Robert Andrews Millikan (22.03.1868 —19.12.1953) was an American experimental physicist and a member of the National Academy of Sciences (1915). He was born in Morrison. He graduated from Oberlin College (1891) and continued his studies at Columbia University and the University of Chicago, at the latter of which he received the degree of Doctor of Philosophy in 1895. In 1896 — 21 he worked at the University of Chicago (a professor from 1910), and in 1921 - 45 at the California Institute of Technology. His work was in the fields of atomic physics, spectroscopy and cosmic-ray physics. In 1906 he developed the drop method, which made it possible to measure the charge of individual electrons, and carried out (1910—14) a large number of experiments on the precise determination of the charge of the electron (in 1910 he obtained the value 4.891 * 10-10, in 1913 - 4.774* 10-10 electrostatic units). In this way the discreteness of electric charge was proved experimentally and its magnitude was measured for the first time with sufficient accuracy. He tested Einstein's equation for the photoelectric effect in the region of visible and ultraviolet rays and determined the Planck constant (1914). For his work on elementary charges and the photoelectric effect he was awarded the Nobel Prize in 1923. He carried out a large series of studies of cosmic rays, in particular experiments (1921 — 22) with balloons carrying self-recording electroscopes at altitudes of about 15500 m. In 1925—27 he showed that the ionising action of cosmic radiation decreases with depth and confirmed with certainty its extraterrestrial origin, and proposed the name “cosmic rays” for it. Studying the tracks of cosmic particles and their curvature, he was one of the first to establish the complex character of cosmic rays, detecting in them alpha particles, fast electrons, protons, neutrons, positrons and gamma quanta. Independently of S. N. Vernov he discovered the latitude effect of cosmic rays in the stratosphere. In 1916 —18 he was president of the American Physical Society. He was an honorary member of many academies of sciences and scientific societies, including a foreign corresponding member of the USSR Academy of Sciences (1924).