SUBDIVISIONS OF THE RING 183 



cost in time and comfort, by the sacrifice of which it is 

 purchased for mankind. 



That Herschel was surprised by the brightness of 

 the rings, the greater brightness of the shining points 

 he saw on them, and the yellowish light of the planet, 

 is quite clear. Whether he ever suspected a light or 

 phosphorescence of its own in the system of Saturn, as 

 some observers have now come to think exists, is 

 another matter. But he was on the threshold of that 

 discovery, if discovery it be. He entertained no such 

 idea in 1789 when he classed all the planets " under 

 one general definition, of bodies not luminous in them- 

 selves," though two years of farther reflection and 

 observation may have wrought a change in a man of 

 his clear perception and quickness. On another view 

 developed since his day he almost anticipated recent 

 research. He denied that the ring was subdivided by 

 many dark lines into a series of concentric rings, " as 

 has been represented in divers treatises of astronomy." 

 He firmly held to only one division ; but he was not 

 far from the modern view, which represents the ring 

 as a mighty mass of revolving satellites, kept in posi- 

 tion by the gravity of the planet and the velocity of 

 their rotation round him. 



Herschel's memoirs on Saturn cover about one 

 hundred and seventy pages quarto, and the plates that 

 accompany them give a distinct idea of what he saw. 

 By comparing letterpress and plate we may better 

 understand the relation in which he stood to his fol- 

 lowers in this field of research and discovery. With 

 one of the new specula, which he ground apparently for 

 the purpose of observing the ring of Saturn more care- 

 fully, he got views that he speaks of as " uncommonly 



