All Chemical Reactions Involve Negative and Positive Forces

... every chemical combination is wholly and solely dependent on two opposing forces, positive and negative electricity, and every chemical compound must be composed of two parts combined by the agency of their electrochemical reaction, since there is no third force. Hence it follows that every compound body, whatever the number of its constituents, can be divided into two parts, one of which is positively and the other negatively electrical.

Jons Jakob Berzelius, Essai sur la théorie des proportions chimiques et sur l'influence chimique de l'électricité (1819)

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