born Sept. 2, 1877, Eastbourne, Sussex, Eng.
died Sept. 22, 1956, Brighton, Sussex
British chemist.
He worked with Ernest Rutherford to develop a theory of the disintegration of radioactive elements. In 1912 he was among the first to conclude that elements might exist in forms (isotopes) of different atomic weight s but indistinguishable chemically. In Science and Life (1920) he pointed out the value of isotopes in determining geologic age (see carbon-14 dating ). For his investigations of radioactivity and isotopes, he received a 1921 Nobel Prize.