Alexander Crum Brown
Brown, Alexander Crum (1838-1922), was a Scottish chemist who established the system of representing chemical compounds in the form of diagrams, with connecting lines representing bonds.
The son of a clergyman and nephew of a chemist, Alexander Brown was fascinated by models from childhood. After he graduated from Edinburgh University in 1858, he received a medical degree in 1861 for a thesis on the theory of chemical combination. In his thesis, he discussed chemical structure and the application of mathematics to chemistry.
Brown was dissatisfied with then-existing attempts to display the structure of compounds in diagrammatic form, and in the 1860's, he devised his own system. He represented each of the atoms in a compound by drawing a circle around its letter symbol and then used lines to indicate how the atoms were linked. In 1865, he began to use two parallel lines to indicate a double bond.
Brown's academic appointment at Edinburgh University, where he taught from 1863 until 1908, was in chemistry. However, he also made a significant contribution in physiology by advancing knowledge about the canals of the inner ear.