oro, neto; Franqueo, 25
cents extra. (Great Britain, 9S.; POSTAGE 6D.)

THE ELEMENTARY PRINCIPLES OF WIRELESS TELEGRAPHY.

By R. D. BANGAY. In two Parts. Price 3S. each. (POSTAGE 4D.) Or in one
Volume, price 7S. net. (POSTAGE 6D.) Used by H.M. Government for
instructional purposes.

PRINCIPIOS ELEMENT ALES DE TELEGRAFIA SIN HILOS.

Por R. D. BANGAY. (Partes 1a y 2a en un Volumen.) PRECIO: Espana, 10
pesetas; Franqueo, 1 peseta extra. America Latina, $2.25, oro, neto;
Franqueo, 25 cents extra. (Great Britain, 9S.; POSTAGE 6D.)

PRINCIPES ELEMENTAIRES DE TELEGRAPHIE SANS FIL.

Par R. D. BANGAY. (Great Britain, 9S.; POSTAGE 6D.)

MAGNETISM AND ELECTRICITY FOR HOME STUDY.

By H. E. PENROSE. Crown 8vo. Over 500 pages. Price 5S. net, (POSTAGE 6D.)
Contains fifty complete lessons.

THE CALCULATION AND MEASUREMENT OF INDUCTANCE AND CAPACITY.

By W. H. NOTTAGE, B.Sc. Invaluable to all engaged in Telegraph Engineering.
Indispensable to the Wireless Engineer, Student and Experimenter. Price 3S.
6D. net. (POSTAGE 5D.)

A SHORT COURSE IN ELEMENTARY MATHEMATICS AND THEIR APPLICATION TO WIRELESS
TELEGRAPHY.

By S. J. WILLIS. To Students in Wireless Telegraphy, as well as those
engaged in the practical application of this Science, this book should
prove of real value. Price 3S. 6D. net. (POSTAGE 6D.)

THE MARCONI OFFICIAL GRAMOPHONE RECORDS.

For self-tuition in receiving Morse Signals. Price 4S. each, double-sided.
(POSTAGE 9D.) Set of Six Records, 24S. post FREE.

THE MAINTENANCE OF WIRELESS TELEGRAPH APPARATUS.

By P. W. HARRIS. An up-to-date Manual, full of practical hints and
explanations. Diagrams of all ship installations, from 1/4 kw. to 5 kw.
Price 2S. 6D. net. (POSTAGE 4D.)

DICTIONARY OF TECHNICAL TERMS USED IN WIRELESS TELEGRAPHY.

By HAROLD WARD. Vest Pocket Edition. 2nd Edition, revised and enlarged.
Contains over 1500 definitions. Price 2S. 6D. net. (POSTAGE 2D.)

ARMATURE MODEL FOR 1-1/2 KW. ROTARY CONVERTER.

Shows every Winding of the Converter Armature from start to finish. Price
1S. net. (POSTAGE 3D.)

MORSE MADE EASY.

By A. L. RYE. Linen backed, for rapidly learning the Morse Code. Price 3D.
net, or post free 3-1/2D.

MORSE CODE CARD.

Contains full alphabet, with punctuation marks, figures, abbreviations and
contractions. Price 2D., post free.

PRACTICAL WIRELESS TELEGRAPHY.

By E. E. BUCHER. 352 pages. 340 Illustrations. Price 12S. 6D. (POSTAGE 6D.)

RADIO-TELEPHONY.

By ALF