THOMAS A. EDISON
Pioneer Electrical Investigator and Inventor of Numerous Telegraph, Telephone,Lighting, and Other Electrical Devices.
Cyclopedia
of
Telephony and Telegraphy
A General Reference Work on
TELEPHONY, SUBSTATIONS, PARTY LINE SYSTEMS, PROTECTION, MANUAL
SWITCHBOARDS, AUTOMATIC SYSTEMS, POWER PLANTS, SPECIAL
SERVICE FEATURES, CONSTRUCTION, ENGINEERING,
OPERATION, MAINTENANCE, TELEGRAPHY, WIRELESS
TELEGRAPHY AND TELEPHONY, ETC.
Prepared by a Corps of
TELEPHONE AND TELEGRAPH EXPERTS, AND ELECTRICAL ENGINEERS OF
THE HIGHEST PROFESSIONAL STANDING
Illustrated with over Two Thousand Engravings
F O U R V O L U M E S
CHICAGO
AMERICAN SCHOOL OF CORRESPONDENCE
1919
COPYRIGHT, 1911, 1912,
BY
AMERICAN SCHOOL OF CORRESPONDENCE
COPYRIGHT, 1911, 1912
BY
AMERICAN TECHNICAL SOCIETY
Entered at Stationers' Hall, London
All Rights Reserved
Authors and Collaborators
KEMPSTER B. MILLER, M.E.
Consulting Engineer and Telephone Expert
Of the Firm of McMeen and Miller, Electrical Engineers and Patent Experts, Chicago
American Institute of Electrical Engineers
Western Society of Engineers
GEORGE W. PATTERSON, S.B., Ph.D.
Head, Department of Electrical Engineering, University of Michigan
CHARLES THOM
Chief of Quadruplex Department, Western Union Main Office,New York City
ROBERT ANDREWS MILLIKAN, Ph.D.
Associate Professor of Physics, University of Chicago
Member, Executive Council, American Physical Society
SAMUEL G. McMEEN
Consulting Engineer and Telephone Expert
Of the Firm of McMeen and Miller, Electrical Engineers and PatentExperts, Chicago
American Institute of Electrical Engineers
Western Society of Engineers
LAWRENCE K. SAGER, S.B., M.P.L.
Patent Attorney and Electrical Expert
Formerly Assistant Examiner, U.S. Patent Office
GLENN M. HOBBS, Ph.D.
Secretary, Am