ASTRONOMY: F. H. SEARES 
219 
for but lower limits the differences suggest a divergence of the scales, 
or, perhaps, an increase in the average color of the stars. The faint 
stars are really redder, at least in certain regions; but, by itself, increased 
color is inadequate as an explanation. On the other hand, there is 
evidence that below the 10th magnitude Parkhurst's photometric 
standards, upon which Kapteyn's scale is based, are increasingly too 
bright. Kapteyn's tabulated densities therefore properly apply to 
magnitudes which are fainter, by gradually increasing amounts, than 
those used as arguments for his tables. The probable amount of the 
scale divergence is sufficient to account for the relatively rapid increase 
of Kapteyn's totals, which, in any case, must be associated mainly 
with the characteristics of the photometric standards; for the supposi- 
tion that Parkhurst's scale is normal would imply that the fainter stars 
are very red, and Kapteyn's large totals would then be referable to 
the high color thus presupposed. 
The differences in galactic condensation shown under {h) are more 
difficult to explain. Scale differences between galactic and non-galac- 
tic regions, and systematic errors in the counts depending on galactic 
latitude are factors which obviously might enter. Some information 
is given by the photographic magnitudes of stars in the Selected Areas 
now being determined at Mount Wilson.^ Ultimately these will yield 
results for graduated intervals of magnitude, but at present only total 
densities to the limiting magnitude of the plates are available. 
ZONE 
TOTAL NXntfBER 
OF STARS 
LOG MEAN NUM- 
BER STARS 
MEAN GAL. LAI. 
GAL. LAT. 
S - 
a 
6 
o 
1^ 
MW minus 
C and M 
GRONINGEN 
MAGNITUDE 
i ^ 
MVJ minus 
KAPTEYN 
I 
13,702 
3.10 
2° 
5° 
4.12 
+0.74 
16.2 
4.17 
-0.05 
II 
12,322 
3.05 
11 
15 
3.86 
+0.57 
16.3 
3.86 
0.00 
III 
6,010 
2.74 
19 
25 
3.53 
+0.37 
16.2 
3.58 
-0.05 
IV 
2,751 
2.40 
29 
35 
3.26 
+0.29 
16.1 
3.33 
-0.07 
V 
1,743 
2.20 
39 
45 
3.10 
+0.28 
16.2 
3.14 
-0.04 
VI 
1,350 
2.09 
48 
55 
2.98 
+0.13 
16.35 
2.97 
+0.01 
VII 
987 
1.95 
59 
65 
2.89 
+0.08 
16.6 
2.82 
+0.07 
VIII 
767 
1.84 
73 
80 
2.79 
+0.04 
16.9 
2.665 
+0.125 
The counts, now complete for 88 areas, include nearly 40,000 stars. 
These have been divided into eight groups according to galactic latitude, 
as shown in the first four columns of the table. Variations in the limit- 
ing magnitude from plate to plate cause some uncertainty; but, since 
