Picric acid is an industrial chemical best known as an explosive. It combines with metals to form salts called picrates. Most picrates are unstable, and they are used to set off more stable explosives. Picric acid is used in electric batteries and ointments for burns, and in processes for dyeing textiles, etching copper, and manufacturing colored glass. Its name comes from a Greek word meaning bitter, because a solution of the acid in water has a bitter taste. Peter Woulfe, a British chemist, first isolated the acid in 1771.