WOOD PIPES. Bored logs were used at Bos ton, in the first public water-supply system in the United States, in 1652, and at Bethlehem. l'a.. in the pumping system of water-works built from 1754 to 1761. :Most, if not all, these primi tive wood pipes were simply logs with holes bored in their centres, and one end of each log tapered off to fit into the bore hole of the next log. similar pipes are still used, but principally in the rural districts, Improvements have re sulted in a style of pipe with a smooth circular interior and exterior, an asphalt-coated iron or steel band wound tightly around the pipe to give it strength, and a coating of asphalt over both the bands and wood for preserving the ex terior from alternate drying and wetting. The joints are made by boring out one end of each pipe to a larger diameter than the other, and turning down the other end to a like exterior diameter, then inserting the small end of one pipe in the large end of the next: or both ends of the pipe may be bored, as described. and the space thus formed may be filled by inserting a short length of pipe just thick enough so its inner side will be flush with the inside of the main pipe.
To avoid the limitations in size incident to bored logs, and to secure still greater facility in transportation and construction, particularly in rough country, pipes built up in place from wood staves are now used. in its present form wood stave pipe is composed of staves cut internally and on the edges (or radially) to form a conduit of the desired diameter. By breaking joints a continuous pipe is secured. The staves are held together and strength to resist any desired moderate pressure is secured by the use of steel band: or rods, provided with screw ends and nuts for tightening.
Since about 1S95 smaller sizes of stave pipe, for which the construction just described is not suitable, have been made by winding them spirally with steel rods under tension by means of a machine: a little later small, wire-wound stave pipe was put on the market.