CHEMICAL ELEMENTS AND ATOMS URBAIN 207 



ter we had expected of them. Bohr's atom is not a clear explana- 

 tion, for the privileged orbits are not understandable in themselves ; 

 neither are the " quanta of energy," set free by the electrons in 

 leaping from one privileged orbit to another. In the future are 

 theories to be built upon such contradictions ? 



The atom of Rutherford, which is otherwise satisfactory, has the 

 objection of unceasing radiation. In time it should wear itself out. 

 Each outer electron must gradually approach the central nucleus 

 of the atom, finally falling into it, which means its death. Of 

 course, we must resign ourselves to death. We might have accepted 

 the death of the stars without the optimistic invention of Arrhenius, 

 but we can not that of the atoms; that would mean a definite 

 end of the universe which we find it comforting to look upon as 

 eternal. Bohr, in revivifying our hopes, is a great benefactor. Fur- 

 ther, if the electron revolving about the positive center of the atom 

 radiated constantly, matter should be always luminous, which is far 

 from the fact. This seems a critical objection. 



It seems necessary either to resign ourselves to not understand- 

 ing, as Bohr has done, or to resign ourselves to a model in flagrant 

 violation with experience. There is no doubt as to our choice. To 

 one who finds fault that the electrons in their privileged orbits do 

 not obey the laws of electromagnetism, we may reply that so far 

 as known these laws relate only to large-scale phenomena. They 

 may not apply to the electron or to the atom, but only statistically 

 when a large number of them are under consideration. Men en- 

 dowed with excellent individual qualities may make detestable 

 crowds. Atomists take the Carnot principle as a collective law for 

 which the little demon of Maxwell ^ has no power. Thus Bohr may 

 be less revolutionary than he seems at first sight. He can intrench 

 himself behind an illustrious precedent. 



Our ideas relative to the older elements, which are really not ele- 

 mentary, have not reached the end of their vicissitudes. Radicals 

 composed of electrons and protons they may be. On such terms 

 they have lost nothing of their older significance in chemistry. 

 Chemistry ceases to concern itself with the primary elementary 

 forms. Its domain henceforth is one of secondary combinations 

 now that its ancient elements have become divisible and composite. 



It might be more philosophical to enlarge the realm of chemistry 

 to include not only radioactivity but also electronics. But then 

 we must cross the barrier which has separated chemistry and 

 physics. The shadow of Auguste Comte would shake with indig- 

 nation. The old modes of thought, molded by the routine of 



^ An imaginary being invented by J. C. Maxwell, wlio is supposed to witness the 

 actual working of the law of thermodynamics, and to be able to control it. 



