PHYSICS: ANSLOW AND HOWELL 
411 
sary to establish the triplets, there seems little reason to doubt that the 
frequency difference 3053 is characteristic of the radium spectrum. 
In figure 2 the logarithms of the frequency differences are plotted 
against the logarithms of the atomic weights. The general result is 
the same, but less accurate than in figure 1. The points plotted for 
radium in figures 1 and 2 are the points found with the actual values 
for the atomic number and the atomic weight. They fall almost exactly 
on the lines through calcium, strontium, and barium, in the one case above 
the line, in the other case below. Extrapolating from the curve we find 
values of 87 for the atomic number and of 231.7 for the atomic weight, 
which are remarkably close to the true values, 88 and 226. 
The triplets as identified so far are given in table 1. H indicates 
principal series; I N first subordinate; and II N second subordinate. 
TABLE 1 
108 
FREQUENCY 
X IN A. TJ. 
108 
FREQUENCY 
A IN A. TJ. 
INT. 
DIFFER- 
INT. 
DIFFER- 
X 
ENCE 
X 
ENCE 
H III 1 
6200.6 
10 
16127.47 
I N II 
3 
5081.2 
6 
19680.39 
2015.07 
1043 . 15 
129.04 
HII 1 
5823.9 
5 
17170.62 
I N II 
3 
5048.1 
1 
19809.43 
2017.74 
2038.13 
93.05 
H I 1 
5205.96 
6 
19208.75 
I N II 
3 
5024.5 
1 
19902.48 
2017.77 
I N III 3 
4826.12 
20 
20720.58 
1040.19 
II N I 3 
5958.4 
10 
16783.03 
99.31 
2015.06 
I N III 3 
(4803.1) 
2 
20819.89 
1010.46 
II N II 3 
6319.69 
6 
18798.09 
1037.2 
INI 
4 
4882.3 
2 
20482.15 
II N III 3 
5041.52 
6 
19835.29 
95.35 
INI 
4 
4859.7 
1 
20577.40 
II N I 4 
4997.4 
1 
20010.41 
94.05 
II N II 4 
3060.20 
INI 
4 
4837.59 
2 
20671.45 
II N III 4 
4334.5 
5 
23070.71 
I N II 
4 
4444.4 
2 
22500.22 
2018.07 
INI 3 
5660.81 
10 
17665.32 
93.54 
126.37 
I N II 
4 
4426.0 
4 
22593.76 
2016.36 
INI 3 
5620.6 
3 
17791.69 
92.92 
I N III 4 
4245.4 
2 
23554.91 
1054.69 
INI 3 
5591.4 
1 
17884.61 
In addition to the series triplets in table 1 there are three pairs with 
a frequency difference of 1035.34 and one of 2017.57 as shown in table 
2. There is one weak triplet at XX 6487.4, 5729.2, and 5409.16 with 
vi V2 = 3071.16, which does not fit into any series. A stronger pair 
at XX 4903.2 and 4265.1 with a frequency difference of 3051.27 may pos- 
sibly be a part of the I N 4 group. 
