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BELL SYSTEM TECHNICAL JOURNAL 



genealogical line to which it belongs. These are the conspicuous 

 differences between the isotopes comprised in a single element, when 

 the element is one of the eight final ones of the periodic table; and 

 they are so conspicur)Us and iniprossi\c that the indi\idiial isotopes 



Fig. 11 — Table of the Elements from the Eighty-Second to the Ninety-Second 



(Inclusive) Showing the Names and the Presumed Atomic Masses of Their 



Isotopes. (.Xndradc, The Structure of the Atom) 



enio\- iiuii\idual names, while the element to which the>' all Ijehmg 

 usually has no all-embraring name of its own, — quite the opposite 

 of the state of affairs among the stable elements, each of which has 

 its own name while the isotopes compo.sing it are known only by the 

 numbers giving their atomic masses. Fig. 11 displays these last 



