The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 418
s jarrah wood) or with othermaterial to conform, with the general construction. Obstructions.—In laying the pipes and making the man-holes obstructions are frequently met with, owing to the exist-ence of gas, water, and other mains, and much engineeringskill has to be exercised in order to avoid… … Fig. 388.—Plan of Manhole under Roadway (Scale ^-~) so as to avoid obstructions in the shape of gas, water, andhydraulic mains. Concrete-Moulded Manholes.—The standard practice inAmerica is to make the manholes of concrete moulded in posi-tion by the help of temporary wooden templates or moulds.The…
Telephone
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