John Playfair

John Playfair FRS, FRSE
Born	(1748-03-10)10 March 1748[citation needed] Benvie, Forfarshire, Scotland
Died	20 July 1819(1819-07-20) (aged 71) Burntisland, Fife, Scotland
Resting place	Old Calton Burial Ground
Alma mater	University of St Andrews University of Edinburgh
Known for	Playfair's axiom Playfair (lunar crater) Playfair (Martian crater) playfairite
Scientific career
Fields	Mathematics, natural philosophy, geology
Institutions	University of Edinburgh

John Playfair FRSE, FRS (10^{[citation needed]} March 1748 – 20 July 1819) was a Church of Scotland minister, remembered as a scientist and mathematician, and a professor of natural philosophy at the University of Edinburgh. He is best known for his book Illustrations of the Huttonian Theory of the Earth (1802), which summarised the work of James Hutton.^[1] It was through this book that Hutton's principle of uniformitarianism, later taken up by Charles Lyell, first reached a wide audience. Playfair's textbook Elements of Geometry made a brief expression of Euclid's parallel postulate known now as Playfair's axiom.

In 1783 he was a co-founder of the Royal Society of Edinburgh. He served as General Secretary to the society 1798–1819.^[2]