IN 1896 Prof. E. C. Pickering discovered a series of lines in the spectrum of the star ζ Puppis which has been attributed to hydrogen in consequence of numerical relationship to the Balmer series ...
THE SPECTRUM OF HYDROGEN IN NEBULÆ.—If hydrogen gas in a Geissler tube be examined spectroscopically, the brightest line observed is Hα. If, on the other hand, the lines of hydrogen in nebulæ be ...