Profesor Jean Dumas, French organic chemist, mid 19th century.
© Science Museum / Science & Society Picture Library
Engraving by S Freeman after E Desmaisons, with the sitter's signature. Profesor Jean Dumas (1800-1884) helped found the Ecole Centrale des Arts et Metiers in 1829 and in 1835 became profesor of chemistry at the Ecole Polytechique. Dumas, with J G Stas, determined the atomic weight of carbon in 1849.