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BELL SYSTEM TECHNICAL JOURNAL 



TABLE lA 



Resistance of Cotton and Silk Fibers 



R is the resistance in megohms of a single fiber Y2 in. long. Time allowed for 

 equilibrium, 20 hrs. or more. Room temperature 



* Each group consisted of 60 single fibers attached to the electrodes so that they 

 were in parallel, i?* is the average resistance per single fiber calculated from that 

 of 60 in parallel. The experimental technique is described elsewhere.^" 



t The values of R* for silk at this humidity were found to be of the order of 

 several million megohms, i.e., beyond the limit of accurate measurement with equip- 

 ment available at the time the study of single fibers was under way. 



which, considering the nature of the material, is surprisingly uniform 

 for different fibers taken from the same material. Similarly, Table \B 

 shows that threads ^ of cotton and silk also have a uniform resistance; 

 this suggests that the interfiber contacts do not have a large effect on 

 the resistance of the thread as a whole. Table \C shows the resistance 

 of the servings on wires; the resistances are for short twisted pairs 

 (2 in. long). This shows also that even where the voltage is applied 

 transversely to the long axis of the fibers — which would tend to 

 make contact resistances more important than when the voltage is 

 applied parallel to the long axis — the resistance of different samples 

 of the same material is fairly uniform. These facts suggest that inter- 



^ Because of their uniformity, small samples of thread (V2 in. lengths) have been 

 used in this laboratory as a convenient means of comparing the insulating quality 

 of cottons and other textiles. 



