38 BULLETIN 852, U. S. DEPARTMENT OF AGRICULTURE. 
pump was lifting water to the outlet of the 24-inch pipe. On reach 
No. 28b a water column was used as gauge 1 and a mercury manom- 
eter as gauge 2. On reach No. 28 the water column was moved 
667.6 feet nearer the inlet, but the mercury manometer remained 
the same as before. Air troubles at gauge 1 were minimized by the 
device shown in Plate V, figure 1. Piezometer tubes of type A were 
used for both gauges, No. 1 being slipped into the pipe through a 
one-eighth-inch wrought-iron nipple, while No. 2 was thrust down 
an air valve. Velocities were determined by timing fluorescein from 
its injection at gauge 1 to its appearance at gauge 2. For drawing 
off the colored water a " gooseneck" of one-fourth-inch brass pipe 
was inserted down the air valve and the color detected in a white- 
lined pan. 
For some reason that the writer is not able to explain the friction 
factors are erratic and inconsistent. 
No. 29, Experiment S-36. — 36-inch jointed reinforced concrete 
pipe, Deer Flat Forest pipe line, Boise project, United States Reclama- 
tion Service, Idaho. — Water for irrigation is conveyed across a wide 
depression, just below the dam of Deer Flat Reservoir, in a concrete 
siphon pipe 8,575 feet long and 36 inches inside diameter. 1 As 
shown in Plate IV, figure 1, this line is straight in horizontal align- 
ment and without vertical curves other than two gentle bends at the 
bottom of the slopes near the inlet and outlet. The maximum head 
is about 70 feet. 
The pipe units, 6 feet in length, were cast on the ground in steel 
forms. A very wet mixture of 1 part cement to 2\ parts sand and 3 
parts well-graded gravel resulted in a dense concrete. The shell is 
3 inches thick, reinforced with five-sixteenth-inch wire. As shown 
in the plate, the joints were made with reinforced collars, each 3 
inches thick and 8 inches wide in addition to the usual bevel and 
taper. The joints were calked on the inside with great care, the 
mixture used being 1 part cement to 2 of sand and tempered with 
hydrated lime in the proportion of 10 per cent of the cement by 
volume. 
A reach of this pipe 7,282 feet long from the foot of the first slope 
to the outlet was chosen for test. Gauge No. 1 was a mercury 
manometer attached to the pipe at a small hole through a cast-iron 
manhole cover. At the outlet a piezometer tube of type A was 
thrust 2 feet into the pipe, and the pressure head conveyed by tubing 
to a stilling box within the outlet chamber, the elevation of the 
water in the box being determined by a hook gauge. 
Unfortunately, in 1915 it was not feasible to vary the discharge 
through the pipe, so only one observation could be made. The 
velocity of the water was determined by accepting the mean of five 
batches of fluorescein, injected at gauge No. 1 and observed at the 
outlet. Accepting the mean diameters of 6 units of pipe remaining 
from construction, 2.999 feet, as the mean diameter of the pipe line, 
then the discharge was 24.6 second-feet, while the mean discharge 
over a weir below the outlet was 24.3 second-feet and the discharge 
as measured by a Price current meter, using the integration method, 
was 24.57 second-feet, and using the 0.2 and 0.8 depth method was 
25.15 second-feet (see Table 2, p. 18). 
i Engin. News, Aug. 8, 1912, vol. 68, p. 248. 
