8 BEJ.L SYSTEM TECfl.XICAL JOrRXAL 



Oniiik Aim i.u ATioNs of 1-;m.im;i:rin(. Cost Snniics 



l'"rom wlial has uIr'.kK liccii said, it should ikiL lie ink'ncd lh.it 

 the sole application ol eii.uiiieerin.n cost studios is in connection with 

 the problems arising in the operating field. The question whether 

 or not a more efficient piece of apparatus at a higher cost is war- 

 ranted enters into most of our develcjpment problems. The econ- 

 omies of the case lie at the root of our development work in all (ion ions 

 of the plant. 



At this point I should like to call attention lo the fact that our 

 development work covers not only what are termed "transmission" 

 matters, but also very important problems in switchboards, outside 

 plant and other phases of the business. 



The service which we provide is a communicatioji service, which 

 involves important problems affecting the means for connecting 

 and disconnecting the parties as well as those other important prob- 

 lems, to which your attention has been particularly directed, relating 

 to the loudness and quality of the transmitted speech. 



In cable design, particularly in the case of intercity cables and 

 interoffice trunk cables, the average separation between wires in 

 the cable affects the electrostiitic capacity of the circuits and there 

 is a definite capacity which represents the most economical degree 

 of concentration of the w'ires in the cross-section of the cable. The 

 spacing and inductance of loading coils presents another problem 

 in balanced costs. K\-en in the case of wooden poles we make use of 

 economic cost studies. 



The length of life of a jjole depends upon a \'ariet>- of factors, the 

 most important of which are the character of the timber; whether 

 or not a preservati\e treatment is employed and, if so, the nature 

 of the treatment; the local climatic and soil conditions and the 

 original size of the pole. 



The strength of a pole varies with the cube of the diameter of the 

 sound wood at the weakest section. If the original size of the pole 

 is onh- slightly more than the critical size at which replacement 

 should be made, the life of the pole will be \cry short, as dcca\ will 

 reduce the size at the ground line to the critical size within .1 lew 

 years. On the other hand, a pole of huge size at the ground line 

 would have a very long life before rotting sufficiently to require 

 replacement, but the first cost of so stout a pole might readily be 

 so great that its annual cost would exceed that of a smaller and 

 cheaper pule. In f)ur specifications for poles we have constantly 



