452 
ASTRONOMY: C. E. ST. JOHN 
Comparative Solar and Terrestrial Wave-Lengths of Lines of the Nitrogen 
(Cyanogen) Bands 
GROUP A 25 LINES 
GROUP B 18 LINES 
INTENSITY 
INTENSITY 
At center 
00-1 
2-4 
a. Direct comparison of sun and arc 
0.000 
+0.0013 A 
0.000 
+0.0026 
c. (R— I) for band lines minus "Standard" (R— I) . . 
-0.003 
+0.0010 
—0.001 
_i_n nnns 
-0.001 
+0.0014 
17 LINES INTENSITY 
18 LINES INTENSITY 
At limb 
00-1 
2-4 
0.000 
+0.0037 
b. (X center— X arc)+(X limb— X center) 
0.000 
+0.0035 
0.000 
+0.0036 
balancing the gravitational effect; at the limb where its influence would 
disappear, a displacement to the red of 0.008 A should be observed. For 
the lines of highest weight the displacement at the limb is zero, the mean 
for all lines +0.0018 A. Owing to the probable occurrence of blends 
in this region, the displacement to the red for the broader lines of group B 
may be in part at least attributed to this influence, as the effect of blends 
with metallic lines is to introduce systematic displacement to the red 
even for lines normally undisplaced at the Hmb. 
The general conclusion from the investigation is that within the lim- 
its of error the measurements show no evidence of an effect of the order 
deduced from the equivalence relativity principle. Two other series 
of observations at Mount Wilson are at variance with the relativity prin- 
ciple, the equal wave-lengths of the H and K lines of calcium in the arc 
and at the sun's Hmb^ and a center-arc displacement of 0.004 A at X 6300 
for iron lines instead of 0.013 A required by the relativity principle. 
1 Einstein, A., Ann. Physik, Leipzig, 35, 1911, (898-908). 
2 Eddington, A. S., Mon. Not. R. Astr. Soc, London, 77, 1917, (377-382). 
8 Dyson, F. W., Observatory, London, 40, 1917, (153-154); Mon. Not. R. Astr. Soc, London, 
77, 1917, (445-447). 
4 Freundlich, E., Astr. Nachr., Kiel, 202, 1916, (20-23). 
^FrevLndlich, E.,Fhysik Zs., Leipzig, 15, 1914, (369-371); Schwartzschild, K., Berlin, 
Sitz. Ber. Ak. Wiss., 1914, (1201-1213). 
« St. John, C. E., and Ware, L. M., Mt. Wilson Contrib., No., 120; Astroph. J., Chicago, 44, 
1916, (311-341). 
7 St. John, C. E., Mt. Wilson Contrib., No. 48; Astroph. J., Chicago, 32, 1910, (36-82). 
