114 J. N. Lockyer on the supposed Compound 
ordinary hydrogen, I begged my friend, Mr. 
F.RS., chemist to the Mint, to charge a piece of palladium 
with hydrogen for me. This he at once did, and I take this 
present opportunity to express my obligation to him. I exhibit 
to the Society a photograph of this palladium and of indium 
side by side. It will be seen that one form of hydrogen in 
indium has distinctly recorded itself on the plate, while that in 
palladium has not left a trace. I should add that the pal- 
ladium was kept in a sealed tube till the moment of making 
the experiment, and that special precautions were taken to pre- 
vent the two pieces between which the arc was taken becoming 
unduly heated. 
To sum up, then, the facts with regard to hydrogen: we have 
h differentiated from the other lines by its appearance alone in 
indium, by its absence during the eclipse in 1875, when the 
other lines were photographed by its existence as a short line 
only in the chromosphere of the sun, and by the fact that im 
the experiments of 1869 a very high temperature was need 
to cause it to make its appearance. 
Fig. 6. 
A @ 2 c 
Aes 
de 
With regard to the isolation of the F line I have already 
referred to other experiments in 1869, in which Dr. Frankland 
and myself got it alone. I exhibit to the Society a globe com 
taining hydrogen which gives us the F line without either the 
red or the blue one. : 
The accompanying drawing (Fig. 6) shows how these lines 
are integrated in the spectra of the sun. 
ments that occluded hydrogen behaves in this respect like 
Mr. W. C. Roberts, 
Fig. 7 
hk G F 1474 Ds C 
| Sun. 
’ Chromosphere: 
Jar Spark. 
Spark without Jar 
Feeblest spark at 
lowest pressure. 
7] Cooler still. 
I have other evidence which leads to the conclusion that the 
substance which gives us the non-reversed line in the chromo 
sphere and the line 1474 of Kirchoff’s scale, termed the coronal 
line, are really other forms of hydrogen. One of these js more 
