Portrait of Joseph Priestley (detail). Attributed to Ozias Humphrey (British, 1742-1810). The Chemists' Club Collection, CHF Collections. Photograph by Will Brown.		Discovery of oxygen and the chemical revolution Joseph Priestley (1733–1804) and Karl Wilhelm Scheele (1742–1786) each independently discovered oxygen gas, while Antoine-Laurent Lavoisier (1743–1794) elucidated its role in combustion, calcification of metals, and respiration. This led Lavoisier to a more sophisticated understanding of chemical reactions as the joining of elements to form compounds or the decomposition of compounds into their component elements. He also devised the first systematic chemical nomenclature, naming compounds based on the elements that formed them.