distances and positions of 380 double and triple stars , &c. 105 
Castor continued. 
Mean result. 
Position (by the observations of 1821) 2 0 53' sp ; 1821.21 mean date. 
By those of 1823 5 1 sp; 1823.1 1 ditto. 
Distance by all the observations 5". 355 5 1822.10. 
The observations of this star as given by different astro- 
nomers may be arranged as follows : 
Position. 
1759.80 
1 77 9 . 8 + 
1791.64 
* 795 * 9 6 
1802.04 
1813.83 
1816.97 
1819.10 
1821.21 
1823.1 1 
56°. 5 np. 
32.79 np. 
25.10 np. 
13.90 n P‘ 
1 1.36 np. 
2.86 np. 
0.00 p. 
0.40 sp. 
2.88 sp. 
5.02 sp. 
Bradley and Maskelyne, cited by Sir W. Herschel 
“ Account, &c.” 
H. “ Account of the Changes, & c. 1803.’* 
H. ditto, ditto. Mean of two measures, 1791, 1792. 
Ditto, ditto, single measure. 
Ditto, ditto, mean of 9 measures, Phil. Trans. 1803, p. 365. 
Struve, by projection micrometer. Dorpat Obs. Cat. ii. 50. 
Herschel, Jun r . Seven-feet reflector. Slough. 
Struve; Additamenta, See. p. 176. 
24 measures. 
I H - 
and S. ut supra 
26 measures. 
To these we may add 
1820.66 2.34 sp. Struve, Dorpat Observations, iii. by 42 measures. 
1780.43 s" 2 9 ° Sir W. H. (MS.) Mean of six measures taken between 1779.84 
and 1781.16. From what source the measure 5". 156 in the 
Catal. of 1782 was derived, does not appear. 
1819.10 5 480. Struve, Additamenta, Sec. page 176. 
1822.10 5 355. H. and S. ut supra, mean of 37 measures. 
That this beautiful double star is truly characterized by Sir 
W. Herschel as a binary system, there can now be no doubt. 
In 63.3 years the change of the angle of position amounts to 
6T.5, being on the average o°.97i per annum. The mean 
angular velocity, computed from the ensemble of the above 
observations, giving them all equal weight, is o°.965. Mean- 
while the distance continues precisely what it was. This 
would indicate a circular orbit at right angles to the line of 
mdcccxxiv. P 
