ASTRONOMY: ADAMS AND STROMBERG 
231 
gains more and more in accuracy as the material upon which it is based be- 
comes larger and more reliable. 
o 
Ma 
tol 

» 
0+2+4+6 +8 +10 +12 
FIG. 2 
To illustrate the present state of agreement between the spectroscopic and 
the trigonometric parallaxes the following table is added for purposes 
of comparison. The stars are divided into groups and the limits of proper 
motion for each group are given under the heading fi. The symbols, M 
and IT represent the average absolute magnitude and parallax, respectively. 
The last column of the table shows the differences between the spectroscopic 
and the trigonometric parallaxes. The agreement may certainly be regarded 
as satisfactory in view of the number of stars involved. 
Apparent Magnitudes 3.5 to 6.5 
No. 
M 
""spec. 
'^trig. 
^Of020 
23 
-0.4 
0'r009 
+0'{008 
+0!'001 
0''021-0':040 
19 
+0.2 
0.013 
0.007 
+0.006 
0.041-0.070 
36 
+0.3 
0.013 
0.016 
-0.003 
0.071-0.100 
29 
+0.7 
0.016 
0.021 
-0.005 
0.101-0.150 
38 
+0.8 
0.021 
0.026 
-0.005 
0.151-0.200 
31 
+2.3 
0.039 
0.038 
+0.001 
0.201-0.300 
35 
+2.7 
0.042 
0.043 
-0.001 
0.300-0.500 
51 
+3.2 
0.042 
0.042 
0.000 
In conclusion a few words may be added about the extent to which the spec- 
troscopic method of determining parallaxes has been applied at Mount Wilson. 
Between 1500 and 1600 stars have now been investigated in this way includ- 
ing nearly all stars with trigonometric parallaxes and an extensive list of those 
with very large and very small proper motions. It is of interest to note that 
in this large amount of observational material hardly a single serious contra- 
