THE LIBRARY OF WORK AND PLAY
Electricity and Its Everyday Uses

THE LIBRARY OF WORK AND PLAY

Drawing by J. Hodson Redman

Harold Sending the C. Q. D. Message (See page 355)

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