To those familiar with the application of electricity, it is clearly evident that, as yet, we are only beginning to deal with this unknown force. For generations to come, developments will take place and invention follow invention until electricity assumes its rightful place as the motive force of the world. To the boy interested in this subject a wide field is open, and the youth of to-day, who are taking up this study, are destined to become the successful electrical engineers and inventors of the future. There is no better education for any boy, in the application and principles of electricity, than to begin at the very bottom of the ladder and climb up, constructing and studying as he progresses. When he attempts to design more technical and difficult apparatus the lessons learned in a practical way will be of inestimable value, greater by far than any theoretical principles deduced from books; he knows his subject from the ground up; he understands his machine because he has constructed it with his own hands. As I have said already, the necessary tools are few in number and not expensive. They may include a hammer, a plane, awls, pliers, wire-cutters, and tin-shears. The raw material is also cheap--lead, tin, wire, wood, and simple chemicals. The laboratory may be a corner in the attic, or even in a boy’s bedroom, so far as the finer work is concerned, while the hammering and sawing may be done in the cellar. The other best plan, of course, is to get the use of a spare room which may be fitted with shelves, drawers, and appliances for serious work. To enthusiastic beginners, as well as to those who have had some experience in electricity, a needed warning may be given in three words: “Take no chances.” Electricity, the subtle, stealthy, and ever-alert force, will often deal a blow when least expected. For that reason, a boy should never meddle with a high-tension current or with the mains from dynamos. The current in the house, used for lighting, cooking, or heating purposes, is always an attractive point for the young electrician, but the wires should never be touched in any way. Too many accidents have happened, and the conductors, lamp-sockets, and plugs should be carefully avoided. The boy should keep strictly to his batteries, or small dynamos run by water-power from a faucet; in no case should the wire from power-houses be tampered with. One little knows what a current it may be carrying and what a death-dealing force it possesses. Always bear in mind that a naked wire falling from a trolley equipment carries enough force to kill anything it strikes.