Cyclopedia of Telephony and Telegraphy, Vol. 2 / A General Reference Work on Telephony, etc. etc.

by American School of Correspondence

SILVANUS P. THOMPSON, D.Sc., B.A., F.R.S., F.R.A.S.

Principal and Professor of Physics in the City and Guilds of London Technical College.
Author of "Electricity and Magnetism," "Dynamo-Electric Machinery," "Polyphase Electric Currents and Alternate-Current Motors," "The Electromagnet," etc.

ANDREW GRAY, M.A., F.R.S.E.

Author of "Absolute Measurements in Electricity and Magnetism."

ALBERT CUSHING CREHORE, A.B., Ph.D.

Electrical Engineer; Assistant Professor of Physics, Dartmouth College; Formerly Instructor in Physics, Cornell University.
Author of "Synchronous and Other Multiple Telegraphs;" Joint Author of "Alternating Currents."

J. J. THOMSON, D.Sc., LL.D., Ph.D., F.R.S.