liv PROFESSOR CHALLIS'S REPORT TO THE OBSERVATORY SYNDICATE. 



300 stars, whose positions I recorded that night, I fixed on one which appeared to have 

 a disk, and which proved to be the planet. This was the third time it was observed 

 before the announcement of the discovery reached me. This last observation may be 

 regarded as a discovery of the planet, due to the good definition of the noble instru- 

 ment which we owe to the munificence of our Chancellor. 



From the reduced places of the planet, on August 4 and August 12, and from 

 observations since its discovery extending to October 13, Mr Adams calculated, at my 

 request, values of its heliocentric longitude at a given epoch, its actual distance from 

 the Sun, longitude of the node, and inclination of the orbit, which were published as 

 early as October 17. I am now diligently observing the planet with the meridian instru- 

 ments, and when daylight prevents its being seen on the meridian, I propose carrying on 

 the observations as long as possible with the Northumberland Equatorial, for the purpose 

 of obtaining data for a further approximation to the elements of the orbit. 



My report of proceedings relating to the planet here terminates. I beg permis- 

 sion to add a few remarks, which the facts I have stated seem to call for. It will 

 appear by the above account, that my success might have been complete, if I had trusted 

 more implicitly to the indications of the theory. It must, however, be remembered, that 

 I was in quite a novel position : the history of astronomy does not afford a parallel instance 

 of observations undertaken entirely in reliance upon deductions from theoretical calcula- 

 tions, and those too of a kind before untried. As the case stands, a very prominent part 

 has been taken in the University of Cambridge, with reference to this extension of the 

 boundaries of astronomical science. We may certainly assert to be facts, for which there 

 is documentary evidence, that the problem of determining, from perturbations, the unknown 

 place of the disturbing body, was first solved here ; that the planet was here first sought 

 for ; that places of it were here first recorded ; and that approximate elements of its orbit 

 were here first deduced from observation. And that all this may be said, is entirely due 

 to the talents and labours of one individual among us, who has at once done honour to 

 the University, and maintained the scientific reputation of the country. It is to be re- 

 gretted that Mr Adams was more intent upon bringing his calculations to perfection, than 

 on establishing his claims to priority by early publication. Some may be of opinion, that 

 in placing before the first astronomer of the kingdom results which showed that he had 

 completed the solution of the problem, and by which he was, in a manner, pledged to 

 the production of his calculations, there was as much publication as was justifiable on the 

 part of a mathematician whose name was not yet before the world, the theory being one 

 by which it was possible the practical astronomer might be misled. Now that success has 

 attended a different course, this will probably not be the general opinion. I should 

 consider myself to be hardly doing justice to Mr Adams, if I did not take this opportunity 

 of stating, from the means I have had of judging, that it was impossible for any one to 

 have comprehended more fully and clearly all the parts of this intricate problem ; that 

 he carefully considered all that was necessary for its exact solution; and that he had a 

 firm conviction, from the results of his calculations, that a planet was to be found. 



