232 PHYSICAL SCIENCE BK. vi 



a boat leans over to one side away from the straight, 

 the result is that it ships water. And, generally 

 speaking, in the case of all objects which water 

 supports, if they are unduly sunk, the water either 

 pours over them or at any rate rises to right and 

 left above its ordinary height. 



3 Now, no lengthened consideration is needed 

 to prove the falsity of this view. Why, if the 

 earth were supported by water, and from time 

 to time shaken by it, it would be in perpetual 

 shock ; the wonder would be not that it was 

 tossed about sometimes, but that it was ever at 

 rest. Then, again, it would be shaken all over and 

 not at a single point : we never find only half the 

 ship tossed by the waves. But, according to present 

 experience, a shock never occurs over the whole 

 earth simultaneously, but is always felt at some 

 particular spot. How, then, can it be that what is 

 carried as a whole is not shaken as a whole, if the 

 shock comes from the body by which it is carried ? 



4 But, it may be urged, why do waters burst out at 

 the time of earthquakes ? Well, in the first place, 

 there has often been earthquake without any fresh 

 supply of water appearing. Secondly, if the sup 

 posed cause of the water rushing forth were the 

 true one, it would pour all round the sides of the 

 earth, as we see happening under similar circum 

 stances in sea and rivers : when boats sink, the 

 increase of water shows itself chiefly over the sides. 

 Finally, the outburst of waters which Thales de 

 scribes would not be so small as he says, nor would 

 it ooze in like bilge-water through a chink, but from 

 the exhaustless reservoir that upbears all creation, 

 a mighty deluge would ensue. 



