John Playfair, Scottish mathematician, physicist and geologist, early 19th century.
© Science Museum / Science & Society Picture Library
Engraving made in 1816 of John Playfair (1748-1819) who in 1785 became joint Profesor of Mathematics at Edinburgh. In 1805, Playfair changed appointments for the chair of natural philosophy and was a keen supporter of James Hutton's (1726-1797) theory in geology. Playfair travelled widely in order to make geological observations, enabling the writing of his important geological work 'Illustrations of the Huttonian Theory' (1802).