French chemist and saltpetre maker · 1777–1838
Bernard Courtois
Bernard Courtois discovered iodine by accident in 1811, while making saltpetre for Napoleon’s gunpowder.
How Iodine was found
Courtois extracted sodium and potassium compounds from the ash of seaweed collected on the coasts of Normandy and Brittany. To clean his vats he added sulfuric acid to the residue, and a cloud of violet vapour rose and condensed into dark, shining crystals.
He passed samples to other chemists, and Gay-Lussac and Davy both showed it was an element. Gay-Lussac named it iode, from the Greek for violet.
Life and career
Born 1777 · Died 1838
Courtois was born in Dijon, the son of a saltpetre maker, and trained as a pharmacist. After Napoleon’s wars ended, demand for saltpetre collapsed and his business failed.
He tried to make a living producing iodine, which had begun to be used in medicine, but died poor. The French Academy awarded him a prize for the discovery in 1831.
Discovered in the same era
Other elements identified within ten years of 1811.