14 BELL SYSTEM TECIIXIC.IL JOVRS'AL 



additiuii must be engineering cost studies to assist in luinisliing 

 the answers to the three questions: 



Why do it at all? 

 Why do it now? 

 \\'h\- do it this way? 



But it must always be borne in mind that these studies do not and 

 can not, in themselves, constitute the sole criterion for determining 

 what should be done. They are, at the best, only an aid, guide and 

 check to be utilized, within their limitations, in arri\-ing at conclu- 

 sions that must, in the last analysis, rest upon seasoned judgment 

 and experience. 



Nevertheless, so great do we find the importance of these engineer- 

 ing cost studies in our work, and so great must be their importance in 

 the engineering of any other kind of growing plant, tiiat the question 

 might be raised whether, in courses of engineering instruction, a few 

 hours at least could not advantageously be devoted to acquainting 

 the student with the nature and importance of these economic 

 problems. 



