Antoine Laurent Lavoisier (1743-1794), French chemist, analysing atmospheric air. Lavoisier is considered to be the founder of modern chemistry. He was instrumental in the use of accurate measurement in chemistry for the study of the composition of materials, oxidation and other combustion reactions. Lavoisier deduced that air consisted of oxygen and nitrogen. His book Methods of Chemical Nomenclature (1787) set the method of naming substances by their composition of elements, a method that is still used today. Engraving from The Atmosphere (1873) by Camille Flammarion.