190

MINES.

high and the low Alps , several lead and copper mines are mentioned, all inconsiderableand abandoned at the present time, with the exception of some workings of galena,which furnish also a little graphite.

During some of the last years of the eighteenth century, there was mined at la Gardettein the Oisans, department of the Isere , a vein of quartz which contained native goldand auriferous pyrites; but the product has never paid the expenses, and the mine hasbeen abandoned. The Oisans presented a more important mine, but it also has beengiven up; it was the silver mine of Allemonl or Chalanches The ore consisted ofdifferent mineral species more or less rich in silver, disseminated in a clay which filledthe clefts and irregular cavities in the middle of talcose and hornblende rocks. Thismine yielded annually toward the conclusion of the eighteenth century, so much'as 2,00®marcs of silver, along with some cobalt ore. Among the great number of mineral sp e "cies, which occurred in too small quantities to be worked to advantage, there was nativeantimony, sulphuret of mercury, &c. The Oisans present, moreover, some rather un-productive mines of anthracite. Mines of an analogous nature, but more valuable, arein activity at the western foot of the Alps , at la Mothe, Notre-des-Vamx et Putteville , ®few leagues southeast of Grenoble.

From the entrance of the valley of the Oisans to the valley of the Arc in Savoy, thereoccur on the N.W. slope of the Alps , a great manymines of sparry iron. The localityof this ore is here very difficult to define. It appears to form sometimes beds or massed'and sometimes veins amid the talcose rocks. Some is also found in small veins in thefirst course of the calcareous formation which covers these rocks. These mines are verynumerous; the most productive occur united in the neighborhood of Allevard , depart-ment of the Isere , and of Saint Georges d’Hnretieres in Savoy. Those of Forneaux an®Laprat, in the latter country, are also mentioned. The irregularity of the mining op"erations surpasses that of the deposites ; the mines have been from time immemorial 1 ®the hands of the inhabitants of the adjoining villages, who work in them, each on h®jown account, without any prearrangement, or other rule than following the masses elore which excite hopes of the most considerable profit in a short space of time. Wh a *occurs in almost every mine of sparry iron, is also to be seen here—most imprude®workings. Themine called the Grand Fosse, at Saint Georges d’Hurelieres, is prolong e<1.without pillars or props, through a height of 130 yards, a length of 220 yards, and ®breadth equal to that of th^deposite, which amounts in this place to from 8 to 13 yards ithus a void space is exhibited of nearly 300,000 square yards. The sparry iron extra etcfrom these different mines supplies materials to 10 or 12 smelting-furnaces, the cast-ir°®of which, chiefly adapted for conversion into steel, is manufactured in part in the cel e "brated steel works of Rives , department of the Isere . There occurs in some parts of i® emines of Saint Georges d’HutcHeres copper pyrites, which is smelted at Aiguebcllc■

Savoy presents celebrated lead mines at Pescy and at Macot,l leagues to the east o^Moutiers. Galena , accompanied with quartz, sulphate of baryta, and ferriferous ca ®jbonate of lime, occurs in mass in talcose rocks.. The mine of Pescy had been rcst° rt _to activity by the French government, which established there a practical school of ra' aeS ,’and in its hands the mine produced annually as much as 440,000 libs, avoird. of l e ® Jand 2,500 marcs of silver. It is now explored on account of the king of Sardinia ; ®it begins to be exhausted, and yields less products. That of Macot, opened a fewago, begins to give considerable returns. The mine of copper pyrites of Servoz, ,n ,valley of the Arve , may also be mentioned. The ore occurs both in small veins* ®disseminated in a clay slate; but the exploration is now suspended. Lastly, sligh*Jproductive workings of anthracite are mentioned in several points of these mounta 1 >and in the conterminous portions of the Alps . . eS

There exist in Piedmont some small mines of argentiferous lead. The coppp® inI j a j iof Allagne, and those of Ollomont, formerly yielded considerable quantities of this j®® eTheir exploration is now on the decline. The manganese mines of Saint-Marcel efew outlets; whence they have been feebly developed. Mines of plumbago, ^worked, occur in the neighborhood of Vinay, and in the valley of Pellis, not fa® 0 fPignerol . Some mines of auriferous pyrites have also been worked in this distri gcountry; among others, those of Macugnaga, at the eastern foot of Monte-Rosa- . ^pyrites of this mine afforded by amalgamation only 11 grains of gold per quinta ’ ^gthis gold, far from being fine, contained one fourth of its weight of silver; they . - oH sless rich in proportion as they receded from the surface. The explorations of auri ^pyrites in Piedmont are now abandoned, or nearly so. The only important ®® 0 fthis country are those of iron. These generally consist of masses of black oxi 0 firon, of a nature analogous to those of Sweden ; the principal ones being nS jd-Cogne and Traverselle, which are worked in open quarries. Some others, less ,^ n a-erable, are explored by shafts and galleries. These ores are reduced in 33 sa®cupolas, 55 Catalan forges, and 105 refinery-hearths. The whole produce aboutons of bar-iron.