CHAPTER VI. 



THE OUTER PLANETS. 



JUPITER, the greatest planet of the Solar System, 

 has perhaps been more persistently studied by 

 astronomers than any other. In the early 

 nineteenth century the prevalent idea was that 

 Jupiter was a world similar to the Earth, only 

 much larger, a view held by Herschel and other 

 famous astronomers, and put forward by Brewster 

 in ' More Worlds than One/ This view prevailed 

 for many years, although Buffon in 1778, and 

 Kant in 1785, had stated their belief in the idea 

 that Jupiter was still in a state of great heat 

 in fact, that the great planet was a semi-sun. 

 This idea, however, was long in being adopted 

 by astronomers, and very little attention was 

 paid to Nasmyth's expression of the same opinion 

 in 1853. The older view still held the field 

 namely, that the belts of Jupiter represented 

 trade -winds, and that a world similar to the 

 terrestrial lay below the Jovian clouds. In 1860 



