, the director general of the mines of Mexico, and by several members of the superior council of mines, is, that in uniting together all the silver minerals annually extracted, it would be found from the mixture, that their mean produce is from 0.0018 to 0.0025 of silver, that is to say in the common language of miners, that a quintal qfore (of one hundred pounds, or 16,000 ounces) contains
flom three to finer ounces of silver. This im