DErOSITS FROM HOT WATER. 261 



tain, for the water of the mine carries a large amount of them, and, in the 

 underground workings near ore, I collected efflorescences largely consisting 

 of them, as was proved by analysis. Indeed, analyses of the salts crystal- 

 lized out on the walls of the drifts showed all of the bases and acids de- 

 tected in the water or the ore, excepting hyposulphurous acid, gold, and 

 nickel. As cobalt was present in two cases, nickel might doubtless have 

 been detected in traces. Hyposulphurous acid I suppose to result only 

 from the oxidation of alkaline sulphides and gold is present only in very 

 minute quantities in the marcasite. The waters as they reach the surface 

 are far from being saturated solutions of borax or of alkaline chlorides, and 

 there is no reason to assume any tendency for the metallic bases detected 

 to decompose sodium chloride. On the other hand, sulphates of the alkaline 

 earths are comparatively insoluble and might be deposited with the ore. 

 Sulphuric acid has, moreover, constantly formed at the surface, diffusing 

 downward to a greater or less extent. It is very likely that a large part of 

 the sulphates now present in the ores of the surface workings have formed 

 since the ground was broken, for the excavations have interfered with the 

 flow of the water to the lake. 



It is plain from the foregoing that the waters are capable of depositing 

 exactly such mineral mixtures as the oi*es represent, with the very impor- 

 tant exception of the cinnabar. The conclusion that the ores have been de- 

 posited from similar waters is inevitable. At the time of deposition either 

 some slight variation in composition — possibly the absence of ammonia — 

 enabled these waters to hold cinnabar in solution at ordinary pressures or 

 they are now capable of dissolving cinnaljar under somewhat different 

 physical conditions, as was suggested above. 



Precipitation of the ore. — Tlio liypothesis that tlicse waters under other physi- 

 cal conditions would dissolve cinnabar finds some support from observa- 

 tions of tlie circumstances attending the deposition of the ore. Cinnabar was 

 found in the workings of the Hermann shaft several hundred feet below the 

 surface, and in the open workings the richer portion of the ore occurs in 

 part beneath the basalt and in part in its lower portion. Above the richer 

 bodies comes a mixture of sulphur and cinnabar and at the original sur- 

 face no mercuric sulphide whatever was found. These facts can hardly be 



