v METEORS AND COMETS 277 



of time, when the glare began to die down, it 

 recovered the distinctive appearance of a comet. 

 In this fiery phenomenon there were many points 

 worthy of remark, none more so than this, that, 

 immediately it shone in the sky, the sea came 

 over Buris and Helice. Did Aristotle, then, one 4 

 may ask, believe that not merely that beam but 

 all beams are comets? Surely not, for there is 

 this difference, that beams have their fire continuous, 

 while in the other bodies it is dispersed. Beams 

 have a regular flame, not interrupted or dull at 

 any point, while in the end parts it is condensed, 

 just like what Callisthenes describes the one to 

 have been, to which I referred a moment ago. 



VI 



THERE are, Epigenes goes on to say, two classes i 

 of comets. One kind sheds its light on all sides 

 without changing its position ; the other extends a 

 loose kind of fire in one direction, after the fashion 

 of hair, and passes through among the stars ; of 

 the latter kind were the two seen in our own days. 

 The former variety, with hair on all sides, that 

 do not move, are usually low down, and arise from 

 the same causes as beams and torches, that is, 

 from a distempered thick atmosphere that carries 

 in it many of the earth's exhalations, both dry and 

 moist. Air driven out through narrow apertures 2 

 is capable of setting on fire the atmosphere situated 

 over it, which is full of elements suitable for feeding 

 a fire ; and it is able after that to drive it forward 

 from the clear space, lest from any cause it should 

 fall back and relax its force. After that, it can rise 



