5 o RESPONSE IN THE LIVING AND NON-LIVING 



on the surface. After a while the current of injury was 

 found to disappear. On exciting the stem by taps or 

 torsional vibration, a responsive current was observed 



which flowed inwards from 

 the more disturbed outer 

 surface to the shielded core 

 inside (fig. 29). Hence it is 

 seen that when a wave of 

 disturbance is propagated 



FIG. 29.-EADIAL E.M. VARIATION alon g the P lant > tnere ^ a 



concomitant wave of radial 



E.M. variation. The swaying of a tree by the wind 

 would thus appear to give rise to a radial E.M.F. 



