THE FLOW OF WATER IN - WOOD-STAVE PIPE. 13 
conducted on these units that it appears best to construct separate 
formulas with terms in both inches and feet. 
Also in the same discussion 1 J. S. Moore, who aided in the experi- 
ments and computation of the Moritz data, offers tests on 48| and 
31-inch pipes (Nos. 43 and 36). The 48|-inch pipe appears to have 
been very smooth and the tests confirm the Moritz formulas. How- 
ever, it must be borne in mind that this pipe is part of the same 
siphon and subject to the same conditions as those affecting the 551- 
inch pipe which contributed so largely to the data from which the 
Moritz formulas were derived. Advocating the use of all previous 
data accepted as criteria, Moore suggests the intercept line for the 
exponential formula as shown by the dash line in figure 4. This 
line approaches the position of the intercept line for the new formula 
which considers all reliable data. 
RECAPITULATION. 
The above outline indicates that 25 years ago Kutter's formula, 
with a value of n of 0.010, was accepted as accurate in the design of 
wood pipes. As tests were made on larger sizes of pipe, higher values 
of n were found. These results were not accepted unreservedly, 
however; rather were the experiments discredited by some designers 
on the grounds that conditions in the pipes were not properly ascer- 
tained or that methods of making observations were erroneous. 
The experimenters themselves suggest that perhaps a constant value 
of n should not be used; that is, that Kutter's formula does not 
apply if a constant value of n is to be taken. The data were too 
meager to develop the variation in n with the diverse elements. 
As data accumulated authorities suggested interpreting results 
by exponential formulas; but not being well known this method was 
not extensively accepted until used by Moritz in interpreting his own 
results. He attempted to compare his formulas with the results of 
other experimenters but found this "a difficult and discouraging 
problem. " This was true because all previous data on large pipes 
showed a much smaller relative capacity than the one pipe contribut- 
ing so largely to his formulas. Though but tentatively offered by 
Moritz, his formulas appeared to be the best available and have been 
extensively accepted, in spite of the fact that Moore, who was per- 
fectly familiar with the Moritz tests, suggests a formula that more 
nearly fits all previous observations. 
In the following pages of this publication, particularly beginning on 
page 28, the writer will endeavor to show analytically the following: 
1. That an exponential formula most nearly applies to the flow of 
water in wood-stave pipes. 
i Trans. Amer. Soe. Civ. Engin., 74 (1911), p. 463. 
