Chapter V.—ARRANGEMENT AND OPERATION OF THE APPARATUS. Aerial Switches.

The Buzzer Test. Using More Than One Detector. Shunting the Detector. Complete Outfits. Portable Sets. The Operation of the Station, Etc.

*LESSONS IN WIRELESS TELEGRAPHY*

FOURTH EDITION

72 Pages 66 Illustrations

A systematic course in the elementary principles. Written so you can understand it. In 35 lessons.

1.—Magnetism. 2.—Magnetic Induction. 3.—Primary and Secondary Cells. 4.—Electric Currents. 5.—Electromagnetism. 6.—Dynamo-Electric Machinery. 7.—The Induction Coil. 8.—The Transformer. 9.—Leyden Jars and Condensers. 10.—Electromagnetic Theory. 11.—Electric Waves. 12.—Principles of Wave Telegraphy. 13.—The Aerial. 14.—The Wireless Coil. 15.—The High Potential Transformer. 16.—The Oscillation Condenser. 17.—The Helix. 18.—Spark Gaps. 19.—The Key. 20.—Aerial Switches. 21.—Anchor Gaps. 22.—Detectors. 23.—Tuning Coils. 24.—Loose Couplers. 25.—Fixed Condensers. 26.—Variable Condensers. 27.—Telephone Receivers. 28.—Hot Wire Ammeter. 29.—Potentiometer. 30.—Dead End Losses and Switches. 31.—Distributed Capacity. 32.—Poulsen Arc. 33.—Receiving Undamped Waves. 34.—The Audion Amplifier. 35.—Hook-Ups.

*Price, 25 Cents, Postpaid*

If you want to understand your apparatus and how it works, you will need this book—over 15,000 copies in use.

*Price, 25 Cents, Postpaid*

*Model Flying Machines*

*HOW TO BUILD AND FLY THEM*

Will prove interesting and valuable.

Have you ever built and flown a Model Racer?

If not, you have missed something.

Price, 25 Cents, Postpaid.

Model Aeroplaning is one of the most fascinating and instructive of sports.

Thousands of young men and boys have formed Model Aero Clubs and organized Flying Contests throughout the country.

"MODEL FLYING MACHINES" of the _Arts and Sciences_ series is the only book giving reliable data and instructions for the construction of practical Model Aeroplanes.

IF YOU ARE A BEGINNER, this is the book that you ought to have. It will start you right. It tells how to build seven different types of machines, starting with the simplest Monoplane and finishing with several Long Distance Racing Models.

IF YOU ARE INTERESTED IN MODEL AEROPLANING, this book will prove the one you have been looking for. Gives valuable "Kinks". Tells how to carve propellers, make winders, adjust and fly machines, etc. Fully illustrated with large size, detailed working drawings, showing the exact size of each part. Twelve full-page plates.

Printed on first-class paper. Heavy cover in three colors.

Sent postpaid by return mail upon receipt of 25 cents.

*EVERY MODEL AVIATOR OUGHT TO HAVE A COPY*

*Wireless Construction and Installation for Beginners*

SEVENTY-THREE PAGES SIXTY-SEVEN ILLUSTRATIONS.

(Second Edition.)

A Practical Handbook giving detailed instructions for the Construction and Operation of a Boy’s Wireless Outfit.

*Only 25c. Prepaid*

An indispensible book for the young wireless experimenter. It not alone shows how to build the various instruments but describes their actual workings and tells how to operate them.

*EVERY BOY IS ADVISED TO*

*SEND FOR A COPY*

Written in a very clear and simple style, the book is invaluable to a beginner. He will be able with its aid to construct simple apparatus of the latest and approved type. The instruments described in the book have been the subject of considerable experimental work and special study. They are modeled along simple lines so that they will be easy and inexpensive to construct, but at the same time combine features which make them very sensitive and capable of receiving or transmitting messages greater distances than some more complicated apparatus.

*THIS BOOK, CONSIDERING ITS WORTH, IS A GIFT AT 25c.*

There are no old or obsolete forms of wireless apparatus discussed, but only the latest types of tuning coils, receiving transformers, fixed condensers, keys, spark coils, detectors, etc. The book is illustrated by numerous detailed working drawings giving all dimensions. Several full-page views of the apparatus enable the beginner to fully comprehend the text.

*THE MOST THOROUGH AND COMPLETE ELEMENTARY WIRELESS*

*CONSTRUCTION BOOK PUBLISHED*

The pages on the construction and installation of aerials will be found to be of considerable help to the experimenter, for it is here that the most trouble is experienced by the beginner. The practical and helpful information on this subject is alone worth several times the cost of the book.

*PARTIAL CONTENTS*