in the relative Situation of double Stars. 
37i 
FI. 21 Ursa. II, 73. 
Nov. 17, 1782, the two stars were in the position of 36° 45' 
north-preceding; and. May 20, 1802, I found them 47° 37'; 
which gives a change of io° 52', in 19 years and 184 days. A 
parallactic motion will account for it ; unless, hereafter, a proper 
motion of the large star should be found to have a different 
tendency. 
FI. 4 Aquarii , I. 44. 
The position of the two stars, July 23, 1783, was 8i° 30' 
north' preceding ; and, by a mean of two observations, August 
28 and 29, 1802, it was 61° f north-following. Both the last 
measures are positive, with regard to the position being follow- 
ing, and not preceding, as it certainly was in the year 1783. 
This proves a change of 37 0 25', in 19 years and 37 days. The 
distance is perhaps a little increased. Sept. 5, 1782, it was •§■ 
diameter of S. August 29, 1802, less than \ diameter of S. 
A parallactic motion of the large star, would have brought on a 
retrograde motion of the small one, which, on the contrary, we 
find has been direct. This proves a real motion, the nature of 
which cannot remain many years unknown; its velocity, hitherto, 
having been at the rate of nearly 2 degrees per year, of angular 
change. 
South-preceding v Serpentis. I, 81.* 
The position,. March 7, 1783, was 49 0 48' south-preceding. 
August 30, 1802, it was 59 0 5'. The change is 9 0 17', in 19 
years and 176 days. If the stars were a little more different in 
* We now have the place of this double star in Bode’s Catalogue, where it is called 
J12 Serpentis. 
