Jagadish Chandra Bose

“ It did not matter in the least whether the vibration commenced with a right- or left-handed twist.
It may be stated here that similar electromotive variation is obtained by molecular disturbance produced by a tap.
I shall now describe the effect of mechanical stimulus of varying intensities and durations. The intensity may be varied by varying the amplitude of vibration. We shall also study the effect of a single stimulus, or the summated effect of rapidly succeeding stimuli. ”

“ When the particles become continuous, the radiation can only affect the extremely thin layer of molecules on the surface, the mass in the interior being shielded by the outer conducting sheet; the molecular changes produced on the surface layer do not affect to any appreciable extent the conductivity of the mass. ”

“ If the conductivity variation under the stimulus of electric radiation and the electromotive variation under mechanical stimulus are but expressions of some molecular effect, we may expect the peculiarity of one kind of response reflected in the other. We shall presently see how closely the normal effects in the two classes resemble each other. Still more extraordinary are the similarities that exist even in abnormalities, several instances of which will be given later. I shall mention ”

“ Under the action of electric radiation, light, and mechanical vibration, two opposite effects are exhibited; by the conductivity variation method this is seen in the diminution or increase of resistance; by the electromotive variation method we get positive or negative variation.
5. In the curve of response, in all the above cases, the ascending portion is abrupt, whereas the fall during recovery is at first rapid, then comparatively slow, the curve of recovery being thus convex to the abscissa.
6. Under rapidly succeeding stimuli, there is a fusion of individual effects ”

“ The effect of electric radiation is very great in changing the conductivity of a mass of discontinuous particles. It is to be borne in mind that the effect of electric radiation is only skin-deep. As the action is one of surface, the larger the surface the greater is the effect produced. ”

“ It will be seen that the rise is quick, whereas the fall is comparatively slow, specially in the later part.
If sufficient time be allowed the recovery is complete. (In the curves given only 30 seconds were allowed, hence the recovery was not complete.) On the cessation of disturbance the electromotive variation gradually disappears, the wires returning to their original condition, after which similar cycles of operation may be repeated for any length of time.
In the case of molecular distortion due to electric radiation we met with similar instances of complete recovery. ”

“ Successive dots in the ascending portion of the curve represent effect of rotation through 360°. The descending curve represents recovery.
here only one case. We have seen in experiments with electric radiation that substances sometimes fall into a sluggish molecular condition, when the responses almost disappear. Strong stimulation (induction shocks, &c.) or annealing is found to restore the sensitiveness. The same peculiarity is observed in the strain-cell. Lead, for example, specially on cold days, is apt to fall into a sluggish condition, when it becomes almost irresponsive. ”

“ In the case of effect of rapidly succeeding flashes of electric radiation on Ag′, it was shown (see fig. 14) that the partial effects were fused together and there was produced a limiting effect, kept balanced by the force of restitution. With rapidly succeeding mechanical stimuli, we again obtain an exactly similar result. Fig. 15 (a, b) shows the effect of continuous vibration on tin cell, with different intensities of vibration, the vibration-frequency being two in a second. The curve gradually rises and attains a maximum, at which position it is ”

“ We see that in loose particles the effective surface acessible to radiation is very much enlarged. Moreover, the resistance offered to the particles is not due to the individual solid lumps, but to the resistance of surface layer. ”