510 JAMES CLERK MAXWELL. 



the waves may be so broken and confused as to be incapable of 

 mounting up to the height at which they would begin to destroy 

 the arrangement of the ring. In this way it may be conceived 

 to be possible that the gradual disarrangement of the system may 

 be retarded or indefinitely postponed. 



But supposing that these waves mount up so as to produce 

 collisions among the particles, then we may deduce the result 

 upon the system from general dynamical principles. There will 

 be a tendency among the exterior rings to move farther from the 

 planet, and among the interior rings to approach the planet, and 

 this either by the extreme interior and exterior rings diverging 

 from each other, or by intermediate parts of the system moving 

 away from the mean ring. 



The final result, therefore, of the mechanical theory is, that 

 the only system of rings which can exist is one composed of an 

 indefinite number of unconnected particles revolving round the 

 planet with different velocities, according to their respective dis- 

 tances. These particles may be arranged in a series of narrow 

 rings, or they may move through each other irregularly. In the 

 first case the destruction of the system will be very slow, in the 

 second case it will be more rapid, but there may be a tendency 

 towards an arrangement in narrow rings which may retard the 

 process. 



The transparency of the inner ring, which allows the 

 planet to be seen through it without distortion, and the 

 observed changes in the configuration of the rings themselves, 

 all favour this conclusion. 



If the changes already suspected should be confirmed by 

 repeated obser\ 7 ations with the same instruments, it will be worth 

 while to investigate more carefully whether Saturn's rings are 

 permanent or transitionary elements of the solar system, and 

 whether in that part of the heavens we see celestial immutability 

 or terrestrial corruption and generation, and the old order giving 

 place to new before our own eyes. 



The apparatus constructed by Maxwell to illustrate the 

 motions of the satellites in the rings has been already referred 

 to. 1 It is an arrangement in which ivory balls are made 

 to go through the motions belonging to the first or fourth of 



1 See p. 295. 



