E. THE CENTROSPHERE OR BARYSPHERE. 



CHAPTER XXIII. 



DIASTROPHISM, OR THE MOVEMENTS TAKING PLACE WITHIN 

 THE EARTH'S CRUST AND THEIR CAUSES.^ 



In discussing the subject of diastrophism under the heading 

 of the Centrosphere, it is intended to emphasize the fact that 

 the great mass of such movements is directly or indirectly induced 

 by gravity, i. e., the terrestrial phenomenon of weight or downward 

 acceleration,* which has for its two components the gravitation or 

 attracting force between bodies and the centrifugal force due to 

 the rotation of the earth on its axis. 



Other forces which induce earth movements have their origin 

 in the interior heat of the earth ; in chemical combination ; in molec- 

 ular attraction and repulsion ; in radio-activity ; in electrical and 

 vital energy; in the centrifugal energy due to the rotating of the 

 earth on its axis and its revolution around the sun ; in the attraction 

 of the moon and sun ; and in the radiant energy of the sun. Im- 

 pact with heavenly bodies may be further mentioned as a source 

 of possible energy. But all of these, except perhaps the last, 

 are of minor significance as compared with gravity as the great 

 source of energy influencing earth movements. The displacement 

 of the earth's center of gravity through any cause, and the conse- 

 quent displacement of the earth's axis, would also be a direct cause 

 of the setting free of a vast amount of available energy. 



CLASSIFICATION OF EARTH MOVEMENTS. 



Earth movements may be classified either as local disturbances 

 or as widespread or regional ones. The movements are manifested 



* The amount of downward acceleration is about 385.1 inches (978 centi- 

 meters) per second at sea-level at the equator, and 387.1 inches at sea-level at 

 the poles, diminishing slightly on mountain tops. The centrifugal force at the 



I 



equator is of gravity. 



880 



