A History of the Discovery of Helium Gas (266 words, 1 pages)
A French astronomer, Pierre-Jules-Csar Janssen (1824-1907), first obtained evidence for the existence of helium during the solar eclipse of 1868 in India when he detected a new yellow line (587.49 nm) in the solar spectrum very close to the yellow sodium D-line. It was not possible to produce this line ...
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