1902.] On Electromotive Wave accompanying Disturbance. 27o 



" On Electromotive Wave accompanying Mechanical Disturbance 

 in Metals in Contact with Electrolyte."* By Jagadis 

 Chunder Bose, M.A., D.Sc, Prof. Presidency College, Calcutta. 

 Communicated by Professor Keinold, E.Pt.S. Eeceived 

 March 14 — Eead May 15 — Eevised May 21, 1902. 



Take a rod of metal, and connect the two points A and B with a 

 galvanometer by means of non-polarisable electrodes. (Fig 1, a.) If 

 the point 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 dis- 

 turbance. 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 E A - E B where E A and E B are 

 the electric variations produced at A and B. The electric changes at 



¥ia. 1. — In (a) mechanical disturbance applied at O produces similar electrical 

 disturbances at A and B ; there is no resultant effect. In (b) owing to a 

 clamp, disturbance applied at A cannot reach B. A tap or vibration im- 

 parted to the end A produces responsive current which flows in the wire 

 from the unexcited B to the excited end A. Disturbance of B gives rise to 

 a current in the opposite direction, (c) gives the record of the response to 

 equal stimuli applied to A and B. The ascending part of the curve shows the 

 effect of stimulus, the falling part shows recovery, (d) Simultaneous stimu- 

 lation of A and B gives no resultant response. (In the records dotted lines 

 represent recovery.) 



A and B will continuously balance each other, and the resultant effect 

 on the galvanometer will be zero, (1) if the mechanical disturbance 

 reaches A and B at the same time and with the same intensity, (2) when 

 the molecular condition is similar at the two points, and (3) when 

 the rate of rise and subsidence of disturbance is the same at the two 



* A preliminary account of this investigation was given in a paper " On 

 Response in Inorganic Substances," read before the Society, June 6, 1901. 

 VOL. LXX. U 



