Today is the birthday of Friedrich Ostwald, born in 1853, he is one of the founders of physical chemistry because of his work on catalysis, equilibria, and reaction velocities, he developed the Ostwald process for making nitric acid in 1902. Ostwald was also an accomplished painter who made his own pigments.
Frederick Soddy, born in 1877, coined the term isotope, he died in 1956 at age 79.
Woldemar Voigt, born in 1850, the word tensor was named by him, he discovered the voight effect and is known for voight notation. He died in 1919 at age 69.