xxxiv BIOGRAPHICAL NOTICE. 



two or three synodic periods, but that the case is different when, as in this instance, it 

 was only required to represent the perturbations for a fraction of a synodic period. 



Before leaving the subject of Neptune, it should be stated that Adams always ex- 

 pressed the warmest appreciation of Le Verrier's work. It was a great pleasure to him 

 when they met at Oxford in 1847. In the same year Le Verrier visited Adams at 

 Cambridge. The honorary degree of LL.D. was conferred upon Le Verrier in 1874 by 

 the University of Cambridge, and it cannot be doubted that this was owing to the action 

 of Adams. In 1876, when Adams was President of the Royal Astronomical Society 

 for the second time, the gold medal was awarded to Le Verrier for his planetary 

 researches. In delivering the medal Adams spoke of " the admiration we feel for the 

 skill and perseverance by which he has succeeded in binding all the principal planets 

 of our system from Mercury to Neptune in the chains of his Analysis." 



In 1847 Adams communicated to the Royal Astronomical Society a paper on an im- 

 portant error in Bouvard's tables of Saturn. Having been engaged upon a comparison 

 of the theory of Saturn with the Greenwich observations, he was struck with the 

 magnitude of the tabular errors in heliocentric latitude, which could not be attributed 

 to imperfections in the theory. He found that the error was one of computation, two 

 terms of different arguments having been, in effect, united into one. 



In 1848 he was occupied with the determination of the constants in Gauss's theory 

 of terrestrial magnetism. This investigation he afterwards resumed, and the calculations 

 connected with it, upon which he was engaged in the later years of his life, were left 

 unfinished at the time of his death. When failing health prevented him from any 

 longer giving his personal attention to the work, he placed the manuscripts in the hands 

 of his brother, Professor W. G. Adams, for completion. 



In 1851 he was elected President of the Royal Astronomical Society, and held the 

 office for the usual term of two years. As president he delivered the addresses on the 

 presentation of the medal to Peters and to Hind. In 1852 he communicated to the 

 Society new tables of the Moon's parallax, to be substituted for those of Burckhardt. 

 Henderson had compared the parallaxes deduced from observation with those derived by 

 calculation from the tables both of Damoiseau and of Burckhardt, finding a difference of 

 no less than 1"'3, according as one set of tables or the other was employed. The parallax 

 in Damoiseau's tables is given at once in the form in which it is furnished by theory, 

 but that in Burckhardt's tables is adapted to his peculiar form of the arguments, and 

 requires transformation in order to be compared with the former. When this was done, 

 Adams found that several of the minor equations of parallax deduced from Burckhardt 

 differed completely from their theoretical values as given by Damoiseau. He discovered 

 that these errors were due to Burckhardt's transformations of Laplace's formula, and he 

 succeeded in tracing them to their sources. He also examined carefully the theories of 

 Damoiseau, Plana, and Pontecoulant, with respect to the same subject, and supplied a 

 number of defects and omissions. Burckhardt's value of the parallax having been em- 

 ployed in the Nautical Almanac, Adams gave, in addition to the new tables, a table of 

 corrections to be applied to the values in the Nautical Almanac for every day of the year 

 from 1840 to 1855 inclusive. This contribution to astronomy is very characteristic of 

 its author. It contains the results of a great amount of intricate and elaborate mathe- 

 matical investigation, carried out with great skill and accuracy in all its details, both 

 analytical and numerical, but no part of the work itself is given. The method of pro- 



