300 R. Meldola—Bright Lines in the Solar Spectrum. 
lines in its spectrum would result. In the earlier stages of ° 
what may be called the “chemical period” of a star’s history— 
a period into which our sun may be supposed to have entered 
—the lines of the non-metallic elements would alone appear 
bright, for the reasons detailed in the foregoing portions of this 
paper (paragraph 11), and, owing to their comparative faint- 
ness, would be lost at the enormous distances which the light 
of the star has to traverse before reaching our spectroscopes. 
metals which will ultimately appear as bright lines. Such 
appears to be the case with the hydrogen in @ Orionis; and 
according to the present views it might perhaps be predicted 
that this star will sooner or later show a permanent hydrogen 
spectrum of bright lines. It is conceivable that in certain cases 
ee ; 
London, June 6, 1878. 
