Page:A history of the theories of aether and electricity. Whittacker E.T. (1910).pdf/100

 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 Rive, little real progress was made with the special problems of the cell; but meanwhile 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, Jöns Jacob Berzelius (b. 1779, d. 1848).

Berzelius founded his theory, which had been in one or two of its features anticipated by Davy, 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