Book I. DIRECT CURRENT.

Book II. ALTERNATING CURRENT.

Book III. HIGH-FREQUENCY CURRENT AND WAVE PRODUCTION.

Book IV. THE 1½ KW. SHIP SET.

Book V. THE OSCILLATION VALVE.

The Oscillation Valve: The Elementary Principles of its Application to Wireless Telegraphy.

By R. D. Bangay. 215 pages. Price 5s. (Postage 3d.)

The Thermionic Valve and its Developments in Radio-Telegraphy and Telephony.

By Dr. J. A. Fleming, M.A., D.Sc., F.R.S., M.Inst.E.E., etc. 279 pages. Price 15s. (Postage 6d.)

Alternating Current Work: An Outline for Students of Wireless Telegraphy.