364 PROF. A. FOWLER AND MR, C. C. L. GREGORY ON THE ULTRA-VIOLET 
Table IV.—Evidence for S Series in the Solar Spectrum, 
Ammonia. 
Sun. 
Intensity 
in arc. 
A 
(Rowland). 
d\> 
do. 
Origin. 
1 
Intensity. 
A. 
d x . 
d<i. 
4 
3349-69 
3-93 
00 
3349-695 
3-934 
4 
45-76 
3-80 
13 
00 
45-761 
3-794 
140 
4 
41-96 
3-72 
08 
Ti 
4 
41-967 
3-720 
074 
4 
38-24 
3-63 
09 
0 
38-247 
3-634 
086 
4 
34-61 
3-57 
06 
0 
34-613 
3-557 
077 
5 
31-04 
3-50 
07 
IN 
31-056 
3-523 
034 
5 
27-54 
3-42 
08 
Ni 
2 
27-533 
3-404 
119 
5 
24-12 
3*35 
07 
0 
24-129 
3-346 
058 
4 
20-77 
3-26 
09 
Mn, Fe 
2 
20-783 
3-269 
077 
3 
17*51 
3-19 
07 
0 
17-514 
3-180 
089 
3 
14-32 
3-09 
10 
Mn 
0 
14-334 
3-096 
084 
3 
11-23 
2*99 : 
10 
0 
11-238 
2-999 
097 
3 
08-24 
2-89 
10 
ON 
08-239 
2-885 
114 
2 
05-35 
000 
05-354 
3314'334) produce no appreciable disturbance of the first and second differences, 
some disturbance is caused by the unidentified line 3331‘056, and by the nickel line 
3327'533. If, however, the former be assumed to include a line shorter in wave¬ 
length by only 0'016A, and the latter to include a line of wave-length greater by 
O'OIOA, the series connection would be shown as accurately by the solar lines as by 
those of ammonia.* The probable composite character of 3331'056 is in fact 
suggested by its nebulous appearance, and by its intensity being too great to allow of 
its being assigned wholly to ammonia. The agreement in the intensities is also 
satisfactory on the whole. The series investigation, so far as it goes, thus confirms 
the identification of some of the solar lines with band lines of ammonia. A general 
consideration of the intensities of the representatives of the a to £ series in the solar 
spectrum appears to indicate a closer agreement with the arc than with the flame 
spectrum, the lines in the neighbourhood of the central maximum being relatively 
* The second differences 077, 034, 119, 058 would then become 061, 076, 083, 068. 
