80 BULLETIN 376, U. S. DEPARTMENT OF AGRICULTURE. 
the end of about 3,000 feet a head of nearly 60 feet is attained and the pipe ckanged 
to a 55f-inch continuous-stave pipe of Douglas fir. A reach of this pipe 2,848.2 feet 
long was tested in 1909 and again in 1910. At the time of the first series of tests the 
pipe had been in operation about five months. It was new, well rounded, and con- 
tained but minor distortions. There was no deposit or growth inside. Cross-sec- 
tional areas of pipe interior were determined by taking four diameters every 200 feet 
throughout the reach tested. Velocity in the pipe was determined by dividing the 
discharge, as found by the 18-foot weir, by the mean inside cross-sectional area of the 
pipe. Mercury manometers were used at both ends of the reach. A comparison of 
the capacities of this pipe and nearly all other large pipes shows that this siphon is 
remarkably smooth. This fact is also borne out by the tests on the 48f-inch pipe dis- 
cussed as No. 43, which is part of this same siphon. This fact is also clearly shown by 
the relative positions of the points for this pipe in Plate VI. The two series of tests 
on this pipe were the only ones on any pipe of greater diameter than 18 inches not 
rejected by Moritz in deriving his formula. This accounts for the difference between 
the Moritz formula and those of Williams-Hazen, Tutton, and the writer. Giving all 
weight for large pipes 1 to these two series develops a formula indicating a far greater 
capacity for large wood-stave pipes than a study of all available tests on such pipes 
will warrant. If the new formula represents the flow in an average pipe, shown in 
Tables 2 and 3 to be true, then this pipe will carry more than 18 per cent more water 
than the average pipe. While conducting tests for the Department of Agriculture the 
writer visited this pipe after a lapse of four years with a view to securing additional 
information, but the pipe leaked so badly that tests were not feasible. The pipe was 
rebuilt in 'the winter of 1914-15. 
No. 49. Moon Island Conduit, Boston, Mass. 1 — In October, 1884, E. C. Clarke 
made one test on a rectangular conduit, flowing full; that is, as a pipe. This conduit 
is a tight wooden flume 6 by 6 feet, made of planed plank, laid lengthwise. The ex- 
perimental section was straight, 2,486.5 feet in length. During this test the flow con- 
sisted of about one-fourth sewage and about three-fourths salt water. The sides of 
the conduit were covered with from one-eighth to one-fourth inch of slime below the 
ordinary flow line. Above this line, on the sides and top, there was some slime but 
not so much as below the line. Discharge was measured with approximate accuracy 
by the strokes of the pump pistons. This test was used by Tutton in deriving his 
formula but rejected by other authorities as the conditions did not parallel those for 
which the usual pipe is designed. 
Nos. 47-48. 72^-inch Continuous-Stave Douglas Fir Power Trunk Line, 
Pioneer Electric Power Co., Ogden, Utah. 2 — Soon after the construction of the 
Ogden Canyon pipe line supplying the Pioneer Electric Power Co. plant, near Ogden, 
Utah, tests were made by Profs. Marx, Wing, and Hoskins, of Leland Stanford 
Junior University. These tests covered loss of head in the 6-foot wood-stave pipe 
and the riveted-steel pipe leading from the stave pipe to the power house. Experi- 
ments were first made in 1897 3 but were supplemented by a second series of tests in 
1899. 4 In both series the discharge was measured through the Venturi meter installed 
at the plant. The loss of head was measured by the mercury manometers afterwards 
used by Moritz in the Sunnyside experiments. The relative elevations of the gauges 
were determined by the static head in the piezometers with the valves closed so that 
there was no velocity in the pipe. A constant reduction factor was used in converting 
the mercury column to the equivalent water column. These experiments have been 
criticized for this reason, but the writer is of the opinion that no error of moment was 
thus introduced since, in the tests conducted by him, hydrometer readings were taken 
i E. C. Clarke. Main Drainage Works of the City of Boston, Mass., 2d ed., 1886. 
2 Trans. Amer. Soc. Civ. Engin., 38 (1897), p. 246. 
»Id., 40(1898), p. 471. 
* Id.. 44 (1900), p. 34. 
