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BULLETIN" 115, U. S. DEPARTMENT OF AGRICULTURE. 



Suggested design for proportional division box. — The structure 

 shown in Plate VII, figure 2, is a very common and very faulty 

 type of installation. The division board is set so as to divide the 

 check board in the box in the same proportion as the water right of 



the consumer taking water through the small opening at the left of 

 the box bears to the total water in the ditch. The area of the cross 

 sections of the water in the two portions of the box may be propor- 

 tional in the correct ratio, but the discharge through each part of 

 the box equals the area multiplied by the velocity, and the latter is 



