A STUDY OF TELEPHONE LINE INSULATORS 729 



this variable component about in half at that frequency thus reducing 

 the total wet-weather attenuation of these wires to about 75 per cent of 

 its former value. For smaller sizes of wires the percentage reduction 

 is correspondingly less. 



The benefits of the lesser attenuation can be utilized in the plant in 

 various ways, depending on local conditions ; for example, in increasing 

 repeater spacing, in employing smaller gages of wires, or in increasing 

 the number of insulators per mile to provide for better transposition 

 designs. 



In addition, the new insulators, in having reduced the variable com- 

 ponent of loss, improve the stability of carrier circuits to a marked 

 degree. 



Acknowledgment 



Only the electrical features of the new designs have been discussed. 

 Closely related to these are the many mechanical problems which 

 naturally arise in new construction. These latter problems, during the 

 development of the new designs, came under the supervision of Mr. C. 

 S. Gordon, assisted by Mr. J. T. Lowe. 



The Corning Glass Works has cooperated in molding special experi- 

 mental insulators of various compositions. 



Data on the electrical properties of numerous glass compositions 

 have been supplied by the Bell Telephone Laboratories. 



The writer desires to express his thanks to Messrs. F. A. Leibe, L. R. 

 Montfort and L. Staehler for assistance in the measurements and to 

 Mr. H. R. Nein for assistance in the preparation of this paper. 



