336 Statistical Account of 



has been confounded, to constitute the mineral riches which arc- 

 contained witliin this vast cavern. 



Enormous heaps of shells are mixed with mercury, bitumen, 

 and sulphur. The ores are therein disseminated in the most un- 

 equal ami most original manner, so that the indications which 

 were favourable at one time are not met with again for a great 

 length of time, and even never. What we discover one moment 

 is lost the next, and almost always it is chance only wliich leads 

 to rich beds : thus, when discoveries have been made, great care 

 is taken to oeconomize them. 



In general the mercury obtained at Idria is combined with 

 sulphur, bitumen, and iron. The substanceswhich serve for its 

 matrix are often very complex, as will be seen on becoming ac- 

 quainted with the principal varieties of these ores. 



1. We have native mercury disseniinated through a gray, 

 leafy, argillaceous schist, in considerable beds in the part which 

 adjoins the pit of St. Francis. Graiie sckiefer. 



2. Native mercury in masses of black schists, disposed in la- 

 miufe, joined together by small layers of hydrogcnated red sul- 

 phuretted mercury, called hepatic mercury. Scliivartze schiefer. 



3. Native mercury united to sulphuretted iron, in flat buttons 

 or nipples, enveloped with a blackish argillaceous schist. 

 Krczel schiefer. 



4. Mercury combined with sulphur or sulphurated mercury, in 

 very close compact masses, steel grained, of a more or less in- 

 tense red, mixed with sulphurated iron. Staal-erz. 



5. Compact sulphurated mercury of a deeper red than tTie 

 foregoing, mixed with fine freestone and sulphurated iron of a 

 brick colour, called slegel-trz. 



6. Compact sulphurated mercury, in masses or tables which 

 are separated in polygons, without any very decided form, of a 

 fine liver red, with pohshed surfaces often striated. Leler-erz. 



7 . Sulphurated mercury united with a variety of bitumini- 

 ferous mercury or brand-erz, lighter than the foregoing, or 

 mixed leber-erz. 



8. Oxide of mercury combined with bitumen in a slight brit- 

 tle mass, very variable in cclour from the dark brown to the 

 gray, more inflammable than the foregoing, burning with flames, 

 and emitting white mercurial vajiours of an agreeable bituminous 

 smell, without being sensibly mixed with sulphur, called Irand- 

 erz*. 



9. Sulphurated mercury mixed with abundance of grayish 



argil, 



* This species of combinrition,extreiiieIy cirioiis, is almost always found 

 filling tlif intervals wliicli stfiaiate tv\()lii)'eis of leber-crz, of which it takes 

 the imprcseion. It is rernarlsHhie for its lipbtnf-ss, its combustibility, and 

 particularly for the yellow bituminous matter which it furnishes, wlien we 



tresit 



