ipe diameters, and open stand-pipes limiting the pressure to
130 lb. per sq. in., except on 19 miles of the pump main between Coyote
and Corona where the estimated maximum pressure is 310 lb.

Investigation justified the assumption that wood pipe under a pressure
of 130 lb. would give satisfactory service for 25 years, on which basis
it would be less expensive than cast iron, and therefore it was used.
Cast iron was considered preferable to steel for pressures not exceeding
310 lb. on account of its greater durability.

_Wood Pipe_.--Machine-made, spirally-wound, wood-stave pipe, made in
sections from 8 to 12 ft. long, with the exterior surface covered with a
heavy coat of asphalt, was selected in preference to unprotected,
continuous, stave pipe. The diameters were not so great as to require
the latter.

The first 40 miles of wood pipe was furnished by the Wykoff Wood Pipe
Company, of Elmira, N.Y., and the Michigan Pipe Company, of Bay City,
Mich., delivered the remaining 76 miles.

The pipe is wound with flat steel bands of from 14 to 18 gauge and from
1 to 2 in. wide. The machine winds at any desired pitch and tension. At
each end the spiral wind is doubled two turns, the second lying over the
first and developing a frictional resistance similar to that of a double
hitch of a rope around a post. The ends of the band are held by screw
nails or a forged clip, the latter being the better. It has two or three
spikes on the under side which seat into the stave, and two side lugs on
top which turn down over the band. The latter passes twice over the seat
on the clip, the first turn holding the clip to the stave, while the
second turn is held by the lugs which are hammered down over it. The end
of the band is then turned back over the clip and held down by a staple.

The staves are double-tongued and grooved and from 1-3/8 to 2 in. thick.
The smaller thickness is sufficient. The exterior face of the staves
should be turned concentric with the axis of the pipe and form a circle,
so that the band will have perfect contact with the wood.

The joints are formed by turning a chamber in one end of the pipe and a
tenon on the other, or both ends are turned to a true exterior circle
and driven into a wood or steel sleeve. The chamber and tenon were used
in this work.

Finally, each piece of pipe is covered with as much hot asphalt as it
will carry.

_Steel Bands_.--The specifications required bands of mild steel, of
60,000