CONQUEST OF DISTANCE BY WIRE TELEPHONY 347 



side lines in the plant of the American Company and the New England 

 Company for experimental purposes. 



Basically, the transmission tests were talking tests, usually with both 

 ends of the circuit accessible at the test point, i.e., loop tests. The trans- 

 mission equivalents of lines, and apparatus losses, were determined in terms 

 of miles of reference cable. In tests to determine apparatus losses in lines, 

 the losses were sometimes estimated on a percentage basis, when it was in- 

 convenient to use the reference cable. Transmission quality judgments 

 involving frequency distortion effects were usually expressed with a variety 

 of non-standard adjectives, ranging from "sharp" to "boomy" or "drummy" 

 and including others with a more salty personal flavor. 



The non-availability of portable "high frequency" tone generators pre- 

 vented the making of single frequency measurements in the field. How- 

 ever, in the period under discussion, considerable progress had been made in 

 laboratory measurements of low amplitude alternating currents by means of 

 thermocouples. 



1906 AND 1907 AT Boston 



During 1906, much effort of Jewett's group was devoted to field investiga- 

 tion and analytical studies of conditions affecting long distance telephone 

 service, in consequence of transmission complaints by important users of 

 the service. Much of the poor transmission was found to be due to defec- 

 tive apparatus and to departures from standard maintenance and operating 

 practices. This transmission inspection work later became so extensive as 

 to require the organization of a separate group of engineers. By progres- 

 sive evolution, such investigations and corrective measures eventually led 

 to the thorough organization of transmission maintenance work as we know 

 it, now such an important factor in making the actual transmission per- 

 formance of commercial telephone circuits closely approximate their theo- 

 retical design performance. 



In 1906 a substantiall}" increased fraction of the department effort was 

 concentrated upon various phases of electrical interference work. This 

 was made necessary by the increasing use of alternating current traction on 

 interurban trolley lines, and the projected single-phase electrification of 

 some important railroad systems, notably the N. Y., N. H., and H. R. R. 

 This particular project continued to require a lot of attention for over a 

 decade, initially in the electrification to Stamford and later in the exten- 

 sion to New Haven. 



Engineering and apparatus problems arising from the rapid growth of 

 loading, and the need to realize its maximum benefits took a great deal of 

 time. Thus, loaded underground toll cables between New York and Phila- 

 delphia, and between New York and New Haven, were completed during 

 1906. 



