xxv FAMOUS EARTHQUAKES 257 



standing above the area of disturbance are thrown 

 down. Sometimes it goes to such lengths that 

 the walls by which the whole roof of the cavern is 

 supported fall right down into that vacant under- 

 ground space, and cities sink entire into the 

 unfathomed depths. Long ago, if one may believe 2 

 the story, Ossa and Olympus were united; subse- 

 quently they were separated by an earthquake, and 

 the one great mountain was split into two. Then 

 the Peneus made its escape, draining the marshes 

 with which Thessaly was overspread, and drawing 

 off the waters, which from want of exit had hitherto 

 formed a lake. It was an earthquake that let loose 

 Ladon, the river which flows between Elis and 

 Magalenopolis. What, it is asked, do these facts 

 go to prove ? Simply that air gathers in the spacious 3 

 caves for what other name can I apply to the 

 empty places under the earth ? Were this not so, 1 

 great spaces of the earth would be convulsed, and 

 many of them would totter to ruin at one and the 

 same time. As it is, only small portions suffer, nor 

 does a shock ever extend as much as two hundred 

 miles. Look at the recent one, the marvellous tales 

 of which have filled the whole world ; it did not 

 pass beyond Campania. Need I say that when 4 

 Chalcis felt the earthquake shock Thebes did not 

 fall ? when Aegium suffered, Patras, which is quite 

 close by, only learned by report about the earth- 

 quake ? That mighty shock, which swallowed up 

 the two cities Helice and Buris, stopped short 

 of Aegium. Plainly, then, the movement extends 

 only such distance as the empty space underground 

 stretches. 



I.e. were the air distributed all through the earth. 



