CIRCULATION OF WATER. 665 



As to the direction of circulation for a given depth, it can be said that 

 the movements would be from places of greater pressure and higher tem- 

 perature to places of less pressure and lower temperature. It seems 

 probable that the water would move laterally from places of intense orogenic 

 movement to places of less strong orogenic movement. It seems probable 

 that water would move away from places of igneous intrusions, because 

 these produce high temperatures and pressures. 



But the water movements of greatest geological interest are the 

 vertical movements. Does water make its way downward from the belt 

 of cementation or upward from the centrosphere into the zone of 

 anamorphism? 



It has been explained that the water at the upper part of the zone of 

 anamorphism is under great pressure and at high temperature. It might be 

 supposed, under these circumstances, that the water would make its way 

 downward into the rocks below. This has been a favorite hypothesis of 

 those who have explained the water contained in magmas issuing from 

 volcanoes as of surface origin. The experimental work of Daubree has 

 been appealed to in support of this view. Daubree showed that water gas 

 at a temperature of 160° C. penetrated through a slab of fine-grained sand- 

 stone 2 centimeters thick, and produced a pressure upon the other side of 1.9 

 atmospheres (1,963.2 grains per sq. cm.).° However, it is to be remarked that 

 an essential point in this experiment is that the amount and pressure of water 

 gas are very much less upon the side of the rock to which the water makes 

 its way than upon the other side, for to hold water as liquid at a temperature 

 of 160° C. a pressure of about six atmospheres is required. If there were 

 no water in the zone of anamorphism there is little doubt that the water 

 would make its way from the belt of cementation into the zone of anamor- 

 phism until equilibrium were reached. The force tending to carry this water 

 downward is that of gravity, and is equal to the pressure of a column of 

 water from the bottom of the belt of cementation to the surface. But before 

 we can assume that this pressure is sufficient to drive the water into the 

 zone of anamorphism we must be certain that the pressure in that zone is 

 not as great as or greater than in the lower part of the belt of cementation. 



We have seen that water may be present in the zone of anamorphism 

 from at least three sources. This water is under the high pressure of the 



"Daubree, A., Etudes Synthetiques de Geologie Experimentale, pt. 1, Paris, 1879, pp. 236-241. 



