HARRIS C. TROW, S.B., Managing Editor
Editor-in-Chief, Textbook Department, American School of Correspondence
Authorities Consulted
The editors have freely consulted the standard technical literature of America and Europe in the preparation of these volumes. They desire to express their indebtedness particularly to the following eminent authorities, whose well-known works should be in the library of every telephone and telegraph engineer.
Grateful acknowledgment is here made also for the invaluable co-operation of the foremost engineering firms and manufacturers in making these volumes thoroughly representative of the very best and latest practice in the transmission of intelligence, also for the valuable drawings, data, suggestions, criticisms, and other courtesies.
ARTHUR E. KENNELY, D.Sc.
Professor of Electrical Engineering, Harvard University.
Joint Author of "The Electric Telephone," "The Electric Telegraph," "Alternating Currents," "Arc Lighting," "Electric Heating," "Electric Motors," "Electric Railways," "Incandescent Lighting," etc.