The
(Santa Barbara) asphaltum, in small pieces, and the coal-tar are heated
to about 400 degrees Fahr. and well stirred. The pipe is thoroughly
dried and immersed in the mixture, where it remains until it acquires
the same temperature as the mixture. When coated it is removed, placed
on a trestle to drip and dry in the sun and air. For convenience of
immersion wrought-iron troughs, some 30 feet long, 3 feet wide, and 2
feet deep, are used. No. 14 iron requires immersion for about 7
minutes, and No. 6 for 12 to 15 minutes.
Filling Pipes.—A
pipe-line being finished, water must be admitted in such a way as to
prevent the air from being sucked in, which will happen (and to a great
extent) unless care is taken. The best plan is to put a gate in the
pipe below the level where the water enters, and thus regulate the
flow, maintaining a steady pressure and avoiding violent oscillations.
The common plan of admitting the water through a pen-stock, which is
kept filled so that the water is quiet, will answer if proper care is
exercised.
STATISTICS OF PIPE-LINES.
La Grange Hydraulic Mining Company.—The
following
are the details of the cost and construction of 1,233-1/2 feet of
22-inch wrought-iron pipe made at the works of the La Grange Hydraulic
Mining Company, Stanislaus County, California.
The iron used was No. 16, U. S. wire gauge, or 0.05
