ASTRONOMY: W. S. ADAMS 357 
These results may be represented by the following equations in which AX 
is the displacement. In the case of Nova Aurigae the results are too frag- 
mentary to allow of an accurate determination of the coefficient of X. 
Displacement 
at \ 4500 
NovaAquilae: AX = 0.00513 X —23.1 
NovaPersei: AX = 0.00510 X -22.9 
Nova Geminorum: AX = 0.00257 X —11.5 
Nova Aurigae: AX = 0.0025 X —11.4 
TABLE 2 
MEAN X • 
MEAN 
AX 
NUMBER OF 
LINES 
o-c 
MEAN X 
MEAN 
AX 
NUMBER OF 
LINES 
o-c 
Nova Aquilae 
Nova Geminorum 
4020 
4155 
4260 
4345 
4450 
4540 
4630 
4820 
4990 
5230 
5350 
5510 
5670 
5890 
6390 
20.8 
21.5 
22.0 
22.5 
22.9 
23.6 
24.0 
24.6 
25.5 
27.2 
27.6 
28.1 
27.8 
29.4 
32.7 
5 
4 
7 
11 
7 
13 
2 
4 
3 
8 
8 
5 
4 
5 
10 
+0.2 
+0.2 
+0.1 
+0.2 
+0.1 
+0.3 
+0.2 
-0.1 
-0.1 
+0.4 
+0.2 
-0.2 
-1.3 
-0.8 
-0.1 
4220 
4350 
4445 
4540 
4935 
5896 
6563 
10.6 
10.9 
11.2 
11.8 
12.8 
15.3 
17.9 
7 
7 
5 
13 
3 
1 
1 
-0.2 
-0.3 
-0.2 
+0.2 
+0.1 
+0.2 
+ 1.1 
Nova Per set (H lines) 
3890 
3970 
4102 
4341 
4862 
19.3 
20.0 
20.5 
22.2 
25.7 
1 
1 
1 
1 
1 
-0.5 
-0.2 
-0.4 
+0.1 
+0.9 
Nova Aurigae (H lines) 
4102 
4341 
4862 
10.3 
11.4 
11.9 
1 
1 
1 
0.0 
+0.5 
-0.4 
The differences, observed minus computed, are given under O — C in table 2. 
The agreement is close except in the less refrangible part of the spectrum where 
the determinations of wave-length are least accurate. 
We find, accordingly, the surprising result that the displacements of the 
lines in all of these stars are directly proportional to wave-length and divide 
themselves into two pairs of equal amount. Of these the first pair of stars 
has exactly twice the displacement of the second, and it is perhaps a significant 
fact that Nova Aquilae and Nova Persei were much brighter stars apparently, 
and probably intrinsically as well, than Nova Geminorum and Nova Aurigae. 
A very peculiar phenomenon in the case of Nova Aquilae is the progressive 
increase in the values of the displacements of the absorption lines at successive 
dates. Thus in the region between X 4250 and X 4600 we find for the dates 
June 10 to June 15: 
