22 HISTORY OF ASTRONOMY. 



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Le Verrier was of opinion that the new planet might be 

 found by its possession of a visible disc, and therefore 

 without any very great labor. 



Soon after this communication was made to the 

 Academy, Le Verrier, in acknowledging the receipt of 

 a memoir, made use of the opportunity thus afforded to 

 request Dr. Galle, of the Berlin observatory (where is 

 found one of the largest telescopes of Europe), to under- 

 take a search for his computed planet, and he assigned its 

 supposed place in the heavens. The Berlin Academy 

 had just published a chart of this part of the heavens, 

 indicating the exact place of every star down to the 

 tenth magnitude. On the evening of the very day .upon 

 which this letter was received (September 23), Galle 

 found near the place computed by Le Verrier, a star of 

 the eighth magnitude, not contained on the Berlin chart. 

 Its place was carefully measured ; and the observations 

 being repeated on the succeeding evening, showed a 

 motion of more than a minute of space. The new star 

 was found in longitude 325 52' ; the place of the planet 

 computed by Le Verrier was 324 58' ; so that this body 

 was within one degree of the computed point. Its 

 diameter measured nearly three seconds. A coincidence 

 so exact, left no doubt that this was really the body 

 whose effects had been detected in the motions of 

 Uranus. Mr. Galle accordingly writes to Le Verrier, 

 " the planet whose position you marked out actually exists." 

 The news of the discovery spread rapidly over Europe. 

 The planet was observed at Gottingen on the 27th of 



