Excerpt from International Library of Technology: A Series of Textbooks for Persons Engaged in the Engineering Professions and Trades or for Those Who Desire Information Concerning Them; Fully Illustrated and Containing Numerous Practical Examples and Their Solutions This is the second Of a set of three volumes covering the subject of telegraphy. In it are treated the more complex forms Of telegraphy, such as the duplex, quadruplex, multiplex, printing, submarine, and high-speed systems and the methods of testing circuits. The Operation of many of these systems involves the most ingenious applications of electrical and mag netic laws and; therefore, the utmost care has been taken to make comprehensive the explanations Of the actions Of the devices employed. Circuit diagrams and illustrations of apparatus are freely employed, the former being of especial value as aids to the proper understanding of the operations of the systems as a whole. A very complete treatment is accorded the adjustment of apparatus and the location of troubles both within the Office and on the line. A high order of technical knowledge and skill are required to Operate and to maintain in efiicient condition modern telegraph systems, and there are no textbooks printed better fitted to help the ambitious Operator to advance than those provided in this set of volumes. The method of numbering the pages, cuts, articles, etc. Is such that each subject or part, when the subject is divided into two or more parts, is complete in itself; hence, in order to make the index intelligible, it was necessary to give each subject or part a number. This number is placed at the top of each page, on the headline, Opposite the page number; and to distinguish it from the page number it is preceded by the printer's section mark Consequently, a reference such as 16, page 26, will be readily found by looking along the inside edges of the headlines until 16 is found, and then through 16 until page 26 is found. 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.