COMETS. 21 7 



like condition, and at that time capable of emulating 

 the comet-expelling feats of the great central sun. 



Are these thoughts too wild and fanciful to be 

 entertained? They may appear so; yet where are 

 we to find others less amazing ? The comets of the 

 various orders short-period, long-period, and non- 

 periodic are there. Their existence has to be in some 

 way accounted for ; or if such explanation is at present 

 impossible, as seems likely, we may yet follow the 

 various lines of reasoning which present themselves. 

 And we have very little choice. Take a comet of long 

 period passing near the orbit, let us say, of Uranus 

 even as Tempel's comet, the parent of the November 

 meteors, is known to do. Either that comet has been 

 gathered in from outer space by the sun, and compelled 

 to follow its present path by the disturbing influence 

 of Uranus, or else what ? Only two other theories 

 are available. Trace back the comet's path in imagin- 

 ation, round and round that oval path, which carries it 

 across the paths of Uranus and the earth but nowhere 

 else brings it within millions of miles of any possible 

 disturbing influences. Rejecting the earth as insuffi- 

 cient in attractive might (or, at least, so inferior to 

 Uranus as to leave us in no doubt in selecting between 

 the two), we have only during the past of the comet, 

 as so traced, the planet Uranus to which we can refer 

 it. We have rejected the attractive influence of 

 Uranus ; but two other influences remain. Eruptive 

 action in a former sun-like state, an action correspond- 

 ing to the eruptive processes known to be taking place 



