266 CHAP. XXIV. THE AFTER-EFFECT OF LIGHT 



The after-effect at post-maximum is an overshooting 

 below the position of equiUbrium. 



The mechanical effects and after-effects of light are similar 

 to the corresponding electric effects. The pre-maximum 

 after-effect is a continuation of positive tropic movement 

 followed by recovery ; the after-effect at maximum is a 

 recovery to the normal position of equilibrium ; the post- 

 maximum after-effect is an overshooting, that is, a fall to 

 below the normal position. 



