WOOD PIPE FOR CONVEYING IRRIGATION WATER. 33 
For replacing 280 feet 40-inch pipe, January, 1911. 
Item. 

Cents 
Cost. | ner foot. 
Hauling staves, 78 ton-miles, $37.30... ... UIE I ESE Ne aga pera in aga em $29. 30 10.4 
Peer UPMURLGAUIM SU O White cone crac Mg ees naa wea lence eeactense vere nene 41.00 14.4 
EEUU GS ieee 6 2 ie tc Soe SRT A eS RD Bs enn ee 81. 90. 29.3 
Se [ATER PUTT C I SB get OSs Ae Te a a a ta UR Sl od io 30. 00 10.7 
MPM IDUOLG ITT DOD erat so: =. isk nas fara = Soc bs g NEE IN Gf IOUAUN. Folie ren caps PAC SE TRY 9.00 3.3 
Lego, Gers del, Eh CAS aoe leer: leg I cia alent heh yell ee aan ieee RL Caled pal 187. 60 67.0 
TDI re ny 0 Soe SBE Cat CRS EATS Ema eta lr A a BR a 378. 80 135.1 
DURABILITY OF WOOD PIPE AND FACTORS AFFECTING IT. 
“ How long will it last?” is a question asked perhaps oftener than 
any other in the discussion of wood pipe. It was the common ques- 
tion during the early years of its manufacture, and it is common 
to-day after the experience of more than 30 years of extensive use. 
The failure of wood pipe is in general due either to decay of the 
wood or corrosion of the bands, though wearing out of the wood is 
also under certain conditions a matter upon which the life of a pipe 
may depend. The range of variability with reference to these points 
in the life of the pipes that have been built has been such as to demon- 
strate conclusively that how long any pipe will last can not be accu- 
rately predicted without a thorough knowledge of all the conditions 
involved. 
Sufficient time has not yet elapsed to show the life of some of the 
earliest continuous stave pipes that were built, while others have 
endured but from 5 to 12 years. In support of the foregoing state- 
ment specific data bearing upon the durability of a number of pipe 
lines, several of which were inspected by the writer, are given in the 
following pages. 
In writing of the first continuous stave pipe built in the West, at 
Denver, in 1884, S. Fortier states '— 
The pipe was laid in a portion of its length about 15 inches above the 
hydraulic gradient. Native pine, whose durability under unfavorable condi- 
tions is from three to five years, composed the staves, and in. the portion of 
the line referred to the pipe was never more than two-thirds full of water. 
The top staves decayed rapidly. In the fall of the year (1889) the Denver 
Water Co. had bands loosened and the staves from the upper are removed 
without shutting off the water. It was then found that the lumber was per- 
fectly sound up to the surface of the water in the pipe, and in the next stave 
above on either side, whereas the remaining staves which the water could 
not reach by capillary attraction or otherwise were rotten. 
A part of this line, lying close to the river, under conditions where 
both exterior and interior are kept wet, was said to be still in use 
in 1912. 

1Ann, Amer. Soc. Irrig. Engin., 1892-93, p. 11. 
