60 



IRRIGATION. 



form, and may be of galvanized iron, of zinc, lead, or 

 wrought iron, or of hard brick laid in cement. The dis 

 charge pipe may be of cast iron. This form of tank 

 has been found to work with the greatest ease ; two quarts 

 of water suddenly discharged into it when full being suf 

 ficient to set the flush into operation. This apparatus 

 consists of the cylindrical tank, A, with a trapped inlet, 



Fig. 25. SELF-DISCHARGING SLOP-TANK. 



which also forms a movable cover to give access to the 

 inside of the tank. The pipe from the sink discharges 

 over the grating of the inlet, B, as shown in the figure. 

 A socket, c, is prepared for a ventilating pipe. There is 

 also the siphon, D, and what is called the &quot; discharging 

 trough,&quot;/, consisting of a small chamber made to turn 

 round, so that its mouth may be set in the direction that 



