HOWIETOUN DIVIDING-BOX. 223 



ment was furnished with an overflow-board rising from the bottom, 

 about half the depth of the dividing-box ; and the end of this 

 compartment is again subdivided into three, this time laterally, 

 by two divisions of flooring-boards held in position by a frame, 

 in which are grooves to receive small pieces of flooring, so as to 

 shut off any of the three small compartments, each of which 

 communicated with one of the 130-feet ponds. Below is a section 

 of the dividing-box, showing distribution (Fig. 155). 









FIG. 155 scale 



This box passes the water to the overflow-board so dead that 

 the division is absolutely dependent on the width of the three 

 divisions on that board. Thus it is evident that the supply can be 

 regulated to the three ponds in any given proportion desired, 

 merely by contracting this width by slipping a piece of flooring 

 into one of the grooves, so as to contract the space without alter- 

 ing the height of the overflow ; and to isolate a pond entirely, all 

 that requires to be done is to slip the piece of flooring (cut to the 

 size) between two grooves. To reduce or limit the whole supply, 

 remove the clay and the two sets of boards in the subsidiary box 

 and replace the front set arranged to any height suitable. This 

 acts as a safety-valve; if more than one of the 130-feets is shut 

 off' at the same time, it is almost always necessary to use the 

 waste-pipe. The water was taken from the dividing-box and 

 passed through screens, to prevent the upward passage of the fish 

 from the ponds. These screens were, in fact, wooden trap-boxes, 

 so constructed that all the sand that got into them fell to the 

 bottom, while the water flowed through the screen without 



