xi 3 ° 
Journal of Agricultural Research 
Vol. V, No. 34 
Steel weir plates having rectangular crests and sides made of brass, 
with nominal crest lengths of i, 1.5, 2, 3, and 4 feet, were successively 
attached to the steel frame anchored in the concrete wall. A 2-inch 
angle iron, dressed and trued, was set flush in the floor section, and by 
means of bolts the floor section was drawn tightly against the weir 
plate. The angle iron formed the crest of the weir and it was sufficiently 
rigid to prevent any trouble due to the possible warping of the floor, 
and also insured the crests remaining at the same elevation as the floor. 
The water passed through the weir notch with full lateral expansion and 
complete aeration of 
nappe. 
The head was deter¬ 
mined in the concrete 
hook-gauge still box 
which was connected 
to the weir box by 
four pieces of K'-inch 
hose attached to 1- 
inch pipe nipples 
screwed upward 
through the floor un¬ 
til flush with the sur¬ 
face. The auger holes 
into which the pipes 
were screwed were 
placed near the side 
of the weir box in a 
line 6 feet back from 
the plane of the weir. 
A second hook gauge 
was placed in a tem¬ 
porary still box connected by a hose through the side of the weir box 
near the floor line. This hook gauge was used for check purposes and 
to determine whether any discrepancies would be introduced by apply¬ 
ing the results of the experiments to future installations where the head 
would be communicated to a still box by pipes through the side of the 
weir box. The two sets of hook-gauge readings indicated that no error 
is introduced thereby, provided the pipes are installed at the proper 
distance from the weir, 6 feet, and in a position normal to the side of 
the weir box rather than normal to the axis, because the lines of flow 
are parallel to the side. 
In all these experiments the weir discharges were determined volu- 
metrically in the calibrated concrete tanks. 
Several series of preliminary experiments were made in order to deter¬ 
mine the influence upon the discharge caused by various end contrac- 
Fig. 2.—Plan of experimental weir box for Nos. 7, 12, i8 t ^o, and 30 
to 34 in Table I. 
