Physics: 1900–1950

In Canada, Rutherford feeling isolated from the scientific centers of Europe, in 1907 accepted the Chair of Physics at Manchester University in England. With the German physicist Hans Geiger (1882–1945), they conclusively determined that alpha rays were doubly ionized He atoms. (Geiger eventually became known as the inventor of the Geiger Counter, the instrument they used to measure the alpha radiation.) Rutherford correctly assumed that because the alpha particles were more massive and of atomic dimensions compared to electrons, they would be key to understanding the nature of matter. His intuition was right.