The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 416
Fi~. 385.—Scale … Fig. 386.—Manhole under Footpath * In the latest practice the bottom end only of the pipe is stoppedup with three inches of concrete. 388 PRACTICAL TELEPHONE HANDBOOK thick for the small, and 14 inches thick for the large man-holes under roadways, as shown in Figs. 387 and 388. The roof is…
Telephone
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