THE PLOW OF WATER IN CONCRETE PIPE. 41 



In other words, as is to be expected from the conditions, the weir 

 discharges more water for a given head than a standard Francis weir 

 would have done. As mentioned above, the velocities used in the 

 computations in tables 3 and 4 were all based on the color method. 



The mean diameter of this pipe, found by measuring two diameters 

 on each of nine pieces remaining from construction is 3.50 feet, 

 agreeing with the nominal diameter. All things considered, the 

 writer regards this series as among the best, due to the very favorable 

 conditions for experimentation. The value of C s is about 0.375 and 

 may be taken as for a very smooth pipe with an excess of curvature. 



No. 31, Experiment S-48. — 42-inch jointed reinforced concrete 

 pipe, siphon No. 5, Victoria Aqueduct, Vancouver Island, British 

 Columbia, Canada. — This series of tests was conducted on the last 

 of the siphons on this pipe line, siphon No. 5, located between man- 

 holes 67 and 68. The same general discussion applies to this series 

 as to No. 30. This siphon is much shorter, and in consequence the 

 series should not be as reliable as No. 30. As shown in Plate V, 

 figure 3, the siphon pitches down a steep grade, thence extends 

 horizontally over a concrete trestle, thence climbs a steep hillside 

 •to the outlet manhole (in the foreground) . 



The values of C s being around 0.390 would indicate a higher 

 capacity than the observations on pipe No. 30, but those should be 

 accepted over the tests on siphon No. 5. 



No. 32, Experiment $-35. — 46-inch jointed reinforced concrete 

 pipe, R t siphon, Umatilla project, United States Reclamation Service, 

 Oregon.— Water for irrigation is conveyed across a wide valley, from 

 one open channel to another, by means of an inverted siphon pipe 

 9,830.8 feet long and subject to a maximum pressure head of 110 feet. 

 It was constructed in the winter of 1909-10. The joint units are 8 

 feet in length, reinforced with a spiral of five-sixteenth-inch steel 

 wire wound round longitudinal rods (PI. VIII, fig. 2). The concrete 

 was mixed in a ratio of 1 part cement to 1 .44 parts sand and 2 parts 

 gravel. The units were cast in steel forms and afterward painted 

 on the inside with a grout made by pouring one-half bucket of cement 

 into two-thirds of a bucket of water. This made a full bucket of a 

 mixture of about the consistency of cream. 1 



As shown in Plate VIII, fig. 2, the pipe is straight in alignment, 

 while the profile is evident, with the exception of the deep sag across 

 the lower lands, where the pressure head reaches 110 feet. Within the 

 reach of pipe tested there are eight 6-inch valves, two 6-inch blow-offs, 

 and four manholes, each 12 by 14 inches. 



This line was tested by Mr. Newell in 1911 and again in 1912 (see 

 itfo. 33a, p. 79). During the season of 1915 the writer conducted 

 experiments on the same reach of pipe, between a valve 72 feet from 

 the inlet and the outlet chamber, a distance of 9,774 feet. 



For gauge No. 1 a mercury column was used, while for gauge No. 2 a 

 piezometer tube of type B, extending into the jet at the outlet, led to 

 a stilling box wherein the water-surface elevation was determined 

 with a hook gauge. Two diameters were measured on each of 8 pipe 

 units remaining from the original construction. The mean area of 

 these units was 11.52 square feet, while the exact area of a 46-inch 



1 The details of manufacturing experience and costs covering a period of about three years are given in 

 " Reinforced-Concrete Pressure Pipe on the Umatilla Project, Oreg., U. S. Reclamation Service," by 

 H. D. Newell, Eng. News, vol. 65, Feb. 16, 1911, p. 20S. 



