Doctor and physicist. Engineer of bridges and roads (Ponts et Cahussées) in 1863 and doctor of medicine in 1869. We owe him renowned works of medical physics and biological physics. He was a professor of physics at the School of Bridges and Roads (Ecole des Ponts-et-Chaussées), and at the Faculty of Medicine (1886). He was director of studies and then director of ESPCI (Higher School of Physics and industrial chemistry), where Pierre Curie spent many years. President of the French Association for the Advancement of Science. Member of the Academy of Medicine in 1882. He published a "Treatise on medical physics", and a "Practical treatise on electricity"