‎"SODDY, F. (+) E. RUTHERFORD.‎
‎Intra-atomic Charge [Soddy] (+) The Structure of the Atom [Rutherford]. - [INTRODUCING THE CONCEPT AND COINING THE WORD ""ISOTOPE""]‎

‎London, Macmillan, 1913-1914. Royal8vo. Bound in contemporary half calf with two black leather title label to spine with gilt lettering. Five raised bands. In ""Nature"", Vol. 92, September - February, 1913-1914. Library stamp of Christ Church College, Oxford on first page of index with their bookplate on front free endpaper and that of Dr Lee's Laboratory, Christ Church, on front paste-down. Minor wear to extremities, otherwise a very fine and clean copy.‎

Reference : 47056

‎First printing of this important paper introducing for the very first time the concept of isotopes"" how to designate chemically identical elements with different atomic weights. This is also the first uses the term 'isotope' in print. This work would later award him the Nobel Prize in Physics. ""To be able to refer generically to these active and inactive elements with identical chemical properties, Soddy introduced the technical term ""isotope"" in 1913.10 While chemically inseparable, active isotopes were distinguishable by their radioactive properties, and all isotopes differed in atomic weight. Soddy suggested that the 1912 metaneon of J. J. Thomson be considered ""a case of isotopic elements outside the radioactive sequences.""11 Following Soddy, Aston announced a partial separation in 1913 on this very basis. The connection between chemical properties and the periodic table became increasingly clarified with concurrent developments in the physics and chemistry of the nuclear atom, from the chemical side. Soddy proposed the alpha-ray rule in 1911, the key to the first of two locks. Applying his general principle that the common elements are mixtures of chemically inseparable elements ""differing step-wise by whole units of atomic weight"" specifically to the case of the radioelements, Soddy recognized that the expulsion of an alpha particle would result in a lighter element chemically inseparable from those occupying the ""next but one"" position in the periodic table. The second lock to the displacement law involved the beta transitions."" (DSB)A rather indignant Ernest Rutherford responded [In the second paper]: the nucleus has ""resultant"" positive charge, he said, and as he elaborated, Rutherford came tantalizingly close to postulating the proton"" (Nature Website).‎