76 BULLETIN 376, U. S. DEPARTMENT OF AGRICULTURE. 
irrigation purposes in 1910 and had been in use but three months at the time of tests. 
The line supplements and parallels the pipe described as No. 28. However, the 
vertical curve at the low point is not so sharp as in the 22-inch pipe. A water column 
was used for gauge No. 1 and a mercury manometer for gauge No. 2. The diameter was 
measured at the intake and found to average 12 inches. Discharge was taken over a 
Cipolletti weir at the intake. The loss of head was abnormally great, capacity being 
about 15 per cent below the discharge computed by the new formula. Moritz suggeste 
the possible presence of silt in the lower portions of the pipe, as the normal velocity is 
but 0.8 foot per second and the water is silt-laden. 
Nos. 17, 18. 14-inch Jointed (Machine-Banded) Wood-Stave Pipe, Sunny- 
side Project, U. S. Reclamation Service, Washington. — This pipe for carrying 
irrigation water had been in use five consecutive seasons when tested in 1909. The 
reach included in the tests consists of two tangents intersecting at an angle of 32° 12', 
where a gentle bend of short lengths of pipe is made. The same reach was tested in both 
1909 and 1910. Loss of head appeared less in 1910 than in 1909. This may have been 
partially due to less friction in the pipe at the later date and partially to mere difference 
in experimental results. Mercury manometers were used for both gauges. At a place 
where a stave blew out opportunity was afforded for an examination of the interior of 
the pipe and for measurement for area in addition to inlet and outlet. At this hole the 
softer portions of the fir wood had worn away, leaving longitudinal ridges of harder 
wood. The frictional influence of this condition was problematical. Discharge 
measurements in 1909 were made over a round-crested weir; those in 1910 were made 
over sharp-crested weir. In general the 1910 tests should be given more weight than 
those of 1909. The profile of the line is wavy but without pronounced vertical curve 
or bends. Three summits are indicated by a ground line profile, but their actual 
existence in the pipe is questionable. The capacity of the pipe in 1909 was about 9 
per cent greater than the discharge computed by the new formula, while in 1910 it was 
less than 3 per cent greater than that discharge. 
No. 20. 14-inch Redwood Stave Pipe, West Los Angeles Water Co., Cali- 
fornia. 1 — Arthur L. Adams conducted a series of seven tests upon reaches of various 
lengths of a 14-inch redwood pipe supplying the Pacific Branch of National Soldiers' 
Home, in California. Throughout the length of the pipe line vertical curves were 
quite numerous, but all were made without the use of "specials " and with radii of not 
less than approximately 40 feet. Horizontal curves were few, and 286 feet was the 
minimum radius. The size of the pipe was determined by numerous measurements 
of external circumference, the thickness of the staves being known to be constant. 
The discharge was measured with a 4-foot weir whose coefficient \vas determined by a 
volumetric measurement. The head on the weir was read on a hook gauge. The loss 
of head was observed in open standpipes and other designated structures. Points of 
observation were connected by wye levels. Taking the mean of all the observations 
on this pipe, the capacity is shown to be about 9 per cent less than as computed by 
the new formula. This series was used by Williams and Hazen in determining their 
suggested coefficient of 120. It was also used by the writer in deriving his formulas 
but was rejected by Moritz. 
No. 21. Bonito Pipe Line, New Mexico. — This series is discussed under No. 15 
on page 75. 
No. 22. Rectangular Unplaned Poplar Pipe. — Tests on an experimental pipe 
1.574 feet wide and 0.984 foot deep were made in France in 1859 by Darcy and Bazin. 2 
The discharge was determined by weir measurement and the loss of head by piezo- 
meters. This series was used by Tutton in deriving his formula, but was rejected by 
Moritz and the writer, both of whom considered only round-stave pipes in deriving 
their formulas. 
i Trans. Amer. Soc. Civ. Engin., 40 (1898), p. 542. 
2 Recherches Hydrauliques, Henry Darcy and H. Bazin, Paris, 1865. 
