164 
EASTMAN. 
from the sun, and the apparent stellar proper motions were 
caused by the motion of the solar system in space, then the 
largest stars, or those nearest the sun, in those portions of 
the heavens 90° from the direction of the sun’s motion, would 
show the greatest proper motion. If, on the other hand, the 
solar system is fixed in space and the observed change in 
the positions of the stars is due to an inherent motion of 
those bodies themselves, then the stars nearest the solar sys¬ 
tem would have the greatest apparent motion. But, what 
are the facts ? 
The annual proper motion of Sirius is about 1".30, 
or less than that of some 9th’ magnitude stars which theory 
would place at least twenty-three times as far from the sun. 
The seventh magnitude star, Groombridge 1830, which, ac¬ 
cording to theory, would be more than eleven times the dis¬ 
tance of Sirius from the sun, has an annual proper motion 
of 7".05 or more than 5.4 times that of Sirius. The cases 
just cited are isolated phenomena, and, as the inferences 
drawn from such data are possibly misleading, it has been 
deemed of the highest importance to undertake a more gen¬ 
eral investigation in a much broader field. 
In the Proceedings of the American Association for the Ad¬ 
vancement of Science 32 , for 1889, is published an abstract of the 
methods employed in the investigation of the relation between 
stellar magnitudes and proper motions, together with the re¬ 
sults obtained. In this connection it is unnecessary to cite 
from that paper anything but the data and the results. I first 
investigated the relations of the magnitudes and proper 
motions of 345 stars whose proper motions had served as a 
basis for an Inaugural Dissertation by Dr. 'Johann Bischof. 
This list included the well known proper-motion catalogue 
of 250 stars by Argelander. 33 
The magnitudes of these stars range from the 5th to the 
9th, inclusive, and the observed motions are determined with 
32 Eastman, J. R. Proc. Am. Ass. for Ad. Science, 1889 ; 71. 
33 Argelander, F. W. A. Astronomische Beobachtungen auf der Stern- 
warte zu Bonn. Siebenter Band; 109. 
