some
comprehensive and effective plan to bring back the old-time production
of high-grade wrought iron.

_Wood Staves_.--The staves of this pipe are of Michigan and Canadian
white pine. This pine cannot now be had of clear stuff or in long
lengths in large quantities; otherwise, it is unexcelled. Douglas fir
and yellow pine, coarser and harder woods, have the advantages of clear
lumber and long length. Cypress is not as plentiful, and redwood is
costly. The mill tests did not determine definitely the minimum degree
of seasoning necessary, and press of time compelled the acceptance of
some rather green lumber. Service tests do not show that there is any
abnormal leakage from pipe made of such lumber, and it could not now be
distinguished in the trench by such tests. Undoubtedly, however,
thorough air seasoning should be required.

_Bored Pipe_.--Owing to its small size, a part of the 3-1/2-in. pipe
was bored from the log. This was a mistake, for bored pipe has a rough
interior and a reduced capacity. The inspection and culling are
difficult and unsatisfactory, and imperfections readily apparent in a
stave frequently escape detection in bored pipe.

_Pipe Joints_.--The chamber and tenon of this pipe is an all-wood joint,
4 in. deep. An iron sleeve makes a better and stronger joint. It
compensates for any lack of initial tension in the banding over the
chamber of the wood joint, and secures full advantage of the swelling of
the wood. Cast iron is better than steel; it is more rigid, and its
granulated surface breaks up the smoothness of the wood surface swelling
against it. One objection to the cast-iron sleeve is that of cost, but
it adds 4 in. to the effective length of every section of pipe, as
compared with the wood joints. On the Pacific Coast, a banded wood-stave
sleeve is used with success.

_Coating_.--To preserve the banding from corrosion and the wood from
exterior decay, the pipe is thoroughly enveloped in refined asphalt
having a flow-point adjusted to the prevailing temperature during
shipment and laying. One grade can be used through a considerable range
of temperature. This coating endured a 2,000-mile shipment successfully.
Each piece was carefully inspected along the trench, and any break in
the coating was thoroughly painted with hot asphalt. Enough of the
latter came in barrels, with the pipe, from the factory.

The first 37 miles of this pipe has been in service for two years.
Recent inspections s