Now, no lengthened consideration is needed to prove the falsity of 3 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? But, it may be urged, why do waters burst out at the time of earth- 4 quakes? Well, in the first place, there has often been earthquake without any fresh supply of water appearing. Secondly, if the supposed 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 circumstances in sea and rivers: when boats sink, the increase of water shows itself chiefly over the sides. Finally, the outburst of waters which Thales describes 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. VII Some, who, like Thales, attribute earthquake to the effects of water, 1 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 are lakes of very wide extent, great pools surrounded 2 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 well as above the 3 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 in the place where all waters are. The