Preface 



This book represents a part of a larger undertaking, the goal of 

 which is collection, analysis, and organization of the physical 

 methods used for experimental research or for the development of 

 scientific or technical instruments. The purpose of this volume is 

 to offer research workers, engineers, and students a reasonably com- 

 plete collection of the existing basic methods and systems used as 

 input transducers in electrical instrumentation. Its use as a 

 reference book should minimize literature search and should provide 

 information on particular methods as well as criteria by which the 

 relative merits of existing methods and systems may be evaluated. 



However, I have tried to make the book more than just a collec- 

 tion of unrelated facts and figures. In it, there is an attempt to 

 establish order in the vast field of experimental methodology and 

 instrumentation and to provide an organization which permits 

 logical and simple grouping of the numerous varieties of methods 

 and systems described in the literature. I feel that the establish- 

 ment of such a logical organization is important, not only in order 

 to assure adequate coverage of the material but also because 

 instrumentation or methodology is not a bag of tricks mastered only 

 by memorizing a huge collection of facts and gadgets, but is a 

 unified field, a branch of physics, which can be taught like any other 

 logical science. I do not claim credit for this crystallization process; 

 such a development is natural, and several attempts in this direc- 

 tion have already been made. 



A further intention has been on my mind while preparing this 

 manuscript. I have frequently observed that creative accomplish- 

 ments in the field of research methods and instrumentation are not 



