Two kinds of potential difference for a capacitor

Abstract

It is shown that contrary to this current belief that the electrostatic potential difference between the two conductors of a capacitor is the same potential difference between the two poles of the battery which has charged it, the first is twofold compared with the second. We see the influence of this in the experiments performed for determination of charge and mass of the electron. 

(26) Two kinds of potential difference for a capacitor (pdf)