Disturbance of the Crust of the Earth, 7 



and tho hot fluid below, a vast amount of elastic matter greatly 

 compressed, and in a highly heated state. 



3. Now, let us suppose the expansive force to have at 

 length overcome the resistance of the solid crust, to have 

 broken it up, and to have elevated the Alps, as we see them, 

 to heights beyond the line of perpetual congelation. A vast 

 amount of compressed elastic matter, escaping by sudden ex- 

 pansion at the moment of the rupture, especially if this took 

 place in the winter season, would be followed by two special 

 effects. The first, from the immense abstraction of heat by 

 the escape of the vaporable matter would be a great refrige- 

 ration of the broken masses. Their exposure to atmospheric 

 influence would also operate in reducing the temperature. 

 The second effect would be, that the expansive force would 

 greatly accelerate the progress of the vapour (which we may 

 safely assume to have been almost exclusively that of water) 

 into the higher regions of the atmosphere, where it would be 

 frozen, and in this state fall back upon the surface and con- 

 tribute still more to its refrigeration. That which fell above 

 the line of perpetual snow would continue long unaffected by 

 subsequent increase of temperature in the crust. That which 

 fell below it would soon become a mass of considerable thick- 

 ness and solidity, but which, in process of time, as the crust 

 of the earth regained its heat from below, would gradually 

 melt and disappear, leaving behind it those phenomena which 

 have given rise to so much discussion in our time. Besides 

 the large supply of vapour from the cavities in which it had 

 been pent up, it does not require any stretch of imagination 

 to suppose, that disruption of the crust would admit much 

 water into contact with the hot matter below it, and that thus 

 a very large additional quantity of vapour would be formed, 

 and ascend to the upper regions, operating also as a refri- 

 gerator.* 



* At the time when this paper was read, I was not aware that Charpen- 

 ticr, in his " Essai sur les Glaciers," &c. printed at Lausanne in 1841, had 

 proposed this access of water to the hot portion of the crust, at the moment 

 of its rupture, to account for the origin of glaciers. I have used it only as 

 a subsidiary means. 



