WILLIAM S. FRANKLIN, M.S., D.Sc.
Professor of Physics, Lehigh University.
Joint Author of "The Elements of Electrical Engineering,"
"The Elements of Alternating Currents."

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LAMAR LYNDON, B.E., M.E.
Consulting Electrical Engineer; Associate Member of American Institute
of Electrical Engineers; Member, American Electro-Chemical Society.
Author of "Storage Battery Engineering."

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ROBERT ANDREWS MILLIKAN, Ph.D.
Professor of Physics, University of Chicago.
Joint Author of "A First Course in Physics," "Electricity, Sound and
Light," etc.

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KEMPSTER B. MILLER, M.E.
Consulting Engineer and Telephone Expert; of the Firm of McMeen and
Miller, Electrical Engineers and Patent Experts, Chicago.
Author of "American Telephone Practice."

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WILLIAM H. PREECE
Chief of the British Postal Telegraph.