686 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



moving when they were abandoned, the planets into which they 

 may be resolved must all move in the same direction — that^ viz., of 

 the rotation of the central orb or sun. Our subject is thus rapidly 

 simplifying. We have already — even at this stage — deduced from 

 this memorable hypothesis the necessity of the principal three of 

 those fundamental arrangen^ents which gravity could not explain. 

 But let us proceed. 



Resuming our direct investigation, we inquire now, what forms 

 would such rings most probably ultimately assume? There are 

 three possible forms : 1. The mass, if tolerably equable in its 

 original constitution, and undisturbed from without, might settle 

 down into a rotating ring; but the cliances against such a result 

 are so numerous, that M-e would expect the phenomenon .to be 

 very rare in the Universe. 2. If the mass broke up or separated 

 while condensing — as its own internal irregularities would, in all 

 probability, constrain it to do — it might divide into a number of 

 portions so equal in attractive energy, that none of them would 

 have any tendency to coalesce with, or fall into the others; so that 

 the ring Avould ultimately be transformed into a number of dis- 

 tinct small solid bodies, revolving around the central mass at 

 nearly the same distance from it. 3. Even this second supposition, 

 however, is not a very probable one, inasmuch as its essential con- 

 dition — the separation of the mass of the ring into equally bal- 

 anced nuclei — could, in the nature of things, occur but rarely. 

 By far the likeliest result is the division of the ring into nulcei of 

 unequal power — the larger of which would, by its superior attrac- 

 tion, assume the others into its mass — the whole solidifying into 

 one considerable erlobe." 



According to our theory, asteroids would be certain to be formed 

 in the interior parts of the system where the rings were narrow, 

 and where an exterior ring or planet was very massive. If we 

 examine the table, we shall see that fifteeu rings have been ren- 

 dered asteroidal by the powerful attraction of Jupiter exterior to 

 them. If our reasoning ma}'' be relied upon, thei*e are asteroids 

 within fifty millions of miles of Jupiter's orbit, though none have 

 yet been found within two hundred millions; there are also aste- 

 roids within ten millions of miles of the orbit of Mars, though 

 none have been seen within fifty millions of miles. The same 

 influence of Jupiter which prevented the known asteroids from 

 becoming planets, came very near preventing the creation of Mars. 



