distances and positions of 380 double and, triple stars , &c. 367 
61 Cygni continued. 
The observations of this remarkable star by different as- 
tronomers, arranged in order of time, are as follows ; — 
Date. 
Position. 
No. 
of 
Obs. 
Distance. 
No. 
of 
Obs. 
ar.a. 
No. 
of 
Obs. 
A decl. 
No. 
of 
Obs. 
Authority, 
* 753*8 
5°4 36 nf 
U 
19.028 
14.40 
2 
16. 0 
I 
Bradley, cited by Bessel. 
1778.0 
39 2 nf 
— 
15.244 
— ■ 
15.00 
6 
9. 6 
5 
Chr. Mayer, Ditto. 
1781.9 
36 1 1 nf 
2 
i 6.333 
3 
Herschel, Catal. and MS. 
1784.4 
— 
22.50 
1 
6. 9 
1 
Dagelet, cited by Bessel. 
i 79 3-6 
37 H nf 
— 
14-873 
_ 
15.00 
1 
9. O 
1 
Lalande, Ditto. 
1800.0 
1 9 43 nf 
— 
19.267 
_ 
2 1.60 
•7 
6. s 
13 
Piazzi, Catal. for 1800. 
1805.0 
11 32 nf 
— 
14.502 
■ — 
18.00 
6 
2. 9 
8 
Ditto, cited by Bessel. Fund. a 
1812.3 
to 53 nf 
— 
16.741 

19.80 
3 - 1 
Bessel, Fund. a Astronomia. 
1813.8 
19.60 
37 
Lindenau, cited by Ditto. 
1814.5 
20.32 
2 
Struve, Catalogus primus. 
1819.9 
6 58 nf 
5 
15.20 
— 
19.10 
H 
1.85 
Struve, Additam. p. 1 80. 
1 822.9 
5 l 9 ”f 
35 
I 5 - 4 2 5 
33 
Herschel and South, mean result . 
The proper motion assigned by Piazzi and Bessel to 61 
Cygni, are -f- 5". 38 in R. A., and 3". 30 in declination. 
This affords indisputable proof of their connection in a binary 
system, otherwise the lapse of nearly 70 years, during which 
they have been observed, one of them would doubtless have 
left the other behind, without supposing a coincidence too 
extraordinary to have resulted from accident. Of the reality 
of this proper motion we have satisfied ourselves by a series 
of more than 500 micrometrical comparisons of the large 
star with minute stars in the neighbourhood, which will more 
properly be reserved for another communication. 
The mean angular motion, as deduced from the micro- 
metrical measures of 1781, 1819,1822, (regarding the latter 
as perfectly correct) comes out o°.7386 per annum. The 
