distances and positions of 380 double and triple stars , &c. 3s 
optima observatione” Dec. 8, 1819, makes it 26°. 51'. Assem- 
bling all in one view we have 
1 783* 15 Position 30 °-95 np or sf 
1802.61 27 .36 
1819.94 2 6 .85 
1820.92 22 .00 Struve, Dorpat, Obs. iii, Obs. 70, 
p. 133, 2 meas. 
1822,86 25 .80 H. and S. ut supra. 
The slow decrease in the angle of position is here suffi- 
ciently evident, though too small to place any confidence in, 
were it not for the progressive steps by which the intermedi- 
ate observations show it to have taken place. The rate of 
decrease, calculating on all the observations according to the 
formula (1) is no more than o°.ii7 per annum, in the direc- 
tion np sf , or retrograde. Supposing it to revolve uniformly 
in a circle, its period would at this rate be 3077 years. 
The distance, in 1783, was i£ diameter of the large star. 
M. Struve, in 1819, made it 5".77, with which ours coin- 
cides, almost to minute precision. The distance, therefore, 
as well as the angle, seems to be subject to a slow variation, 
as a diameter and half between the discs, in equal stars of 
the 7th magnitude, can hardly exceed 4" from centre to 
centre. 
No. X. R. A. o h 42 111 ; Decl. 67° 51' N. (H. and S.) 
Double ; equal ; 8th magnitude. 
Position. 
S «- ,8 1 
56.30 I 
57-35 > H 
54-45 
54 - 3 °J 
55 - 3 ° 
54. o 
54-30 > 
54.25 | 
54. oj 
S 
Nov. 13, 1822. 
Five-feet Equatorial. 
sp 
Position = 55 0 . 1 2' sp 
Distance = 3". 151 
Distance. 
Parts. 
9. o') 
11. o I 
12. o )>H 
13. o 
9 - 5 - 
10. 9' 
10. 2 
1 1. o )> 
11. 5 
11. 8 j 
S 
Mean — 55-12 
Mean =: 10.99 
Z — — 1.01 
MDCCCXXIV. 
F 
9.98 
