660 A TREATISE ON METAMORPHISM. 



in. reference to it, for the laws controlling its movements and metamorphic 

 action are precisely the same as those governing the heated water of the 

 belt of cementation. (See pp. 566-646.) But at depths greater than about 

 11,000 meters the water must be supposed to be gas. Moreover, in conse- 

 quence of igneous intrusions and orogenic movements, the critical tempera- 

 ture is probably frequently attained over extensive areas at depths much 

 less than this. Therefore it is highly probable that for much of the zone of 

 anamorphism the water is in the form of gas, not liquid. 



The general statement may be made that, for the greater part of the 

 zone of anamorphism, water is in the form of water gas, but that for con- 

 siderable portions of the upper part of the zone the water is in the form 

 of liquid. Thus, in this matter the zone of anamorphism is in direct oppo- 

 sition to the zone of katamorphism, where the water is dominantly in the 

 form of liquid and only exceptionally in the form of gas. 



The probable action of water gas in the zone of anamorphism should 

 be considered. What are the differences between the circulation and work 

 of water in the form of liquid at high temperatures and under great pressures 

 and the circulation and work of water gas at such temperatures and 

 pressures? At the pressures existing in the zone of anamorphism it is 

 certain that the gas would be dense. At the depth of 10,950 meters the 

 pressure per square centimeter of a hydrostatic column of water to the 

 surface would be 1,095 kilograms, or 1,060 atmospheres. 



The density of water gas at atmospheric pressure and 100° C. is 

 0.0006 of the density of water at 4° C. Assuming, for purposes of calcu- 

 lation, that, under the temperatures and pressures given, water gas acts as 

 a perfect gas, H. C. Wolff has calculated for me that at a pressure of 1,060 

 atmospheres and at the critical temperature of water (365°), the density of 

 the gas would be 2.32 times the density of water at 4° C, a result almost 

 certainly too great, but still indicating that the gas is very dense. 



In a very dense gas the molecules attract one another," and in so far 

 as this is true the gas approaches a liquid. It is certain that superheated 

 water at high temperature has a low viscosity and remarkable chemical 

 power, as shown on pages 79-81, 105-110, 140-141. In so far as the water 

 gas in the openings of the zone of anamorphism is less dense than the liquid 



«Nernst, W., Theoretical chemistry, trans, by O. S. Palmer, Macmillan & Co., London, 1895, 

 p. 185. 



