338 M. Struve and Prof. Amici’s Observation s on Double Stars . 
have not approached one another. A comparison of the obser- 
vations of Bradley and Piazzi does not shew that any change has 
taken place. 
13. » 70 Serpentarius , R. Asc. 17 h 56'. Deck 2° 34'. 
4th Mag. and 7th Mag. 
The largest of these remarkable stars is yellowish, and the 
smallest red. 
1781.73 
1804.41 
1819.63 
1820 February 16. 
1818 Distance, 
1819 Distance inferred. 
Herschel. 
Do . 
131 19 Do . 
281 18 Struve . 
288 58 Do. 
5 .34 Do. 
1 .05 Do. 
in 1779.77 The angle of Position was 0° 0" 
9 14 
years. 
Hence, in 39.86, the small star has moved through three- 
fourths of its orbit, and it is very probable that it will complete 
its revolution in ten years more. The apparent orbit of it seems 
to be very elliptical. 
14. o Serpent R. Asc. 18 h 48'. Heel. 3° 58' N. 
5th Mag. and 5th Mag. 
Both stars are white, and one a little smaller than the other. 
In 1755, the Diff. of R. Asc. was 21".0 Diff. of Decl. 6" 1 Bradley. 
1778, . . 21. 0 . 6.2 Ch . Mayer. 
1819, . . 22. 5 . 5.5. Struve. 
15* 1. c. 16. Swan, R. Asc. 19h 37'. Decl. 50° 6' N. 
6th Mag. and 6th Mag. 
Both stars are white, the following one being the smallest : 
In 1755, Diff. of R. Asc. 34 /, .40 Diff. of Decl. 26 // .6 Bradley . 
1819, . 41 .25 . 28 .0 Struve. 
1819, Distance, . 38 . 5. 
1819, Angle of Position, 46° 36' S. Fol. Struve. 
16. 61. Swan. R. Asc. 20 h 59' Decl. 37° 52' N. 
5th Mag. and 5th and 6th Mag. 
The larger star is yellow, and the smaller one a deep-red. 
The relative motion of these stars was discovered by M. Piazzi, 
in 1804. M. Bessel examined them in 1812. 
In 1819, Angle of position was 6°. 58' N. Fol. Struve. 
1819, Distance, 
15".2 
1812.3 Diff. of R. Asc. 
19 .8 
Diff. of Decl. 13". 20 Bessel. 
1819,9 . * 
19 .1 
.. . 1 .85 Struve. 
