302 Royal Astronomical Society. 



are as follow : — Supposing the assumed solar parallax, 8"\578, to 

 be corrected as in the Cambridge Observations for 1832, pages 138 

 and 139, so that the true parallax is 8"*578 (I+aO, the value of jx is 

 determined as follows : — 



Compared with Lhnb Valnoofw Parallax of © from 



the Cape Obe. ljimb * Value of ^. mea n of preceding. 



Cambridge North -j- 0-01271 c „ - OQ 



South -0-0102 f 8 ' 588 



Greenwich \ /North -f 0*0895 \ 



9"*076 

 9"*343 



(Troughton) J '""[South -j- 0*0265 J ""•• 



Greenwich 1 /North -f 0-0632) 



(Jones) J '" I South -j- 0-1 152 j* 



* The chief inference," Mr. Henderson remarks, " to be drawn 

 from the above observations appears to be, the probable accuracy 

 to be expected from similar observations at future periods." 



Mr. Henderson states that the season in which these observations 

 were made was not favourable for delicate astronomical observations 

 at the Cape, as the south-east wind was generally prevalent, during 

 which the atmosphere is in a disturbed state. The season best 

 adapted for accurate observations there is from March to October, 

 or during the winter months. 



IV. On a Clock for giving Motion in Right Ascension to Equa- 

 torial Instruments. By the Rev. R. Sheepshanks. This paper, il- 

 lustrated by an engraving, is given in the Monthly Notices of the 

 Society. 



V. Stars observed with the Moon at Cambridge Observatory, in 

 the month of March 1834. Long. 23 s *54« east of Greenwich. 



May 9. — The following communications were read : — 



I. Second Series of Micrometrical Measures of Double Stars 

 chiefly performed with the 7-feet equatorial. By Sir J. Herschel. 



This second series is a continuation from vol. v. p. 90 of the Me- 

 moirs, and begins with No. 736, the last in the above-mentioned 

 page being 735. The observations have been almost entirely made 

 with the same achromatic of five inches aperture, except in the case 

 of a few difficult objects, for which the 20-feet reflector was used. 

 Many of them, and in particular all those of 1833, were made with 

 an increased magnifying power, which Sir J. Herschel calls 500, but 

 thinks may be something less. The action of the instrument under 

 this power is perfectly good ; and, having provided himself with 

 still higher powers, Sir. J. Herschel expects to be able in future to 

 avail himself fully of the excellent quality of the Object-glass, which 

 has hitherto become uniformly more apparent with every increase 

 of power which has been applied to it. 



Sir John Herschel's observations end at No. 1, 111, and to them 

 are added a few made by Captain Smyth and the Rev. W. R. Dawes. 



II. Micrometrical Measures of the Positions and Distances of 

 121 Double Stars, taken at Ormskirk, in the years 1830^-33. By 

 the Rev. W. R. Dawes. 



These observations are given in the same manner as those of Sir 

 J. Herschel, and are 406 in number. For a description of the in- 

 strument employed, see Memoirs, vol. v. p. 1 35. Mr. Dawes further 



