Felix Ehrenhaft (24.04.1879-4.03.1952) was an Austrian physicist. He was born in Vienna. He graduated from the University of Vienna (1903), where he worked until 1938 (professor from 1911), and at the same time at the university's Physical Institute.
His work concerned statistical physics and atomic physics. In 1907 he observed Brownian motion in gases, and developed the droplet method for measuring the elementary electric charge. He came to the conclusion that there exists a particle whose charge is smaller than the charge of the electron (the Ehrenhaft subelectron).