APPENDIX II. 
No. 3. Bradley 3210 m. 
This star is 2 3062 and is a binary. See (Stellar Systems) assigned a period of 104.6 years. 
His orbit is employed here in making further deductions. The adopted magnitudes of the com¬ 
ponents are 6 M 6 and 7 M 6; the distance is always less than 2". The majority of the observers appear 
to have taken the star as one mass; though it is not always easy to determine what has been done. 
The weight of the meridian-observations is totally insufficient to determine the relative masses in 
this case, because of this uncertainty as to the pointing, which may have been on the principal star 
in one case, on the general mass of light in another, and on the mean in still another. From ex¬ 
perience with similar systems (see Introduction), it is very probable that the mass of the brighter 
star is not much greater than that of the fainter star. Accordingly, it has been assumed that the 
masses of the two stars are equal. Thus the catalogue-position refers to the mean between the 
two stars. 
The following table exhibits the amounts which must be added to the catalogue-position, com¬ 
puted for the respective years, in order to get the position of the brighter star. Subtraction of the 
same quantities is supposed to give the position of the fainter star. Obviously, the predicted 
positions of this star are liable to a material uncertainty beyond that which would in ordinary cases 
attach to the weight of observations. 
To get position of brighter star add to catalogue-position of mean. (Adopted period, 104.6 
years.) 
Date. 
Aa. 
A 8 . 
Date. 
Aa. 
AS. 
1820 
s 
+ .044 
// 
+ .52 
1875 
s 
— .084 
n 
+ .26 
1825 
+ .051 
+ •35 
1880 
— .078 
+ •36 
1830 
+ .044 
+ .11 
1885 
-.068 
+•47 
1835 
+ .028 
-.14 
1890 
-.056 
+.56 
1840 
— .002 
-•34 
1895 
-•043 
+.63 
1845 
-.036 
-•38 
1900 
— .029 
+ .68 
1850 
— .060 
-•34 
1905 
— .014 
+ .71 
1855 
— .076 
-.24 
1910 
+ .002 
+ .72 
i860 
— .084 
— .12 
1915 
4 - .018 
+ .69 
1865 
-.088 
— .02 
1920 
+ .034 
+ .62 
1870 
-.088 
+ •13 
1925 
+ .045 
+ .50 
No. 168. tj Cassiopeiae, 2 60. 
The annual parallax of this star may be taken as o'.'ij. This is a binary of period 233.3 years, 
according to Lewis (Mem. R.A.S., Vol. LVI, p. 16). Adopting these elements, meridian-observa¬ 
tions in R. A. indicate that the center of gravity is at the distance 0.62 (wt. 60) from the principal 
toward the fainter star; from equations in declination the corresponding quantity is 0.29 (wt. 85). 
Accordingly, the ratio of the masses is assumed to be as 1.0 to .76, the brighter star being the unit. 
This result is very uncertain, however, owing to the interdependence of the expressions for orbital 
and proper motions respectively. The adopted magnitudes are 3^6 and 7^9. The position in the 
catalogue is given for the adopted center of gravity. The following little table shows the quanti¬ 
ties which must be added to this catalogue-place of the center of gravity in order to produce the 
predicted place of the brighter star. If these quantities be multiplied by —1.33 and added to the 
catalogue-place, we shall have the predicted positions of the fainter companion. 
264 
