226 Professor Gustav Bischof on the 



spar, &c. in the supposed gaseous form, would immediately 

 become condensed at a temperature below that required for 

 their vaporization. We must, therefore, assume that the 

 walls of the fissures, as far upwards as vein-masses are 

 found in them (therefore in most cases as high as their out- 

 goings), must have been heated to the temperature required 

 for their vaporization, if indeed the vapours did not neces- 

 sarily condense beneath. Such a high temperature could 

 not, however, be imagined with regard to the crystalline 

 rocks, if the formation of the vein immediately followed the 

 crystalline consolidation ; because the point of vaporization 

 of the granite could not be considered as higher than that of 

 heavy-spar, quartz, &c., for the latter are more fixed than 

 granite is. Still less can a cause be discovered for the 

 heating of the walls of fissures in neptunian rocks to such a 

 degree that the sublimations should reach to the outgoings 

 of the veins. I believe, however, that it is unnecessary to 

 pursue the argument further against the sublimation-hypo- 

 thesis. 



In conclusion, I may be allowed to speak of two other 

 topics. In the first place, of the possibility of a watery solu- 

 tion of all the vein-masses occurring in metalliferous veins ; 

 and, in the second place, the manner in which the circulation 

 of watery solutions can be conceived to have taken place in 

 vein-fissures. 



Silica, and the bicarbonates of lime, magnesia, protoxide of 

 iron, and protoxide of manganese, are soluble in water, and 

 they are the usual constituents of mineral waters ; the for- 

 mation, therefore, of quartz, calcareous-spar, sparry-iron, 

 manganese-spar, and brown-spar, in the moist way, cannot, in 

 the smallest degree, be doubted. I have shewn, in regard to 

 heavy-spar, that it can be dissolved in a warm solution of 

 the carbonate of soda, which is diluted to the extent it is in 

 our carbonated mineral waters containing soda ; in which 

 case a mutual decomposition takes place, but subsequently, 

 during the cooling, a regeneration.* The possibility of the 

 introduction of heavy-spar into fissures in the moist way, 



* Poggendorffs Annalen, vol. Ix., p. 291. 



