1 8 NEW YORK STATE MUSEUM 



the water manifested in volcanic eruptions as too improbable to 

 deserve confidence. Water locked up in hydrated silicates which 

 are melted into a rising flood of fused rock might become in- 

 volved. Possibly confined reservoirs of artesian water which 

 had no escape might also be absorbed, but it seems still more 

 reasonable to -think of the water gas, the carbonic acid and the 

 other gases as original component parts of the magma, belonging 

 to it as much as the silica and the common run of bases. 



The presence of this water is still further shown by the effects 

 exerted upon limestones where penetrated by masses of molten 

 rock which have never reached the surface. So many new 

 minerals have been produced partly from the limestone and 

 partly by contributions from the igneous mass, that the agency 

 of magmatic waters has been invoked by almost all students of 

 the subject in order to explain the results. 



In regions of dying volcanic activity, hot springs and emis- 

 sions both of carbonic acid gas and of carbonated waters are the 

 rule. Where the composition of the waters is markedly different 

 from the composition of the rocks through which they rise, some 

 observers have seen reason to attribute to them a deep-seated 

 magmatic source. Carlsbad, Bohemia, with its springs rich in 

 lime, arising from granite, a rock extremely poor in lime, is a 

 famous case in point. Deep-seated magmatic waters, have seemed 

 to some observers the simplest explanation. 



The waters are presumably evicted from the molten mass in its 

 process of crystallization into the anhydrous silicates which make up 

 the ordinary igneous rock. Obviously existing first as gases in the 

 deep-seated mass, they pass with loss of heat into the liquid form 

 and furnish hot springs and in their later stages possibly cold ones. 

 The waters were called "juvenile" by E. Suess, the venerable 

 Austrian geologist, because they reach the surface for the first time 

 and therefore are young, or newly born. In America the name 

 magmatic is somewhat more current. 



In the most recent of the more important contributions to this 

 subject,"^ P. Brun gives a number of analyses of gases which he has 

 collected from regions of dying volcanic activity. He fails to find 

 water gas in notable quantity, but does detect much hydrochloric 

 acid. He concludes that the vapors which have been hitherto 

 observed arising from volcanic vents are ammonium chlorid and 



1 P. Brun. Recherches siir I'exhalaison volcaniques, Geneva, 191 1. The 

 work is summarized in English by Alex. Winchell in Economic Geology. 



