Introduction - Chadwick discovers the neutron

The background to Chadwick's discovery in 1932 of the neutron predicted by Rutherford is chronicled. In the same year Cockcroft and Walton split the atom, and the story of this event is told. 1932 also saw the demonstration by Blackett and Occhialini of the existence of the positron. These important contributions to nuclear physics were all made at the Cavendish Laboratory in Cambridge. Photographs, extracts from experimental notebooks and circuit diagrams illustrate this introduction. (UK)