120 A CENTURY'S PROGRESS IN ASTRONOMY. 



marked in the star-maps of the Berlin Observa- 

 tory, which had been recently published. The 

 following night sufficed to show that the object 

 was in motion, and was therefore a new planet. 

 On September 29 Challis found the planet at 

 Cambridge, but he was too late, as the priority 

 of the discovery was now lost to Adams. The 

 planet received the name of "Neptune." 



For some time, indeed, it appeared as if the 

 French astronomer alone was to receive the 

 honour of the discovery. But on October 3, 

 1846, a letter from Sir John Herschel appeared 

 in the ' Athenaeum ' in which he referred to the 

 discovery made by Adams. The French scientists 

 were extremely jealous. Indeed, Arago actually 

 declared that, when Neptune was under dis- 

 cussion, the entire honour should go to Le 

 Verrier, and the name of Adams should not even 

 be mentioned, Arago's line of reasoning being 

 that it was not the man who first made a dis- 

 covery who should receive the credit, but he 

 who first made it public. However, the credit 

 of the discovery is now given equally to Adams 

 and Le Verrier, both of whom are regarded as 

 among the greatest of astronomers. 



Only a fortnight after the discovery of Nep- 

 tune, the astronomer Lassell observed a satellite 

 to the distant planet on October 10, 1846. This 



