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When we distinguish those periods in which the progress of mining has been most rapid, we find the following results:

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This table along with the preceding one, proves that the periods during which the wealth of the mines have most increased, are from 1736 to 1745, from 1777 to 1783, and from 1788 to 1798; but the increase in general has been so little in proportion to the space of time, that the total produce of the mines was:

4 millions of Piastres in 1695

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been tripled in fifty-two years, and sextupled in a hundred years.

After the gold and silver, it remains for us to speak of the other metals, called common metals, the working of which, as we have already stated in the beginning of this chapter, has been very much neglected. Copper is found in a native state, and under the forms of vitreous and oxidulated copper, in the mines of Ingaran, a little to the south of the Volcan de Jorullo, at San Juan Guetamo, in the intendancy of Valladolid, and in the province of New Mexico. The Mexican tin is extracted by means of washing, from the alluvious lands of the intendancy of Guanaxuato, near Gigante, San Felipe, Robledal and San Miguel el Grande as well as in the intendancy of Zacatecas between the towns of Xeres and Villa Nueva. One of the tin mines most common in Mexico is the wood tin of the English mineralogists.

It appears that this mineral is originally found in veins which traverse trap-porphyries; but the natives, instead of working these veins, prefer the extracting of tin from the earth brought down the ravins. The intendancy of Guanaxuato in 1802, produced nearly 9200 arrobas of copper, and 400 of tin.

The iron mines are more abundant than is generally believed, in the intendancies of Valladolid, Zacatecas, and Guadalaxara, and

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We

especially in the provincias internas. have already explained the reason why these mines, the most important of all, are only wrought with any degree of spirit during a period of maritime war, when a stop is put to the importation of steel and iron from Europe; and we have already named the veins of Tecalitan, near Colima, which were successfully wrought ten ten years ago, and afterwards abandoned. Fibrous magnetic iron is found in conjunction with magnetic pyrite in veins which traverse gneiss in the kingdom of Oaxaca. The western slope of the mountains of Mechoacan abounds in ores of compact red iron and hematite brown iron. The former have also been observed in the intendancy of San Luis Potosi near Catorce. I saw christalized micaceous iron, near the village of Santa Cruz, east from Celaya, on the fertile table land extending from Queretaro to Guanaxuato. The Cerro del Mercado, situated near the town of Durango, contains an enormous - mass of ores of brown magnetic and micaceous iron. I enter into the detail of these localities for the sake of proving the falsity of the opinion delivered by several modern natural philosophers, that iron almost exclusively belongs to the most northern regions of the temperate zone. To

*See p. 106 of this volume.

M. Sonneschmidt we owe the knowledge of the meteoric iron*, which is found in several places of New Spain, for example at Zacatecas, Charcas, Durango, and if I am not deceived in the environs of the small town of Toluca.

Lead, which is very rare in the north of Asia, abounds in the mountains of calcareous formation, contained in the north east part of New Spain, especially in the district of Zimapan, near the Real del Cardonal and Lomo del Toro; in the kingdom of New Leon, near Linares; and in the province of New Santander, near St. Nicholas de Croix. The lead mines are not wrought with so much spirit as we could wish for in a country where the fourth part of all the silver minerals are smelted.

Among the metals, of which the use is the most limited, we have to name zinc, which is found, under the form of brown and black blende in the veins of Ramos,

Sonneschmidt, p. 188 and 192. The mass of Zacatecas still weighed ten years ago, near 2000 lib. See a memoir of M. Chladni in the Journal des Mines, 1809, no. 151, p. 79, relative to a meteoric stone, which fell between Cicuic and Quivira according to the testimony of Cardanus and Mercati. The geographical position of Cicuic and Quivira, names which recal to us the fables of the El Dorado of South America, remains still unknown.

Sombrerete, Zacatecas, and Tasco; antimony, which is common to Catorce and los Pozuelos, near Cuencame; arsenic, which is found among the minerals of Zimapan, combined with sulphur, like orpiment. Cobalt, as far as I know, has never yet been discovered among the minerals of New Spain; and manganese*, which M. Ramirez recently discovered in the Island of Cuba, appears to me in general much less abundant in Equinoctial America, than in the temperate climates of the Old Continent.

Mercury, which is very remote from tin, with respect to its relative antiquity, or the period of its formation, is almost as uncommon as it, in every part of the globe. The inhabitants of New Spain have procured for centuries, the mercury necessary in the process of amalgamation, partly from Peru, and partly from Europe; and hence they are accustomed to consider their country as destitute of this metal However, when we consider the examinations carried on under the reign of Charles the 4th, we are forced to admit that few countries have so many indications of cinnabar, as the table land of the Cordilleras from the 19° to the 22° of north latitude. In the intendancies

To the west of the town of Cuenca, in the kingdom of Quito, there exists earthy grey manganese, which forms a bed in the freestone.

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