revolution made him unpopular among both common people and the aristocracy. In
1791, his home and laboratory were raided by a mob, and after some time in
London, he immigrated to America in 1794. He died in 1804, faithful to the
phlogiston theory until the end. Priestley was a skilled experimentalist, but his
theoretical knowledge was limited. As a chemist, he has to be regarded as an
amateur and his theories gained little support. On the other hand, he freely admitted
his mistakes.
Fig. 21.3 Joseph Priestley. Engraving from William Ramsay’s book. The gases of the
atmosphere, 1896
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21 The Discovery of Oxygen