Astrofiomkal Society. 391 



IV. Stars observed with the Moon at Blackheath, from August 

 1831 to January 1832, by Mr. Wrottesley. The observations were 

 made with a five-foot transit. 



V. Observations made at the East India Company's Observatory 

 at St. Helena, by Mr. Johnson. 



These consist, first, of observations of the moon and moon-culmi- 

 nating stars from January to August 1830; secondly, of observations 

 of the solstices of December 18'29, and of June and December 1830. 

 The latitude of the observatory deduced from them is 15° 55' 23"'G5 ; 

 while from .several of the Greenwich stars, observed alternately by 

 direct vision and reflexion, it is 15° 55' 26"-54. 



VI. On the Planetary Theory, by Mr. Lubbock. 



The object of this paper is to point out some simplifications which 



may be obtained in developing the functions R and r (-7—) by the 

 use of the binomial theorem. Mr. Lubbock applies this method to 

 the determination of that part of r ( -j— f which contains the first 



powers only of the eccentricities. 



VII. On the Rotation of Venus, by the Rev. Mr. Hussey. 



Mr. Hussey 's object in this paper is to show that the time of rota- 

 tion of Venus asserted by Bianchini, of 23 days and 8 hours, is a near 

 approximation to the truth, in opposition to Cassini and Schroeter, 

 who fixed the same, the former at 23'' 15"', the latter at 23" 21'" ; 

 and to Sir W. Herschel, who, though he declares the time of rotation 

 to be doubtful, tliinks it cannot be so much as 24 days. The obser- 

 vations of Bianchini are quoted at length, in his own words, by Mr. 

 Hussey, who also enters minutely into the arguments used by the 

 younger Cassini, in support of his father's observations. From a re- 

 view of the whole argument, Mr. Hussey concludes from Cassini, Ma- 

 raldi, and Herschel, not having been able with powerful instruments to 

 distinguish the spots of Venus, that their latitudes were unfavourable 

 for such observations ; that the observations of Schroeter are not to 

 be depended upon, as Sir W. Herschel was unable to verify the same, 

 with a more powerful telescope ; that Cassini's observations are in 

 the same predicament, having been made with an inferior instrument, 

 imperfectly mounted and without a micrometer, and not having been 

 much relied on by the observer himself; that we are justified in 

 placing confidence in the observations of Bianchini, from the favour- 

 able circumstances under which, they were made, the minuteness 

 with which they are detailed, from their correctness having been 

 ascertained by several bystanders, from the superior nature of the 

 instruments employed, from the measurements being micrometrical, 

 and from the character of the observer. Annexed to this paper were 

 several diagrams of the spots of Venus. 



VIII. Observations on the Magnitudes of Stars. By Mr. Birt ; 

 communicated by Mr. Lubbock. 



These observations were made between April 1830 and January 

 1831. In the notes subjoined to them, the author has pointed out 

 various discrepancies between the magnitudes assigned to the same 

 star by difl'ercnt observers, from all of which, in some cases, his own 



