1980 - John Hasbrouck van Vleck died.

Vleck was an American physicist who shares the 1977 Nobel Prize in Physics with Philip Anderson and Nevill Mott for their research into the behavior of electrons in magnetic non-crystalline solids. He also proposed a model describing the electronic structure of transition metal compounds known as crystal field theory. This would eventually become the basis of ligand field theory.

1968 - Lise Meitner died.

Meitner was an Austrian-Swedish physicist who discovered nuclear fission with Otto Hahn and Fritz Strassmann when they bombarded uranium with neutrons. She was the one who identified that fission had occurred after examining the data. She also discovered the first long lasting isotope of the element protactinium with Otto Hahn. Element 109, meitnerium was named in her honor.

1845 - Jean Charles Athanase Peltier died.

Antoine Maurin

Peltier was a French scientist who discovered the heating or cooling effect of a junction of two metals in a circuit is related to the electric current passing through the junction. This became known as the Peltier effect.

1827 - Marcellin Berthelot was born.

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Berthelot was a French chemist who believed all chemical reactions depended on the action of physical forces that could be measured. He was also partly responsible for the end of the vitalism theory of organic chemistry. It was generally believed that organic compounds could only be formed from other organic sources and required some 'vital spark'. He synthesized hydrocarbons, natural fats and sugars from inorganic sources to disprove this theory. He was responsible for the Thomsen-Berthelot principle in thermochemistry that postulated chemical changes produce heat and will produce the change that generates the most heat. This theory would be modified later by Helmholtz to consider not just heat, but the reaction's free energy.