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.

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HENRY SMITH CARHART, A.M., LL.D.
Professor of Physics and Director of the Physical Laboratory,
University of Michigan.
Author of "Primary Batteries," "Elements of Physics," "University
Physics," "Electrical Measurements," "High School Physics," etc.

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FRANCIS B. CROCKER, M.E., Ph.D.
Head of Department of Electrical Engineering, Columbia University,
New York; Past-President, American Institute of Electrical Engineers.
Author of "Electric Lighting;" Joint Author of "Management of
Electrical Machinery."

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HORATIO A. FOSTER
Consulting Engineer; Member of American Institute of Electrical
Engineers; Member of American Society of Mechanical Engineers.
Author of "Electrical Engineer's Pocket-Book."

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