364 



WOOD TRANSPOKT BY WATEE. 



as long as the end (??i) of the lever (s d in} rests against the 

 peg (b), the cylinder is kept closed, but when s is pressed 



' ! 



Fig. 236. Sluice-gate. 



down, b is released, and the gate opens. This mode of 

 opening is used chiefly when the walls of the dam are high. 



