Page:Collected Physical Papers.djvu/297



Take a rod of metal, and connect the two points A and B with a galvanometer by means of non-polarisable electrodes. (Fig. 71a.) If the point O is struck, a wave of molecular disturbance will reach A and B. It will be shown that this is attended by a wave of electric variation. The mechanical and the attendant electrical disturbance will reach a maximum and then gradually subside. The resultant effect on the galvanometer will be due to EA − EB where EA and EB are