XIX. On the Stability of the motion of Saturn's Rings. 



[An Essay, which obtained the Adams Prize for the year 1856, in the University 



of Cambridge.] 



ADVERTISEMENT. 



THE Subject of the Prize was announced in the following terms : 



The University having accepted a fund, raised by several members of St John's College, 

 for the purpose of founding a Prize to be called the ADAMS PRIZE, for the best Essay 

 on some subject of Pure Mathematics, Astronomy, or other branch of Natural Philosophy, 

 the Prize to be given once in two years, and to be open to tfte competition of all persons 

 who have at any time been admitted to a degree in tliis University : 



The Examiners give Notice, that the following is the subject for the Prize to be adjudged 

 in 1857: 



The Motions of Saturn's Rings. 



*#* The problem may be treated on the supposition that the system of Rings is exactly or 

 very approximately concentric with Saturn and symmetrically disposed about the plane of his Equator, 

 and different hypotheses may be made respecting the physical constitution of the Rings. It may 

 be supposed (1) that they are rigid: (2) that they are fluid, or in part aeriform: (3) that they 

 consist of masses of matter not mutually coherent The question will be considered to be answered 

 by ascertaining on these hypotheses severally, whether the conditions of mechanical stability are 

 satisfied by the mutual attractions and motions of the Planet and the Rings. 



It is desirable that an attempt should also be made to determine on which of the above 

 hypotheses the appearances both of the bright Rings and the recently discovered dark Ring may 

 be most satisfactorily explained; and to indicate any causes to which a change of form, such as 

 is supposed from a comparison of modern with the earlier observations to have taken place, may 

 be attributed. 



E. GUEST, Vice-chancellor. 



J. CHALLIS. 



8. PARKINSON. 



W. THOMSON. 

 .VarcA 23, 1855. 





