THE FLOW OF WATER IN WOOD-STAVE PIPE. 9 
test is the more remarkable in view of the fact that there are "in 
addition to a succession of sweeping horizontal and vertical curves, 
27 cast-iron bends with a radius of curvature of 5 feet, and with an 
average central angle of about 31°." (See PL XIV, fig. 1.) 
The next test (No. 32), spoken of by F. B. Gutelius, * was conducted 
by D. C. Henny 2 on the Butte, Mont., 24-inch pipe in 1892. In this 
test the value of n was found to be 0.0103. Here again was a value 
so close to 0.010 that it tended to establish the fact that 0.010 was, 
closely, the proper value. After these three tests by three different 
experimenters an extensive series of tests would naturally be required 
to convince the profession that a higher value of n should be used. 
Attention may here be directed to the fact, however, that in the 
three last-mentioned tests but one or two runs of water, with little 
or no variation in velocity, had been observed. 
In 1897 Profs. Marx, Wing, and Hoskins 3 of Leland Stanford 
Junior University, made a careful and vastly more extensive series 
of tests than any previously carried through (No. 47). The values 
of n varied inconsistently between 0.010 and 0.0204. (See Table 2 
column 10.) Of the 22 runs in this series, all but one showed a value 
of n above 0.0123, and most of them showed it above 0.013. 
The experimenters did not publish their results as values of n, 
merely stating: 4 
In regard to trie applicability of Kutter's formula it is to be said that the experiments 
on the wooden pipe herein described give values of n ranging from 0.012 to 0.015, an 
average value being perhaps 0.013. The difference between this value and those given 
for the Denver and Butte city conduits can hardly be attributed to the greater rough- 
ness of the Ogden pipe. It is rather to be supposed that the Kutter formula is defec- 
tive. (See p. 56.) 
In correspondence relating to these tests T. A. Noble offers the 
values of n for the various observations. 5 These have been checked 
by the writer and are found in Table 2, column 10. In the same 
correspondence (p. 544) A. L. Adams offers his tests on the West 
Los Angeles pipe (No. 20) where the values of n range from 0.0105 to 
0.0111. Mr. Adams voices the following warning: 
These values * * * do not indicate 0.01 as being a safe assumed value for n 
as have all previous experiments. 
Various arguments were brought forward to furnish a reason for 
the unprecedentedly high values of n in the Ogden pipe. These 
included the following: That Kutter's formula did not apply to pipes 
as large as 6 feet in diameter; that sediment had deposited in the pipe; 
that the nominal area was not the true area; that a constant reduc- 
tion factor should not be used in computing the equivalent water 
column from the mercury column. 
i Journal Assoc. Engin. Socs., 12 (1893), p. 219. * Id., p. 516. 
* Journal Assoc. Engin. Socs., 21 (1898), p. 250. 6 Id., p. 547. 
* Trans. Amer. Soc. Civ. Engin., 40 (1898), p. 47L 
