Produced by Joe Longo and the Online Distributed
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WARNING: This book of one hundred years ago describes
experiments which are too dangerous to attempt by either
adults or children. It is published for historical
interest only.
THE "HOW-TO-DO-IT" BOOKS
ELECTRICITY FOR BOYS
[Illustration: Fig. 1. WORK BENCH]
THE "HOW-TO-DO-IT" BOOKS
ELECTRICITY FOR BOYS
A working guide, in the successive
steps of electricity, described in
simple terms
WITH MANY ORIGINAL ILLUSTRATIONS
By J. S. ZERBE, M.E.
AUTHOR OF
CARPENTRY FOR BOYS
PRACTICAL MECHANICS FOR BOYS
[Illustration: Printer's Mark]
THE NEW YORK BOOK COMPANY
NEW YORK
COPYRIGHT, 1914, BY
THE NEW YORK BOOK COMPANY
CONTENTS
INTRODUCTORY Page 1
I. ELECTRICITY CONSIDERED. BRIEF HISTORICAL
EVENTS Page 5
The Study of Electricity. First Historical Accounts. Bottling
Electricity. Discovery of Galvanic Electricity. Electro-motive Force.
Measuring Instruments. Rapidity of Modern Progress. How to Acquire the
Vast Knowledge. The Means Employed.
II. WHAT TOOLS AND APPARATUS ARE NEEDED Page 11
Preparing the Workshop. Uses of Our Workshop. What to 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-magnetic Material. Action of a
_Second_ Magnet. What North and South Pole Mean. Repulsion and
Attraction. Positives and Negatives. Magnetic Lines of Force. The
Earth as a Magnet. Why the Compass Points North and South. Peculiarity
of a Magnet. Action of the Electro-Magnet. Exterior Magnetic Influence
Around a Wires Carrying a Current. Parallel Wires.
IV. FRICTIONAL, VOLTAIC OR GALVANIC AND ELECTRO-MAGNETIC
ELECTRICITY Page 29
Three Electrical Sources. Frictional Electricity. Leyden Jar. Voltaic
or Galvanic Electricity. Voltaic Pile; How Made. Plus and Minus
Signs. The Common Primary Cell. Battery Resistance. Electrolyte and
Current. Electro-magnetic Electricity. Magnetic Radiation. Different
Kinds of Dynamos. Direct Current Dynamos. Simple Magnet Construction.
How to Wind. The Dynamo Fields. The Armature. Armature Windings.
Mounting the Armature. The Commutator. Commutator Brushes. 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 of Current. Simple
Current Detector. How to Place the Detector. Different Ways to Measure
a Current. The Sulphuric 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 to Make 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. A
Standard of Measurement. The Ampere Standard. The
Voltage Standard. The Ohm. Calculating the Voltage.
VII. PUSH BUTTONS, SWITCHES, ANNUNCIATORS, BELLS AND
LIKE APPARATUS Page 65
Simple Switches. A Two-Pole Switch. Double-Pole Switch. Sliding
Switch. Reversing Switch. Push Buttons. Electric Bells. How Made. How
Operated. Annunciators. Burglar Alarm. Wire Circuiting. Circuiting
System with Two Bells and Push Buttons. The Push Buttons, Annunciators
and Bells. Wiring Up a House.
VIII. ACCUMULATORS, STORAGE OR SECONDARY BATTERIES Page 82
Storing Up Electricity. The Accumulator. Accumulator Plates. The Grid.
The Negative Pole. Connecting Up the Plates. Charging the Cells. The
Initial Charge. The Charging Current.
IX. THE TELEGRAPH Page 90
Mechanism in Telegraph Circuit. The Sending Key. The Sounder.
Connecting Up the Key and Sounder. Two Stations in Circuit. The Double
Click. Illustrating the Dot and the Dash. The Morse Telegraph Code.
Example in Use.
X. HIGH-TENSION APPARATUS, CONDENSERS, ETC. Page 98
Induction. Low and High Tension. Elastic Property of Electricity. The
Condenser. Connecting up a Condenser. The Interrupter. Uses of
High-tension Coils.
XI. WIRELESS TELEGRAPHY Page 104
Telegraphing Without Wires. Surging Character of High-tension
Currents. The Coherer. How Made. The Decoherer. The Sending Apparatus.
The Receiving Apparatus. How the Circuits are Formed.
XII. THE TELEPHONE Page 110
Vibrations. The Acoustic Telephone. Sound Waves. Hearing Electricity.
The Diaphragm in a Magnetic Field. A Simple Telephone Circuit. How to
Make a Telephone. Telephone Connections. Complete Installation. The
Microphone. Light Contact Points. How to Make a Microphone.
Microphone, the Father of the Transmitter. Automatic Cut-outs for
Telephones. Complete Circuiting with Transmitters.
XIII. ELECTROLYSIS, WATER PURIFICATION, ELECTROPLATING Page 123
Decomposing Liquids. Making Hydrogen and Oxygen. Purifying Water.
Rust. Oxygen as a Purifier. Composition of Water. Common Air Not a
Good Purifier. Pure Oxygen a Water Purifier. The Use of Hydrogen in
Purification. Aluminum Electrodes. Electric Hand Purifier.
Purification and Separation of Metals. Electroplating. Plating Iron
with Copper. Direction of Current.
XIV. ELECTRIC HEATING. THERMO-ELECTRICITY Page 135
Generating Heat in a Wire. Resistance of Substances. Signs of
Connectors. Comparison of Metals. A Simple Electric Heater. How to
Arrange for Quantity of Current Used. An Electric Iron.
Thermo-Electricity Converting Heat Directly into Electricity Metals.
Electric, Positive, Negative. Thermo-electric Coupler.
XV. ALTERNATING CURRENTS, CHOKING COIL, TRANSFORMER Page 145
Direct Current. Alternating Current. The Magnetic Field. Action of a
Magnetized Wire. The Movement of a Current in a Charged Wire. Current
Reversing Itself. Self-Induction. Brushes in a Direct Current Dynamo:
Alternating, Positive and Negative Poles. How an Alternating Current
Dynamo is Made. The Windings. The Armature Wires. Choking Coils. The
Transformer. How the Voltage is Determined. Voltage and Amperage in
Transformers.
XVI. ELECTRIC LIGHTING Page 161
Early conditions. Fuels. Reversibility of Dynamo. Electric arc.
Mechanism to maintain the arc. Resistance coil. Parallel carbons for
making arc. Series current. Incandescent system. Multiple circuit.
Subdivision of electric light. The filament. The glass bulb. Metallic
filaments. Vapor lamps. Directions for improvements. Heat in electric
lighting. Curious superstitions concerning electricity. Magnetism.
Amber. Discovery of the properties of a magnet. Electricity in
mountain regions. Early beliefs as to magnetism and electricity. The
lightning rod. Protests against using it. Pliny's explanation of
electricity.
XVII. POWER, AND VARIOUS OTHER ELECTRICAL MANIFESTATIONS Page 175
Early beliefs concerning the dynamo. Experiments with magnets.
Physical action of dynamo and motor. Electrical influence in windings.
Comparing motor and dynamo. How the current acts in a dynamo. Its
force in a motor. Loss in power transmission. The four ways in which
power is dissipated. Disadvantages of electric power. Its advantages.
Transmission of energy. High voltages. The transformer. Step-down
transformers. Electric furnaces. Welding by electricity. Merging the
particles of the joined ends.
XVIII. X-RAY, RADIUM AND THE LIKE Page 184
The camera and the eye. Actinic rays. Hertzian waves. High-tension
apparatus. Vacuum tubes. Character of the ultra-violet rays. How
distinguished. The infra-red rays. Their uses. X-rays not capable of
reflection. Not subject to refraction. Transmission through 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.
LIST OF ILLUSTRATIONS
FIG.
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
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
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
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
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
INTRODUCTORY
Electricity, like every science, presents two phases to the student, one
belonging to a theoretical knowledge, and the other which pertains to
the practical application of that knowledge. The boy is directly
interested in the practical use which he can make of this wonderful
phenomenon in nature.
It is, in reality, the most successful avenue by which he may obtain the
theory, for he learns the abstract more readily from concrete examples.
It is an art in which shop practice is a greater educator than can be
possible with books. Boys are not, generally, inclined to speculate or
theorize on phenomena apart from the work itself; but once put them into
contact with the mechanism itself, let them become a living part of it,
and they will commence to reason and think for themselves.
It would be a dry, dull and uninteresting thing to tell a boy that
electricity can be generated by riveting together two pieces of
dissimilar metals, and applying heat to the juncture. But put into his
hands the metals, and set him to perform the actual work of riveting the
metals together, then wiring up the ends of the metals, heating them,
and, with a galvanometer, watching for results, it will at once make him
see something in the experiment which never occurred when the abstract
theory was propounded.
He will inquire first what metals should be used to get the best
results, and finally, he will speculate as to the reasons for the
phenomena. When he learns that all metals are positive-negative or
negative-positive to each other, he has grasped a new idea in the realm
of knowledge, which he unconsciously traces back still further, only to
learn that he has entered a field which relates to the constitution of
matter itself. As he follows the subject through its various channels he
will learn that there is a common source of all things; a manifestation
common to all matter, and that all substances in nature are linked
together in a most wonderful way.
An impulse must be given to a boy's training. The time is past for the
rule-and-rote method. The rule can be learned better by a manual
application than by committing a sentence to memory.
In the preparation of this book, therefore, I have made practice and
work the predominating factors. It has been my aim to suggest the best
form in which to do the things in a practical way, and from that work,
as the boy carries it out, to deduce certain laws and develop the
principles which underlie them. Wherever it is deemed possible to do so,
it is planned to have the boy make these discoveries for himself, so as
to encourage him to become a thinker and a reasoner instead of a mere
machine.
A boy does not develop into a philosopher or a scientist through being
told he must learn the principles of this teaching, or the fundamentals
of that school of reasoning. He will unconsciously imbibe the spirit and
the willingness if we but place before him the tools by which he may
build even the simple machinery that displays the various electrical
manifestations.
CHAPTER I
THE STUDY OF ELECTRICITY. HISTORICAL
There is no study so profound as electricity. It is a marvel to the
scientist as well as to the novice. It is simple in its manifestations,
but most complex in its organization and in its ramifications. It has
been shown that light, heat, magnetism and electricity are the same, but
that they differ merely in their modes of motion.
FIRST HISTORICAL ACCOUNT.--The first historical account of electricity
dates back to 600 years B. C. Thales of Miletus was the first to
describe the properties of amber, which, when rubbed, attracted and
repelled light bodies. The ancients also described what was probably
tourmaline, a mineral which has the same qualities. The torpedo, a fish
which has the power of emitting electric impulses, was known in very
early times.
From that period down to about the year 1600 no accounts of any
historical value have been given. Dr. Gilbert, of England, made a number
of researches at that time, principally with amber and other materials,
and Boyle, in 1650, made numerous experiments with frictional
electricity.
Sir Isaac Newton also took up the subject at about the same period. In
1705 Hawksbee made numerous experiments; also Gray, in 1720, and a
Welshman, Dufay, at about the same time. The Germans, from 1740 to 1780,
made many experiments. In 1740, at Leyden, was discovered the jar which
bears that name. Before that time, all experiments began and ended with
frictional electricity.
The first attempt to "bottle" electricity was attempted by
Muschenbr[oe]ck, at Leyden, who conceived the idea that electricity in
materials might be retained by surrounding them with bodies which did
not conduct the current. He electrified some water in a jar, and
communication having been established between the water and the prime
conductor, his assistant, who was holding the bottle, on trying to
disengage the communicating wire, received a sudden shock.
In 1747 Sir William Watson fired gunpowder by an electric spark, and,
later on, a party from the Royal Society, in conjunction with Watson,
conducted a series of experiments to determine the velocity of the
electric fluid, as it was then termed.
Benjamin Franklin, in 1750, showed that lightning was electricity, and
later on made his interesting experiments with the kite and the key.
DISCOVERING GALVANIC ELECTRICITY.--The great discovery of Galvani, in
1790, led to the recognition of a new element in electricity, called
galvanic or voltaic (named after the experimenter, Volta), and now known
to be identical with frictional electricity. In 1805 Poisson was the
first to analyze electricity; and when [OE]rsted of Copenhagen, in 1820,
discovered the magnetic action of electricity, it offered a great
stimulus to the science, and paved the way for investigation in a new
direction. Ampere was the first to develop the idea that a motor or a
dynamo could be made operative by means of the electro-magnetic current;
and Faraday, about 1830, discovered electro-magnetic rotation.
ELECTRO-MAGNETIC FORCE.--From this time on the knowledge of electricity
grew with amazing rapidity. Ohm's definition of electro-motive force,
current strength and resistance eventuated into Ohm's law. Thomson
greatly simplified the galvanometer, and Wheatstone invented the
rheostat, a means of measuring resistance, about 1850. Then primary
batteries were brought forward by Daniels, Grove, Bunsen and Thomson,
and electrolysis by Faraday. Then came the instruments of precision--the
electrometer, the resistance bridge, the ammeter, the voltmeter--all of
the utmost value in the science.
MEASURING INSTRUMENTS.--The perfection of measuring instruments did more
to advance electricity than almost any other field of endeavor; so that
after 1875 the inventors took up the subject, and by their energy
developed and put into practical operation a most wonderful array of
mechanism, which has become valuable in the service of man in almost
every field of human activity.
RAPIDITY OF MODERN PROGRESS.--This brief history is given merely to show
what wonders have been accomplished in a few years. The art is really
less than fifty years old, and yet so rapidly has it gone forward that
it is not at all surprising to hear the remark, that the end of the
wonders has been reached. Less than twenty-five years ago a high
official of the United States Patent Office stated that it was probable
the end of electrical research had been reached. The most wonderful
developments have been made since that time; and now, as in the past,
one discovery is but the prelude to another still more remarkable. We
are beginning to learn that we are only on the threshold of that
storehouse in which nature has locked her secrets, and that there is no
limit to human ingenuity.
HOW TO ACQUIRE THE VAST KNOWLEDGE.--As the boy, with his limited vision,
surveys this vast accumulation of tools, instruments and machinery, and
sees what has been and is now being accomplished, it is not to be
wondered at that he should enter the field with timidity. In his mind
the great question is, how to acquire the knowledge. There is so much to
learn. How can it be accomplished?
The answer to this is, that the student of to-day has the advantage of
the knowledge of all who have gone before; and now the pertinent thing
is to acquire that knowledge.
THE MEANS EMPLOYED.--This brings us definitely down to an examination of
the means that we shall employ to instil this knowledge, so that it may
become a permanent asset to the student's store of information.
The most significant thing in the history of electrical development is
the knowledge that of all the great scientists not one of them ever
added any knowledge to the science on purely speculative reasoning. All
of them were experimenters. They practically applied and developed their
theories in the laboratory or the workshop. The natural inference is,
therefore, that the boy who starts out to acquire a knowledge of
electricity, must not only theorize, but that he shall, primarily,
conduct the experiments, and thereby acquire the information in a
practical way, one example of which will make a more lasting impression
than pages of dry text.
Throughout these pages, therefore, I shall, as briefly as possible,
point out the theories involved, as a foundation for the work, and then
illustrate the structural types or samples; and the work is so arranged
that what is done to-day is merely a prelude or stepping-stone to the
next phase of the art. In reality, we shall travel, to a considerable
extent, the course which the great investigators followed when they were
groping for the facts and discovering the great manifestations in
nature.