PREVIOaS INVESTIGATIONS. 23 



ble indication for the future of the Comstock Lode ; as, besides the growinj^ 

 difficulty of metallurgical treatment, the conclusion would be justified that 

 lead ores would more and more replace those of silver, and the limits of 

 profitable productiveness would soon be reached. But as it is, no deterio- 

 ration is to be expected, even if an impoverishment takes place. It thus 

 approaches in its ore-bearing character the great mother-veins of Mexico, 

 and is different from those of Hungary. 



Conclusions. — Considcring these facts exhibited by the Comstock vein 

 itself, and comparing them with what is known about similar argentif- 

 erous veins, we believe we are justified in drawing the following conclu- 

 sions : 



1st. That the continuity of the ore-bearing character of the Comstock 

 Lode in depth must, notwithstanding local interruptions, be assumed as a 

 fact of equal certainty with the continuity of the vein itself. 



2d. That it may be positively assumed that the ores in the Comstock 

 Lode will retain their character of true silver ores to indefinite depth. 



3d. That it is highly probable that extensive bodies of ore equal in 

 richness to the surface-bonanzas will never recur in depth. 



4th. That an increase in size of the bodies of ore in depth is more 

 probable than a decrease, and that they are more likely to increase than 

 to remain of the same size as heretofore. 



5th. That a considerable portion of the ore will, as to its yield, not mate- 

 rially differ at any depth from what it is at the present lower levels; while 

 besides there will be an increasing bulk of low-grade ores. We are led to 

 this supposition by the similarity in character of all the deposits outside of 

 the rich surface-bonanzas, and the homogeneous nature which almost every 

 one of them exhibits throughout its entire extent. 



6th. That the ore will shift at different levels from certain portions of 

 the Lode to others, as it has done up to the present time. More equality 

 in its distribution may, however, be expected below the junction of the 

 branches radiating toward the surface, when the vein will probably fill a 

 more uniform and more regular channel. Some mines which have been 

 heretofore almost unproductive, as the Central, California, Bullion, and others, 

 have therefore good chances of becoming metalliferous in depth. But 



