EXCITATORY CHARACTER OF SUCTIONAL RESPONSE 369 



Balance is employed, which depends upon an application of 

 compensation, by which, under normal conditions, the water- 

 index is kept stationary, though the suctional movement in 





FIG. 2 1 8. The Shoshungraph 



plant-vessel ; R, reservoir ; c, compensator, whose balancing height is 

 adjusted by rack and pinion, s ; K, key for manipulation of four- way 

 stop-cock ; p, recording pen, with counterpoise M, manipulated by 

 wheel, w. The drum | is rotated by the clock at uniform speed. 



