Perrin, Jean Baptiste (1870–1942)
French physical chemist who was awarded the 1926 Nobel Prize in Physics
for work on the structure of matter and for his studies of cathode
rays and Brownian motion in
which, by examining colloidal particles, he was able to arrive at a good
value of the Avogadro number.
Perrin wrote several books, including The Elements of Physics (1930).