cigarette box containing absorbers and two discs of paraffin wax, used by James Chadwick, (26mm and 48mm in diameter), 33 pieces of aluminium foil and five other metal plates of various sizes together with a metal holder for these plates 44mm in diameter

James Chadwick's toolbox was an old Rhodian cigarette carton in which he kept apparatus used in his scientific work, particularly during his discovery of the neutron. Chadwick (1891-1974) used the pieces of paraffin wax in his neutron detector, while the silver and aluminium foils of different thicknesses were used as barriers to help assess the strength of radiation. Chadwick's theories and experiments helped to rewrite existing beliefs concerning what was contained in the nucleus of an atom.