March 26th
1753 Count Rumford (Benjamin Thompson) invented simple photometer; researcher in heat; demonstrated first law of thermodynamics; improved cooking and heating systems and animal breeding; married Antoine Lavoisier's widow, was born.
1838 A. Crum Brown devised modern structural formulae, 1864; formulated rules for substitution in benzene derivatives named after him; researcher in theory of isomerism and organic compounds of sulfur, was born.
1903 Ferdinand G. Brickwedde codiscovered deuterium, 1932, with Harold C. Urey and G. M. Murphy, was born.