Portal:Scotland/Selected article/Week 45, 2008

Professor John Playfair FRSE (March 10, 1748 – July 20, 1819) was a Scottish scientist.

Playfair was professor of mathematics and later professor of natural philosophy at the University of Edinburgh. He is perhaps best known for his book Illustrations of the Huttonian Theory of the Earth (1802), which was a summary of the work of James Hutton. It was through this that Hutton's principle of uniformitarianism, later taken up by Charles Lyell, first reached a wide audience.

In 1795 Playfair published an alternative, more stringent formulation of Euclid's parallel postulate called Playfair's axiom; though the axiom bears Playfair's name, he did not create it, but credited others, in particular William Ludlam, with the prior use of it.

Born at Benvie, Angus, Scotland, where his father was parish minister, he was educated at home until the age of fourteen, when he entered the University of St Andrews. In 1766, when only eighteen, he was candidate for the chair of mathematics in Marischal College, University of Aberdeen, and, although he was unsuccessful, his claims were admitted to be high.

Six years later he made application for the chair of natural philosophy in his own university, but again without success, and in 1773 he was offered and accepted the benefice of the united parishes of Liff and Benvie, vacant by the death of his father. He continued, however, to carry on his mathematical and physical studies, and in 1782 he resigned his charge in order to become the tutor of Ferguson of Raith. By this arrangement he was able to be frequently in Edinburgh and to cultivate the literary and scientific society for which it was at that time specially distinguished.