278 
PRELIMINARY GENERAL CATALOGUE OF STARS FOR 1900 
No. 6172. Br. 3198. 85 Pegasi. p 733. 
This is a binary with a period of about 25.7 years, according to Burnham, whose orbit is here 
adopted for special discussion of irregular proper-motion. The magnitudes of the components are 
6 M o and ii m o respectively. The meridian-observations have a total weight of only 22.5 in R. A., 
and of 25.2 in declination, much less than the weights for any other binary treated in these notes. 
They give for the proportional distance of the center of gravity to the entire distance from the bright 
to the faint star: 
From right-ascensions 0.51 ± .16 
From declinations 0.84 ± .20 
Mean by weights 0.64 ± .13 
This corresponds to a mass for the faint star of 1.8 — the bright star having been taken as the unit. 
The aspect of these numbers lends plausibility to the hypothesis of greater mass for the fainter star. 
But the meridian-observations are not entirely inconsistent with the hypothesis of equality of mass, 
as may be supposed from the probable error. There is no other instance in which it has been pos¬ 
sible to demonstrate with a strong preponderance of probability that the fainter component of a 
binary star has the greater mass, while the strong natural inference must be in favor of greater mass 
for the brighter component, especially when the discrepancy in brightness is very great, as in the 
present instance. Accordingly, it is here assumed that the two masses are sensibly equal and that 
the center of gravity is halfway between the two stars. The Catalogue gives the position of the 
center of gravity. Adding to this position quantities derived from the following table, we have for 
the respective dates the positions of the brighter star. In like manner the position of the fainter 
star is obtained from this table after reversal of signs. 
Date. 
Aa. 
A 8 . 
Date. 
Aa. 
AS. 
1880 
1905-7 
s 
+ .024 
// 
— .12 
1895 
1920.7 
s 
+ .004 
// 
+ .38 
1881 
1906.7 
+ .019 
— .16 
1896 
1921.7 
+ .008 
+ .36 
1882 
1907.7 
+ .012 
— .18 
1897 
1922.7 
+ .012 
+ -34 
1883 
1908.7 
+ .OOI 
-.18 
1898 
1923-7 
+ .Ol6 
+ .30 
1884 
1909.7 
— .006 
— .12 
1899 
1924.7 
+ .Ol8 
+ .26 
1885 
1910.7 
— .014 
-.04 
1900 
1925-7 
+ .022 
+ .21 
1886 
1911.7 
— .020 
+ .08 
1901 
+ .024 
+ .16 
1887 
1912.7 
— .020 
+ .18 
1902 
+ .026 
+ .10 
1888 
1913-7 
— .020 
+ .24 
1903 
+ .027 
+ .04 
1889 
1914-7 
— .019 
+ .30 
1904 
+ .027 
— .02 
1890 
I 9 I 5-7 
— .0x6 
+ .34 
1905 
+ .026 
— .08 
1891 
1916.7 
— .012 
+.38 
1906 
+ .022 
-•13 
1892 
1917.7 
— .009 
+ •39 
1893 
19x8.7 
-.005 
+ .40 
1894 
1919.7 
.OOO 
+ .40 
