[p. i]

CONTENTS

Introductory[Page 1]
I.Electricity Considered. Brief Historical Events[Page 5]

The Study of Electricity. First Historical Accounts. BottlingElectricity. Discovery of Galvanic Electricity. Electro-motive Force.Measuring Instruments. Rapidity of Modern Progress. How to Acquire theVast Knowledge. The Means Employed.

II.What Tools and Apparatus are Needed[Page 11]

Preparing the Workshop. Uses of Our Workshop. Whatto Build. What to Learn. Uses of the Electrical Devices.Tools. Magnet-winding Reel.

III. Magnets, Coils, Armatures, Etc. [Page 18]

The Two Kinds of Magnets. Permanent Magnets. Electro-Magnets.Magnetism. Materials for Magnets. Non-magneticMaterial. Action of a Second Magnet. WhatNorth and South Pole Mean. Repulsion and Attraction.Positives and Negatives. Magnetic Lines of Force.The Earth as a Magnet. Why the Compass Points Northand South. Peculiarity of a Magnet. Action of theElectro-Magnet. Exterior Magnetic Influence Around aWires Carrying a Current. Parallel Wires.

IV. Frictional, Voltaic or Galvanic and Electro-magnetic Electricity [Page 29]

Three Electrical Sources. Frictional Electricity. Leyden[p. ii]Jar. Voltaic or Galvanic Electricity. Voltaic Pile;How Made. Plus and Minus Signs. The CommonPrimary Cell. Battery Resistance. Electrolyte andCurrent. Electro-magnetic Electricity. Magnetic Radiation.Different Kinds of Dynamos. Direct CurrentDynamos. Simple Magnet Construction. How to Wind.The Dynamo Fields. The Armature. Armature Windings.Mounting the Armature. The Commutator. CommutatorBrushes. Dynamo Windings. The Field.Series-wound Field. Shunt-wound. Compound-wound.

V. How to Detect and Measure Electricity [Page 49]

Measuring Instruments. The Detector. Direction ofCurrent. Simple Current Detector. How to Place theDetector. Different Ways to Measure a Current. TheSulphuric Acid Voltameter. The Copper Voltameter.The Galvanoscope Electro-magnetic Method. The Calorimeter.The Light Method. The Preferred Method.How to Make a Sulphuric Acid Voltameter. How toMake a Copper Voltameter. Objections to the Calorimeter.

VI. Volts, Amperes, Ohms and Watts [Page 60]

Understanding Terms. Intensity and Quantity. Voltage.Amperage Meaning of Watts and Kilowatt. AStandard of Measurement. The Ampere Standard. TheVoltage Standard. The Ohm. Calculating the Voltage.

VII. Push Buttons, Switches, Annunciators, Bells and Like Apparatus [Page 65]

Simple Switches. A Two-Pole Switch. Double-PoleSwitch. Sliding Switch. Reversing Switch. Push Buttons.[p. iii]Electric Bells. How Made. How Operated. Annunciators.Burglar Alarm. Wire Circuiting. CircuitingSystem with Two Bells and Push Buttons. ThePush Buttons, Annunciators and Bells. Wiring Up aHouse.

VIII. Accumulators, Storage or Secondary Batteries [Page 82]

Storing Up Electricity. The Accumulator. AccumulatorPlates. The Grid. The Negative Pole. Connecting Upthe Plates. Charging the Cells. The Initial Charge.The Charging Current.

IX. The Telegraph [Page 90]

Mechanism in Telegraph Circuit. The Sending Key. TheSounder. Connecting Up the Key and Sounder. TwoStations in Circuit. The Double Click. Illustratingthe Dot and the Dash. The Morse Telegraph Code. Examplein Use.

X. High-tension Apparatus, Condensers, Etc. [Page 98]

Induction. Low and High Tension. Elastic Property ofElectricity. The Condenser. Connecting up a Condenser.The Interrupter. Uses of High-tension Coils.

XI. Wireless Telegraphy [Page 104]

Telegraphing Without Wires. Surging Character ofHigh-tension Currents. The Coherer. How Made. TheDecoherer. The Sending Apparatus. The ReceivingApparatus. How the Circuits are Formed.

XII. The Telephone [Page 110]

Vibrations. The Acoustic Telephone. Sound Waves.[p. iv]Hearing Electricity. The Diaphragm in a MagneticField. A Simple Telephone Circuit. How to Make aTelephone. Telephone Connections. Complete Installation.The Microphone. Light Contact Points. How toMake a Microphone. Microphone, the Father of theTransmitter. Automatic Cut-outs for Telephones. CompleteCircuiting with Transmitters.

XIII. Electrolysis, Water Purification, Electroplating [Page 123]

Decomposing Liquids. Making Hydrogen and Oxygen.Purifying Water. Rust. Oxygen as a Purifier. Compositionof Water. Common Air Not a Good Purifier.Pure Oxygen a Water Purifier. The Use of Hydrogenin Purification. Aluminum Electrodes. ElectricHand Purifier. Purification and Separation of Metals.Electroplating. Plating Iron with Copper. Direction ofCurrent.

XIV. Electric Heating. Thermo-Electricity [Page 135]

Generating Heat in a Wire. Resistance of Substances.Signs of Connectors. Comparison of Metals. A SimpleElectric Heater. How to Arrange for Quantity of CurrentUsed. An Electric Iron. Thermo-Electricity ConvertingHeat Directly into Electricity Metals. Electric,Positive, Negative. Thermo-electric Coupler.

XV. Alternating Currents, Choking Coil, Transformer [Page 145]

Direct Current. Alternating Current. The MagneticField. Action of a Magnetized Wire. The Movement ofa Current in a Charged Wire. Current Reversing Itself.Self-Induction. Brushes in a Direct Current Dynamo:[p. v]Alternating, Positive and Negative Poles. How an AlternatingCurrent Dynamo is Made. The Windings.The Armature Wires. Choking Coils. The Transformer.How the Voltage is Determined. Voltage and Amperagein Transformers.

XVI. Electric Lighting [Page 161]

Early conditions. Fuels. Reversibility of Dynamo.Electric arc. Mechanism to maintain the arc. Resistancecoil. Parallel carbons for making arc. Seriescurrent. Incandescent system. Multiple circuit. Subdivisionof electric light. The filament. The glassbulb. Metallic filaments. Vapor lamps. Directionsfor improvements. Heat in electric lighting. Curioussuperstitions concerning electricity. Magnetism. Amber.Discovery of the properties of a magnet. Electricityin mountain regions. Early beliefs as to magnetismand electricity. The lightning rod. Protestsagainst using it. Pliny's explanation of electricity.

XVII. Power, and Various Other Electrical Manifestations [Page 175]

Early beliefs concerning the dynamo. Experimentswith magnets. Physical action of dynamo and motor.Electrical influence in windings. Comparing motorand dynamo. How the current acts in a dynamo. Itsforce in a motor. Loss in power transmission. Thefour ways in which power is dissipated. Disadvantagesof electric power. Its advantages. Transmission ofenergy. High voltages. The transformer. Step-downtransformers. Electric furnaces. Welding by electricity.Merging the particles of the joined ends.

XVIII. X-Ray, Radium and the Like [Page 184][p. vi]

The camera and the eye. Actinic rays. Hertzianwaves. High-tension apparatus. Vacuum tubes. Characterof the ultra-violet rays. How distinguished.The infra-red rays. Their uses. X-rays not capableof reflection. Not subject to refraction. Transmissionthrough opaque substances. Reducing rates of vibration.Radium. Radio-activity. Radio-active materials.Pitchblende. A new form of energy. Electrical source.Healing power. Problems for scientists.

Glossary of Words Used in the Text [Page 189]
Index [Page 207]

[p. vii]

LIST OF ILLUSTRATIONS

1. Work bench[Frontispiece]
PAGE
2.Top of magnet-winding reel[14]
3.Side of magnet-winding reel[14]
4.Journal block[15]
5.Plain magnet bar[19]
6.Severed magnet[20]
7.Reversed magnets[21]
8.Horseshoe magnet[22]
9.Earth's magnetic lines[23]
10.Two permanent magnets[24]
11.Magnets in earth's magnetic field[24]
12.Armatures for magnets[25]
13.Magnetized field[26]
14.Magnetized bar[26]
15.Direction of current[27]
16.Direction of induction current[28]
17.Frictional-electricity machine[30]
18.Leyden jar[32]
19.Galvanic electricity. Crown of cups[33]
20.Voltaic electricity[34]
21.Primary battery[36]
22.Dynamo field and pole piece[39]
23.Base and fields assembled[41]
24.Details of the armature, core[42]
25.Details of the armature, body[42]
26.Armature Journals[43] [p. viii]
27.Commutator[43]
28.End view of armature, mounted[44]
29.Top view of armature on base[45]
30.Field winding[47]
31.Series-wound[47]
32.Shunt-wound[48]
33.Compound-wound[48]
34.Compass magnet, swing to the right[50]
35.Magnetic compass[50]
36.Magnet, swing to the left[50]
37.Indicating direction of current[51]
38.The bridge of the detector[52]
39.Details of detector[53]
40.Cross-section of detector[54]
41.Acid voltameter[56]
42.Copper voltameter[56]
43.Two-pole switch[66]
44.Double-pole switch[66]
45.Sliding switch[67]
46.Rheostat form of switch[68]
47.Reversing switch[69]
48.Push button[70]
49.Electric bell[71]
50.Armature of electric bell[72]
51.Vertical section of annunciator[72]
52.Front view of annunciator[72]
53.Horizontal section of annunciator[72]
54.Front plate of annunciator[72]
55.Alarm switch on window[76]
56.Burglar alarm on window[76]
57.Burglar alarm contact[77]
58.Neutral position of contact[78]
59.Circuiting for electric bell[79] [p. ix]
60.Annunciators in circuit[80]
61.Wiring system for a house[80]
62.Accumulator grids[83]
63.Assemblage of accumulator grids[85]
64.Connecting up storage battery in series[87]
65.Parallel series[88]
66.Charging circuit[88]
67.Telegraph sending key[91]
68.Telegraph sounder[92]
69.A telegraph circuit[94]
70.Induction coil and circuit[99]
71.Illustrating elasticity[100]
72.Condenser[101]
73.High-tension circuit[102]
74.Current interrupter[103]
75.Wireless-telegraphy coherer[105]
76.Wireless sending-apparatus[107]
77.Wireless receiving-apparatus[108]
78.Acoustic telephone[111]
79.Illustrating vibrations[111]
80.The magnetic field[112]
81.Section of telephone receiver[114]
82.The magnet and receiver head[115]
83.Simple telephone connection[116]
84.Telephone stations in circuit[117]
85.Illustrating light contact points[118]
86.The microphone[119]
87.The transmitter[119]
88.Complete telephone circuit[121]
89.Device for making hydrogen and oxygen[124]
90.Electric-water purifier[127]
91.Portable electric purifier[129][p. x]
92.Section of positive plate[130]
93.Section of negative plate[130]
94.Positive and negative in position[130]
95.Form of the insulator[130]
96.Simple electric heater[137]
97.Side view of resistance device[139]
98.Top view of resistance device[139]
99.Plan view of electric iron[140]
100.Section of electric iron[141]
101.Thermo-electric couple[143]
102.Cutting a magnetic field[146]
103.Alternations, first position[148]
104.Alternations, second position[148]
105.Alternations, third position[148]
106.Alternations, fourth position[148]
107.Increasing alternations, first view[149]
108.Increasing alternations, second view[149]
109.Connection of alternating dynamo armature[150]
110.Direct current dynamo[151]
111.Circuit wires in direct current dynamo[152]
112.Alternating polarity lines[154]
113.Alternating current dynamo[155]
114.Choking coil[157]
115.A transformer[158]
116.Parallel carbons[164]
117.Arc-lighting circuit[165]
118.Interrupted conductor[166]
119.Incandescent circuit[167]
120.Magnetic action in dynamo, 1st[177]
121.Magnetic action in dynamo, 2d[177]
122.Magnetic action in dynamo, 3d[178]
123.Magnetic action in dynamo, 4th[178][p. xi]
124.Magnetic action in motor, 1st[179]
125.Magnetic action in motor, 2d[179]
126.Magnetic action in motor, 3d[180]
127.Magnetic action in motor, 4th[180]

[p. 1]

INTRODUCTORY