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BELL SYSTEM TECHNICAL JOURNAL 



differs greatly from this figure, it is necessary to correct the leakage 

 values accordingly. Differences in the number of insulators per mile 

 result from the use of different types and numbers of transpositions, 

 different pole spans, double crossarm construction, etc. 



Fig. 7 — Types of insulators employed in the Bell System. 



a. Toll insulator. 



b. DP insulator. 



c. CW insulator and pin thimble. 



d. CS insulator. 



