French <a href="https://en.wikipedia.org/wiki/Astronomer" id="mwjA" rel="mw:WikiLink" title="Astronomer">astronomer</a> <a href="https://en.wikipedia.org/wiki/Pierre_Janssen" id="mwjQ" rel="mw:WikiLink" title="Pierre Janssen">Pierre Janssen</a> <a class="mw-redirect" href="https://en.wikipedia.org/wiki/Timeline_of_chemical_element_discoveries" id="mwjg" rel="mw:WikiLink" title="Timeline of chemical element discoveries">discovers</a> <a href="https://en.wikipedia.org/wiki/Helium" id="mwjw" rel="mw:WikiLink" title="Helium">helium</a>.