FIRE AS CAUSE 237 



in seeking an exit meets obstructions and bursts 

 through all obstacles, until it has either found a way 

 of escape to the light through the narrow passages, 

 or has made one for itself by violence and destruc- 

 tion. Other writers who still believe the cause to lie 

 in fire do not suppose that this is its method of 

 action : they think the fire presents itself in more 

 than one place and burns away everything in the 

 vicinity. Then if the parts eaten away fall in at 

 any time, a shock follows in the portions which are 

 deprived of their supports ; they first totter and then 

 collapse ; nothing encounters them to support their 

 weight. Then chasms and vast gulfs are opened 3 

 up, or it may be, after hanging a long time in the 

 balance, the ground settles down over what is still 

 left standing. We see the same thing happen ordi- 

 narily as often as a part of the city suffers from a fire. 

 The joists are burnt through, or what gave support 

 to the upper part of the buildings is undermined. 

 Then the roofs after tossing about for a long time 

 fall in ; their swaying and oscillating continue until 

 they find a resting-place on solid ground. 



ANAXIMENES affirms that the earth is itself the 

 cause of the earthquake, and that nothing encounters 

 it from without to give it a shock. Within it, he 

 thinks, certain parts of its substance fall of themselves, 

 either loosened by moisture, or eaten away by fire, 

 or shaken off by the violence of air. But even in 

 absence of such active cause there is not wanting 

 sufficient to account for the loss or removal of some 

 portion of the earth. In the first place, all things 



