THE FLOW OF WATER IN CONCRETE PIPE. 31 
No. 14, Experiment S-58. — 18-inch jointed cement pipe, Edwards 
private line, in Oakdale irrigation district, Calif. — Water for irri- 
gation is conveyed across a depression from a main lateral of the 
Oakdale district to a knoll, in a plain cement-pipe inverted siphon 
1,283.6 feet long, subject to a maximum head of about 11 feet. 
The pipe was made on the ground by the owner of the farm, aided 
by a man with a small amount of practical knowledge of pipe mak- 
ing. There is one 12-inch standpipe and one 12-inch valve near the 
low point. As both inlet and outlet of this line were submerged 
and it was not possible to vary the discharge to secure much 
variation in the velocity, practically all of the line was used in 
the experiments. Water columns attached to piezometer tubes of 
type A were used at both ends of the reach. Piezometer No. 1 was 
set 5.1 feet down the pipe from the intake chamber and No. 2 
was thrust upstream from the outlet chamber a distance of 7 feet. 
Velocities were determined by the use of a saturate solution of po- 
tassium permanganate, injected at the inlet and observed at the out- 
let of the siphon. The nominal size of the pipe was accepted, as 
it was not feasible to secure measurements of the pipe itself. 
From the fact that the value of C s is very low, about 0.254, the 
Writer would judge that sediment has obstructed this pipe more or 
less. 
No. 15, Experiment S-56. — 18-inch jointed cement pipe, Batdorf 
line, Oakdale irrigation district, Calif. — Irrigation water is conveyed 
from one open-channel lateral to another down a gentle hillside and 
across about 600 feet of level field by means of an 18-inch cement 
pipe made of jointed units each 2 feet long. There are four vertical 
standpipes rising above the hydraulic gradient on the total length 
of about 2,500 feet. Examination of the pipe at these standpipes 
showed that the line was full of water only through about the last 700 
feet. A reach was chosen from a standpipe to the outlet, a length of 
582.3 feet. A tube of type A was dropped down the standpipe and 
carried by the current 2 feet down the pipe. A similar tube was 
thrust 21 feet up the pipe from the outlet. Gauge No. 1 was a 
water column in a glass tube, while piezometer tube No. 2 was con- 
nected with a stilling box and the surface of the water determined 
by a hook gauge. The velocity was determined with a solution of 
potassium permanganate, timed from the standpipe to the outlet. 
As it would have been a difficult matter to determine the moment 
of injection down a standpipe 10 or 15 feet high above the pipe 
line, the solution was placed in a corked bottle held in a sack made 
from a piece of fly screen which was wired to the end of a long one- 
eighth-inch iron pipe. The bottle was thrust down the standpipe 
and smashed against the bottom of the pipe line, thus releasing the 
color but retaining the glass within the screen. The line under the 
standpipe was clean of deposit, as nearly as could be determined by 
feeling with the iron pipe rod, and from the appearance of the outlet. 
The value of the friction factor would indicate this to be true. The 
pipe is straight, buried about 3 feet, appeared from inspection of 
the outlet to have good joints, and was probably in good condition. 
The value of C s is 0.284. 
No. 16, Experiment S-42. — 20-inch jointed concrete pipe, lateral 
C, British Columbia Fruitlands Co., Kamloops, British Columbia, 
Canada. — The main canal on this project is concrete lined, skirting 
