Charles Dupin, French mathematician, 1810s.

FRANCE - JUNE 10: Engraving by R Cooper of Pierre-Charles-Francois Dupin (1784-1873). While still an undergraduate he discovered 'Dupin's cyclides'. On graduation in 1803 he became a naval engineer, during which time he studied the differential geometry of surfaces and applied mechanics. In 1813 he set up a maritime museum in Toulon and published his 'Developpements de geometrie' which deals with conjugate and asymptotic lines on a surface, and also his invention of the 'Dupin indicatrix'. While a professor at the Conservatoire des Arts et Metiers in Paris (1819-1854) he gave many popular public lectures on the applications of mathematics and mechanics to industry. Dupin was made minister of maritime affairs in 1834. (Photo by SSPL/Getty Images)