268 WH AT IS LIFE 



**intuitiv erfasst.** However, that the *'Bohr atom" 

 is signally successful in interpreting the spectral lines 

 of the atoms and the chemical behavior of the ele- 

 ments, is evident to everyone who is familiar with 

 the problems that are involved. The modified Bohr 

 atom today is accepted by most if not by all physi- 

 cists and chemists. Nevertheless, it is true that the 

 precise relations — positions and motions, of the orbi- 

 tal electrons of the atoms of nitrogen, oxygen, 

 sodium, etc., are not yet known. The negative 

 electron, thanks especially to the exact measurements 

 of Millikan, is a known constant; the value of the 

 positive electron, too, Millikan has stated. Planck's 

 constant has its definite value. The ratio of charge 

 to mass is readily determined. But the normal orbits 

 of the electrons that revolve about the nucleus of 

 the atom are still unknown, and thus the changes 

 caused in these orbits by the relations of the atom 

 with other bodies are unknown; therefore the exact 

 values of the electron that depend on position and 

 velocity, are undetermined. Mathematical proof of 

 the theory, then, plainly, is not possible yet. Any 

 mathematical work lacking this knowledge of exact 

 quantitative values, in its skillful use of variables and 

 factors might be a thing of art, and in the ease of its 

 presentation a veritable mathematical poem, but it 

 could not be proof. 



