128 Sherman—Study upon the Atmosphere of 8 Lyre. 
The whole of this evidence, the low temperature of the 
hydrogen spectrum, the apparent ease with which the hydro- 
carbon* compound forms, the fact that during its formation 
there is an increase in the star’s variable light without accom- 
panying evidence of combustion and the spectra of the nega- 
tive glow, presents us with the fact of an electric discharge in 
which hydrogen plays the part of the positive pole, and oxygen 
and nitrogen the parts of the negative pole. From evidence 
presented by the bright linet stars, noting that, roughly speak- 
ing, the high erexcitation hydrogen belongs to the brighter, the 
lower to the fainter stars, we are inclined to think this charge 
the residual of that produced by chemical action, perhaps simply 
dissociation taking place in the interior. We will not stop here 
to recall to the student of terrestrial and cosmical physics the 
evidence presented by comets, by the magnetic needle, by cer- 
tain bands of the solar spectrum, by sun spots, by the zodiacal 
hight perhaps, and many similar phenomena, not only of an 
electric charge upon the sun, but also of a cold atmosphere be- 
tween it and our earth. 
We have studied these spectra with regard to their appear- 
ance in time, and find evidence of a force especially evident in 
the nitrogen negative glow, in the magnesium and in the hydro- 
. Ne ee 
aor 
Faces ae eR 
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eel 
Light Hae 
0 Be wda LOmatl 
DAYS. 
Light curve of 8 Lyre. Observation by Sawyer. 
gen, whose laws our short series does not permit us to deter- 
mine, but which is probably the cause effecting the disappear- 
ance of the hydrogen lines in 1874,f and their reappearance 
in 1883, and is perhaps similar to that causing the sun spots. 
* We have also studied the spectra with regard to the varia- 
fon of the star’s hight, a single period of which derived from 
observations by Sawyer is represented in the adjoining cut. 
And we find in the spectra of hydrogen, oxygen and their car- 
bon compounds a simultaneous variation. ‘To any one ac- 
quainted with Berthelot’s§ work, upon the action of mixtures 
of these gases under an electric spark, this will appear quite 
natural. The rise in the curve from primary minimum to pri- | 
mary maximum corresponds to a period of increasing oxygen, 
* Ann. Chim. et Phys., III, Ixvii, 67, 1863. +The Astron. Jour., No. 4, vol. vii. 
¢ Astronomische Nachrichten, No. 2581. § Comptes Rendus, t. xviii, 1869. 
