Joseph Priestley, British chemist, born March 13, 1733; died Feb. 6, 1804. Portrait of the theologian, philosopher, political economist and chemist Joseph Priestley. Best known as the discoverer of oxygen, Priestley carried out research into the composition and nature of air. He was the first person to recognize that respiration in animals produces carbon dioxide whereas in plants it produces oxygen. In his work on carbon dioxide, Priestley invented soda water; the precursor to all carbonated drinks.