1$0 Royal Astronomical Society, 



the predominant movement being replaced at intervals by distinct 

 paroxj^sms. 



On a comparison of these cases with the few others on record, 

 and with the experiments of Flourens and Majendie, it was inferred 

 as ])robable, that one class of tlie movements, viz. the rotatory, de- 

 pended on disorder in the cerebellum or its transverse commissure, 

 the pons. With regard to the other movements, it appeared that 

 there were no sufficient grounds for even a probable conjecture as 

 to the particular part of the encephalon, the excitement or disorder, 

 of which might act as an immediate cause of the movements. 



The remote causes were such as under other circumstances are 

 known to excite the common convulsive diseases, such as chorea and 

 epilepsy. Tliese remote causes were in most cases eccentric. 



ROYAL ASTRONOMICAL SOCIETY. 

 [Continued from vol. xxix. p. 232.] 



Nov. 13, 1846. — An Explanation of the observed Irregularities 

 in the Motion of Uranus, on the Hyjjothesis of Disturbance caused 

 by a more distant Planet ; with a Determination of the Mass. Orbit, 

 and Position of the disturbing body. By J. C. Adams, Esq., M.A., 

 F.R.A.S., Fellow of St. John's College, Cambridge*. 



The author introduces the subject by remarking, that when Bou- 

 vard constructed his Tables of Uranus (those now commonly in use), 

 he found it impossible to reconcile the ancient observations, made 

 before the discovery of Uranus as a planet, with the modern obser- 

 vations, and that therefore in the formation of his tables he relied 

 solely upon the latter ; but that in a very few years the still more 

 modern observations exhibited a departure from the tables nearly as 

 great as the ancient ones, and therefore there seemed now to be no 

 sufficient reason for rejecting the ancient observations. The author 

 then states that his attention was first directed to this subject by 

 reading the report on the recent progress of astronomy made to the 

 British Association at their meeting in Oxford ; and that in July 

 1841 he formed a design of investigating the yet unaccounted-for 

 motions of Uranus, in order to discover whether they could be ex- 

 plained by an exterior disturbing planet. In 1843 he made a first 

 attempt, supposing the orbit of the disturbing planet to be a circle, 

 and its mean distance twice that of Uranus. This investigation was 

 founded exclusively on the modern observations, using, as far as 1821, 

 the errors given in the equations of condition in Bouvard's tables, 

 and for subsequent years the errors given in the Astronomische 

 Nachrichten, and the Cambridge and Greenwich Observations. The 

 result showed a good general agreement of the observed disturbance 

 with the disturbance which would be produced by the action of such 

 a planet. In February 1844, the author received from the Astro- 



• This paper was presented to the Society on the evening of Nov. 13, 

 1846. It has since been published entire as an extract from the Appendix 

 to the Nautical Ahnanac for 1851. 



