SHOOTING STARS AND FIRE BALLS. 



toward the opposite. Now, although the observations seem to 

 show that the predominating direction is from north-east to south- 

 west, yet shooting-stars are observed on the same nights to 

 emanate from all points of the heavens, and to move in all 

 possible directions. 



Secondly, their average velocity (especially as determined by 

 Wartmann) greatly exceeds that which any body circulating 

 about the sun can have at the distance of the earth. 



Thirdly, from their appearance, and the luminous train which 

 they generally leave behind them, and which often remains 

 visible for several seconds, sometimes for whole minutes, and 

 also from their being situated within the earth's shadow, 

 and at heights far exceeding those at which the atmosphere can 

 be supposed capable of supporting combustion, it is manifest that 

 their light is not reflected from the sun ; they must therefore be 

 self-luminous, which is contrary to every analogy of the solar 

 system. 



Fourthly, if masses of solid matter approached so near the 

 earth as many of the shooting-stars do, some of them would 

 inevitably be attracted to it ; but of the thousands of shooting- 

 stars which have been observed, there is no authenticated 

 instance of any one having actually reached the earth. 



Fifthly, instead of the meteors being attracted to the earth, 

 some of them are observed actually to rise upward, and to 

 describe orbits which are convex toward the earth, a circumstance 

 of which, on the present hypothesis, it seems difficult to give 

 any rational explanation. 



From the difficulties attending every hypothesis which has 

 hitherto been proposed, it may be inferred how very little 

 real knowledge has yet been obtained respecting the nature 

 of the shooting-stars. It is certain that they appear at great 

 altitudes above the earth, and that they move with prodigious 

 velocity, but everything else respecting them is involved in 

 profound mystery. From the whole of the facts, M. Wart- 

 mann thinks that the most rational conclusion we can adopt 

 is, that the meteors probably owe their origin to the dis- 

 engagement of electricity, or of some analogous matter, which 

 takes place in the celestial regions on every occasion in which 

 the conditions necessary for the production of the phenomena 

 are renewed. 



The presumption in favour of the cosmical origin of the 

 shooting-stars is chiefly founded on their periodical recurrence 

 at certain epochs of the year, and the extraordinary displays of 

 the phenomena in various years on the nights of the 12th or 13th 

 of November. 



151 



