In this, his experience coincided with
that of the author. Cedar was considered, but could not be obtained in
sufficient lengths or quantity, and long-leaf pine which would have
passed the somewhat rigid specifications would have been difficult to
secure. It is believed, however, that there is a field at least for
long-leaf pine for such construction. Washington fir was found admirable
in every respect, and was moderate in cost at that time.
The bands were bent in the field, and, after heating in an oven for
about 3 min., were dipped in bunches of five into a kettle of melted
mineral rubber at a temperature of about 400 deg. Fahr., and then hung up
for the coating to harden. This took place rapidly, as the work was done
in winter. If the band were wound spirally, the coating would have to be
done in the shop, but field coating is preferable, as it avoids injury
to the coating during transportation.
An advantage of wood pipe for conveying water is its low coefficient of
friction. The results obtained by the author (_n_ = 0.00866 to 0.0092)
appear to be very low as compared with determinations made for
wood-stave pipe. Kutter's coefficient for the latter varies from 0.0096
in the case of the 30-in. pipe at Denver,[B] to from 0.012 to 0.015 as
determined by Messrs.
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