S70 Mr. South' s re-examination of the apparent distances 



No. XXVI. R. A. 17^ 56"^ ; Decl. 2° 53' N. 



70 p Ophiuchi ; II. 4 ; H. and S. 258. 

 continued. 

 " May 11, 1780, 5".468 ; but very difficult to take, and 

 " therefore not much to be depended on/'. . . . " I am 

 " apt to believe that this method generally gives the 

 " distance too large." 

 " June 19, 1780. If diameter, or between i|- and 1^ by 



" very exact estimation By measures ^'.si5." 



" August 28, 1780. 4".53i. Almost 2 diameters of the 

 " largest, which is the preceding star. The difference 

 " in size almost 2 to 1, or 1^ to 1." 

 " May 27, 1781. Much above 2 diameters of the largest 



" with 460." 

 " April 28, 1783. Above 2 diameters.*' 

 From all these observations, it is clear that the interval 

 between the stars about the year 1780 could not be less 

 than 2 diameters, and by a mean of all the estimations, must 

 have been about this quantity, or rather more than less. The 

 small star being taken at 0.6 of the diameter of the large, 

 the distance of their centres must have been 2.8 D, and the 

 distance, including the diameters, 3.6 D. Now as this distance 

 by the mean of all the measures, was 4'^492, we have D = 

 i".25 and 2.8 D = 3".5oo. 



Again ; we find the following observation, the only one 

 which occurs in the interval in question. 

 *' June 3, 1804. About i^ diameter of L." 

 This would give for the distance between the centers 



2.05D = 2".5625. 



So far then as estimations by diameters can go, these 



