ii2 RESEARCHES ON IRRITABILITY OF PLANTS 



handle k. The winding disc is attached to the revolving 

 axis of a phonograph motor. The disc is wound in a right- 

 handed direction, which at the same time winds the spring 



Fig. 66. — Apparatus for determination of latent period of Mimosa : u, 

 spring motor ; w, winding disc ; c, projecting catch ; k, release- 

 handle, pressure of which also completes primary circuit of induction- 

 coil ; k 1 , short-circuit key. The automatic break consists of contact- 

 rod adjusted by micrometer-screw a. 



of the phonograph motor. The circumference of the disc 

 is the same as the length of the recording-plate. One 

 complete turn pulls the recording-plate up to its highest 

 position. A projecting catch below the disc is caught by 



