L. Trouveht — Physical Observations of Saturn. 463 



Though in general, the level of the ring C is always higher 

 than that of the rest of the system, it does not seem, "however, 

 to be uniform and permanent, but varies, either by the rotation 

 of the rings upon an axis, or by some local changes in the cloud- 

 forms themselves ; as in several instances I have observed quite 

 rapid and striking changes taking place during the course of 

 one evening in the indentation of the shadow shown at x, fig. 1. 

 Sometimes the indentation appeared to increase, indicating a 

 higher level ; and sometimes to decrease, indicating a lower 



That the thickness of the rings is increasing from the interior 

 margin of the dusky ring to the outer border of the bright ring 

 C, seems to be corroborated by the phenomena which I have 

 observed on the dusky ring, and of which I shall speak pres- 



On all favorable occasions, I have made careful searches on the 

 dusky ring for the divisions suspected by Bond ; but I have never 

 had the faintest glimpses of thera. The dusky ring appears 

 to me to be continuous, though it is certainly not of the same 

 thickness throughout. Whatever may be the material of which 

 this ring is composed, it is quite rarefied ; and it becomes more 



""-^ — -■* approaches its inner margin. There, '* °--'— 



f discrete particles, each of which refi 

 ; separately ; and by applying high powers to telescopes 

 '■■■'■ " -' ' ■' upposedp 



separa' "-'^ ' " 

 power. I do not pretend to 



large aperture, I have had the impression that the 

 tides were more widely 



posed of discrete particles, each of which reflects the 

 ipplying high powers to telescopes of 

 the impression that the supposed par- 

 Darated by the increase of magnifying 

 i to have seen distinct and isolated 

 3g; but by instants my impressions 

 decided, that it seemed as if only a little more 

 favorable conditions were required to enable me to see separate 

 corpuscles of matter. The appearance was somewhat like fine 

 particles of dust floating in a ray of light traversing a dark 

 chamber. 



The inner border of the dusky ring, notwithstanding its dark 

 appearance, is sharply defined on the dark sky within the ansae ; 

 but it loses this sharpness of outline in that part which is seen 

 projected upon the disk of the planet There it appears very 

 diffused and ill-defined. 



The inner border of the dusky ring, as seen withm the ansae, 

 forms a part of a perfect ellipse concentric with the other rings ; 

 but these graceful curves are remarkably and quite abruptly 

 distorted where they enter upon the disk of the planet at m and 

 p, fig. 1. At these points, they are seen turning up rapidly, 

 describing a short curve; after which they continue parallel 

 with the curves of the other rings until they meet at A. If the 

 ellipse described within the ansae should cross the planet with- 

 out any deflection, it would be seen along the dotted Ime, fig. 



