338 Siulistical Account sf 



20. The foregoing variety is an argillaceous schist inix<^d 

 with sulphurated iron, which gives rise to s'llphated iron by the 

 spontaneous decomposition which it undergoes. 



21. Sulphurated, not hydrogenated mercury of a bright ted, 

 in thin layers, pulverulent, accompanying the crystallized cinna« 

 bar, called native vermilion. 



22. Sulphurated mercury, not very perceptible to the eye, 

 disseminated throughout a black earthy schistus, mixed with 

 sulphated iron which crystallizes in annular prisms several inches 

 in length, mixed with sulphates of lime, aluminc, and magnesia; 

 a mixed salt affecting the silky form, reticulated or straight, se- 

 veral inches in length. This pha;nomenon is visible in such 

 specimens as collections afford. 



23. Black schistus, very poor in mercury, in masses shin- 

 ing at the surface, composed of curvilinear laminae. Sc/nvartze 

 schiefer. 



24. The same as the foregoing, in masses not so leafy, di- 

 vided into angular fragments, of the appearance at first of com- 

 pact lignite, but more friable, very poor in mercury. 



25. Black schistus, mixed with bitumen, foetid, in tables a 

 foot and a half broad, with soft and shining surfaces like a mirror, 

 Spiegel schiefer. 



26. Black or brown schistus, in tablesmoreor less thick, with 

 smooth surfaces strewed with carbonated lime and pulverulent 

 sulphuret of mercury. Flamherg schiefer. 



27. Calcareous breccia strewed with abundance of sulphurated 

 mercurv, crystallized confusedly, or in powder, of a very lively 

 carmine red. 



28. Argilo-calcareous rock, mixed with sulphurated mercury 

 and sulphated iron in decomposition, proper for the stampers 

 and the washings. Wasche gaarid. 



29. Compact rock, a kind of hard marl, veined with bromi 

 schist : treated as the above. 



I could describe many more rocks, schist^ &c. which are met 

 with in the mines of Idria ; but the above 1 presume will give a 

 correct idea of the substances with which the mercury is in ge- 

 neral combined. 



The interior of the mine is very dry, most of the borings are 

 shored up with wood or walled with stone. Where the solid 



at [drin.; but tliis is not tlie case, for it is neither abundant nor rich: and 

 as it is decomposed iren in the interior of the works, it produces the silky 

 sulphates which are found in the galleries. It is a kind of sulphurous hy- 

 <irate of mercury, and is put through the washers' hands before it can be 

 used. 



rock 



