466 THE POPULAR SCIENCE MONTHLY. 



PLA^^ETAKY KINGS AND NEW STAKS. 



By Peofessoe DANIEL VAUGHAN. 



THE study of celestial phenomena which represent changes of the 

 greatest magnitude is an important source of intelligence respect- 

 ing the course of creation and the diversified condition of the universe. 

 In all well-directed efforts to explore the more profound secrets of 

 space and of time, it is necessary to be guided by certain conspicuous 

 marks which even unseen planets may leave behind them, on assum- 

 ing new forms or in closing an inconceivably long term of existence. 

 Within the solar domain there is, perhaps, no object which claims 

 more interest or value for original inquiries in astronomy than Saturn's 

 rings — whether they be regarded as presenting a picture of the first 

 or the last stages of planetary life. With a wide deviation from the 

 ordinary figure of worlds, they exhibit changes which are interesting on 

 account of the vast scale on which they occur, and the light which they 

 throw on the past and the future history of the solar system. In the 

 absence of those restraints which secure much repose on the surface 

 of our globe, the Saturnian girdle is abandoned to rage of the most vio- 

 lent commotions and becomes occasionally the seat of disturbances 

 which, though transpiring at the distance of about 900,000,000 miles, 

 are yet revealed by the telescope. The temporary divisions which 

 have been so often observed in the rings are evidences of the terrific 

 scenes of turmoil in this remote theatre of chaotic activity ; as the 

 opening and closing of visible chasms must be attended with physi- 

 cal convulsions immeasurably greater than any ever witnessed on our 

 terrestrial abode. 



From well-established principles of physical astronomy, it is easy 

 to prove the impossibility of tranquil movements in a region so close 

 to the great planet. Whether tenanted by innumerable solid masses 

 or even by a vast expanse of fluid, the zones in which the Saturnian 

 sway is so powerful must present a long-continued struggle for op- 

 posite ends. The matter spread over the wide annular fields is ever 

 iirged by its own attraction to collect together and form satellites, 

 which are soon destroyed by the attractive disturbance of the primary, 

 and have their parts scattered once more over a wide space. From 

 the gravity due to their preponderating masses, the mountains or in- 

 equalities observed on the ring can not be prevented from growing at 

 the expense of the matter along the zone in which they circulate ; but 

 with the increasing size the vast structures become at last incapable 

 of sustaining the crushing strain in certain directions ; so that a dilapi- 

 dation and a dispersion of their materials become inevitable. It is in 

 consequence of the ephemeral character of these mountains or em- 

 bryonic satellites, that observations on them have sometimes led as- 



