92 C. V. L. CHARLIER, 
I give on plates II—IV the projection of the Galaxy of the B- 
stars on the three coordinate planes. The most distant star — which 
is not represented on the plates! — is N:o 612. It belongs to the 
subclass 61 and has an apparent magnitude equal to 7, 6. Its distance 
from the sun amounts to 267 Siriometers and its distance from the 
centre is 250 Sir. The faintest star of the spectral type B recorded 
in the Harvard Annals is N:o 591 in the square E,. It has the magni- 
tude 8.4, belongs to the subclass Bo and is at a distance of 148 Sirio- 
meters. Though the star N:o 612 is somewhat brighter its computed 
distance is greater, because the subclass Bı is characterized by a 
greater luminosity. 
All stars, excepting N:o 612, lie within a sphere with a radius 
of 200 Siriometers having the sun as centre. In the direction of the 
poles of the Galaxy the remotest star has a distance of 78 Sir. and only 
7 stars have a z-coordinate exceeding 50 Sir. We have found in § 21 
that the dispersion in the distribution of the stars amounts to 37 Sir. 
in the XY-plane of the Galaxy and to 13 Sir. perpendicular to it. 
We find from table 16 that the nearest star of the spectral type 
B is the star N:o 423, « Eridanus, with a distance of only 4 Sir. 
(a = 0''.0516). Next to it we find the bright stars in Orion, of which 
the three stars in the girdle — d, e, © — have a distance of about 
8 Sir. Owing to the great distances of the B-stars a direct determi- 
nation of the parallax is extremely difficult and precaricus. In the 
»List of parallax determinations compiled by Prof. I. C. Kapteyn and 
D:r H. A. Weersma» published in N:o 24 of the »Publications of the 
astronomical laboratory at Groningen» there are in all 6 stars of the 
spectral type B (Bo to Bs) for which a positive parallax has been 
found. These stars are the following ones: 
Type N:o Name ze Aut. -T 
Bs 423 c Eridani + 0.051 += 07022 Gill + 0"0516 
B 3 50 48c Persei + 0.012 + 0.013 Schlesinger + 0.0090 
Bi 641 @ Crucis + 0.050 + 0.030 Gill + 0.0129 
Bi 647 8 Crucis + 0.008 + 0.012 Gill-Finlay + 0.0138 
Bi 674 B8 Centauri + 0.037 + 0.022 Gill + 0.0187 
Bs 780 a Gruis + 0.024 + 0.010 Gill + 0.0229 
! It is the only B-star which is not represented on the diagrams. 
Ee — 
ame Aes" aod amem. 
Dc 
