i8o III RSCHEL AND HIS WOKK 



width between the two parts. 1 The black dUcor U-li was 

 DOt in the middle of tin- ring's luvadth. h i a xonr 

 of considerable breadth, \\hich WOH always seen por- 

 main nt ly in 1 1 1 same place. As it was not, \vli.-ii Bond 

 i to have supposed, the shadow of a vast range of 

 mountains on the ring's surface, he resolved to wait 

 till the planet came into a position which would ma Mr 

 him to sci' the stars through the black belt, if it r ally 

 were a division in tin- rin^. a window, aw it \v. iv, 

 through which In- could look out into space be; 

 lie does not appear to have been successful in this 

 quest, and it has not been done by others. That th it- 

 were two unequal rings, 2 separated by this black line, 

 he was satisfied. They were bright rin^s, but 

 inner was the brighter of the two. Near the outeq 

 edge of the outer ring, he observed and 11 

 black list," fainter than the dividing gulf. He did not 

 consider it a division in the outer ring, but it is now 

 a recognised feature, traceable all round. Herschel also 



1 The dimensions of Saturn and his rings are, according to Proctor 

 (Encyc. Brit., "Astronomy," p. 783) 



Diameter of the planet . . . 70,136 miles. 



Between planet and " crape " ring . 9,760 

 Breadth of " crape " ring . . 8,660 



,, of inner bright rin^ . . 17,605 



, , of division between brigh t rings 1 , 680 

 ,, of outer bright ring . . 9,625 



The diameter of the ring system is thus about 165,000 miles. Hcrschel 

 made it about (204,883) 205,000 miles in diameter. He believed that 

 the breadth of the ring is to the space between the ring and the planet 

 as 5 to 4 (Phil. Trans., 1806, p. 463). If the "crape" be left out of 

 account in measuring the ring, the proportion is about 5 to 3 "l 

 Trans, for 1792). He estimates the vacant space between the outer 

 and inner rings at nearly 2513 miles. 



In the proportion of 805 to 280, while the space between was 

 reckoned llo. 



