414 PROF. J. C. BOSE ON THE 
Investigation on the Cause of the Double 
Electric Response. 
I now proceed to adduce considerations and experiments 
which will offer an explanation of the double electric response 
corresponding to a single mechanical vibration. We have to 
explain (1) why the response should be double, and (2) why, of 
the two, the principal wave of electric response should be larger 
than the subsidiary wave. 
I must here recapitulate briefly certain results I obtained 
with ordinary plants, which have a special bearing on the 
present subject. I found (Journ. Linn. Soc., Bot. xxxv. 
(1902) p. 283) that when a plant is mechanically stimulated, 
say by torsional vibration, then keeping the amplitude of 
vibration constant, the intensity of electric response depends 
on the quickness with which the vibration is effected,—the 
quicker the motion, the stronger is the response. This is 
clearly seen in the records given in fig. 7, where successive 
Fig. 7. 
\ 
Successive responses to vibrational stimulus of the same amplitude 30°, 
imparted with increasing rapidity. It will be seen how the response 18 
enhanced with the rapidity of the onset of disturbance. 
vibrational stimuli of the same amplitude were imparted to 
the plant, but with increasing rapidity. Again, when the 
plant is in any way disturbed mechanically, whether by bend- 
ing or by torsion, the electric response takes place during 
distortion. Thus, when the plant was twisted through a definite 
angle, there was a response, say an upward galvanometer move 
ment during twist, but while the plant continued to be held 
in the twisted position the electric disturbance disappeared, 
the deflected galvanometer spot of light returning to 7€TO 
If, then, the plant were untwisted and brought back to its 
original position, there was a second response, in the same 
