NEPTUNE. 179 



Mr. Adams, of St. John's College, Cambridge. The historic- 

 al facts which refer to these labors, and to Leverrier's and 

 Galle's happy discovery of the new planet, have been circum- 

 stantially and impartially developed from reliable sources in 

 two works, by the astronomer royal, Airy, and by Bernhard 

 von Lindenau.=^ Intellectual endeavors, almost' simultane- 



* Airy, in the Monthly Notices of the Royal Astronomical Society, vol. 

 vii.-, No. 9 (November, 1846), p. 121-1.52. Bernhard von Lindenau, 

 Beitrag ziir Geschichte des Neptuns-Entdechmig, p. 1-32, and 235-238. 

 At the instigation of Arago, Leverrier commenced, in the summer of 

 1845, his investigations of the theory of Uranus. The results of this in- 

 vestigation he laid before the Institute on the 10th of November, 1845, 

 the 1st of June, 31st of August, and 5th of October, 1846, and published 

 them at the same time ; but the most extensive and important of Lever- 

 rier's labors which contained the solution of the whole problem appeared 

 in the Connaissance des Temps four Van 1849. Adams laid the first 

 results which he had obtained for the disturbing planet before Profes- 

 sor Challis in September, 1845, without having them printed, and, to 

 gether with some alterations in October of the same year, before the 

 astronomer royal, still without making them public. The latter re- 

 ceived the final results of Adams, with fresh corrections referring to a 

 decrease of the distance, in the commencement of September, 1846. 

 The young Cambridge geometrician expresses himself upon the chro- 

 nological succession of the investigations which were directed to one 

 and the same object with as much modesty as self-denial : " I mention 

 these earlier dates merely to show that my results were arrived at in- 

 dependently and previously to the publication of M. Leverrier, and not 

 w^ith any intention of interfering with his just claims to the honor of 

 the discovery ; for there is no doubt that his researches were first pub- 

 lished to the world, and led to the actual discovery of the planet by Dr. 

 Galle ; so that the facts stated above can not detract in the slightest 

 degree from the credit due to M. Leverrier." Since, in the history of 

 the discovery of Neptune, mention is frequently made of an early share 

 which the great Konigsberg astronomer took in the hope already ex- 

 pressed by Alexis Bouvard (the author of the tables of Uranus) in the 

 year 1834, "of the disturbance of Uranus by a yet unknown planet," 

 it will, perhaps, not be unacceptable to many readers of the Cosmos if 

 I introduce here part of a letter which Bessel wrote to me on the 8th 

 of May, 1840 (therefore two years before his conversation with Sir 

 John Herschel, during his visit to CoUingwood) : " You request me to 

 give you information as to the planet beyond Uranus. I could indeed 

 refer you to friends in Konigsberg who, from misunderstanding, fancy 

 that they know more about the matter than I do myself. I chose as 

 the subject of a public lecture delivered upon the 28th of February, 

 1840, the development of the connection hetween astronomical obsffnoa- 

 tions and astronomy. The public know no diflerence between the two; 

 consequently, their opinion was to be corrected. The indication of the 

 development of astronomical knowledge from observations naturally 

 led to the remark that we can by no means affirm that our theory ex- 

 plains all the motions of the planets. Uranus afforded a proof of this, 

 the old observations of which do not at all accord with elements which 

 coincide with the later observations from 1783 to 1820. I believe that 



