The subject of electricity is so fascinating and it covers so many important and interesting application that a study of the laws under which the mysterious force moves is not only attractive is fundamental in its character. Since the beginning of our electrical knowledge we have struggled to determine its nature and origin. But we know how electricity behaves and how to harness it. This work is not intended as an unsystematic popularized treaties on electricity but is worked out in a thorough careful manner. The authors are authorities in the electrical field, not only from scientific but also from teaching standpoint