110 J. N. Lockyer on the supposed Compound 
the blue line; replace the Bunsen’s burner by a jet of hydro- 
gen (the temperature of which is higher than that of the Bun- 
sen’s burner) and the blue line appears, faint, it is true, but 
sharp and quite unmistakable. If oxygen now be solely 
turned into the jet, the brilliancy of the blue line increases 
until the temperature of the flame rises high enough to fuse 
the platinum, and thus put an end to the experiment.” 
These observations of Professors Tyndall and Frankland 
differentiate this blue line from those which are observed at 
low temperatures. The line in the violet to which I have 
already referred, is again differentiated from all the rest by the 
fact that it is the only line in the spectrum of the sun which is 
strongly reversed, so far as our present knowledge extends. 
The various forms of lithium, therefore, may be shown in the 
following manner. 
EF SUN 
| { ae i ‘ ARC 
oT | a 
ee I | 
Fig. 5.—The Molecular Groupings of Lithium. 
It is remarkable that in the case of this body which at rela- 
tively low temperature goes through its changes, its compounds 
are broken up at the temperature of the Bunsen burner. The 
spectrum, e. g. of the chloride, so far as I know, has never beet 
seen. 
Hydrogen. 
All the phenomena of variability and inversion in the ordet 
of intensity presented to us in the case of calcium can be par 
alleled by reference to the knowledge already acquired regard: 
ing the spectrum of hydrogen. 
r. Frankland and myself were working together on the 
subject in 1869. In that year (Proc., No. 112) we pointed out — 
that the behavior of the A line was hors ligne, and that the 
whole spectrum could be reduced to one line, F. 
“1, The Fraunhofer line on the solar spectrum, named h by 
tr6m, which is due to the absorption of hydrogen, pe { 
Hiniis 
visible in the tubes we employ with low battery and Leya@ 
jar power ; it may be looked upon, therefore, as an indication — 
of relatively high temperature. As the line in question has 
been reversed by one of us in the spectrum of the chrome 
sphere, it follows that the chromosphere, when cool enough ! 
absorb, is still of a relatively high temperature. 
“2. Under certain conditions of temperature and pressur® 
drt ache ieee all are 
CN Re Sas AM Ss Nag a a ee a al oy 
