362 Mr. South's re-examination of the apparent distances 



No. XXIV. R. A. 17^ 4" ; Decl. 26** i8' S. 



36 Ophiuchi ; H. and S. 243. 



continued. 



suppose, that the star was by one and the other observed as 

 single ; our observations therefore must be corrected by half 

 the difference of declination, and by half the difference of 

 right ascension, which with the preceding distance, and 

 position 41° 32' will be i".724 in declination, and i".946 on 

 the parallel, equal to o".i47 of right ascension in time. 



For the star 38 Ophiuchi no correction of this sort will be 

 required : its smaller star was certainly neither seen by 

 Bradley nor by Piazzi ; and its magnitude, even were it at 

 the time closer than it now is, would not sensibly alter the 

 apparent centre of the disc of A of 38. 



But the differences of declination observed by us are un- 

 corrected for refraction : the necessary equations being 

 appHed, we get, 

 Diff. of decl. of A of 36 Ophiuchi & of 30 Scorpii 3' 2".403 



&Aof 38 Ophiuchi 5' 25". 764; 



and when the corrections to reduce these results to observa- 

 tions of the centre of the two stars of s6 Ophiuchi are 

 applied, the quantities become 3' 4^.127 and 5' 24*.o4o for 

 the differences of declination ; and for differences of right 

 ascension (in time) 5^" -591 and 2' ii".905 respectively. 

 , Now by Bessel's proper motion,* the difference of declina- 

 tion of 36 Ophiuchi and of 30 Scorpii, Epoch 1825.57, should 

 be 3' 4 '.930, differing with our determination only 8-tenths of 

 a second : hence in declination, the two stars have either the 

 same, or no proper motion. 



But Bessel does not give the proper motion in right 

 ascension, for it appears that BRADLEY-f did not observe the 



* Vide Fundam. Astronom. page 311 



f In Bradley's published observations I have not met with any observed R. A. 

 of 30 Scorpii, nor have I found any observation of 38 Ophiuchi, in the manuscript 



