January 23th
1872 Paul Langevin, a researcher on molecular structure of gases, analysis of secondary emission of X-rays from metals exposed to radiation and for his theory of magnetism, was born.
1876 Otto Paul Hermann Diels was born. He developed the diene synthesis and practical method for making ring compounds from chain compounds (Diels-Alder Reaction). He won the Nobel Prize (1950) with Kurt Alder for their discovery and development of the diene synthesis.