SCIENCE PHOTO LIBRARY SCIENCE PHOTO LIBRARY
Archibald Scott Couper (1831-1892), the Scottish organic chemist. In 1858, after two years in Paris researching benzene compounds, he finished a paper 'On a New Chemical Theory' and asked C.A. Wurtz to present it at the French Academy. Wurtz delayed and in the interim F. A. Kekule published his own theory of organic structure, similar to but less clearly expressed than Couper's. Couper guessed that carbon had a valence of 2 or 4; and that its atoms could self-link to form chains. He also proposed the first ring structure of any compound, although again history was to favour Kekule who came up with a ring structure for benzene 7 years later. Couper lived his later years in obscurity.
Model release not available. Property release not required.