676 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
plate S, and tliis can be moved up and down by means of the screw Y. 
The hopper E is divided into two compartments a and b , so that the 
water, which is introduced into the hopper through a pipe, may pass 
Fig. 79. 
Fig. 80. 
both on to the wheel R and through a tube P on to the test-tube. 
The surplus water collects in a reservoir, from which it passes out 
through an overflow pipe (not shown in the illustration). 
