86 WHAT IS LIFE 



or a beta particle is transformed into a different 

 element. The remarkable experiments of Ruther- 

 ford in dislodging positive electrons (hydrogen 

 nuclei) from an atom, can only be interpreted as 

 constituting experimental transmutation of one ele- 

 ment into another. Sommerfeld says what becomes 

 of the shattered atom cannot yet be definitely 

 stated in every instance, but probably nitrogen in 

 losing two hydrogen nuclei is changed into carbon. 

 Aston asserts: "There can be no doubt that al- 

 chemical transmutation has been achieved."^ That 

 Dr. Adolf Miethe's experiment (1924) in which he 

 believed mercury had been converted into gold 

 has been discredited by H. H. Sheldon and by 

 other physicists, obviously does not affect Aston's 

 statement. 



So long as the nucleus of the atom remains 

 intact the element retains its individuality and 

 position, or atomic number, in the series of the 

 elements. 



Since it has been established that the atom is a 

 system that consists of positively charged nucleus 

 and (negative) electrons, the question has been how 

 to conceive of the grouping of the electrons around 

 the nucleus. 



In 1913, Niels Bohr, accepting the "nucleus" atom 



* Isotopes, second edition, 125. 



