Origin of Quartz and Metalliferous Veins. 229 



know what the mineral waters of the present day deposit 

 in their channels. These channels cannot yet be blocked 

 up, otherwise the springs must long ago have ceased to flow. 

 Moreover, it is not necessary for us exclusively to assume a 

 circulation of water in the manner of our existing mineral 

 springs in the fissures of metalliferous veins. It can have 

 taken place in a simpler way, which is equally conceivable, 

 at every level, — whether in the silver mines of Huantajaya 

 in Peru, which are situated at a height of 12,000 feet above 

 the level of the sea, or in the mines of Cornwall, which de- 

 scend to a depth of a thousand feet below the sea. 



Thus, when the first fissures, however narrow they were, 

 were formed in a rock, they must have been immediately 

 filled with meteoric water. If the fissures did not traverse 

 the rock throughout its whole length, that is to say, if they 

 were closed or terminated like a wedge, they must have re- 

 mained filled with water. Now, as this water penetrated to 

 a great depth where a high temperature prevailed, it would 

 be heated to a great degree, or even if the hydrostatic pres- 

 sure admitted of it, converted into vapour. If vein-masses 

 existed at these depths, they would be dissolved by the hot 

 water and by the vapour ; and, in this manner, the hot, and 

 specifically lighter fluid, would rise up from beneath. A 

 circulation would thus be established like that we see in our 

 vessels containing water when they are heated from below. 

 Hence we can understand how, in fissures, after they have 

 been once filled with water, an uninterrupted aqueous circu- 

 lation would take place, by means of which substances would 

 be transported from beneath to the surface. The water lost 

 by vaporization would continue to have its place supplied by 

 new meteoric water. 



and Micuipampa in Peru indicate their great riches on the surface of the 

 soil, as well in the mountains of Gualgoyac, as at Fuentestiana, Cor- 

 molache, and in the Pampa of Navar. On the last mentioned plateau, 

 everywhere within a circuit of more than half a league in extent, vitre- 

 ous silver and filiform native silver are found attached to the grass roots 

 whenever the turf is removed (Von Humboldt in Karsten's Archiv, vol. 

 xvii. p. 368). The same was the case in early times at Johann-Georgen- 

 stadt. 



