4 o8 HERMANN VON HELMHOLTZ 



as a rule produce nor maintain vibrations of the length of a 

 single period. It is only when the ponderable particles carry 

 charges of true electricity that the periodic alternations of 

 electrical momentum in the ether can produce pondero-motive 

 forces of the same period. The corresponding view that the 

 embedded atoms can only contain northern or southern 

 magnetism was rejected by Helmholtz as too improbable. On 

 the other hand, the electrolytic phenomena, especially Faraday's 

 law of electrolytic equivalents, had long ago convinced him that 

 electric charges of definite size are attached to the valency 

 points of chemically combined ions, which may either be posi- 

 tive or negative, but must everywhere have the same absolute 

 magnitude for each valency point of every atom. 



Helmholtz therefore assumes that the embedded 'atoms are 

 the carriers of definite quantities of true electricity, as required 

 by Faraday's law. If the ether in the vicinity of a pair of 

 associated ions is acted on and dielectrically polarized by 

 electrical forces, the axis of the pair of ions will be prolonged 

 or shortened, and bent towards or away from the direction of 

 the lines of force. It must be presupposed that the forces 

 which spread out into space from the ions as their centres, 

 alter in correspondence with the alterations occurring in the 

 position of the molecules, and are displaced in space, in the 

 manner required by Maxwell's equations. The only thing de- 

 manded by the electrochemical theory beyond what Maxwell's 

 equations imply is the possibility that these centres of the 

 electrical forces shall be able to shift in chemical reactions 

 from one ion to the other, and that with a great expenditure 

 of work, as if they were bound up with a material carrier, 

 which is attracted by the valency points of different ions with 

 different degrees of force. If the ether surrounding a pair of 

 associated ions is acted on by electrical forces, and polarized 

 dielectrically, the antagonistically polarized ions will be exposed 

 to the tensions falling in the direction of the lines of force, i. e. 

 two equal but opposite forces, forming together a couple, which 

 does not throw the centre of gravity of the molecule into motion, 

 but prolongs or shortens the electric axis of the molecule, and 

 deflects it to or from the direction of the lines of force. 



The problem, as mathematically determined by this assump- 

 tion, gives a kinetic potential, the exact discussion of which 



