Pierre Janssen
Pierre Janssen was born on February 22, 1824. See ranking, bio blurb, and everyone else born that day.
About Pierre Janssen
Pierre Jules César Janssen (22 February 1824 – 23 December 1907), usually known as Jules Janssen, was a French astronomer who, along with English scientist Joseph Norman Lockyer, is credited with discovering the gaseous nature of the solar chromosphere, and with some justification the element helium.