30 C. V. L. CHARLIER, 
that b and «a are nearly independent of À, whereas the value of D 
is directly proportional to the adopted value of R. 
I^get, for the different subclasses, the following values of $'", 
11 "I. 
He and se 
M (8) M (q^) M(£") 
Bo — 2.228 + 3.044 — 6.892 
Bi — 0.647 + 1.409 — 2.740 
B 2 + 0.384 + 2.539 — 0.177 
Bs — 1.658 + 2.625 — 3.894 
Bs — 0.250 + 1.724 — 3.314 
Adopting the values of R given in table 4 we get, for the dif- 
ferent subclasses, the following coordinates of the centre 
M(x") M (y^) M (2^) 
B o — 6.88 + 9.40 — 91.29 
Bi — 5.21 + 11.35 — 22.07 
B 2 + 2.62 + 17.35 — 1.21 
Bs — 5.81 + 9.20 — 13.64 
B5 — 0.82 + 5.66 — 10.87 
The corresponding polar coordinates are (in the last column 
stands the number of stars in each subelass): 
D b a N 
Bo 24,27 = 8b.4 248 
Bi 22.07 — 57.8 6.9 37 
B 2 17.58 — 4.0 5.4 59 
B 3 17.45 — 51.4 8.1 251 
Bs 12.28 16070 6.6 156 
The values of D are expressed in Siriometers. The concordance 
between the values obtained from different subclasses is satisfactory 
and confirms the relative values of R obtained from the proper motions. 
Possibly there is reason to suspect a somewhat higher value for R 
for stars of the subclass Z5. The good agreement between the values 
obtained for this subclass from the brighter and the fainter stars ma- 
kes, however, a correction of À in this case less probable. 
The polar coordinates of the centre deviate rather much for 
subclass B2. The small number of stars in this subclass give, mean 
while, less weight to this determination. Besides, it is not — a priori 
— necessary to accept that all subelasses are symmetrically distributed 
"TX«—— + si 
