DISCOVERY OF A NEW RING TO SATURN. 117 



The precise definition of its edges renders it unlike any 

 other specimen of nebulae ; while on the other hand its 

 certain translucencj deprives it of all resemblance to the 

 other solid bodies of our system." The drawing on page 

 115 is copied from one furnished by Mr. Lassell from his 

 observations made at Malta in 1852. 



Mr. Gr. P. Bond maintains that Saturn's ring is in a 

 fluid state, or at least does not cohere strongly. The 

 following are some of the considerations upon which he 

 founds this conclusion. Several observers, among whom 

 are Kater, Encke, De Vico, and Lassell, have seen, di- 

 visions both of the outer and inner ring. On the other 

 hand, some of the best telescopes in the world, in the 

 hands of Struve, Bessel, Sir John Herschel, and others, 

 have given no indication of more than one division, 

 when the planet has appeared under the most perfect 

 definition. The fact also that the divisions on both rings 

 have not usually been visible together, and that the 

 telescopes which have shown distinctly several intervals 

 in the old ring, have failed to reveal the new inner ring, 

 while the latter is now seen, but not the former, indicates 

 some real alteration in the disposition of the material 

 of the rings. 



These facts are most easily explained by supposing 

 that the rings are in a fluid state, and within certain 

 limits change their form and position in obedience to the 

 laws of equilibrium of rotating bodies. This hypothesis 

 is favored by considerations drawn from the state of 

 the forces acting on the rings. On the assumption that 



