which form Binary Systems. 95 



The angle of position for 1825.46 is 63° 32 np^ and the dis- 

 tance VA2\. '• If this double star," says Messrs Herschel 

 and South, " be a binary sytem, of which there can be little 

 doubt, its period is about 622 years, and the most probable 

 mean annual motion is 0^.5783 in the direction s p^ nfy or re- 

 trograde. 



9. ^ Serpentis, R. Asc. 15^ 26. N. decl. 11 °9. 



The two stars which compose this double star are both blue, 

 and of the 8th and 9th magnitude. The following are the 

 angles of position: — 



1782.99 4^2<^ m sp\^ ^ ^ ^^ 



1802.10 61 27 ^^l^ir >^^- «erscnei. 



1819.70 67 41 sp\^^ 



1820.12 71 .H 



1821.33 70 37 sp. Herschel and South. 



1825.46 69 49 sp. South. 



The distance at this last epoch was 3".268. The mean an- 

 nual motion is — 0.726. But, as Mr Herschel remarks, instead 

 of advancing 3° as it should have done since 1821, it has re- 

 ceded nearly 50'. 



10. 49 Serpentis, R. Asc. 16'^ 4'. N. decl. 14P V. 



The two stars are of the 8th and 8J magnitude, and both 

 white. Its position was 



1781.18 21° 33' 7ip. Sir W. Herschel. 



1820.10 46 33 np. Struve. 



1825.41 48 10 np. South. 



The distance at this last epoch was 3".501. The mean an- 

 nual angular motion is -|-0°.510. 



11. (7 Coroncv Bor. R. Asc. 16^^ 8'. N. Decl. 84° 20'. The 

 two stars are of the 6th and 8th magnitude, and the small one 

 is blue. There is another of the 15th or'20th magnitude, 42" 

 distant. The angles of position are 



1781.79 77°32'm;>1 „ „. „ , , 



1802.79 78 36 nf ] S"" ^- Herschel. 



