INFLUENCE OF MOISTURE UPON INSULATORS 229 



TABLE IB 



Resistance of Cotton and Silk Threads 



Length J2 in. Temperature 25 deg. cent. 



Resistance Megohms 

 Cotton Silk (Spun) 



Sample Humidity 77% Humidity 90% 



1 4160 21,100 



2 4220 22,700 



3 4100 ■ 28,000 



4 3730 14,500 



5 4020 30,600 



6 3820 



7 3900 



8 3715 



9 4050 



10 4100 



Aver. 3982 23,380 



TABLE IC 



Resistance between Twisted Pairs of Cotton and 

 Silk Insulated Wires 



Humidity 77 per cent Temperature 25 deg. cent. 



Resistance Megohms 

 Sample Cotton Silk (Tussah) 



1 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



fiber contact resistances are only secondary or negligible in deter- 

 mining the resistance of a thread or other mass of fibers. Further 

 evidence of this is given by the data in Table II, which show that 

 even when the length of a thread considerably exceeds the length of a 

 single cotton fiber, the resistance is approximately proportional to 

 the length; if interfiber resistances were large, the resistance per unit 

 length would increase considerably with the length of the thread 

 measured. 



The above results also suggest that electrical conduction takes 

 place primarily through moisture in the interior of the fibers rather 



