10 



No. 44. These events, comprising a period of a quarter of a century, have 

 ended by enriching astronomy with a new primary planet and satelhte, and with 

 the removal from the pages of its history of all the anomahes of Uranus, which 

 for many years had formed its last and only remaining opprobrium. 



SECTION 2. 



DETAILED ACCOUNT OF THE DISCOVERY OF THE TWO ANCIENT PLACES OF NEPTUNE, OBSERVED BY 



LALANDE, JUNE 8 and 10, 1795. 



No. 21. During my connexion with the National Observatory, under the 

 direction of Lieut. Maury, the news of the optical discovery of Neptune was 

 received on the 24th of October, 1846, and the duty of making a series of 

 investigations, with reference to this new member of our system, having been 

 assigned to me by the Superintendent early in November, I commenced the 

 researches, of which the following is an account : 



Mr. E. C. Herrick, of New Haven, had called attention to the fact of the 

 proximity of position and probable identity of Neptune with the Wartman planet 

 of 1831. My first labors were directed to the search for the approximate 

 elements of the two planets, which soon led to the conclusion that they were 

 not the same, and that no satisfactory orbit could be formed for Wartman's 

 planet from the imperfect tracing of its path in the Comples Rendus for 1836. 



No. 22. The first inquiry concerning the motions of Neptune, had shown 

 the near approach of its orbit to the circular form. The same analogies of the 

 system that furnished Adams and Leverrier the clue to their analytical predic- 

 tion of its place, in 1845 and 1846, were to serve as guides in the first attempt 

 to sketch its orbit. 



No. 23. It was naturally to be presumed that the inclination and eccentricity 

 of this primary planet were small, and that the daily variations of the radius 

 vector and angular orbital motion, impressed by the sun, at a distance of nearly 

 double that of Uranus, must be very small fractions of their total values. 

 Hence, in a first approximation, these daily variations, as well as their differences 

 and terms of a higher order, might be neglected. 



No. 24. Accordingly 1 commenced with the simple hypothesis of constancy 

 of the radius vector from September 24 to November 21, a period of 58 days, 

 leaving the character of the orbit, whether nearly circular or much flattened, 

 to be the result of the investigation. 



