304 PHYSICAL SCIENCE BK. vii 



north, and passing by way of the west, reached the 

 southern quarters, and was elevating its orbit when 

 3 it faded from sight. That other one, in Claudius 

 reign, also first appeared in the north, and con 

 tinued without intermission to rise straight up to 

 a higher elevation until it disappeared. Such are 

 the matters relating to comets which have had 

 weight with others and with myself. Whether they 

 are true or not, those who attain knowledge of the 

 truth must decide. We are permitted only to con 

 jecture and grope in the dark, with no assurance of 

 discovery, and yet not without hope. 



XXX 



1 ARISTOTLE has finely said that we should never be 

 more reverent than when we are treating of the 

 gods. We enter a temple with all due gravity, 

 we lower our eyes, draw up our toga, and assume 

 every token of modesty when we approach the 

 sacrifice. How much more is all this due when 

 we discuss the heavenly bodies, the stars, the 

 nature of the gods, lest in ignorance we make 

 any assertion regarding them that is hasty, or dis- 



2 respectful ; or lest we wittingly lie. Let us not 

 be surprised that what is buried so deeply should 

 be unearthed so slowly. Panaetius and others, 

 who will have it that a comet is not an ordinary 

 star but the mere counterfeit of a star, have bestowed 

 careful treatment on the question whether all seasons 

 of the year are equally fitted to produce comets, 

 and whether all quarters of the sky are equally 

 suitable for their creation. They have inquired, 

 too, whether they can be formed in all regions 



