390 Asttunoviical Society. 



ASTRONOMICAL SOCIETY. 



April 11. — A paper by Colonel Beaufo)s was read, containing his 

 Observations of Eclipses of Jupiter's Satellites, from January 2 to 

 May 15, 1826, together with some Observations of occultations of 

 stars by the moon. 



A paper was also read " On the Longitude of Madras, as deduced 

 from Observations of Eclipses of the first and second Satellites of 

 Jupiter, taken between the years 1817 and 1826. By John Gold- 

 ingham, Esq. F.R.S." 



The eclipses stated in this paper are 96 in number, being Immer- 

 sions and Emersions of the Jst and 2nd Satellites only. Of these, 

 11 are directly comparable with those of Colonel Beaufoy, made 

 at Bushey Heath, viz. 8 of the 1 st, and 3 of the 2nd ; and their mean 

 result, which of course is independent of the errors of the tables, is 

 stated by Mr. Goldingham at 5'' 21"' 9''3, being the longitude of 

 Madras east of Greenwich. The remainder, consisting of 34 Emer- 

 sions and 55 Immersions of the first Satellite, and 12 Emersions and 

 4 Immersions of the second, are not directly comparable with Colo- 

 nel Beaufoy 's. Mr. Goldingham endeavours, however, to render them 

 so, or at least to elim.inate the errors of the tables, by determining 

 the latter from Colonel Beaufoy 's observations made nearly about 

 the same time, and then applying it to the results of a comparison 

 of his own with the Nautical Almanac as a correction ; and in this 

 way deduces a conclusion agreeing almost exactly with the fore- 

 going. 



This is not the place to enter into any discussion on the legiti- 

 macy of the process pursued by Mr. Goldingham for this purpose, 

 or of its general applicability in the present state of the tables. The 

 end of this iibstract will be better answered by presenting in one 

 view the results of these several classes of observations as obtained 

 separately, by direct comparison with the Nautical Almanac, uncor- 

 rected by reference to Colonel Beaufoy 's, or any other observations, 

 which may be stated as follows : 



Madras East of Greenwich. 



By 3t Emersions of the 1st Satellite observed at") ^,, ^j... q^.^ 

 Madras, and compared with the Nautical Almanac. J 



By 35 Immersions of ditto, similarly observed and> ^ ^j i2-4. 



compared S 



Mean Longitude of Madras 5 21 Q-* 



Difierence of Immersions and Emersions . . 5*9 



By 12 Emersions of the 2nd Satellite, similarly ^b-l ^i, c)i„, q>.^ 



served and compared J 



By 4 Immersions of ditto 5 21 33*1 



Mean Longitude 5 21 16'8 



Difference of Immersions and Emersions . , 32*6 



The latter series has, however, only the weight of four double ob- 

 servations, and is therefore no way to be put in competition with 

 the former, corroborated as it is to minute precision by the results 



of 



