Although a number of excellent works on practical electrical engineering are already in use, the author believes there is a place for a volume that will present the subject from an experimental standpoint. For many years the author has taught the subject of electrical engineering by means of experimental lectures and laboratory work to large numbers of practical men. Since these students have often lacked mathematical training, it has been nec essary to explain the subject-matter in a very Simple way, Showing, wherever possible, its practical features. The same method of presentation has been used in this text, and it is hoped that a much larger audience may thus be reached and benefited. This volume is particularly adapted to courses of instruction given to those engaged in actual electrical work; it Should likewise prove useful as a text for high schools and for college laboratory courses.