IN CONNEXION WITH THE SPECTRUM OF THE SUN. 
263 
determine their position with sufficient accuracy to reproduce them in my drawing. 
The two bright green bands do not correspond to dark bands in the solar spectrum ; so 
that, as far as I have been able to determine, silicium is not visible in the solar atmo- 
sphere.” 
It will be seen from the foregoing that Kirchtioff dealt mainly with the brightest 
lines, although the test failed him in the case of cobalt, for a reason I shall show 
further on. Hence, as a result of Kieciihoff’s work, we have in the solar atmosphere : — 
Present. 
Doubtful. 
Absent. 
Sodium. 
Cobalt. 
Gold. 
Iron. 
Silver. 
Calcium. 
Mercury. 
Magnesium. 
Aluminium. 
Nickel. 
Cadmium. 
Barium. 
Tin. 
Copper. 
Lead. 
Zinc. 
Antimony. 
Arsenic. 
Strontium. 
Lithium. 
Silicium. 
O 
Angstrom* gives no list such as this, but in its place a table of coincidences observed. 
Thalen, his associate, in 
a separate 
memoir jy gives, however, 
as present in the sun : — 
Sodium, 
Chromium, 
Hydrogen, 
Iron, 
Nickel, 
Manganese, 
Calcium, 
Magnesium, 
Cobalt, 
Titanium, 
thus rejecting zinc and barium from Kirciihoff’s list of accepted elements, adding 
o 
cobalt from the doubtful list, and hydrogen and manganese from Angstrom’s, and 
titanium from his own observations. 
The table of coincidences referred to and Angstrom’s remarks thereon explain the 
cause of this. Kirchhoff’s evidence for zinc had depended upon the coincidence of 
two lines only, and these were doubtless thought insufficient, as 
in the cases of the metals 
retained in the list the number of the coincidences was much greater, viz. : — 
Sodium . 
. 9 (all) 
Magnesium 
. . 4 (3 1) 
Iron . . . . 
450 
Chromium , 
. . 18 
Calcium . . 
75 
Nickel . 
, . 33 
Cobalt . . . 
19 
Hydrogen 
. . 4 (all) 
Manganese . 
. 57 
Titanium . 
. . 118 
* Recherches sur le spectre solaire, 
o 
par A. J. Angstrom. Spectre noi 
rmal du Soleil. Berlin, 1869. 
t Longueurs d’oude des raies metalliques, p. 11. Nova Acta. Upsala, 1868. 
2 n 2 
