In a letter to the editor published in the Dec. 4, 1913, issue of Nature, English radiochemist Frederick Soddy proposed the isotope concept—that elements could have more than one atomic weight. The ...
Radioactivity, by Ernest Rutherford, second ed., 475 (Camb. Univ. Press, 1904). Daily Mail, June 4th, 3, col. 4. (1921). Radioactivity, by Frederick Soddy, 34, 170 ...