126 Star anfr TOeatber (gossip 



in its most interesting aspect in a quite recent com- 

 munication to me, he says he believes that planets, 

 asteroids, comets and meteors, whether original 

 members of the Solar System or received into it by 

 capture, are all moving round the sun in ellipses, 

 parabolas, or hyparabolas, but much the greater part 

 in ellipses, and therefore with periodic returns, though 

 some of the ellipses are very elongated, and the corre- 

 sponding periods very long. " When a body thus 

 travelling is of small size and enters the atmosphere 

 with the high velocity due to its orbit, it becomes 

 red-hot from the heat developed by the friction, then 

 white-hot, then it melts, and finally it vaporises and 

 disappears by getting mingled with the air. It is not 

 burned." 



Different meteors enter the air with different 

 velocities. As Mr. Monck says : " One with a retro- 

 grade orbit will be going faster than one with a direct 

 orbit, and one of long period than one of short. Where 

 an initial velocity of 40 miles per second would lead 

 to the dissipation of the meteor at the height of, say, 

 25 miles, the same meteor, if entering with a velocity 

 of 10 miles per second, might escape complete dissipa- 

 tion and drop on the earth an unmelted core." The 

 Leonids and Perseids have high velocities and conse- 

 quently do not produce aerolites or meteorites. Mr. 

 Monck contends that most feeble showers may give 

 rise to aerolites if they enter the atmosphere with 

 much diminished speed. He points out that Prof. 

 Newton, from an investigation of the narratives of 

 stone-falls, concluded that in the majority of cases they 

 were travelling in ellipses with direct motion and 

 small inclination to the ecliptic " like miniature 



