of Guanaxuato and Mexico, we find it almost wherever pits are dug between San Juan de la Chica and the town of San Felipe ; near Rincon del Centeno, in the environs of Celaya; and from Durasno, and Tierra Nueva to San Luis de la Paz, especially, near Chapin, Real de Pozos, San Rafael de los Lobos and la Soledad. Sulphuretted mercury has been also discovered at Axuchitlan and Zapote *, near Chirangangueo, in the intendancy of Valladolid; at los Pregones near Tasco, in the district of mines of the Doctor; and in the valley of Tenochtitlan to the south of Gassavé in the road from Mexico to Pachuca. The works by which these different mineral depositories were proposed to be discovered, have been so frequently interrupted, and they have been conducted with so little zeal, and generally with so little intelligence, that it would be very imprudent to advance, as has been often done, that the mercury mines of New Spain are not worth the working. It appears, on the contrary, from the interesting information which we owe to the labours of M. Chovel, that

*In the mines of San Ignacio del Zapote, where the cinnabar is constantly mixed with blue carbonated copper, ́while at Schemnitz and Poratich in Hungary the antimoniated grey copper (graugültigerz) contains 0.06 mercury. Klaproth, iv p. 65.

the veins of San Juan de la Chica, as well as those of the Rincon del Centeno, and the Gigante, are very deserving of the attention of the Mexican miners. Was it to be expected that superficial works which were merely begun, should in the very first years, yield a net profit to the shareholders?

The mercury mines of New Spain are of very different formations. Some are found in beds in secondary earths; and others in veins which traverse trap porphyries. At Durasno, between Terra Nueva, and San Luis de la 'Paz, cinnabar mixed with a number of globules of native mercury, forms a horizontal bed (manto) which reposes on porphyry. This manto which has been pierced by pits of five or six metres * in depth, is covered with beds of slate clay, which contains fossil, wood, and coals. On examining the roof of the manto, we find from the surface, first a bed of slate clay (schieferthon) impregnated with nitrate of potash, and containing fragments of petrified vegetables; then a strata of slate coal (schie'ferkohle) of a metre † in thickness; and lastly slate clay which immediately covers the cin'nabar minéral. From this mine there was drawn, eight years ago, in a very few months

16 or 19 feet.

+ 3.28 feet.

nearly 700 quintals of mercury which were not sufficient to pay the expences of working, although the ore contained a pound of pound of mercury for every load of three quintals and a half. The carelessness with which the mine of Durasno was wrought, has been so much the more prejudicial, as on account of the small degrees of solidity of the rock of the roof, and its horizontal position, it very frequently fell in. The mine is at present drowned, and to resume the operations would not be attended with profit. It has constantly enjoyed very high celebrity in the country, not on account of its wealth which is inferior to that of the veins of San Juan de la Chica, but because it admitted of being wrought sub dio, and because its produce was very abundant. They attempted in vain to discover a second bed of mercury ore below that of Durasno.

The cinnabar vein of San Juan de la Chica, is two or three and sometimes even six metres in extent (puissance). It traverses the mountain of los Calzones, and extends to Chichindara. Its ores are extremely rich but by no means abundant; I have seen there masses of compact and fibrous sulphuretted mercury of a bright red, twenty centimetres in length, and three in thickness*; and these specimens resembled

* 7.87 inches by 1.18. Trans.

from their purity the richest produce of Almaden and Wolfstein in Europe. The mine of Chica has been only yet wrought to the depth of fifty metres; * and it is found, and this geological fact is very remarkable, not in freestone or slate, but in a true porphyritic pitch stone (pechstein-porphyr) divided into balls with concentrical beds of which the interior is lined with mammelonneous hyalite (müllerisch-glass). The cinnabar and a little native mercury, are sometimes observed in the middle of the porphyritic rock at a very considerable distance from the vein. During my stay at Guanaxuato, ouly two mines were wrought in all Mexico, those of Lomo del Toro, near San Juan de Chica, and Nuestra Señora de los Dolores, a quarter of a league to the south-east of the Gigante. In the first of these mines a load of mineral yields from two to three pounds of mercury; and the expences of working are very moderate. The mine of the Gigante from which there is even drawn six pounds of mercury per load (carga) of mineral, furnished from 70 to 80 pounds weekly; and it is wrought on the account of a rich individual Don Jose del Maso, who has the merit of having first excited his countrymen during the lat war to the working of mercury mines, and the manufacture of steel. The cinnabar

164 feet. Trans.

extracted from the veins of the mountain del Fraile, near the Villa de San Felipe is found in a porphyry with hornstone base which is traversed by veins of tin, and is undoubtedly more antient than the porphyritic pitchstone (pechstein porphyr) of Chica.

America in its present state is the tributary of Europe with respect to mercury; but it is probable, that this dependance will not be of long duration, if the ties which unite the Colonies with the mother country remain long loosened, and if the civilization of the human species in its progressive motion from East to West is concentrated in America. The spirit of enterprize and research will increase with the population; the more the country shall be inhabited, the more they will learn to appretiate the natural wealth which is contained in the bowels of their mountains. If they discover no single mine equal in wealth to Huancavelica, they will work several at once, by which the united produce will render the importation of mercury from Spain and Carniola unnecessary. These changes will be so much the more rapidly operated, as the Peruvian and Mexican miners shall feel 'themselves impeded by the want of the metal *necessary' for amalgamation. But let us enquire "what would be the consequence to the silver

t

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