The natural and artificial disintegration of the elements / An address by Professor Sir Ernest Rutherford

The address surveys evidence for natural and artificial disintegration and its implications for atomic nuclei, arguing that atoms have tiny positive nuclei surrounded by electrons, with nuclear charge equaling atomic number; discusses alpha-particle scattering experiments that establish inverse-square forces and estimate nuclear dimensions; presents isotopic mass measurements implying protons and electrons as principal constituents and the helium nucleus as a composite unit; considers energy changes in assembling nuclear building blocks, limitations of whole-number mass rules, and experimental methods such as alpha bombardment that probe nuclear structure, while noting unresolved questions about internal arrangement and binding forces.