in the relative Situation of double Stars , &c. 
377 
Observed 
Calculated 
Differences. 
Times of the observations. 
angles. 
angles. 
August 31, 1780 
3 2 ° 
* 9 ' 
33 ° 
58' 
— i° 39 ' 
March 13, 1781 - 
3 ° 
21 
34 
*3 
— 3 52 
May 10, 1781 
33 
1 
34 
18 
— 1 17 
Feb. 17, 1782 
38 
26' 
34 
4° 
+ 3 4 6 ‘ 
August 18, 1 796 
45 
32 
4 1 
40 
+ 3 52 
Jan. 28, 1802 
49 
18 
44 
19 
+ 4 59 
August 31, 1802 
46 
47 
44 
3 6 
-f-211 
March 23, 1803 
43 
43 
44 
52 
— 1 9 
March 26, 1803 - 
44 
5 2 | 
44 
52 | 
0 0 
The real motion from h to h' is projected into that from x to 
x'; and, while the elliptical arch subtends an angle of 12 0 33', 
the circular one will be about 4 0 50'. 
From the figure of the orbit, we may conclude that the small 
star, in its first position, at x or b, was not more than between 
30 and 40 years past its conjunction ; and that, consequently, 
the parts of the arch xx', were nearly proportional to the times 
of their being described. The positions have been calculated 
upon this principle ; but with some allowance for the first ob- 
served angle, which I suppose to have been a little too small ; 
and, though the differences of the observed and calculated angles 
are pretty considerable, the observations are still sufficiently con- 
sistent to prove the gradual change of the situation of the small 
star. 
The quantity of the change in 22 years and 207 days, will 
show that a periodical revolution cannot take up less than 1681 
years. The real figure and situation of the orbit, with many 
other particulars, are still unknown ; it is, therefore, unnecessary 
