CONQUEST OF DISTANCE BY WIRE TELEPHONY 351 



ing of the New York-Denver Line in 1911 proved, however, that the essen- 

 tial problems had been solved. A subsequent discussion includes a brief 

 statement of the high spots of this and other developments that were es- 

 sential to its success. 



The early work on the problems involved in the use of repeaters on loaded 

 lines was not so successful as that on the other concurrent major projects, 

 a topic that we shall return to in connection with the planning of the trans- 

 continental telephony project. 



1908 Happenings 



During 1908, Jewett's department initiated several additional important 

 developments, including duplex (quadded) cable and low loss repeating coils 

 for toll lines. 



Over a long period, prior to 1908, many sporadic and unsuccessful ex- 

 periments had been made, here and abroad, to obtain quadded cable suit- 

 able for phantom working. By the middle of 1908, however, very encourag- 

 ing results had been obtained in the Bell System development work on open- 

 wire phantom loading. Forecasts of the substantially universal use of 

 loaded, phantomed, lines brought into sharp focus the need for loaded 

 quadded entrance cables in the future open-wire toll plant. Also, if a satis- 

 factory type of quadded cable could be developed and loaded, very large 

 economies could be anticipated in long distance telephone cable systems 

 that as yet were in the dream stage. These incentives were tremendous 

 relative to those that governed the previous unsuccessful experiments re- 

 ferred to, and in fact compelled the success that was achieved in due course 

 by the concentrated engineering efforts of the American Company and 

 Western Electric Company, beginning in 1908. The first question to be 

 decided by experiment and study was concerned with the type of con- 

 struction that would offer the best chance of ultimate success. The leading 

 competitors were the spiral-four type quad, and the multiple-twin quad, con- 

 sisting of twisted pairs, twisted about one another. The twisted-pair 

 quad eventually won out partly because of crosstalk considerations, but a 

 not-negligible factor in the decision was the fact that if the new cable should 

 not turn out to be completely satisfactory for phantom working, the side 

 circuits of the twisted-pair would have characteristics more closely similar 

 to those of non-quadded twisted-pair cable than would the side circuits of 

 spiral-four quads. This was a powerful plant flexibility and homogeneity 

 argument. 



The cable development became commercially fruitful in 1910, and is 

 described in a subsequent section of this story. 



The 1908 repeating coil project mentioned in an earlier paragraph in- 

 cluded high-efl&ciency phantom-deriving repeating coils especially for use on 



