(September 15, 1736 - November 12, 1793)
Jean-Sylvain Bailly was a French astronomer and orator, one of the leaders of the early part of the French Revolution. He served as the mayor of Paris from 1789 to 1791 and was ultimately guillotined during the Reign of Terror.
(February 22, 1824 - December 23, 1907)
Pierre Jules César Janssen, usually known in French as Jules Janssen, was a French astronomer who, along with the English scientist Joseph Norman Lockyer, is credited with discovering the gas helium.