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BELL SYSTEM TECHNICAL JOURNAL 



employed in the previous paper in a similar derivation for wires on 

 the surface. For our present problem we use his formulae for the 

 Hertzian vectors due to horizontal and vertical electric antennai above 

 the surface of the earth. It is important, at first, to retain a non- 

 1.3 



1.2 



4 5 6 



VALUES OF r' 



Fig. 13 — Real and imaginary parts of 



7 8 



iVo(r') 



vanishing value of the capacitivity of the air. From these formulae we 

 obtain the vector II, due to a current flowing through a horizontal 

 element of wire of length dS at height // above the surface of the 

 earth, grounded by vertical wires at its end-points. Next, we obtain 

 the electric field E in the air by the relation: 



