S W Proceedings of Philosophical, Societies. [ A p r i e, 



Jlions of the fixed stars, tending either to the enlargement and per- 

 fection of our present catalogues, or to the more accurate determi- 

 nation of the variable ones in size, colour, or situation ; us well as 

 observations on double stars, tending in like manner not only to 

 the enlargement and perfection of the present catalogues, but also 



to the determination of their anovular distance and of their ang-le of 



« • • • 



position; together with observations on nebulae, — appear proper 



subjects of such reward. To these may be added, observations 

 on refraction, with a view to the more perfect theory of that 

 phenomenon, particularly at low altitudes where irregularities 

 take place, wheii little or no variation has taken place in the 

 "barometer or thermometer ; observations on the tides, particu- 

 larly in situations where the current is not influenced by any 

 contiguous continent; observations tending to determine the 

 true figure of the sun, or of the earth ; and, in short, any obser- 

 vations which may be considered likely to advance and improve 

 the science." 



Having mentioned several other subjects, such as the reduc- 

 tion of observations when made ; the formation of various new 

 tables, and the improvement of others ; the comparison of the 

 places of the planets; the examination of the recorded observa- 

 tions of preceding astronomers ; and every improvement of 

 instruments which may tend materially to advance the science, 

 for which the Society's medals will be bestowed, the Council 

 proceeds to recommend the proposal of the gold medal, and 

 twenty guineas for the solution of the following question ; a ques- 

 tion requiring the synthetic application of the Newtonian doc- 

 trines, together with the highest refinements of modern analysis : 



'* For the best paper on the theory of the motions and pertur- 

 bations of the satellites of Saturn. The investigation to be so 

 conducted as to take expressly into consideration the influence ' 

 of the rings, and the figure of the planet as modified by the 

 attraction of the rings, on the motions of the satellites : to furnish 

 formulae adapted to the determination of the elements of their 

 orbits, and the constant coefficients of their periodical and secu- 

 lar equations, from observation : likewise to point cut the obser- 

 vations best adapted to lead to a knowledge of such determination. 

 The papers to be sent to the Society on or before the first day of 

 February, 1823." 



The Council, however, while thus taking advantage of the 

 stimulus to inquiry which medals and prizes produce, have esta*- 

 blished, in the follovving impressive sentences, their claim to the 

 possession of a full sense of the magnificence of their science, 

 and the comparative insignificance of their rewards : " It may 

 indeed appear extraordinary that no mention should yet have 

 been made of the great desiderata of astronomy; those questions 

 \^hich have exercised the curiosity and employed the time and 

 attention of astronomers, ever since the science has assumed its 



