REFUTATION OF STOICS 295 



XXII 



I DO not agree with my school here, for I cannot i 

 think a comet is a sudden fire, but I rank it among 

 Nature's permanent creations. First of all, every- 

 thing that the atmosphere creates is short-lived ; 

 such things arise in an element that is fugitive and 

 changeable. How can anything continue the same 

 for long in the air, which itself never remains the 

 same ? It is always in a state of flux, and its quiet 

 is short-lived. It changes within a brief moment 

 to another condition from that in which it had been. 

 It is now rainy, now clear, now alternates from 2 

 one to the other. The clouds, so intimately con- 

 nected with it, into which it collects and from which 

 it is released again, now gather, now disperse, but 

 never remain at rest. Fire cannot possibly abide 

 securely in a volatile body, nor can it keep its place 

 so persistently as does a fire that Nature has fixed 

 never to be dislodged. Further, if the fire stuck 

 close to its fuel, it would always sink. For the air 3 

 is the thicker, the nearer it is to the earth. But a 

 comet is never depressed to the lowest strata of the 

 atmosphere, nor does it ever approach the ground. 

 Besides, fire either goes in the direction its nature 

 prompts, that is, upwards, or else in the direction 

 in which it is drawn by the material on which it 

 has fastened, and on which it feeds. 



XXIII 



IN none of the ordinary fires in the sky is the route 

 curved ; it is distinctive of a star (planet) that it 



