The Mighty Deep 



Such shocks are fearfully common in some 

 parts. In Japan, for instance, it was noted that 

 nine thousand had been felt in the course of 

 only eight years ; and in one great earthquake 

 alone — that of October 26th, 1891 — almost ten 

 thousand human beings perished. 



Movements of the crust, whether slow or 

 rapid, are not due always and only to the 

 shrinkage of the central portions of our g.obe, 

 and to the sinking and re-adjustment of the 

 strata. 



There are mighty fire-forces below ; rrolten 

 materials pent up, waiting for the slightest yield- 

 ing of the solid crust to fight their way out ; 

 heated and imprisoned gases struggling for 

 freedom. Sometimes these captive giants escape 

 through what may be termed the orthodox safety- 

 valves, old volcanic vents. Sometimes they break 

 open new craters for themselves. Sometimes 

 they fail to get out, and only shake the ground, 

 or force it gently upward. Though earthquakes 

 are more usually ascribed to the effects of a 

 steady " crust-creep," they are sometimes caused 

 by heated gases seeking liberty. 



These heavings and twistings, these crumplings 

 and sweiyings, of the earth-crust do not belong 

 only to land, but go on in the same manner 



120 



