The integrations in the formula for Zst are extended over the wires 

 S and s; whose elements dS and ds are separated by distance r, and 

 include the angle « between their directions; the wires extend 

 from >1 to B and from a to b, respectively. Distances are in cm.; 

 conductivity in abmhos per cm. 



i=V^i 



w = 25r/=Radian frequency 



y = Horizontal separation between wires 



7^ = i4;r(DX a' = tt*+7» y^ = iATTu\j a,' = u^+y,^ 7'=land2 

 g>^r'+W 



X,+X, 



Struve's associated Bessel function, zero order.* 

 " " " " , first order.* 



Bessel function of first kind for imaginary argument, zero order.* 

 " " " " , first order.* 



" , zero order.* 

 Dnd kind for imaginary argument, zero order.* 

 ' " " " " , first order.* 



' " , zero order.* 

 ' " , first order.* 



Ei = Exponential integral, as defined by Jahnke and Emde, Funktionentafeln. 



.W°s. = Mutual Neumann integral of wires 5 and s = ff^^^dSds 

 -lKl) = .5772 = Euler'B Constant. 

 • As defined in G. N. Watson's "Theory of Bessel Functions," Cambridge, 1922. 



References 

 i Springer, Berlin, 1928, pp. 69-71. 

 o. 10, Nov. IS, 1930, pp. 1579-1588. 



unendlich langen Wechselstromdurchflossenen Einfachleitung, E. N. T., 3, Sept. 1926, pp. 339-359; 4, Jan. 1927, pp. 18-30. 

 1 Overhead Wires with Ground Return, Bell System Technical Journal, 5, Oct. 1926, pp. 539-554. 

 J von Wechselstrom durch die Erde, Z. ang. Math. «. Mech., S, Oct. 1926. 



(6) Breisig, F.; " Theoretische Telegraphie," F. Vieweg u. Sohn, Braunschweig, 1910, p. 86. 



(7) Campbell, G. A.: Mutual Impedances of Grounded Circuits, Bell System Technical Journal, Vol. II, No. 4, Oct. 1923. 



(8) Mayr, O.: Die Erde als Wechselstrom leiter, E. T. Z., Sept. 1925, pp. 1352-1355, 1436-1440. 



(9) Foster. R. M.: Mutual Impedance of Grounded Circuits, Bull. Am. Math. Soc, Vol. XXXVI, pp. 367-368, May 1930; Bell System Tech. 



(10) Carson, J. R.: Ground Return Impedance: Underground Wire with Earth Return, Bell System Technical Journal, Vol. VllI, pp. 94-98, J; 



(11) Rudenberg, R.: Die Ausbreitung der Erdstrome in der Umgebung von Wechselstrom Leitungen, Z. ang. Math. u. Mech., S, Oct. 1925, pp. 



(1) Ollendorff, F.: " Erdstrome," Juliu 



(2) Evans, H. P.: Phys. Rev., vol. 36, i 



(3) Pollaczek, F.: Ueber das Feld einei 



(4) Carson, J. R.: Wave Propagation i 



(5) Haberland, G.: Theorie der Leit 



Journal, Vol. X, pp. 408-419, July 1931. 



,n. 1929. 



361-389. 



