IIOO 
Journal of Agricultural Research 
Vol. V, No. 23 
For the purpose of throwing light upon what would be the probable 
shape of a type of notch the discharges through which, with the given 
head, would be proportional to the crest length, the data obtained for 
the 2-foot rectangular, the 2-foot Cipolletti, and the 2-foot trapezoidal 
notches with side slopes 1 to 3 and 1 to 6 were plotted, a set of curves 
being made for each of the following heads: 0.4, 0.5, 0.6, 0.7, 0.9, and 
1 foot (fig. 17). Lines A were obtained by plotting the actual dis¬ 
charges through the rectangular and Cipolletti notches with a given head 
against twice the discharges through i-foot notches with the same head. 
Since no experiments were made with i-foot notches having side slopes 
