NEW YORK ACADEMY OF SCIENCES 655 



that they are very important foundations of local institutions 

 and profitable enterprises. Professor Suess, whom I have 

 earlier cited, delivered an address a few years ago at an anni- 

 versary celebration in Carlsbad, Bohemia, in which he stated 

 that Rosiwal, who had studied the Carlsbad district, could not 

 detect any agreement between the run of the rainfall and the 

 outflow of the springs, and that both the unvarying composition 

 and amount through wet seasons and dry were opposed to 

 a meteoric source. Water, therefore, from subterranean igneous 

 rocks, well known to exist in the locality, was believed to be 

 the source of the springs. The same general line of investigation 

 has led Dr. Rudolf Delkeskamp, of Giessen, and other observers 

 to similar conclusions for additional springs, so that magmatic 

 waters have assumed a prominence in this respect which leaves 

 little doubt as to their actual development and importance. 



All familiar with Western and Southwestern mining regions 

 know, as a matter of experience, that the metalliferous veins are 

 almost always associated with intrusive rocks, and that in very 

 many cases the period of ore formation can be shown to have 

 followed hard upon the entrance of the eruptive. The conclu- 

 sion has, therefore, been natural and inevitable that the mag- 

 matic waters have been, if not the sole vehicle of introduction, 

 yet the preponderating one. 



With regard to their emission from the cooling and crystal- 

 lizing mass of molten material we are not, perhaps, entirely clear 

 or well established in our thought. So long as the mass is at 

 high temperatures the water is potentially present as dissociated 

 hydrogen and oxygen. We are not well informed as to just 

 what is the chemical behavior of these gases with regard to the 

 elements of the metallic minerals. Hydrochloric acid gas is 

 certainly a widely distributed associate. If, as seems probable, 

 these gases can serve, alone or with other elements, as vehicles 

 for the removal of the constituents of the ores and the gangue, 

 the possibilities of ubiquitous egress are best while the igneous 

 rock is entirely or largely molten. In part even the pheno- 

 mena of crystallization of the rock-forming minerals themselves 

 may be occasioned by the loss of the dissolved gases. Through 

 molten and still fluid rock the gases might bubble outward if 



