 Phlogiston theory was developed further by Henry Cavendish (1731–1810) and Joseph Priestley (1733–1804), who both attempted to better characterize the properties of phlogiston itself. After 1760, phlogiston was commonly identified with what they called ‘inflammable air’ (hydrogen), which they successfully captured by reacting metals with muriatic (hydrochloric) acid. Upon further experimental work on the production and characterizations of these “airs,” Cavendish and Priestley identified what we now call oxygen as ‘dephlogisticated air’ and nitrogen as ‘phlogiston-saturated air.’