A Short Wave Regenerative Receiver, with One Variometer and Three Variable Condensers--The Variocoupler--The Variometer--Connecting Up the Parts--Short Wave Regenerative Receiver with Two Variometers and Two Variable Condensers--The Parts and How to Connect Them Up.

[XII. INTERMEDIATE AND LONG WAVE REGENERATIVE RECEIVING SETS]

Intermediate Wave Receiving Sets--Intermediate Wave Set With Loading Coils--The Parts and How to Connect Them Up--An Intermediate Wave Set with Variocoupler Inductance Coils--The Parts and How to Connect Them Up--A Long Wave Receiving Set--The Parts and How to Connect Them Up.

[XIII. HETERODYNE OR BEAT LONG WAVE TELEGRAPH RECEIVING SET]

What the Heterodyne or Beat Method Is--The Autodyne or Self-heterodyne Long Wave Receiving Set--The Parts and Connections of an Autodyne or Self-heterodyne, Receiving Set--The Separate Heterodyne Long Wave Receiving Set--The Parts and Connections of a Separate Heterodyne Long Wave Receiving Set.

[XIV. HEADPHONES AND LOUD SPEAKERS]

Wireless Headphones--How a Bell Telephone Receiver is Made--How a Wireless Headphone is Made--About Resistance, Turns of Wire and Sensitivity of Headphones--The Impedance of Headphones--How the Headphones Work--About Loud Speakers--The Simplest Type of Loud Speaker--Another Simple Kind of Loud Speaker--A Third Kind of Simple Loud Speaker--A Super Loud Speaker.

[XV. OPERATION OF VACUUM TUBE RECEPTORS]

What is Meant by Ionization--How Electrons are Separated from Atoms--Action of the Two Electrode Vacuum Tube--How the Two Electrode Tube Acts as a Detector--How the Three Electrode Tube Acts as a Detector--How the Vacuum Tube Acts as an Amplifier--The Operation of a Simple Vacuum Tube Receiving Set--Operation of a Regenerative Vacuum Tube Receiving Set--Operation of Autodyne and Heterodyne Receiving Sets--The Autodyne, or Self-Heterodyne Receiving Set--The Separate Heterodyne Receiving Set.

[XVI. CONTINUOUS WAVE TELEGRAPH TRANSMITTING SETS WITH DIRECT CURRENT]