174 ON THE ORIGIN OF THE PLANETABY SYSTEM. 



the nebulous balls of the adjacent fixed stars, possessed 

 a slow movement of rotation. It became condensed 

 under the influence of the reciprocal attraction of its 

 parts ; and, in the degree in which it condensed, the 

 rotatory motion increased, and formed it into a flat 

 disk. From time to time masses at the circumference 

 of this disk became detached under the influence of 

 the increasing centrifugal force ; that which became 

 detached formed again into a rotating nebulous mass, 

 which either simply condensed and formed a planet, or 

 during this condensation again repelled masses from 

 the periphery, which became satellites, or in one case, 

 that of Saturn, remained as a coherent ring. In an- 

 other case, the mass which separated from the outside 

 of the chief ball, divided into many parts, detached 

 from each other, and furnished the swarms of small 

 planets between Mars and Jupiter. 



Our more recent experience as to the nature of 

 star showers teaches us that this process of the conden- 

 sation of loosely diffused masses to form larger bodies 

 is by no means complete, but still goes on, though the 

 traces are slight. The form in which it now appears 

 is altered by the fact that meanwhile the gaseous 

 or dust-like mass diffused in space had united under 

 the influence of the force of attraction, and of the 

 force of crystallisation of their constituents, to larger 

 pieces than originally existed. 



