PREFACE 



In this book it is intended to give a general treatment of the 

 subject of electrical measurements, special emphasis being placed 

 on those matters which are important to the student of electrical 

 engineering. 



In^ preparing a book of this character one has to consider, not 

 only the mature reader who may desire a compendium of methods 

 together with certain practical suggestions, but the student who 

 is beginning the study of Electrical Engineering and who should 

 acquire early in his course a sound knowledge of the process of 

 electrical measurement. This knowledge is fundamental not 

 only to much of the work which the student is required to do in 

 the dynamo laboratory as a matter of engineering training, but 

 to an adequate understanding of electrical testing as it is en- 

 countered in the practice of the electrical engineering profession. 

 In the preparation of the text this second class of readers has 

 been particularly in mind. 



It is assumed that those who use this text have had courses in 

 physics, the theory of electricity, and in mathematics, such as 

 are given to third year students in technical schools of the first 

 rank. 



The choice of material and the method of treatment have been 

 determined by the author's experience in directing for many 

 years the work of the laboratory for Technical Electrical Meas- 

 urements at the Massachusetts Institute of Technology, and the 

 hook is intended as a text for the guidance of students working in 

 such a laboratory as well as a general reference book on the 

 subject. 



It is expected that those using the book for purposes of instruc- 

 tion will select such portions as are best suited to their purposes, 

 for more material is presented than can be utilized in both the 

 class room and the laboratory in the time which can properly be 

 allotted to this particular phase of electrical engineering instruc- 

 iion. In this connection it is suggested that interest and dis- 

 cussion are stimulated if the laboratory work is so arranged that 



