116 HISTORY OF ASTKONOMY. 



relative to the effects of irradiation, and can not there- 

 fore be regarded as altogether trustworthy. From a com- 

 parison similar to that instituted in the previous case, M. 

 Struve infers, that during the interval which elapsed be- 

 tween the observations of J. D. Cassini and those of Sir 

 William Herschel, the breadth of the inner ring had 

 increased in a more rapid ratio than that of the outer 

 ring. The subsequent measures seem to indicate a 

 reversal of this process. 



By observations made by Mr. Lassell at Malta in 1852, 

 it appears that the new ring is transparent to such a 

 degree, that the body of the planet can be seen through 

 it. The following is the language of Mr. Lassell : " Per- 

 haps the most remarkable phenomenon which I now 

 notice for the first time is the evident transparency of 

 the obscure ring ; both limbs of the planet being dis- 

 tinctly seen through it where it crosses the ball, quite 

 through to the edge of the inner bright ring. To my 

 apprehension I can not better describe the entire aspect 

 of the obscure ring than by comparing it to an annulus 

 of black crape stretched within the bright ring, which, 

 when projected against the black sky, as at the curve, 

 would, from its reflecting some light, appear of -a dark 

 gray shade ; and when projected on the ball, would, from 

 th* transmission of a portion of the reflected light of the 

 ball, appear of a much lighter gray. What the precise 

 nature of this marvelous appendage can be would be 

 an interesting subject of speculation, exhibiting as it were 

 a connecting link between nebulous and solid matter. 



