1128 
Journal of Agricultural Research 
Vol. V, No. 24 
experiments with weirs having completely suppressed bottom contrac¬ 
tion. The idea previously considered seems to have been the suppres¬ 
sion of the end contractions in order to secure a simple discharge formula, 
but such an arrangement of weir box possesses many of the objectionable 
features of full-contracted weirs. Discharge formulas are infrequently 
used in the field, tables usually being available, and it therefore seems 
preferable to have a weir that is practicable and of permanent accuracy 
rather than to complicate the weir-box conditions in order to simplify 
the discharge formula. 
A series of experi¬ 
ments was made in the 
hydraulic laboratory 
at Fort Collins, Colo., 
during the summer of 
1914, for the purpose 
of developing a weir 
that would be self¬ 
cleaning, require a 
minimum amount of 
labor and material for 
construction, measure 
discharges with an ac¬ 
curacy commensurate 
with field conditions 
and irrigation de¬ 
mands, and be easily 
operated by the ordi¬ 
nary man, which means that only simple readings without any compu¬ 
tations would be required to determine the discharge. 
Weir Box Floor 
SJJ-J 
<52.^54 7VCW < 4 A/& &£C 7 VCW 
Fig. i.—P lan, elevation, and section of concrete weir box in the 
hydraulic laboratory of the Colorado Experiment Station; also 
arrangement of experimental weir section for Nos. 1 to 6 and 13 to 
16, in Table I. 
ARRANGEMENT OF APPARATUS FOR EXPERIMENTS WITH NEW TYPE 
OF WEIR 1 
In the permanent concrete weir box, which is io feet wide and 6 feet 
deep, a wood floor was built of tongue-and-groove lumber (fig. i). The 
wood floor was about 4.5 feet above the concrete floor and was water-tight 
and level throughout. Its length was 20 feet for four sets of experiments, 
but it was extended to 32.67 feet for all other experiments. The sides of 
the temporary weir box were made of single widths of boards set in a 
vertical position, but arranged to be moved to any position or any angle 
and rigidly fastened to the floor. The several arrangements of the weir 
box are given in Table I, and figures 1 to 13, inclusive. 
1 For a description of the hydraulic laboratory and equipment, see Cone, V. M., op. dt., and Cone, V. M., 
Hydraulic laboratory for irrigation investigations, Fort Collins, Colo. In Engin. News, v. 70, no. 14, p. 
662-665, 5 fig*, 1913* 
