INTRODUCTION
Young men and women, and older ones, too, who have time and money at their disposal, who have been blessed with a sufficient preparaatory education, and who desire to learn something about electricity, either for pleasure or profit, may do so by entering and taking the very comprehensive courses at the colleges and technical schools. But there are many of our brightest mechanics, artisans and business men who have not had the benefits of a sufficient primary education, especially in mathematics, to enable them to pass the more or less exacting entrance examinations required by the technical schools and colleges, and these and many others also may not be able to part with the time or money necessary to secure these benefits. It is to these classes of people that the National School of Electricity especially appeals...

LESSON 1. THE NATURE AND PROPERTIES OF ELECTRICITY
The exact nature of the electricity which makes itself evident in so many ways has never been determined. Many surmises or theories have been advanced, but none have yet been able to stand the test of close examination.

The true nature of magnetism seems to be very closely connected with that of electricity and it will probably not be exactly known until the exact nature of electricity is determined. The word magnet probably comes from the Greek word for the country of Magnesia, which is a small division of Ancient Greece, where a deposit of magnetic iron or lodestones (also called loadstones) was known to the Greeks. .... The action of magnets led some of the earlier experimenters to look upon magnetism as due to a magnetic fluid, but this idea has been proved to be wrong. It is found that pieces of steel which touch a loadstone
touch a lodestone or other magnet, become magnets. Magnets thus made are sometimes called artificial magnets, and lodestones are called natural magnets. p 27-28

There are no materials which we may look upon as being really magnetic insulators, as we may look upon some materials as being practical insulators of electricity.

Before the Chicago Electrical Congress was held, the fundamental definition of the ampere had usually been based upon the electromagnetic effect of currents, but at that Congress a definition was adopted which is based on the electrochemical effect of currents. The International Ampere as this defined is the steady current which deposits silver at the rate of .00118 grammes per second from a solution of silver nitrate in water, the solution being of a fixed strength to make sure of the action being regular.

It has been found that electric currents naturally exist in the living muscles and nerves of animals, and that muscular exertion seems to cause them. These currents disappear with the death of the animal, which probably shows that the electric currents have some function in the action of the nervous system.
The physiological action of electric currents gives a good basis for their use in the treatment of some diseases, and they have been used with marked success in some cases.....The indiscriminate use of electrical treatment of any kind is likely to do more harm than good.

While electric cooking can be said to be commercially satisfactory on account of its convenience, cleanliness, and adaptability, electric heating for general purposes can never replace the direct use of coal or the use of steam heating, until electricity is directly generated from the fuel without the intervention of steam engines in which enormous losses of heat are abslutely unpreventable.

The set of rules thus approved are now generally printed by the local Boards of Underwriters of the various cities, and can be obtained from their inspectors. In some cities, the city authorities control this matter and either furnish their inspectors with the generally adopted rules or with some equivalent. The approved rules divide electric light and power circuit into six classes. 1. The circuits inside of central stations and the dynamo rooms of isolated plants. 2. Lines constructed for the purpose of operating arc lamps in series. 3. High pressure alternating current lines. 4. Low pressure continuous current lines, and low pressure inside wiring (low pressure circuits being taken to include all circuits on which the pressure does not exceed 300 volts). 5. Electric railway circuits. 6. Primary and storage battery circuits.