IDRIA, is a district of Carniola, dependent on the circle of Adlerberg, in the dominions of the emperor of Austria. Having been wrested from that monarch by the French in 1809, it was constituted a canton and mayoralty, extending over eleven miles square, and forming part of the Illyrian provinces. It was further sub-divided into the town of Idria, the village of Lower ldria, and eight hamlets. The whole of this territory is mountainous, and interspersed with narrow vallies, which are copiously watered by torrents from the hills. The river Idrixa rises in the Julian Alps, about three leagues from the town of Idria, and after re ceiving the Canomla, Zalla, and several subterraneous streams, it falls into the Isonzo, 19 leagues lower down. This river abounds with fish, among which are fine trout of remarkable size. Several sluices and canals are formed in the valley where it runs, one of which, of superior construc tion, was executed by the French in 1813, on the torrent Woitschaik, for the purpose of floating wood. Thunder storms prevail in summer, and there are sometimes two or three in a day : the heat is then oppressive, owing to the reflexion of the sun from the surrounding hills : autumn is rainy, and winter is of long duration.. The thermometer in the most severe cold falls a few degrees below zero. Two chains of mountains 1728 feet high, bounding the valley of the Idria, are covered with snow nearly six months of the year : and 300 or 400 men are employed while storms pre vail, clearing the great road to Laybach. The medium height of the barometer is 27 inches 5 lines; its variations are neither frequent nor considerable. A strong prejudice subsists in the country regarding the insalubrity of the climate, which of late has been controverted. But although two-thirds of the district are forests, vegetable life is lan guid in the immediate vicinity of the town of Idria ; fruits and grain seldom ripen, and cattle always decline. Tooth ach is universal among the inhabitants, few persons have good teeth, and they are lost by all at an early age. As the inhabitants are principally divided into miners and forres ters, the one class enjoys vigorous health, while the other is subjected to disease : and the consequences are beheld even in their 'respective offspring. Life is here of short duration ; many die young, and forty is an age beyond which great expectations of survivance are not entertained. The unusual insalubrity of Idria is traced to the mines and me tallurgic operations, by those who consider the atmosphere of the same constitution as in other places.
The minerals of Idria are in considerable number and variety, and also of uncommon value, compared with their narrow bounds. Among these are white marble, found in the valley of the Canomla ; thick beds of different coloured Jasper in the country of \Voiska ; fine and coarse free stone ; sulphui etted iron, and indications of coal. But the chief riches of Idria are its quicksilver mines, the largest, most magnificent, and most productive in the world. The
metallic stratum is situated about 240 yards deep ; it ex tends 800 yards in one direction by 1000 in another : and lies in a valley, whose surface is 507 feet above the level of the sea. Six shafts penetrate the mine, four of which are vertical, and two have an inclination. The former are named St. Barba, St. Theresa, St. Francis, and the Empe ror Joseph ; three of them are appropriated for the extrac tion of the mineral substances, or discharging water, which is accomplished by 15 pumps, worked by a hydraulic wheel 36 feet in diameter ; while the fourth is reserved for intro ducing the materials necessary for the operations below.
i Access is gained from within a spacious building, situated In the town of Idria, leading almost horizontally under a lofty vault to a staircase, always kept in excellent repair, constructed mostly of stone steps, but partly of wood. • It reaches to the depth of 150 yards, after which the remainder of the descent is accomplished by wooden ladders, which are sometimes damp, and on that account less convenient and agreeable. Dr. Brown observes, that in leaving the mine he ascended by a ladder of 639 staves. There are several landing places paved with flag stones in the course of the descent, and benches to rest upon: and the whole mine is kept remarkably clean and in good order. The sub terraneous excavations are occupied by nine horizontal galleries, including intermediate ones, with their numerous ramifications, about seven feet high, and as much in width. They are arched over by artificial building, unless where they penetrate the solid rock, which requires no support, and are in general well aired from currents heing establish ed between them.• According to Jars, by whom the mine was visited about the year 1759. the entrance to the princi pal gallery is covered by an iron grating, at the moment the workmen descend, which is kept down until their return. At the distance of 260 yards from the mouth of the same gallery, there is a chapel, where mass is performed on all festival days, and the images of saints, protected by a grat ing, stand in niches. Kuttner says the principal shaft is 86 fathoms in deptb, and Keysler, that the lowest part of the mine lies 840 below the surface of the earth. The tem perature of some parts is such as to cause profuse perspi ration in the workmen : numerous thermometrical observa tions prove, that among great beds of rich ores the heat is from 80° to 95°. Every thing within seems to announce disorder and chaotic confusion : the whole mineral kingdom apparently has been confounded by some catastrophe, to constitute the treasures which this spacious cavern contains. Enormous heaps of shells are intermixed with mercury, bitumen, and sulphur, and the ores are disseminated in the most unequal manner. On account of its uncommon arrangement, the mine of Idria bears no resemblance to any other, and presents none of those facilities in the work ing which are found in mines with veins.