How did Joseph Priestley’s oxygen experiments influence Antoine Lavoisier?

Joseph Priestley’s discovery of "dephlogisticated air" was pivotal to the development of Antoine Lavoisier’s oxygen theory of combustion. Although Lavoisier had been investigating weight changes in calcination and suspected that air played a role in these processes, he initially failed to identify the unique properties of the gas he was studying.1

The influence of Priestley’s work became clear in 1774 when he visited Paris and informed Lavoisier and other members of the Academy of Sciences about his successful isolation of this new air. Recognizing the significance of Priestley’s findings, Lavoisier immediately returned to his laboratory to repeat the experiments. He discovered that this gas was exactly what he needed to complete his chemical theory.12

Lavoisier subsequently renamed the gas oxygen and identified it as the "active" principle in the atmosphere, using it to explain the quantitative and qualitative changes observed in combustion, respiration, and calcination. Despite this collaboration, Priestley remained a staunch defender of the phlogiston theory throughout his life, rejecting Lavoisier’s new system of chemistry.12