and positions of^fSS double and triple stars y &c. 3 



presented to public view, the mean result of each night's 

 work is here noted ; but as the number of observations, and 

 the differences between the extreme measures of eac'i series 

 are also specified, it is hoped that the alteration will be satis- 

 factory to the Society. 



As in these observations I have not had the powerful aid 

 of Mr. Herschel, it has been my endeavour as far as possible 

 to compensate for the loss ; hence, instead of taking ten indi- 

 vidual observations both of distance and position on the same 

 night, and thereby considering the star measured, I have 

 divided the work generally assigned to each star between 

 two evenings, the better to correct any error which unfa- 

 vourable state of atmosphere, inaccurate micrometrical read- 

 ings, or particular bias of judgment might entail ; and when 

 the results have exhibited discordances greater than seemed 

 justified by the difficulty of the observations, a third, or even 

 a fourth night's determination has been found useful. 



To the observations contained in the former Memoir, pecu- 

 liar interest was attached by the comparison of them with 

 the results obtained by other astronomers ; of which by far 

 the most important were those derived from the labours of 

 Sir W. Herschel ; but as the observations which are re- 

 corded in the Philosophical Transactions are (from circum- 

 stances before * adverted to ) of themselves inadequate to 

 furnish the final results arrived at by that illustrious astro- 

 nomer, it is grateful to me, and doubtless will also be to the 

 Society, that the kindness of Mr. Herschel has supplied the 

 necessary information ; thus the existence of fresh connected 

 systems is substantiated, and adegree of /)r^5^w^ importance con- 

 ferred on the following pages, which he alone could bestow. 



* See PhU. Trans, for 1824, Part IIL page 20. 



