SKETCH OF JOHN COUCH ADAMS. 549 



A part of his work in it was to lecture during one term in each 

 year, generally on the lunar theory, but sometimes on the theory 

 of Jupiter's satellites or the figure of the earth. 



In 18G7 he published an account of the results he had obtained 

 with respect to the orbit of the November meteors, in the investi- 

 gation of which he had co-operated with Prof. H. A. Newton, using 

 the data and observations furnished by him. These calculations 

 took notice of all the perceptible effects produced by the planets, 

 and established the correctness of the period of thirty-three and a 

 quarter years for the revolution of the meteoric body. In order 

 to obtain a sufficient degree of approximation, it was necessary to 

 break up the orbit of the meteors into several different parts, 

 for each of which separate calculations had to be made. Prof. 

 Adams afterward subdivided certain parts of the orbit of the 

 meteors into still smaller portions, with a view of obtaining a 

 closer approximation. The calculations on this subject have not 

 been published, but they exist among his papers, and seem to be 

 fairly complete. 



A paper communicated to the Astronomical Society, in No- 

 vember, 1877, embodied a review of a memoir by Mr. G. W. Hill, 

 of Washington, on the part of the motion of the moon's perigee, 

 which is a function of the mean motions of the sun and moon. 

 This paper is pronounced by Prof. Glaisher peculiarly interest- 

 ing, because in it the author expresses his own views with respect 

 to the mathematical treatment of the theory of the moon's mo- 

 tion. He seems to have preferred to treat the subject by its 

 special problems ; while he had great admiration for Delaunay's 

 general theory. 



Prof. Adams also paid much attention to pure mathematics, 

 and treated many abstruse problems in a highly technical man- 

 ner, in papers the very titles of which are an unknown language 

 to all but accomplished mathematicians. 



A large mass of papers which Sir Isaac Newton had left at his 

 death, having been left to the University of Cambridge by Lord 

 Portsmouth, it became Prof. Adams's task to arrange and cata- 

 logue the mathematical part of the collection. The work lasted 

 many years, but proved very interesting to Prof. Adams, by cast- 

 ing light on the methods by which Newton had worked out his 

 results. 



On the resignation by Prof. Challis of the directorship of the 

 observatory at Cambridge in 1861, Prof. Adams was appointed to 

 succeed him, while he still continued in the Lowndean professor- 

 ship. In 1870 the observatory began to co-operate in the scheme 

 of the Astronomisclie Gesellschaft for the observation of all the 

 fixed stars in the northern hemisphere down to the ninth magni- 

 tude, the observations being put under the charge of the first 



