Antoine Francois Fourcroy (1755-1809). 1874 portrait of the French chemist Antoine Francois, comte de Fourcroy. Trained in medicine, Fourcroy was a leader of the active French scientific community in the years before the French Revolution of 1789. As well as supporting and teaching the theories of the great French chemist Antoine Lavoisier, he made several important discoveries. He isolated the double salts of ammonia and magnesia and (with Vauquelin) discovered the element iridium. In 1808 he isolated the excretory chemical urea from animal fluids. He was made a Count of the Empire by Napoleon in 1808. Engraving by A. Tardieu.