SOLAR AND STELLAR PROPER MOTIONS. 
153 
believed that he had detected a lack of uniformity in their 
proper motions; and in 1844 he completed a very elaborate 
discussion of all the data at hand, reaching the conclusion 
that Sirius had a variable proper motion in right-ascension, 
and Procyon in declination; due in each case to the influ¬ 
ence of a not very distant, and possibly an opaque, body of 
immense mass, around which the stars revolved. 
In 1847, Thomas Galloway 18 presented to the R. A. S. an 
investigation of the position of the solar apex, depending on 
the observations of southern stars. He employed seventy- 
eight stars from the catalogues of Johnson and Henderson, 
and compared their places w T ith the positions given by 
Lacaille and Bradley. The difference of epochs was about 
eighty years, and he selected all the stars that appeared to 
have an annual proper motion of more than 0".l. 
Following the line of investigation adopted by Argelander, 
Galloway found the most probable position of the solar apex 
to be in R. A. 260° 0'.6±4° 31'.4 and in Dec. +34° 23'.4± 
5° 17'.2. 
From 1847 to 1856 but little progress was made in mathe¬ 
matical investigation but a number of catalogues of stars 
with suspected proper motion were constructed, and several 
astronomers completed admirable discussions of the sus¬ 
pected irregular motions of Sirius and Procyon. 
In Vol. XIV of the Dorpat Observations, J. IT. Madler 
gives the results of his study of the motion of the solar sys¬ 
tem in space. He adopted the methods of computation em¬ 
ployed by Argelander and divided the 2,163 stars, from 
which he derived his data, into three classes, according to 
the amount of proper motion. 
Class (a) contained 227 stars with proper motion greater 
than O''.25. 
Class ( b ) contained 663 stars with proper motion between 
0".10 and 0".25. 
Class (c) contained 1,273 stars with proper motion between 
0".04 and 0".10. 
18 Galloway, Thomas. Philosophical Transactions, 1847 ; 79. 
