distances and positions of 380 double and triple stars , &c. 149 
| Ursae Majoris continued. 
14 33 np; Struve, Additamenta, &c. 
p. 177; by 2 measures. 
621 np ; Struve, Addit. by 15 meas. 
1 12 sp ; Ditto. Dorpat Obs. iii. p. 361. 
Obs. 57 ; by 3 measures. 
7 21 5/; Struve, mean of 4 measures, 
Dec. 12, 1821, and Jan. 29, 
1822; videZach. viii. p.5i7> 
and Dorpat Obs. iii. p. 144. 
1823.11 (Feb. 12) 10 37 sp ; Herschel and South ut supra. 
1823.28 (April 10) 11 30 sp ; Ditto. 
1823.43 (June 3) 12 23 sp ; Ditto. 
1823.52 (July 9) 12 38 s/> ; Ditto. 
Distance. 
1819.10 
1820.13 
1821.31 
1822.08 
1780 ; y diameter with 222, i£ with 278 = interval of discs, 
which would give about 4" for the distance of the 
centers. 
1819 ; 2". 565 ; Struve, mean of 2". 73 and 2".4. 
1823 ; 2". 80 9 ; H. and S. ut supra. 
The remarkable variation in the angular velocity will best 
appear by taking the mean positions and times as calculated 
from the observations at or near marked epochs by the 
different observers, thus 
Sir W. Herschel’s first determination; 53 ° 47 ' = 53°-79 s f> 1781.97. 
second ditto.; - - 5 .07 sf; 1803.08. 
Mean of M. Struve’s 17 Observations, 1819 and 1820 ; 7 .32 np ; 1820.01. 
Mean of M. Struve’s 7 Observations, 1821 and 1822; 4.71 sp ; 1321.75. 
Mean of the Obs. of H. and S. ; - - 11.55 S P* 1823.29. 
In the first interval, of 21.11 years, 48°.72 were described, 
giving an annual motion of 2°.309. In the next interval of 
