vii WATER AS CAUSE OF EARTHQUAKE 233 



VII 



SOME, who, like Thales, attribute earthquake to the i 

 effects of water, give a different explanation of its 

 operation. There are, they say, many kinds of 

 waters running over the whole earth. In one 

 place there are constant rivers whose size renders 

 them fit for navigation, even without the aid of 

 rains. There is the Nile, rolling down its huge 

 volume all summer long : here are the Danube and 

 the Rhine separating with their streams the peaceful 

 from the hostile, the former checking attacks from 

 the Sarmatians and forming the boundary between 

 Europe and Asia, the latter keeping back the 

 Germans, a nation ever keen for war. Then there 2 

 are lakes of very wide extent, great pools surrounded 

 by tribes mutually ignorant of each other, marshes 

 that no boat can struggle through, that cannot be 

 passed even by the people that dwell on their 

 borders. Add, then, the multitude of fountains, and 

 of river sources that belch out of their recesses full- 

 grown streams. Besides, there are many rushing 

 torrents that gather only for a time, whose force is 

 as shortlived as it is sudden. Now there are waters, 

 in all this variety of form and character, within as 3 

 well as above the earth. Away there below some are 

 borne along in vast bulk, and tumble their whole 

 volume down the steep : others more sluggish are 

 dammed back in shallows, and flow with gentle, quiet 

 stream. And can any one deny that within those 

 vast underground hollows waters are formed, and lie 

 sluggish and inactive in many places? It needs no 

 long proof to show that there must be many waters 



