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H. Draper—Ozxygen in the Sun. «278 
the case, I would ask whether it is antecedently probable that 
there should be any continuous background in the solar _spec- 
trum. If the photosphere is purely gaseous, we should only 
ae bright bands interfered with and modified by absorption 
ines. 
Dr. Gladstone: I have listened with the greatest attention to 
Dr. Draper. When the photographs first came over I was not 
convinced, but certainly he has produced results, which, as 
Mr. Ranyard has shown, have largely increased the evidence of 
there being real coincidences between the oxygen lines and 
bright spaces in the solar spectrum. There seems to be still a 
great question as to whether the solar spectrum is made up only 
of bright and dark lines, or whether thers is a background of 
continuous spectrum. Iam not disposed to give up the idea 
that we have a continuous spectrum underlying these dark lines, 
but think that it is certain that we have also bright lines mixed 
with the dark. We know that when we look at the edge of 
the Sun there are bright lines corresponding to hydrogen, and 
some other elements to be seen, but there are no oxygen lines. 
Now, I would suggest that this shows that the oxygen never 
rises to the level of the chromosphere, so as to be seen at the 
limb of the Sun, and probably thas is just the reason why we . 
see its lines as bright lines and not as dark lines, for it never 
upon the investigation. Dr. Draper had made out a primd facie 
case, which entitled him to demand a careful examination of 
the evidence he had brought forward; but for his own part he 
should like to suspend his judgment until he had had an oppor- 
tunity to reéxamine that part of the spectrum. He preferred to 
wait for a little light, a little sunlight, on the subject, but he 
Wished now to state how thoroughly impressed he was with the 
cautious and careful experimental arrangements which Dr. Dra- 
per had adopted. 
_ Capt. Noble: It seems to me, looking at the photographs 
impartially, that if we are to deny the evidence supplied by 
some of these coincidences, and notably by this group of four 
lines, and accept Mr. Christie’s dicta, we literally should have 
. tangible evidence as to the existence of any element in the 
un at all. 
Mr. Ranyard: I should like to refer to one or two of the 
objections raised by Mr. Christie. I understood him to urge as 
Am, Jour. ee eames Vou. XVI, No. 106.—Oct., 1879, 
