Millikan, Robert A.

Millikan, Robert A. (Andrews) (1868–1953) physicist; born in Morrison, Ill. He was a faculty member at the University of Chicago (1896–1921), then moved to the California Institute of Technology (1921–46). He determined the charge on the electron (1909), then confirmed Einstein's quantum photoelectric equation. These two achievements won Millikan the 1923 Nobel Prize in physics. In 1925 he coined the term "cosmic rays," and proposed, but later rejected, their function as the "building blocks" of atoms.