26 BULLETIN 155, U. S. DEPARTMENT OF AGRICULTURE. 
but what has at some time put in more or less of it, and the demand 
for this purpose continues to require a large output from the fac- 
tories. It is also used a great deal in conveying water supplies for © 
manufacturing purposes and fire protection for factories and mills, - 
for railway tanks, for power plants, hydraulic sluicing operations, — 
etc., and during recent years there has been a great deal of it used 
for irrigation purposes, particularly in the Northwestern States. 
‘In the East it is used to some extent for municipal water supplies, 
considerably for various purposes in the mining regions, and for oil 
conduits, insulated wire conduits, steam pipe casing, ete. 
For municipal waterworks the low first cost of machine-banded 
wood pipe as compared with that of cast iron or steel pipe has in 
most instances been the consideration leading to its use, and many 
communities which now have an abundance of water for domestic 
purposes, fire protection, etc., would still be unsupplied had not some 
such cheap type of pipe been available. 
While possessing some advantages other than that of low first 
cost, machine-banded pipe, according to the experience of many 
localities, has been found inferior in many respects to cast iron and 
steel for city mains and connections. The complaint most fre- 
quently expressed with reference to its use for this service relates to 
trouble arising from leaks, which occur mainly at the joints. Such 
leaks may develop as the result of decayed collars, from carelessness 
in putting the pipe together, from increasing the pressure above 
that for which the pipe was designed, or from other causes. While 
in many cases even a considerable leakage may be permissible, in 
others any material loss is highly objectionable. Leaks are particu- 
larly objectionable where pipes. are located in paved streets, and 
owing to the difficulty in avoiding leaks, as well as because its life 
is usually shorter than that of metal, wood pipe is usually replaced 
before paving, and in the larger cities its use for distributing systems 
is now being very generally discontinued. 
For service of a more or less temporary nature, such as hydraulic 
sluicing, dredging, etc., where absolute tightness is not essential, but 
where low cost, ease of transportation, facility of putting together, 
removing, and relaying at small expense are desirable considerations, 
machine-banded wood pipe is peculiarly well adapted. 
The use of machine-banded wood pipe in connection with irriga- 
tion work is confined to the West, particularly the Northwest, where 
hundreds of miles of it have been installed for delivery pipes of 
small pumping plants, for inverted siphons, etc. In a number of 
places the entire water supply is conveyed through such pipes, de- 
livery being made to each unit of area, often as small as 5 acres or 
less. And beyond this, many farmers use wood pipe instead of 
