Joseph Priestley, the English scientist, nonconformist minister, educator, and philosopher, was born at Birstall, Yorkshire, the son of a cloth dresser. His mother died in 1740, and in 1742 Priestley was adopted by a childless well-to-do aunt, Mrs. Keighley, a convinced but unbigoted Calvinist. A sensitive child, Priestley suffered greatly because he could not convince himself that he had experienced the "new birth" essential, on the Calvinist scheme, for his salvation. As a result of these childhood miseries Priestley was left, he tells us, with "a peculiar sense of the value of rational principles of religion" as opposed to the "ignorance and darkness" of Calvinism.

Until the age of sixteen Priestley was educated at a conventional grammar school. For the next three years, his health being too poor for regular studies, he in large part educated himself, reading his way into mathematics, physics, and philosophy and...