solution was completed in September, 1845. The actual direction of Neptune 

 is here given with a remarkably close approximation, sufficient to place it in the 

 finder of an ordinary sweeping telescope. 



No. 13. M. U. J. Leverrier's revision of the theory of Uranus, ending in a full 

 confirmation of Bouvard's discovery of the anomalies of that planet, published 

 on the 10th of November, 1845 



No. 14. Leverrier's second Memoir on the theory of Uranus, published June 

 1, 1846. The first part confirms the inductive conclusions of Bessel, (No. 2,) 

 and demonstrates that a transuranian planet is the only possible cause of the 

 known anomalies of Uranus. The concluding portion gives the actual direction 

 of Neptune within about a degree of the truth, and within one degree of that of 

 Adams, in 1845. 



No. 15. Sir John Herschel's address to the British Association, Sept. 10, 

 1846: "We see it [the probable new planet] as Columbus saw America, from 

 the shores of Spain. Its movements have been felt trembling along the far 

 reaching line of our analysis with a certainty hardly inferior to that of ocular 

 demonstration." 



No. 16. Leverrier's letter to Prof Airy, June 28, 1846, showing that his new 

 theory of Uranus, with an exterior disturbing planet, represented the quadratures 

 as well as the oppositions, and must, therefore, give the correct radius vector. 



No. 17. Pi'of Airy's remark on receipt of this letter: "I had now no longer 

 any doubt upon the reality and general exactness of the prediction of the planet's 

 place." 



No. 18. Letter of Prof Airy to Prof Challis, July 13, containing " suggestions 

 for the examination of a portion of the Heavens in search of the external planet 

 which is presumed to exist and to produce disturbance in the motion of Uranus." 



No. 19. Answer of Prof Challis, July 18: "1 have determined on sweeping 

 for this hypothetical planet." 



No. 20. Observation of Neptune, August 4 and 12, 1846, by Prof Challis, in 

 his sweeps with the Northumberland equatorial, without knowing at the time 

 that it was not a fixed star. 



No. 21. Leverrier's third Memoir, published August 31, 1846, giving more 



Note to No. 13. — Comptes Rendus, 1845, November 10. 

 Note to No. 14. — Comptes Rendus, 1846, June 1. 

 Note to No. 15. — Airy's Memoir, see note to No. 3. 

 Note to Nos. 16, 17, 18, 19.— Airy's Account, &c. 



Note to No. 20. — First report of Rev. J. Challis to the Syndicate of the Cambiidge University, December 12, 1846. 

 See also Astr. Nachr., 583. 



Note to No. 21. — Comptes Rendus, August 31, 1846. 



