SCIENCE AND MEDICINE - BRANLY Edouard (1844 - 1940) - Autograph letter signed

Bacc in literature, then in science and finally in mathematics. In 1887 he resumed his medical studies, obtaining a doctorate in 1882. In 1890, he devised the filament coheater, the first herzian-wave detector, which was used by Marconi in his wireless telephony experiments. In 1891, he also devised the principle of the transmitting antenna.
Autograph letter signed 29.10.1909 "... vous me donnerez alors les très utiles indications dont j'espère beaucoup…". 1 p. In-8.