A popular history of astronomy during the nineteenth century (1902)
Clerke, Agnes M. (Agnes Mary), 1842-1907 · London : A. and C. Black · leaf 222
ines, accordingly, filled places in a manner already prepared forthem, and were thus unmistakably associated with the hydrogen-spectrum. This is now known to be represented in prominences bytwenty-seven lines,6 forming a kind of harmonic progression, only 1 Astr. and Astrophysics, vol. xi., p.… … A /
Astronomy
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