228 
ASTRONOMY: C E. ST. JOHN 
TABLE I 
Iron Lines of the Same Group and Spectral Region but Differing in Solar Intensity 
Group 
X Rowland 
Intensity \ International R—I 
b 
4337.216 
5 
.052 
0.164 
+0.004 
b 
4352.908 
4 
.740 
0.168 
b 
4383.720 
15 
.548 
0.172 
+0.012 
b 
4404.927 
10 
.753 
0.174 
+0.010 
b 
4427.482 
5 
.314 
0.168 
+0.003 
b 
4443.365 
3 
.198 
0.167 
+0.003 
Mean 
12 
0.173 
+0.011 
Mean 
4 
0.167 
+0.004 
Intensity 12— Intensity 4 
+0.006 
+0.007 
TABLE II 
Iron Lines of Group 
a and d in 
the Same Region 
Group 
X Rowland 
International 
R-I 
Sun — Arc 
d 
5340.121 
.945 
0.176 
-0.003 
a 
5341.213 
.029 
0.184 
+0.009 
d 
5393.375 
.178 
0.197 
-0.006 
a 
5397.344 
.135 
0.209 
+0.008 
Mean Group a. . 
0.196 
+0.008 
Mean Group d , 
0.186 
0.004 
Mean Group a— 
•Group d 
+0.010 
+0.012 
TABLE III 
Iron Lines of Groups a and e 
in Same Region 
Group 
X Rowland 
International 
R-I 
Sun— Arc 
e 
5407.357 
.136 
0.221 
+0.015 
a 
5405.989 
.780 
0.209 
+0.006 
e 
5411.124 
.904 
0.220 
+0.016 
e 
5415.416 
.195 
0.221 
+0.026 
e 
5424.290 
.064 
0.226 
+0.026 
a 
5429.911 
.702 
0.209 
+0.007 
a 
5434.740 
.529 
0.211 
+0.009 
Mean Group a. . 
0.210 
+0.007 
Mean Group e. . 
0.222 
+0.021 
Mean Group e- 
• Group a 
+0.012 
+0.014 
It is evident from the data given that no factor of transformation 
nor any curve can yield true differences between the Rowland and 
international wave-lengths for all lines even for a limited spectral 
region. 
A comparison has recently been made between the separations of 
close pairs as given in the Rowland tables and as measured upon plates 
of higher dispersion than that used by Rowland. For pairs consisting 
of lines of intensities 3 and 4, whose separations are 0.0 to 0.1 A, 0.1 to 
0.2 A, and 0.2 to 0.35 A, the Rowland values exceed those foimd at 
