FIFTH CHAPTER. 



OF THE ORIGIN OF SATURN'S RING AND CALCU- 

 LATION OF THE DIURNAL ROTATION OF THIS 

 PLANET FROM ITS RELATIONS. 



IN virtue of the Systematic Constitution in the Universe, its 

 parts are connected by a gradual modification of their special 

 characteristics; and it may be conjectured that a planet 

 situated in the remotest region of the world, will have almost 

 the same characteristics as the nearest comet would assume 

 if it were raised by the diminution of its eccentricity into 

 the order of planets. We shall accordingly consider Saturn 

 as if it had passed through several revolutions with greater 

 eccentricity in a manner similar to the movement of comets, 

 and that it had gradually been brought into a path more 

 resembling a circle. 1 The heat which was incorporated in 

 it at its perihelion raised the light matter from its surface ; 

 which matter, as we know from the former chapters, is of 

 extreme tenuity in the farthest planets, and in this state 

 it is readily expanded by small degrees of 'heat. Never- 

 theless, after the planet had been brought during a certain 



1 Or, it is more probable, that in its comet-like state which it 

 still exhibits in virtue of its eccentricity before the lightest matter 

 of its surface was completely dispersed, it had diffused a cometic 

 atmosphere. 



H 



