JJean Baptiste Perrin, who lived in the years 1870-1942, was an outstanding French physicist researching cathode rays. In 1895 he proved that those rays convey negative charge. In 1906 his work focused on experimental confirmation of Einstein-Smoluchowski theory describing Brownian movement. The results constituted a very powerful proof confirming the atomic theory of the structure of the world.
Perrin also carried out research of the interaction between radiation and matter. He also focused on fluorescence and organised education in France.