Joseph Priestley

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Joseph Priestley (1733-1804) was an English theologian, educator, and natural philosopher whose experiments with gases made him one of the most productive chemists of the eighteenth century. A Dissenting minister by training and vocation, Priestley combined his religious and educational work with an enthusiasm for experimental science, and he is most often credited with the discovery of oxygen in 1774, though he described it within the framework of phlogiston theory, calling it "dephlogisticated air," and did not draw the conclusions about combustion that Lavoisier later did with the same gas; the Swedish chemist Carl Wilhelm Scheele is also credited with an independent discovery of the same gas around the same time.

Priestley isolated and characterized numerous other gases, including ammonia, sulfur dioxide, and nitrous oxide, and he developed a method for carbonating water, an early step toward the later soda water industry. He described this extensive body of work across several volumes titled Experiments and Observations on Different Kinds of Air, published through the 1770s and 1780s.

Priestley's religious and political views were as consequential as his science: a Unitarian and outspoken supporter of the French Revolution and of religious toleration, he became a target of local hostility in Birmingham, where in 1791 a mob burned his house, laboratory, and library in what became known as the Priestley Riots. He emigrated to the United States in 1794, settling in Northumberland, Pennsylvania, where he continued to write and correspond with prominent Americans, including Thomas Jefferson, until his death there in 1804.

Written by Epoch Voices. Not the figure’s own words.