38 PHYSICAL SCIENCE BK. i 



circular grotto excavated in it. Then there are 

 Pithitae (barrel-shaped meteors) when a vast circular 

 mass of fire like a cask either rushes through the 



2 sky, or blazes away in one spot. There are 

 Chasmata (chasms), too, when there is a subsidence 

 of some portion of the heavens, which sends out 

 hissing flame, as it were, from its hidden recesses. 

 There are also a great number of colours in all 

 these. Some are of brightest red, some of light 

 insubstantial flame, some of white light, some 

 glittering, some with a uniform glow of orange 

 without sparks or rays. We see, therefore, 



The stars' long tracks that gleam white behind. 



3 These stars, for so they appear to be, dart forth 

 and flit across the sky, and by reason of their 

 extraordinary rapidity seem to leave a long trail 

 of fire. Our sight cannot follow their course, and 

 wherever their career leads we imagine the heaven 

 is all on fire. Such is the swiftness of their flight 

 that its separate portions are not distinguished 

 and it can be grasped only as a whole. We are 

 aware rather of the quarter in which the star 



4 appears than of its route. It, therefore, seems to 

 mark its entire course with a line of continuous 

 fire, because the slowness of our vision fails to keep 

 pace with the stages of its career and sees at the 

 same moment the start and the finish ; as happens 

 in a flash of lightning, the fire seems a long train 

 because the meteor traverses its path rapidly and 

 the space through which it falls presents itself to 

 our eyes as a whole. But, as a matter of fact, the 

 fire does not extend itself all through the space 



5 crossed by the meteor. Nor have such long thin 

 bodies strength enough for the effort. How, then, 



