The English physicist Sir James Chadwick (1891-1974) made his most outstanding contribution to modern physics by demonstrating the existence of the neutron.

James Chadwick was born in Manchester on Oct. 20, 1891, the eldest son of John Joseph and Anne Mary Knowles Chadwick. In 1908 he enrolled at Victoria University in Manchester. Although his intention was to study mathematics, Chadwick was admitted to the physics programs and was too shy to correct the error. He graduated from the Honours School of Physics in 1911. During the next 2 years his education was continued in Ernest Rutherford's laboratory at the same university. It was there that Rutherford outlined his planetary theory of the atom. Chadwick's acquaintances in the physics department included Hans Geiger and Niels Bohr.. After Chadwick received his master's degree in 1913, he was awarded the 1851 Exhibition Scholarship, which he used to finance his studies under Geiger in the foremost German research institute...