76 BULLETIN 376^ U. S. DEPARTMENT OP AGRICTJLTUEE. 



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-iach 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 

 CipoUetti 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 suggest? 

 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 smnmits 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.^ — ^Arthiu- 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 was 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, Nevr 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.^ 

 The discharge was determined by weir measmement 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. 



1 Trans. Amer. Soc. Civ. Engin., 40 (1898), p. 542. 



2 Recherches Hydranliques, Henry Darcy and H. Bazin, Paris, 1865. 



