410 PROF. J. C. BOSE ON THE 
Hertzian radiation *. It will thus be seen that the sign of 
response, in certain cases, may vary with the molecular condition 
of the substance or tissue, and also with the intensity of 
stimulus. 
As regards the intensity of electromotive variation, I have 
often obtained as high a value as ‘0025 volt for the larger 
or principal wave. In a more favourable season of the year 
and with a vigorous plant, this value will probably be con- 
siderably enhanced. I give below the absolute values of 
electromotive variation obtained with two different specimens, 
five successive observations being taken in each case. 
TABLE I. 
Number of | E.M. Variation. | ELM. Variation. 
Observation. | Principal wave. Subsidiary wave. 
— | 
1 0014 volt. 00055 volt. | 
2 0013, = 00051, 
3 0014 ,, 00054 _,, 
4 0015s, 00054, 
5 0016 _s,, 
Tasre II. 
Number of E.M. Variation. E.M. Variation. 
Observation. Principal wave. Subsidiary wave. 
1 0024 volt. 0016 volt. | 
2 0025 _,, 0015, 
3 0025, 0016 ,, 
4 0025 _—,, ‘0017 _—,, 
4) 0026 _—,, 
Fatique. 
Some specimens exhibit responses which are uniform, a8 in 
the case given in fig. 2: by uniform I mean that the double 
wave repeats itself without undergoing any variation. But 
in other instances signs of fatigue are evident, the successive 
* Bose, J. C., “On Electric Touch and the Molecular Changes produced in 
Matter by Electric Waves,” Proc. Roy. Soc., Feb. 1900, pp. 452-474. 
