54 ILLINOIS STATE ACADEMY OF SCIENCE 



atoms. It is almost incomprehensible how these elec- 

 trons can be rotating around these atoms in orbits and 

 at the same time bind the atoms together in fixed and 

 definite arrangements of molecular structure. Many 

 chemists therefore have preferred to believe in the static 

 atom, that is, one in which the electrons are arranged in 

 stationaiy shells, preferring to leave the stability of the 

 shells unexplained rather than adopt an explanation 

 which appears to destroy the chemical property of the 

 atom we call valence. 



The plwsicist is concerned mainly with the explanation 

 of such phenomena as radiation, and this dynamic theory 

 of the atom explains radiation very well, provided the 

 physicist discards a considerable portion of the classical 

 theory of electrodynamics. He has the same justification 

 in doing this that the chemist has in discarding 

 Coulombs law as being operative at small distances be- 

 tween electrons and positive nuclei. That is, each expla- 

 nation seems to fit the facts. The facts which the physi- 

 cist and the chemist are trying to explain are thus of a 

 different sort. To the chemist an atom which is radiating 

 light is in a pathological condition. It appears to be im- 

 possible for an atom to be brought into a condition in 

 which it radiates, without destroying the molecule of 

 which that atom is a part. The dynamical theory of the 

 atom, then, explains the properties of the atom in one 

 condition; the static theory explains the properties of 

 the atom when it is in another condition. The two theo- 

 ries may not be contradictory — they may simply apply to 

 two different states of aifairs. The problem to be answer- 

 ed, then, in the immediate future is not whether these 

 two theories may be reconciled, but rather, whether they 

 are dealing with the same phenomena. 



