264 PHYSICAL SCIENCE BK. vi 



why should one think it worthy of remark that a 

 statue had been cut equally into two from base to 

 summit? But why, it may be asked, did the shock last 

 3 for several days ? For Campania went on trembling 

 continuously, more gently it is true, but still causing 

 great damage, because what it shook was already 

 shaken and crushed. Things stood so insecurely as 

 to require only a slight shake, but not a push, to 

 bring them down. The explanation of the prolonged 

 shaking is no doubt that all the air had not yet 

 escaped, but though the greater part was discharged, 

 a remnant was still roaming about here and there. 



XXXI 



THERE is yet a further proof that you may un- 

 hesitatingly add to the others that go to show that 

 all these phenomena are the outcome of air. After 

 the most violent shock that cities and provinces can 

 experience has spent itself, another of like violence 

 cannot immediately follow ; after the crisis there 

 are only slight shocks, just because the most violent 

 one has opened a way of escape for the struggling 

 winds. The remains of the air that is left have not 

 the same power, nor do they require to struggle ; 

 they have now found a way of escape, and follow the 

 path by which the first and greatest shock issued. 



I am of opinion, too, that the observations of a 

 certain learned and grave philosopher of my acquaint- 

 ance deserve to be put on record ; he happened 

 to be taking a bath when the earthquake occurred. 

 He asserted that he saw the tiles with which the 

 floor of the bathroom was paved, separate one 

 from another and unite again. At one moment, 



