264 
MR. J. NORMAN LOCKYER ON SPECTRUM- ANALYSIS 
♦Barium ... 11 (of 26) Zinc . . . . 2 1 (of 27) 
Aluminium . . 21 (of 14) 
O 
From Angstrom’s remarks, which I proceed to give, it is evident that he was not 
quite satisfied with the brilliancy test relied on by Kirciihoff, and that his doubts 
concerning zinc arose from this cause. 
“ L’aluminium possede certainement des raies brillantes en plusieurs endroits du 
spectre, mais les raies situees entre les deux FI sont les seuls qui semblent coincider 
avec les lignes Fraunhoferiennes. Pour expliquer ce phenomene singulier il faut dire 
que les raies violettes se presentent comme les plus fortes dans le spectre de ce metal. 
De meme que les raies jaunes du sodium, ces deux raies d’aluminium ont fait voir 
quelquefois le phenomene d’absorption consistant en ce qu’une raie noire se presente dans 
le milieu de chacune d’elles, ce qui prouve la forte intensite des elites raies. En observant 
les rayons extra-violettes de ce metal, on decidera si les deux raies mentionnees ci-dessus 
coincident on non avec des raies Fraunhoferiennes ; car si ma supposition est vraie, 
les raies extra-violettes doivent coincider aussi avec les lignes obscures du spectre solaire. 
“ A deux raies du zinc que j’ai indiquees sur mes planches comme coincidant avec 
des raies Fraunhoferiennes il en faut ajouter une troisieme, situee a 480 9 -T ; mais, a 
1’egard des deux raies, tres-larges et tres-fortes, d’une apparence nebuleuse, il n’y a pas 
de correspondance visible ; ainsi, la presence du zinc dans le soleil me semble tres- 
douteuse. Je dirai cependant qu’il existe trois raies de magnesium, du meme aspect 
nebuleux, qui ne possedent pas non plus de correspondance avec les raies de Fraun- 
hofer, quoique la presence de ce corps dans le soleil ne permettre pas le moindre 
doute”f. 
In the accompanying maps the lines of certain metallic vapours reversed in the solar 
spectrum are given under the spectrum mapped by the new method. It will be seen 
that invariably the reversed lines are simply those which are longest in the spectrum. 
It is not necessary on the present occasion to dwell upon the great importance of this 
determination, both in connexion with the fact just stated and the other facts touching 
the lines which remain longest in chemical combinations $ and mechanical mixtures. 
It supplies us at once with the true test to apply to the reversal of solar lines, and a 
guide of the highest value in spectrum observations of the chromosphere and 
photosphere. It is one, doubtless, which will shortly enable us to determine the 
presence of new materials in the solar atmosphere, and it is seen at once that to the 
last published table of solar elements (that of Tiialen) must be added, zinc, aluminium, 
and possibly strontium § as a result of the application of the new test. 
* I include this “ below the line,” though I cannot but think that its omission by TnAikN was accidental. 
t It will he seen from my maps that this statement is not accurate. ThalPx’s later work left only one line 
doubtful. 
% A. Mitschermch has noted the disappearance of certain lines in consequence of the presence of several 
substances in the same flame, but he only applies this to the sun by supposing the substances to be combined 
and so not to give a spectrum (Ann. de Chim. et de Pliys. 3 ser. vol. lsix. p. 176). 
§ Barium also, if a lapsus calami has not been made. 
