80 Galvanism, from Galvani to Ohm. 



of any liquid, he attributed the electric effect wholly to the 

 chemical affinity of the air for the metals. 



During the long interval between the publication of the rival 

 hypotheses of Grothuss and De La Bive, little real progress 

 was made with the special problems of the cell ; but mean- 

 while electric theory was developing in other directions. One 

 of these, to which our attention will first be turned, was the 

 electro-chemical theory of the celebrated Swedish chemist, 

 Jons Jacob Berzelius (b. 1779, d. 1848). 



Berzelius founded his theory,* which had been in one or two 

 of its features anticipated by Davy,f on inferences drawn from 

 Volta's contact effects. " Two bodies," he remarked, " which 

 have affinity for each other, and which have been brought into 

 mutual contact, are found upon separation to be in opposite 

 electrical states. That which has the greatest affinity for 

 oxygen usually becomes positively electrified, and the other 

 negatively." 



This seemed to him to indicate that chemical affinity arises 

 from the play of electric forces, which in turn spring from 

 electric charges within the atoms of matter. To be precise, 

 he supposed each atom to possess two poles, which are the 

 seat of opposite electrifications, and whose electrostatic field is 

 the cause of chemical affinity. 



By aid of this conception Berzelius drew a simple and vivid 

 picture of chemical combination. Two atoms, which are about 

 to unite, dispose themselves so that the positive pole of one 

 touches the negative pole of the other ; the electricities of these 

 two poles then discharge each other, giving rise to the heat and 

 light which are observed to accompany the act of combination.! 

 The disappearance of these leaves the compound molecule with 

 the two remaining poles ; and it cannot be dissociated into its 

 constituent atoms again until some means is found of restoring 

 to the vanished poles their charges. Such a means is afforded 



* Memoirs of the Acad. of Stockholm, 1812 ; Nicholson's Journal of Nat. Phil., 

 xxxiv (1813), 142, 153, 240, 319; xxxv, 38, 118, 159. 



t Pnil. Trans., 1807. J This idea was Davy's. 



