THE PLANET NEPTUNE; 29 



motion of the planet, according to the orbit of Mr. 

 Walker. 



Thus, then, we have most unexpectedly secured two 

 good observations in place of one doubtful one. We can no 

 longer withhold our full belief. A single elliptic orbit 

 represents with great precision the two observations 

 of Lalande, and all the observations subsequently 

 made. 



More recently it has been announced that Dr. Lamont, 

 of Munich, had twice observed the planet Neptune as 

 a fixed star in his zones; the first time October 25th, 

 1845, when he estimated it as of the ninth magnitude ; 

 the second time was September 7th, 1846, when it was 

 entered as of the eighth magnitude. The following, then, 

 are the dates of the seven earliest observations of this 

 planet, so far as at present known : 



Let us now compare the predicted orbits of Adams 

 and Le Verrier with the true orbit according to Mr. 

 Walker, and the mass of the planet as deduced from 



