1935 - Science

Science

University of Chicago physicist Arthur Dempster discovers uranium 235 isotope, a fissile version of the atom (see 1940; Urey, 1931). Now 49, Dempster will work on developing a military use for the material (see mass spectrometer, 1918; Dunning, 1939).

Japanese physicist Hideki Yukawa, 28, at Osaka Imperial University proposes a new theory of nuclear forces and predicts the existence of mesons—particles with masses between those of the electron and proton. U.S. physicists will discover one type of meson among cosmic rays in 1937, confirming Yukawa's theory.

Mathematician Emmy Noether dies at Bryn Mawr, Pa., April 14 at age 53 following surgery for a uterine tumor; archaeologist Edward H. Thompson dies at Plainfield, N.J., May 11 at age 78; botanist-geneticist Hugo de Vries outside Amsterdam May 21 at age 87; paleontologist Henry Fairfield Osborn at Garrison, N.Y., November 6 at age 78; Nobel chemist Victor Grignard at Lyons December 13 at age 64.