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If a handy-book of electricity like this had fallen into the hands of Thomas A. Edison when he was a newsboy on the Grand Trunk Railway, or when he was a telegraph operator, he would have devoured it with the utmost eagerness. To be sure, at that time, in the early sixties, all that we knew of electricity and its applications could have been told in a very brief compass. It was an almost unknown field, and the crude form of the telegraph then in use represented its most important application. There were no electric lights; there was no telephone or phonograph; there were no electric motors. Telegraphing, itself, was a slow and difficult process. All the conditions were as far removed as possible from the broad field of applied electricity indicated in this book.

But this does not mean that we have now accomplished all that there is to be done. On the contrary, the next half-century will be full of wonderful advances. This makes it more than ever essential that we should become acquainted with the principles and present conditions of a science which is being applied more and more closely to the work of every-day life. It is necessary to know this from the inside, not simply from general descriptions. Theory is all very well, but there is nothing like mastering principles, and then applying them and working out results for one’s self. Any active and intelligent boy with an inquiring mind will find a new world opened to him in the satisfaction of making electrical devices for himself according to the suggestions given in this book. This will show him the reasons for things in concrete form, will familiarize him with principles, and will develop his mechanical ingenuity. He may be laying the foundation for inventions of his own or for professional success in some of the many fields which electricity now offers. Work of this kind brings out what is in one, and there is no satisfaction greater than that of winning success by one’s own efforts.

The boy who makes a push-button for his own home, or builds his own telephone line or wireless telegraph plant, or by his own ingenuity makes electricity run his mother’s sewing-machine and do other home work, has learned applications of theory which he will never forget. The new world which he will enter is a modern fairyland of science, for in the use of electricity he has added to himself the control of a powerful genie, a willing and most useful servant, who will do his errands or provide new playthings, who will give him manual training and a vast increase in general knowledge. The contents of this book, ranging from the preparation of simple cells to the making of dynamos and motors, and the delightful possibilities of electro-plating, shows the richness of the field which is made accessible by Mr. Adams’ practical explanations, his carefully tested working plans, and his numerous and admirable drawings—all of which have been made for this book.

It is in keeping with the practical character of the Electricity Book that pains are taken throughout to show the simplest and most inexpensive way of choosing materials and securing results. The actual working out of these directions can be done at very small expense. Furthermore, there need be no concern whatever as to possible danger if the book is read with reasonable intelligence. Mr. Adams has taken pains to place danger-signals wherever special precautions are advisable, and, as a father of boys who are constantly working with electricity in his laboratory, he may be relied upon as a safe and sure counsellor and guide.

While this book shows boys what they can do themselves, its scope has been enlarged by Mr. Baker’s chapter explaining briefly the working of electricity all about us, in light and heat, in the trolley-car, and other daily applications. In addition, Mr. Adams has prepared a Dictionary of Electrical Terms, and these brief definitions will be found peculiarly helpful in the first reading of the book. It is believed that there is no book in this particular field comparable to Harper’s Electricity Book in its comprehensiveness, practical character, and the number and usefulness of its illustrations. It follows the successful Out-door Book for Boys in Harper’s series of Practical Books for Boys, and it will be followed by How to Understand Electrical Work, a book, not of instructions in making electrical apparatus, but of explanations of the commercial uses of electricity all about us.