LOADIXG FOR TELEPHONE CIRCUITS 281 



ing is such that it is iiiii)rcicti(-al)Ic' lo assign to each its share of the 

 savings — and t.iking inl(j consideration only the loading of interoffice 

 trunks and toll open wire circuits, it has been estimated that the larger 

 wires which would luuc been recjuired to gixc tlie i)rcsent grade of 

 transmission if lo.iding had not been a\ailable, taken togetlier with 

 the heavier pole lines and additional tniderground ducts, would ha\e 

 entailed an additional inxestnient in Bell System telephone plant of 

 over 5100,000.000. 



BIBLIOGRAPHY 



In addition to the references already cited, the following will be of interest: 



Vaschy, Annales Telegra phiques, \8S6, p. 321. 



Heaviside, Electrician (London) June 3, 1887. 



Vaschy, La Liimiere Electrique, 1889, 31, 83. 



Heaviside, "Electromagnetic Theory," Vol. 1, 1893, p. 441. 



S. P. Thompson, "Ocean Telephony," Proceedings Electrical Congress, World's 

 Fair at Chicago, 1893. 



M. I. Pupin, "Propagation of Long Electrical Waves," Trans. A. I. E. E., \'ol. 16, 

 1899, 93. 



W. A. J. O'Meara, ".Submarine Cables for Long Distance Telephone Circuits," 

 Journal L E. E. London, April, 1910. 



F. Bresig, Theoretische Telegraphie, 1910. 



J. A. Fleming, "Propagation of Electric Currents," Van Nostrand Company, 1911- 



A. E. Kennelly, "The Application of Hyperbolic Functions to Electrical Engineer- 

 ing Problems," University (London) Press, 1912. 



A. Ebeling, ETZ., 1914, p. 695 and p. 728. 



K. W. Wagner, Archiv fiir Electrotechnik, Vol. 3, 1915, p. 315. 



J. G. Hill, "Telephonic Transmission," London, Longmans, 1920. 



K. W'. Wagner, and K. KiifTmuller, Archiv fiir Electrotechnik, Vol. 9, 1921, p. 461. 



Sir Wm. Noble, "Long Distance Telephone Svstem of the United Kingdom," 

 Journal I. E. E., Vol. 59, p. 389, 19.21. 



Das Fernsprechen Im Weitverkehr — Reichspostministerium, Berlin, 1923. 



R. S. Hoyt, Impedance of Smooth Lines and Design of Simulating Networks, BeV- 

 System Technical Journal, .April, 1923. 



L. D. Cahen, Le Progres et I'Etat Actuel de la Technique des Liques Pupinisees — 

 Bulletin de la Societe francaise des Electriciens Aug.-Oct. 1924 (4 Serie), 4:755. 



K. S. Johnson, Transmission Circuits for Telephonic Communication, Van Nos- 

 trand Co., 1925. 



