1 30 Royal Astronomical Society. 



showing the profound acquaintance of their author with every brunch 

 of optical science. Amongst these may be mentioned the paper on 

 the Double Refraction of Quartz, which is of very recent publication, 

 inasmuch as it affords one of the most striking a posteriori proofs 

 which have hitherto been discovered of the truth of the undulatory 

 theory of light ; a most difficult mathematical investigation, essentially 

 founded upon that theory, leads him to expect the appearance of phae« 

 nomena of great beauty and intricacy, as the result of certain experi- 

 ments which are found upon examination to be almost mathematically 

 exact*. It is by such tests, and many others reproducible, that the 

 truth of the theory, which was established and developed by the ge- 

 nius of Young and of Fresnel, becomes established upon evidence 

 scarcely inferior to that of universal gravitation. 



The Society next proceeded to the Election of the Council and 

 Officers for the ensuing year, when the following was declared to 

 be the list: — 



President : His Royal Highness the Duke of Sussex, K.G. — 

 Treasurer: John William Lubbock, Esq. M.A. — Secretaries : Peter 

 Mark Roget, M.D. ; John George Children, Esq. — Foreign Secre- 

 tary : Charles Konig, Esq. 



Other Members of the Council. — Peter Barlow, Esq. ; John Bos- 

 tock,M.D.; Rev. William Buckland,D.D.; Samuel Hunter Christie, 

 Esq. M.A.J Rev. Henry Coddington, M.A.; Charles Daubeny, 

 M.D.; George Dollond, Esq. ; Davies Gilbert, Esq. M.A.; Joseph 

 Henry Green, Esq. ; William George Maton, M.D. ; Roderick 

 Impey Murchison, Esq.; Rev. George Peacock, M.A. ; George 

 Rennie, Esq. ; Captain William Henry Smyth, R.N. ; Nicholas 

 Aylward Vigors, Esq. M.A.; Rev. William Whewell, M.A. 



ROYAL ASTRONOMICAL SOCIETY. 



Dec. 9, 1831. — The following communications were read : viz. 



I . On the proper motion of the Fixed Stars, by Francis Baily, Esq. 

 — The author sets out with lamenting the little attention that has 

 been paid to this subject by preceding astronomers ; and though he 

 by no means pretends that this paper should be considered as a per- 

 fect essay on it, yet he hopes it will be sufficient to induce the prac- 

 tical astronomer to turn his attention to this neglected branch of the 

 science. The most satisfactory mode of determining the proper mo- 

 lion of a fixed star, the author remarks, i.s by a comparison of two 

 catalogues of distant epochs ; for if the difference in its position, at 

 the two epochs, does not correspond with the amount of the preces- 

 sion of the equinoxes, there is good reason to suspect that the star 

 has a proper motion of its own, particularly if the difterence exceed 

 what may be fairly attributed to the errors of observation. But even 

 this is not always a sure guide, unless the interval be considerable ; 

 for the errors of the instrument, the unavoidable mistakes committed 

 in the reduction of the stars, and the errors of the press, are occa- 

 sionally mixed up in such a manner that we are frequently at a loss 

 to know where the truth lies. Moreover, the differences in the con- 

 =* See Phil. Mag. and Annals, N. S. vol. ix. p. 382.-Edit. 



stants 



