Paris. Bernard Curtois succeeded his father, who had been imprisoned for debt, as head of the saltpeter (potassium or sodium nitrate) factory, used at the time to produce gunpowder for Napoleon’s army. Saltpeter was originally produced from wood ash, but Curtois later switched to seaweed. By studying and analyzing the corrosion of copper tanks when sulfuric acid was added to the soda, iodine was isolated, thanks to Joseph-Louis Gay Lussac and Humphry Davy.
