vi PREFACE 



appendices. Those familiar with Oliver Heaviside's writings 

 will notice his influence upon the author, in particular with 

 regard to a uniform and rational nomenclature. The author trusts 

 that his colleagues will judge his treatment and nomenclature 

 upon their own merits, and not condemn them simply because 

 they are different from the customary treatment. 



In the first four chapters the student is introduced into the 

 fundamental electromagnetic relations, and is made familiar with 

 them by means of numerous illustrations taken from engineering 

 practice. Chapters V to IX treat of the flux and magneto- 

 motive force relations in electrical machinery, first at no load, and 

 then under load when there is an armature reaction. The remain- 

 ing four chapters are devoted to the phenomena of stored magnetic 

 energy, namely inductance and tractive effort. The subject is 

 treated entirely from the point of view of an electrical engineer, 

 and the important relations and methods are illustrated by 

 practical numerical problems, of which there are several hundred 

 in the text. All matter of purely historical or theoretical interest 

 has been left out, as well as special topics which are of interest 

 to a professional designer only. An ambitious student will find 

 a more exhaustive treatment in the numerous references given in 

 the text. 



Many thanks are due to the author's friend and colleague, 

 Mr. John F. H. Douglas, instructor in electrical engineering in 

 Sibley College, who read the manuscript and the proofs, checked 

 the answers to the problems, and made many excellent sugges- 

 tions for the text. Most of the sketches are original, and are the 

 work of Mr. John T. Williams of the Department of Machine 

 Design of Sibley College, to whom I am greatly indebted. 



CORNELL UNIVERSITY, ITHACA, N. Y., 

 September, 1911. 



