4,0 Mr. Herschei/s and Mr. South's observations of the apparent 
Polaris continued. 
Mean result. 
Position 6i° 11' sp. Distance i8".7oi. Epoch 1823.06. 
The positions agree very well. The distances are difficult 
to take, from the great inequality of the stars ; but the mean 
here set down being the result of not less than 100 measures, 
is certainly very near the truth. 
Other measures of this star are 
Position. 
Distance. 
1781.50. 
6f. Q'.sp 
1 S''. 468 ; H. means of measures 
in 
the years 1 779, 1781, 1 
782. 
1802.17. 
6 l°. 43 / . sp 
H. MSS. Observation. 
1815. 
6o°. 2'. sp 
18". 50; Struve Addit, p. 182. 
1819. 
60°. 6'. sp 
1 8". 05 ; ditto, ditto. 
1821.80 
18/' 26; Dorpat Obs. iii. p. 1 
39 - 
Obs. 21, 33. 
The observations of stars very near the pole require a correc- 
tion to reduce them from one date to another, by reason of the 
motion of the pole in the heavens due to precession, which 
alters more or less rapidly their angle of position. In Polaris, 
the annual variation of the angle (being sp) is — 195"= — 
3* 15". Hence the correction for 42 years is — 2 0 i6 # , which, 
applied to the measure of 1781.30, reduces it to 64° 46' sp. 
The observation of 1802 similarly treated, becomes 6o° 38 ', 
coinciding very well with the present angle. A correction 
similar in principle, will of course be required for all the 
stars, after the lapse of long periods ; and the only way to 
obviate the necessity of using it, would be to refer all the 
angles to the ecliptic, and its parallels ; but we are at present 
very far from the necessity of a reduction requiring so much 
labour. 
