152 
EASTMAN. 
Lundahl’s result with those from his three classes, Argelan- 
der 15 obtained as the most probable result, for the position 
of the solar apex, from all the observations, a point whose 
R. A. was 257° 49 / .7 ± 2° 49'.2 and Dec. +28° 49'.7 ± 1° 59'.8, 
for the epoch 1792.5. 
In 1841, Otto Struve 16 presented to the Imperial Academy 
of Sciences of St. Petersburg, a very elaborate paper on the 
determination of the constant of precession, with regard to 
the proper motion of the solar system. Employing a greater 
amount of data than any of his predecessors in these inves¬ 
tigations, the author essayed to obtain, not only the correc¬ 
tion to the assumed constant of precession, but also the an¬ 
gular value of the solar motion, from the same set of about 
eight hundred equations. 
He also employed the residuals from the first set of equa¬ 
tions, in a new series of equations to find corrections to Arge- 
lander’s coordinates of the solar apex. From this last cal¬ 
culation, he found the right ascension of the point in the 
heavens, towards which the solar system is moving, to be 
261° 22' d= 4° 50' and the declination + 37° 36' ± 4° 12', 
at the epoch 1790. Combining these values with those de¬ 
termined by Argelander he ^obtained the coordinates 259° 
9'.4 d= 2° 57'.5 and + 34° 36'.5 ± 3° 24'.5 for the epoch 
1790. For the annual amount of translation of the solar 
system, at right angles to the line of sight, as seen from the 
mean distance of the stars of the first magnitude, he found 
the value q = 0"3392 ± 0".0252. 
If the proper motion of any star is due to the action of 
some remote central body, then, like all bodies moving about 
a centre under the influence of gravitation, its path would 
deviate more or less from a straight line, and its apparent 
motion would not be uniform. In comparing the positions 
of Sirius and Procyon, depending on Bradley’s observations 
in 1755, and on later observations in 1820 and 1844, Bessel 17 
15 Argelander, F. W. A. Astronomische Nachrichten, 398 ; 210. 
16 Struve, Otto. Memoiresde PAcademie Imp. des Sciences deSt. Peters¬ 
burg, Vie serie. Sciences, Math, et Phys. Tome III ; 17. 
17 Bessel, F.W. Astronomische Nachrichten, 514,145; 515,169; 516,185. 
