THE SUN’S MOTION IN SPACE. is 
Here again we find a marked and progressive descent of the apex 
toward the equator with the increasing swiftness of the objects serv- 
ing for its determination, jeading to the suspicion that the most north- 
erly may be the most genuine position, because the one least affected 
by stellar individualities of movement. By nearly all recent investi- 
gations, moreover, the solar point de mire has been placed considerably 
farther to the east and nearer to the Milky Way than seemed admis- 
sible to their predecessors; so that the constellation Lyra may now be 
said to have a stronger claim than Hercules to include it; and the ne- 
cessity has almost disappeared for attributing to the solar orbit a high 
inclination to the medial galactic plane. 
From both the Albany and the Bonn discussions there emerged with 
singular clearness a highly significant relation. The mean magnitudes 
of the two groups into which Prof. Boss divided his 279 stars were re- 
spectively 6.6 and 8.6, the corresponding mean proper motions 21.9” and 
20.9’. In other words, a set of stars on the whole six times brighter than 
another set owned a scarcely larger sum total of apparent displacement. 
And that this approximate equality of movement really denoted approx- 
imate equality of mean distance was made manifest by the further cir- 
cumstance that the secular journey of the sun proved to subtend nearly 
the same angle whichever of the groups was made the standpoint for 
its survey. Indeed, the fainter collection actually gave the larger angle 
(13.73 as against 12.39’), and so far an indication that the stars compos- 
ing it were, on an average, nearer to the earth than the much brighter 
ones considered apart. 
A result similar in character was reached by M. Stumpe. © Between 
the mobility of his star groups, and the values derived from them for 
the angular movement of the sun, the conformity proved so close as 
materially to strengthen the inference that apparent movement meas- 
ures real distance. The mean brilliancy of his classified stars seemed, 
on the contrary, quite independent of their mobility. Indeed, its 
changes tended in an opposite direction. The mean magnitude of the 
slowest group was 6, of the swiftest 6.5, of the intermediate pair 6.7 
and 6.1. And these are not isolated facts. Comparisons of the same 
kind, and leading to identical conclusions, were made by Prof. East- 
man at Washington in 1889. (Phil. Soc. Wash. Bulletin, vol. xt, p. 143; 
Proceedings Amer. Association, 1889, p. 71.) 
What meaning can we attribute to them? Uncritically considered, 
they seem to assert two things, one reasonable, the other palpably ab- 
surd. The first—that the average angular velocity of the stars varies 
inversely with their distance from ourselves—few will be disposed to 
doubt; the second—that their average apparent luster has nothing to 
do with greater or less remoteness—few will be disposed to admit. 
jut, in order to interpret truly well-ascertained if unexpected relation- 
Ships, we must remember that the sensibly moving stars used to deter- 
mine the solar translation are chosen from a multitude sensibly fixed, 
H, Mis. 334, pt. 1 8 
