As the mines of Idria arc the most productive which are known, it may not be uninteresting to learn the quan tity of metal obtained from them. It has been different at different periods, which is not surprising, considering the uncertainty which attends subterraneous researches. In the year 1663, they produced 255,981 pounds. About the year 1730, the quantity seems to have been 360,000 ; twen ty years later it was calculated at 300,000 ; and in the year 1799, Kuttner was informed that the product has been known to amount to 1,000,000 or 1,200,000 pounds, which is probably erroneous. But by an accurate computation, made by the director of the mines under the French regime, between the years 1809 and 1813, we learn that the aver age quantity obtained yearly in that time amounted to about 365,928 pounds. Of the total product, there were delivered into the magazines the following proportions, in quintals of 100 pounds each.
Mercury 14,194 quintals 25 lib.
Cinnabar • 702 25 Vermilion 2,700 29 Corrosive sublimate . . . . 24 50 Calomel 64 — Red precipitate 28 67 17,713 96The whole of this was obtained in 56 months. Thus the profits of the mines, which are the property of the Empe ror of Austria, and carried on at his expence, are very considerable ; being at a medium about 800,000 francs, or L35,000 Sterling yearly. To render the average nearly the same, the rich and poor ores are worked at once.
A great quantity of the quicksilver was formerly expor ted to Spain, and from thence to South America, where it was employed in the separation of the metal in the silver mines. The Dutch were accustomed to purchase 100,000 lib. yearly. Most part of it is now carried to Vienna, and a large proportion to England.
In the year 1663, there were 280 miners, but at present 700 are employed, besides 300 wood cutters, who are un der an inspector general ; and there are nearly 600 pen sioners, including women and children. The whole of this great establishment is under the most admirable sys tem of administration. All the workmen are divided into companies, they assemble at three in the morning, when their names are called over, and they descend into the mine, each with a lamp in his hand. Owing to the high tempe rature of the galleries, the rarefaction of the air, and evo lution of certain gases in the combustion of the lamps, as well as the deleterious effluvia escaping from the metals, their health suffers severely. Those who are occupied where native mercury is found inhale small particles of it, and very soon lose their teeth : those employed in sweep ing the chambers of condensation also inspire a considera ble quantity of metal, while detaching it from the sides of the condensers. Thus they undergo a copious salivation.
\Ve saw there," says Dr Pope, a man who had not been in the mines above half a year before, so full of mer cury, that putting a piece of brass in his mouth, or rub bing it in his fingers, it immediately became white like silver. I mean, it had the same effect as if he had rubbed mercury"upon it. And so parLlytic, that he could not, with both his hands, convey a glass half full of wine to his mouth without spilling it, though he loved it too well to throw it away." Some observers affirm, that the quicksilver in sinuates itself into the bodies of those who work the vir gin mercury, so that when they go into the warm bath, or are put into a profuse sweat by steam, drops of pure mer cury have been known to issue thrOugh the pores from all parts of their bodies. This much is certain, however, that the workmen who have been occupied several years in the furnaces, become subject to shiverings, convulsions, decrepitude, and a premature old age. Their wages,
partly in grain, and partly in money, are exceedingly mode rate ; but by the paternal care of government, all are pro vided with a competency when they are unable to continue their labours.
The quicksilver mine of Idria was accidentally discov ered in the year 1497, by a peasant, while receiving the water of a spring into a tub for the purpose of trying if it was tight. He was astonished on emptying its contents to find some metallic globules at the bottom, which he im mediately ascribed to witchcraft. But having conquered his apprehensions, he collected them together for the in spection of a goldsmith in the small town of Bischoflaach, about four leagues distant. Neither promises nor pre sents, however, could induce him to point out the spot ; and he engaged another peasant, Cazian Anderlin, to assist him in working the mine. But soon ceasing to find native mercury, their labours were abandoned. Other peasants followed in their foot-steps, and were equally disappointed. A company of miners nevertheless had better success. In 1525, the works were interrupted, and the miners totally ruined by an earthquake ; nor was the pursuit resumed with activity until 1572. The Archduke Charles of Aus tria having taken possession of the mines, established a re gular system for their management. Vast quantities of mercury were extracted from them ; and their riches to gether with their great extent attracted the notice of the curious from all parts of the world. In 1803. a fire broke out in the mine, which did great damage, and occasioned the loss of several lives ; but it was observed, that the sub terraneous temperature was lower, and that the air of cer tain galleries was less easily vitiated than before. The French extorted the cession of Idria in 1809, and worked the mine for behoof of the order of the three golden fleeces. Numerous and important improvements were made by them, until the Emperor of Austria regained possession of it in 1813.
Immediately above the site of the mines the town of Idria is built, spreading over the valley, and up the sides of the hills. All the houses are detached ; they are small ; but each is inhabited by two or three families, and has a piece of ground from which the owners endeavour to raise a few vegetables. Though irregularly built, its aspect is not unpleasant to the eye, and it exhibits none of that black and dismal appearance, which is common to towns in the vi cinity of mines. Its principal public buildings ate, a hand some parish church ; a very fine hospital, to which two physicians and a surgeon are attached ; and a dispensary ; for supplying medicines to the sick. There is a public school for the education of youth, with six masters, and a female to superintend that of girls. An old castle con tains the treasure for the necessary expenditure, and a magazine for storing up the products of the mine ; also one for provisions to the inhabitants ; several public offi ces, as a hall for the council of administration, and accom modation for its chief director. Some of the edifices de voted to public purposes were erected here during the oc cupation of Idria by the French. In the year 1812, the population of the town amounted to 4095, and that of the whole district to 7060. Lat. 46° 16' NV. ; Long. 3'3° 53 E. Distant 18 miles from Upper Laybach. See Philosophical Transactions, vol. i. iv. ; Brown's Travels, p. 83. ; Kuttner's Travels ; Jar's Voyages Illetallurgiques)tom.ii. ; Keysler's Travels, vol. ii. (c)