"Alternating Currents."

* * * * *

DUGALD C. JACKSON, C.E.
Head of Department of Electrical Engineering, Massachusetts Institute of
Technology; Member, American Institute of Electrical Engineers, etc.
Author of "A Textbook on Electromagnetism and the Construction of Dynamos;"
Joint Author of "Alternating Currents and Alternating-Current Machinery."

* * * * *

MICHAEL IDVORSKY PUPIN, A.B., Sc.D., Ph.D.
Professor of Electro-Mechanics, Columbia University, New York.
Author of "Propagation of Long Electric Waves," and "Wave-Transmission
over Non-Uniform Cables and Long-Distance Air Lines."

* * * * *

FRANK BALDWIN JEWETT, A.B., Ph.D.
Transmission and Protection Engineer, with American Telephone &
Telegraph Co.
Author of "Modern Telephone Cable," "Effect of Pressure on Insulation
Resistance."

* * * * *

ARTHUR CROTCH
Formerly Lecturer on Telegraphy and Telephony at the Municipal Technical
Schools, Norwich, Eng.
Author of "Telegraphy and Telephony."

* * * * *

JAMES ERSKINE-MURRAY, D.Sc.
Fellow of the Royal Society of Edinburgh; Member of the Institution of
Electrical Engineers.
Author of "A Handbook of Wireless Telegraphy."

* * * * *

A.H. MCMILLAN, A.B., LL.B.
Author of "Telephone Law, A Manual on the Organization and Operation of
Telephone Companies."

* * * * *

WILLIAM ESTY, S.B., M.A.
Head of Department of Electrical Engineering, Lehigh University.
Joint Author of "The Elements of Electrical Engineering."

* * * * *

GEORGE W. WILDER, Ph.D.
Formerly Professor of Telephone Engineering, Armour Institute of
Technology.
Author of "Telephone Principles and Practice," "Simultaneous Telegraphy
and Telephony," etc.

* * * * *

WILLIAM L. HOOPER, Ph.D.
Head of Department of Electrical Engineering, Tufts College.
Joint Author of "Electrical Problems for Engineering Students."

* * * * *

DAVID S. HULFISH
Technical Editor, _The Nickelodeon_; Telephone and Motion-Picture Expert;
Solicitor of Patents.
Author of "How to Read Telephone Circuit Diagrams."

* * * * *

J.A. FLEMING, M.A., D.Sc. (Lond.), F.R.S.
Professor of Electrical Engineering in Universit