NEW YORK ACADEMY OF SCIENCES 657 



In closing I may state that, speculative and uncertain as our 

 solution of the problem of the metalliferous veins may seem, it 

 yet is involved in a most important way with the practical 

 opening of the veins and with our anticipations for the future 

 production of the metals. Every intelligent manager, superin- 

 tendent or engineer must plan the development work of his mine 

 with some conception of the way in which his ore-body originated, 

 and even if he alternates, or lets his mind play lightly from 

 waters meteoric to waters magmatic, over this problem he must 

 ponder. On its scientific side and to an active and reflective 

 mind it is no drawback that the problem is yet in some respects 

 elusive and that its solution is not yet a matter of mathematical 

 demonstration. In science the solved problems lose their inter- 

 est; it is the undecided ones that attract and call for all the 

 resources which the investigator can bring to bear upon them. 

 Among those problems which are of great practical importance, 

 which enter in a far-reaching way into our national life and 

 which irresistibly rivet the attention of the observer, there is none 

 with which the problem of the metalliferous veins suffers by 

 comparison. 



