PREFACE. 



THE object of this book is to compile a set of instructions 

 for engineers, which will enable them to make electrical 

 calculations for transmission lines with the least possible 

 amount of work. 



The chart and working formulas have for the most part 

 been developed independently by the author. Where the 

 same or similar methods have been previously published, 

 the fact is generally stated in the footnotes, but it has not 

 been found possible to make these references absolutely 

 complete. 



The second part of the book is for reference and contains 

 the derivation of the principal formulas used in connec- 

 tion with transmission lines. As many recent articles on 

 transmission lines make use of formulas which are only 

 roughly approximate, or are even incorrect, a reliable col- 

 lection of formulas, with the method of obtaining them, 

 should be found valuable. 



It should not be presumed, because the second part of 

 the book requires the use of the integral calculus, that 

 the working formulas will require a knowledge of higher 

 mathematics. The first five or six chapters are complete 

 in themselves, and are planned for the use of those who 

 have an ordinary acquaintance with alternating-current 

 calculations. 



H. B. D WIGHT. 



HAMILTON, CANADA, 

 August, 1912.- 



iii 



