PREFACE 



IN the following pages an attempt is made to furnish the reader with 

 a general account of the principles, construction, and use of alternate- 

 current measuring instruments, generators, motors, and transforming 

 machinery. Special attention is devoted to methods of testing. The 

 first three chapters contain a sketch of alternate-current theory. 

 The author has tried, as far as possible, to exclude everything of 

 purely academic or historical interest ; on the other hand, he has not 

 hesitated to devote a good deal of space to matters which are either 

 not generally understood, or which are of too recent origin to have 

 found their way into many text-books. 



The author desires to express his indebtedness to the various 

 firms who supplied him with working drawings and placed other 

 information at his disposal ; especially would he like to mention in 

 this connection The Electric Construction Co., Ltd. ; Messrs. Everett, 

 Edgcumbe and Co. ; Messrs. Kelvin and James White, Ltd. ; and 

 Messrs. Nalder Bros, and Thompson, Ltd. 



The bulk of the illustrations have been specially prepared for 



this book. 



A. H. 



LONDON, N.W., 



October, 1905. 



