The Library of Work and Play: Electricity and Its Everyday Uses

Part 1

THE LIBRARY OF WORK AND PLAY

CARPENTRY AND WOODWORK By Edwin W. Foster

ELECTRICITY AND ITS EVERYDAY USES By John F. Woodhull, Ph.D.

GARDENING AND FARMING By Ellen Eddy Shaw

HOME DECORATION By Charles Franklin Warner, Sc.D.

HOUSEKEEPING By Elizabeth Hale Gilman

MECHANICS, INDOORS AND OUT By Fred T. Hodgson

NEEDLECRAFT By Effie Archer Archer

OUTDOOR SPORTS, AND GAMES By Claude H. Miller, Ph.B.

OUTDOOR WORK By Mary Rogers Miller

WORKING IN METALS By Charles Conrad Sleffel.

The Library of Work and Play

ELECTRICITY AND ITS EVERYDAY USES

BY JOHN F. WOODHULL, PH.D.

McGOWEN-MAIER & CO. CHICAGO, ILL.

ALL RIGHTS RESERVED, INCLUDING THAT OF TRANSLATION INTO FOREIGN LANGUAGES, INCLUDING THE SCANDINAVIAN

COPYRIGHT, 1911, BY DOUBLEDAY, PAGE & COMPANY

PREFACE

Why do we pursue one method when instructing an individual boy out of school, and a very different method when teaching a class of boys in school?

The school method of teaching the dynamo is to begin with the bar magnet and, through a series of thirty or forty lessons on fundamental principles, lead up to the dynamo, which is then presented, with considerable attention to detail, as a composite application of principles. This might be styled the synthetic method. He who teaches a boy out of school is pretty likely to reverse this order and pursue the analytic method. The class in school has very little influence in determining the order of procedure. The lone pupil with his questions almost wholly determines the order of procedure. Out of school no one has the courage to deny information to a hungry boy; in school we profess to put a ban upon information giving, and we do quite effectually deaden his sense of hunger. The school method rarely yields fruit which lasts beyond the examination period; on the other hand, a considerable number of boys have become electrical experts without the aid of a school. This book is the story of how my boy and I studied electricity together. We have had no other method than to attack our problems directly, and principles have come in only when they were needed.

My boy had learned to read when very young by having stories read to him while he watched the printed pages. The construction of sentences out of words and words out of letters had come to him very incidentally but all in due time, and when he first went to school rather late in life for a beginner he found himself more proficient than the other boys of his own age both in reading and in understanding the printed pages. I could see no good reason why he should not pursue the same method in studying electricity.

We live in a modern apartment house in a great city. My boy likes to visit engine rooms and talk with the engineers about their machinery. His mother and I always encourage him to talk with us about the things in which he is most interested. If the family is alone at dinner, he is quite likely to lead the conversation into the field of electricity. When particularly burdened with my work I have learned to find relief by giving an afternoon to Harold, who generally takes me to some electrical store or power station or to ride by electric train out into the country.

CONTENTS

CHAPTER PAGE

I. The Dynamo and The Power Station 3

II. Dynamo continued--The Magnet 11

III. The Ammeter 25

IV. The Wattmeter 35

Part 2

V. The Electric Motor 43

VI. Applications of the Electro-magnet 57

VII. Electric Heating 97

VIII. Applications of Electric Heating 107

IX. Lighting a Summer Camp by Electricity 160

X. How Electricity Feels 168

XI. The Electric Sparking Equipment for a Gasolene Engine 178

XII. Electricity From Central Stations 204

XIII. Electricity From an Old Mill 218

XIV. Doing Chores by Electricity 240

XV. Electric currents from Chemical Action and Chemical Action from Electric Currents 248

XVI. Electrocution at Millville 271

XVII. The Telephone 274

XVIII. Electric Bell Outfit for the Cottage 296

XIX. Using Electricity to Aid the Memory 300

XX. The Electric Brick Oven 305

XXI. Electric Waves 309

XXII. Ringing Bells and Lighting Lamps by Electric Waves 324

XXIII. Telegraphing by Electric Waves 329

XXIV. Halley's Comet and Electric Waves 333

XXV. How the Idea of a Universal Ether Developed 339

XXVI. Electric Currents Cannot Be Confined to Wires 349

XXVII. Wireless Telegraphy In Earnest 355

ILLUSTRATIONS

Harold Sending the C. Q. D. Message Frontispiece

FACING PAGE

Testing a Generator 8

Wiring 16

Part 3

Wattmeter 40

Testing the Telegraphy Outfit 62

Electric Bell 72

Feeling Electricity 174

Operating the Switchboard 204

Induction Coil of a Wireless 330

ELECTRICITY AND ITS EVERYDAY USES

THE DYNAMO AND THE POWER STATION

One day Harold expressed a desire to see the dynamos, five miles away, which furnish the electric light in our apartment. So I told him to invite his best friend to accompany us and we would go.

When we were some distance from the station the boys noticed the very tall chimneys and inquired why tall chimneys were needed for dynamos. I explained that the dynamos were run by steam-engines, and steam-engines required the burning of coal. "Oh!" said Ernest, Harold's friend, "I read in the paper that electricity is the rival of steam and is going to drive out the steam-engine." I suggested that we were about to see some steam-engines driving electricity out of that power station. But more seriously, I explained that steam-engines were used for many years as locomotives to draw the trains on the elevated railroads of New York City, and when at last they were displaced by electric trains some people thought that it was a case of electricity driving out steam, whereas what had really happened was that the steam power for running those trains had been concentrated at a central station, and its power was merely transmitted to the trains by means of electricity. The trains were, therefore, run by steam power quite as much as ever. In like manner, the surface cars of New York a few years ago were run by a cable, which was merely a very long belt used to transmit to the cars the power of steam-engines located at a central station. When they were changed to electric cars, electricity became the successful rival of nothing else than a twisted wire cable. The cars still run by steam power as before, but that power is transmitted by electricity instead of the discarded cable. Steam has driven out the horse as a power for drawing street cars, and electricity has enabled us to gather all the steam engines into central stations, where now they are furnishing the power for moving surface, elevated, and subway cars for street traffic, as also trains for suburban travel. Central station steam-engines are producing a vast amount of power, distributed all over the city by means of electricity, for doing a great variety of work and for furnishing electric light and heat, all of which we shall presently study. "Just before we go into this central station, can you tell me how the elevator is run in our apartment house?" "It is an electric elevator," said Harold. "And where does the electricity come from?" I inquired. "Well, I know that it comes from the street mains, but do they come from this power station?" "Yes," said I, "and we will now go in and see the steam-engines which lift you up stairs many times each day by sending electricity to run that elevator. If you choose to do so, you may claim for purposes of discussion that your elevator is run by steam."

As we entered the building we came first to the dynamo room and both boys noticed that the tone which met their ears was that which I had produced for them in the telephone the night before. "I shall try to show you before we get through," I said, "that these dynamos are doing something which makes iron pulsate sixty times a second and that that is the cause of the pitch of this tone. But let us begin with the coal which is the source of all this power.

"This particular station at the present time is burning forty tons of coal an hour. That is as much as Mr. ---- uses to heat his twelve-room house for a whole year. One pound of coal is capable of liberating enough energy to supply 5-3/4 horse-power for an hour. (Written for short 5-3/4 H.P.H.) One ton of coal is capable of furnishing (2,000 × 5-3/4) 11,500 H.P.H. Forty tons would yield 460,000 H.P.H. But the best furnaces, boilers, and steam-engines are terribly wasteful of energy. About nine tenths of all this energy is wasted and only one tenth, or about 46,000 horse-power per hour, is delivered by the steam-engines to the dynamos.

"Coal is already scarce in the world and the supply is rapidly being exhausted. Meanwhile we are growing more dependent upon coal. A century ago we used scarcely any power except that of men, horses, and oxen, and what little heat men then used came chiefly from wood. They lived in cold houses, attended cold churches and schools, did not ride in steam or electric cars, and did not have power plants. Our wood is nearly all gone, our coal is going, and we are very rapidly growing more dependent upon heat and power, our chief source of which is coal. Wind power is too uncertain to depend upon, and we turned our backs upon water-power when we began to crowd into cities. What little water-power there is, however, is nearly all in use.

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