CANE SUGAR. 



the object of which is to prevent pieces of cane being carried along the pipe c. 

 In some designs the lower door itself carries the false bottom. The joint in 

 the lower door is a hydraulic one, consisting of a hollow rubber tube provided 

 with a pipe by means of which water is conducted to the tube, which is placed 



FIG. 135. 



in a circular groove contrived either in the door itself or in the bottom of the 

 cell. The water which fills this tube is taken from a tank at a high level, so 

 that in all cases the pressure in the tube is greater than the pressure in the 

 cell. In other cases the rubber tube is connected by a pipe with the main 



228 



