NOMOS. 



then known. These irregularities were considerable, 

 but they were not allowed to cast any doubt upon 

 the theory of universal gravitation; for it was re- 

 membered that the apparent irregularities which had 

 once existed in the orbit of Saturn had been reduced 

 to rule by the discovery of Uranus. Expecting a 

 similar solution, then, astronomers for the most part 

 were content to wait until the telescope should re- 

 veal a new planet ; but all were not so content. On 

 the contrary, M. Leverier and Mr. Adams addressed 

 themselves to the herculean task of searching through 

 the outskirts of space with no other guide than figures; 

 and month after month, and year after year, each sup- 

 posing himself to be alone, they plodded along their 

 weary way in silence, until at last M. Galle received 

 a letter from M. Leverier, in which he was re- 

 quested to look for a planet in the same plane as the 

 ecliptic, or nearly so, and whose heliocentric longi- 

 tude at that time was 326, or thereabouts. This 

 letter arrived at the Royal Observatory at Berlin 

 on the 23rd of September, 1846, and on the night 

 of that very day M. Galle and M. Encke saw an 

 unknown star of the eighth magnitude in 326 52' 

 of this longitude. On the next night this star was 

 found to have moved from its place. It was Nep- 

 tune. On bringing Mr. Adams' calculations up to 

 the same date, the position assigned to the planet 

 was in the plane of the ecliptic and in 329 19' of 

 heliocentric longitude a difference of only 3 19' 

 from the position assigned to it by M. Leverier. 

 The planet was discovered, as we have said, in 

 326 52' of this longitude; and thus the actual 



