distances and positions 0/380 double and triple stars t &c. 231 
No. CCV. R. A. 1 5 h s6 m ; Decl. n°9' N. 
S Serpentis ; Struve, 488 ; I. 42. 
Double ; both blue. 
Position. 
Distance. 
April 28, 1821. 
Parts. 
11. o') 
9- 5 
70.10 j 
7°-39 ) 
70.45 >S 
7i-3° ) 
Position == 7 o°.37' sp 
Distance = "3.053 
Mean = 9.78 
Z ~ — 0.1 1 
9.67 
Mean ~ 70.37 
This is one of the stars enumerated in Sir William Her- 
schel's account of changes in the relative situations of double 
stars as having a considerable angular motion. This is fully 
confirmed by the present observations, as the following 
statement will show. 
1782.99. Position 42 0 48' sp ; Interval £ to \ diam. of S ; H. Catal. of 1785. 
1802.10. 61 27 sp; H. Account of the Changes, &c. 
1819.70. 67 41 sp; Struve, Additamenta, p. 190. 
1820.12. 71 o sp ; D°. Dorpat Obs. vol. iii. ; reported by Zach. 
1821.33. 70 37 sp; H. and S. ut supra. 
M. Struve suspects the distance to have increased. An 
interval of \ diameter of the small star would correspond 
to a central distance of about 2"^ or 2§ . M. Struve mea- 
sured it in 1819, and found it 3". 42, a little larger than ours, 
but his measure was taken with a projection micrometer, 
and may be less accurate on that account ; yet on the whole 
