Chapter I: Preface: To the Second Edition

The great favor with which the first edition of this little work has been received and the steadily growing interest in its subject, together with many valuable improvements and researches, may be given as the reasons for this new edition.

The book has been thoroughly revised, partly rewritten, and considerable new matter, with twenty-six new illustrations, added. It has been brought up to date as far as electrical science has gone.

To detail all that has been done is too great a task for a preface; we may briefly mention the following new matter:

Coils for gas and automobile engines; medical coils, concise directions for operation and repairs; new forms of contact breakers, including electrolytic and mechanical; gas-lighting apparatus; primary and secondary batteries.

The chapter on X-Ray Apparatus has been entirely rewritten, and is thoroughly practical; and an entire chapter on Wireless Telegraphy has been added. In a book of this size it is not feasible to give specific directions and full dimensions for the manufacture of all the apparatus described. Indeed, much of the latter must be adapted to the particular purpose for which it is to be utilized. Again, the same amount of material will not always produce the same results. A little closer winding, greater pressure applied to the cooling wax of a condenser, and the output or capacity of either is changed.

Matters purely of design or taste are to be governed by the creative faculty of the worker; but such general details and rules are given as will be sufficient to enable one possessing ordinary constructive ability to make his own apparatus.

The whole process of coil-making does not require high mechanical skill, but chiefly patience and attention to details; and, perhaps best of all, but few tools are needed, all of a simple kind.

We beg to acknowledge courtesies received from Messrs. Queen & Co., the _Scientific American_ for frontispiece and Fig. 13, Mr. Goldingham's book on Oil Engines for Fig. 12, and others who have been of assistance to the author. The best American and English practice has been adopted; the American standard gauges and sizes of wires are used, except where noted.

A list of works, particularly of value to the coil worker, will be found following the index.

H. S. NORRIE
(Norman H. Schneider.)

APRIL, 1901.

CONTENTS.

CHAPTER I.

COIL CONSTRUCTION.

Construction of Ruhmkorff Coils. Sizes of
Wires. Winding of Primary and Secondary.
Assembling. Connecting Up.
Insulation. Coils in Series. Oil Immersed
Coils. "Tesla" Coil. Disruptive
"Tesla" Coil. Coils for Gas
Engines. Spark Coils. Resistance
Coils. General Remarks on Coils. The
Testing of a Coil for Polarity. Failure
to Work. Medical Coils. Medical Coil
with Tube Regulation. Medical Coil
with Interchangeable Secondaries. Bath
Coils 1-64

CHAPTER II.

CONTACT BREAKERS.

Construction of Contact Breakers. Various
Forms of Simple Contact Breakers.
The Mercury Vibrator. Polechanging
Vibrator. Wehnelt Interrupter. Dessauer
Contact Breaker. Steel Ribbon
Interrupter. Contact Breakers in
Vacuo. Queen Contact Breaker. Adjustable
Contact Breaker for Medical
Coils. The Queen Contact Breaker for
Large Coils, Adjustable Cone Vibrator.
Contacts 65-91

CHAPTER III.

INSULATIONS AND CEMENTS.

Selection of Insulating Materials. Mineral
Oil. Paraffin Wax. Resin Oils. Beeswax.
Shellac Varnishes. Silk. Insulating
Compounds 92-98

CHAPTER IV.

CONDENSERS.

Construction of Condensers. Leyden Jar.
Glass Plate Condenser. Paper Condensers.
Series Condenser. Rolled-Up
Condensers. Adjustable Condensers.
Application of Condensers 99-119

CHAPTER V.

EXPERIMENTS.

Luminous Effects Obtained by Means of a
Ruhmkorff Coil. Materials Used.
Spark Experiments. The Luminous
Pane. Luminous Designs, etc. 120-130

CHAPTER VI.

SPECTRUM ANALYSIS.

Color Produced by Burning Different
Metals. The Spectroscope Shown in
Connection with the Coil. The Screen.
The Color Spaces in the Solar Spectrum.
Color Values 131-139

CHAPTER VII.

CURRENTS IN VACUO.

Different Forms of Mercury Air Pumps.
Geissler Tubes. Discharges in Vacuo.
Characteristic Colors of Different Gases
in Tubes, etc. 140-152

CHAPTER VIII.

ROTATING EFFECTS.

Effects of Discharges in Rotating Tubes.
Construction of Rotating Wheels. Arrangement
of Tubes, etc. 153-163

CHAPTER IX.

GAS LIGHTING.

The Application of the Ruhmkorff Coil for
Lighting Gas. Gas Lighting in Series.
Gas Lighting in Multiple. Gas Lighting
Diagram. Jump Spark Burner.
Automatic Burners 164-177

CHAPTER X.

BATTERIES FOR COILS.

The Selection of Suitable Batteries. Open
Circuit Cells. Closed Circuit Cells.
Description of Cells. Formulæ for Solutions
for Different Kinds of Batteries.
The Grenet Battery. Fuller Battery.
Gravity Battery. Dun Cell. Gethins
Cell. Gordon Battery. New Standard.
Edison-Lalande Cell. Dry Batteries.
Dry Cell Construction, etc. 178-199

CHAPTER XI.

STORAGE OR SECONDARY CELL.

Construction of a Storage Cell. Connecting
Up Cells. Charging Storage Batteries.
Diagram for Charging from Dynamo
Using a Rheostat. Diagram for Charging,
using Lamp instead of Rheostat.
Charging from. Primary Batteries.
Testing Solutions. Setting Up the
Storage Cell. The Harrison Cell. The
"U. S." Storage Cell, etc. 200-223

CHAPTER XII.

TESLA AND HERTZ EFFECTS.

Currents of High Frequency. Electric Resonator.
The "Tesla" Effects. Coil
Connected to Discharger. High Frequency
Currents in Electro-Therapeutics,
etc. 224-234

CHAPTER XIII.

THE "ROENTGEN" RAYS AND RADIOGRAPHY.

General Arrangement of Connections for
Coil and Crookes Tube for Making X Ray
Negatives. The Fluoroscope. Phosphorus
Tube. The Queen Self-Adjusting
Crookes Tube. General Remarks,
etc. 235-247