Janssen, Pierre Jules Cesar

Helium - the atomic number is 2 and the chemical symbol is He. The name derives from the Greek helios for sun . The element was discovered by spectroscopy during a solar eclipse in the sun s chromosphere by the French astronomer Pierre-Jules-Cesar Janssen in 1868. It was independently discovered and named helium by the English astronomer Joseph Norman Lockyer. It was thought to be only a solar constituent until it was later found to be identical to the helium in the uranium ore cleveite by the Scottish chemist William Ramsay in 1895. Ramsay originally called his gas krypton, until it was identified as helium. The Swedish chemists Per Theodore Cleve and Nils Abraham Langet independently found helium in cleveite at about the same time. 

In the year 1868 the French astronomer Pierre-Jules-Cesar Janssen (43, 44) went to India to observe a total eclipse of the sun and to make... 

Pierre-Jules-Cesar Janssen,0 1824-1907. French astronomer who directed many astronomical expeditions. Member of the French Institute and of the Bureau of Longitude. In 1868 he observed in the sun s chromosphere a yellow line, Da, which is now known to belong to the element helium. He was the director of the astrophysical observatory at Meudon. 

The name comes from the Greek helios, meaning the sun. It was first detected by its spectra by Pierre-Jules-Cesar Janssen (1824-1907) in the... 

---