Excerpt from Telephony: A Manual of the Design, Constructions, and Operation of Telephone Exchanges, in Six Parts, Part II. Construction of Underground Conduits, With 62 Illustrations The art of Conduit building may be considered to owe its inception and development to the Telephone Exchange, for electric light and power circuits would have encumbered city streets much longer had it not been for the phenomenal increase in overhead wires necessitated by the telephone. When telephonists solved the problem of the underground circuit and buried their lines, other circuits of all descriptions were compelled to follow; and to Telephone Engineers, as conduit builders, the improved appearance of city streets owe a huge debt of gratitude. As with other inventions, the successful conduit has been a struggle for the survival of the fittest. During the past two decades plan after plan for underground circuits has appeared, lived for a time, and died; but gradually, from the ruins of failure, a system of Conduit building has arisen which has successfully withstood the severe test of more than a decade beneath the streets. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.