IN CONNEXION WITH THE SPECTRUM OF THE SUN. 
267 
Plate XI. Strip III.— SODIUM (continued). 
Wave-length. 
Length. 
Whether re- 
versed in the 
Solar Spec- 
trum. 
Whether in 
the Spark- 
Spectruin of 
the Chloride. 
Remarks. 
4982-5 
1 
Reversed. 
Not present. 
This is really a close pair of lines, represented by 
Thales' as a single nebulous line in the map attached 
to his £ Memoire sur les longueurs d’onde des raies 
brillantes des Metaux,’ but correctly given by him as 
O 
double in the maps in Angstrom’s memoir on the 
solar spectrum. The wave-length here given is the 
mean of the true positions, which are 4983-2 and 
4981-9 respectively. The line, though nebulous, is 
easily divided, and is so represented on the Map. 
Plate XI. Strip IV.— MAGNESIUM. 
5527-4 
3 
Reversed. 
Not present. 
5183-0 
4 
99 
Present. 
b v This is the longest magnesium line. 
5172-0 
4 
99 
99 
b 2 . This is slightly shorter than b v 
5166-7 
4 
99 
99 
b 3 . Slightly shorter than b 2 . 
4703-5 
2 
9 
Not present. 
There is a line coincident with this in Kirchhoff’s 
map of the solar spectrum, but it has been dropped 
O 
out in Angstrom’s. 
4586-5 
Reversed. 
5? 
I have never succeeded in observing this line, 
though very many attempts have been made ; it is 
O 
represented in the solar spectrum by Angstrom as an 
excessively faint line ; and Kirchhoff makes it not 
really coincident but partly overlapping the solar 
line. 
4481-0 
1 
99 
99 
This is a very brilliant winged line, but it appears 
short. Thalen makes it of the same intensity as the 
two at 4703-5 and 4586-5; but while this is exces- 
sively bright to me, 4703-5 is faint and 4586-5 invi- 
sible. Kirchhoff represents it in the solar spectrum 
O 
by a very much broader line than Angstrom does. 
Plate XI. Strip Y. — COBALT. 
6142-5 
2 
Not reversed. 
6121-2 
2 
99 
6003-5 
r 6 
CD 
This line could not be identified. 
5482-4 
4 
Reversed. 
> 
Ph 
This line is represented in the solar spectrum, but 
5452-0 
2 
Not reversed. 
Xfl 
rO 
O 
is not named in Angstrom’s map. 
5443-0 
2 
5368-0 
2 
o 
5362-5 
2 
<u 
5359-5 
2 
5352-4 
" 4 
Reversed. 
o 
5351-2 
4 
o 
5342-6 
4 
5342-1 
4 
99 
