SOURCE OF WATER OF VULCANISM 285 



mines, however, rather goes to show that the permeation of water through 

 pores of rocks gets feeble as we descend." 



Still another argument against the water of vulcanism being derived 

 from the surface has been the fact that the volcanic rocks were largely 

 composed of water-making gases, which entered into combinations far 

 below the surface and under conditions of temperature where surface 

 water could not exist. 



It is well known that the crystals of deep-seated igneous rocks contain 

 gas and liquid-filled cavities, due to the presence of gas or steam in the 

 crystal at the time of consolidation. The usual gas is hydrogen, with 

 traces of oxygen and carbon-dioxide. Sometimes it is entirely carbon- 

 dioxide or hydrogen and hydrocarbons ; the liquid cavities are usually 

 filled with water in which carbon-dioxide may be present. In most of 

 these cases the liquid inclusions are to be referred to the conditions in 

 which the mineral crystallized out of the original magma. 



The fact that granite, a deep-seated magma, when heated to 1,000 de- 

 grees centigrade was found by Gautier to give off more than 20 times 

 its own volume of gases and 89 times its volume of steam as vapors shows 

 that under the conditions of original solidification these gases were present 

 in the deep-seated interior. 



Professor Kemp quotes him as follows : 



11 If we give due weight to the expansive power which these rock gases must 

 develop whenever the pressure upon the heated rock in the interior of the earth 

 permits, we see that the old theory of the production of volcanic outbreaks by the 

 introduction of water is no longer necessary. By a still stronger ignition the volume 

 of the emitted gases appreciably increases. . . . When one realizes the ex- 

 plosive power which this implies, one may dismiss the introduction of surface 

 waters into the glowing reservoirs of rock from the theories of volcanic action." * 



"The abundant occlusion of hydrogen in meteorites and the capacity of many 

 terrestrial substances, notably melted metals, to absorb large quantities of gases 

 and vapors without chemical combination and to emit them on cooling with 

 eruptive phenomena, not unlike those of volcanoes, have also led some observers 

 to conclude that the gaseous ejections at volcanic vents are portions of the original 

 constitution of the magma of the globe, and that to their escape the activity of 

 volcanic vents is due." 



Thinkers who took the view that the water as well as the rocks were 

 protomagmatic did not make much impression against the crustal vul- 

 canologists, however (judging by the way in which crustalists continued 

 to pour in the ocean into the roots of the recently active West Indian 

 volcanoes), until recently when they found a new champion in Professor 

 Suess, of Vienna, who, with Geikie, stands preeminent among the world's 

 greatest geologists. 



*Zeitschrift fur Praetische Geologie, October, 1901, p. 303 ; cited by J. F. Kemp, Trans. Amer. 

 Inst. M. E., October, 1903. 



