64:6 Prof. Morton on the Speed of Propagation and 



It is easy to find the shape of the curve at its extremes : 

 (1) For very large values of x, i. e. well-developed " skin- 

 effect." J,(«VO — ; 



JaO si) 



s/i 



cm- 



1 + 



X loo" 



^2..,log- 



" 2 •s.lo ' 



'-j- • • • (3) 



Oft 



£=_ J - 



2 */2.*.loff- 

 , = 1 1 - 



* \/i . ,<■ . log 



b 



S + V=l (4) 



/. g. a straight line inclined at 45° to the axes. 



This part of the curve is compressed into very small scale 

 at the upper part of the diagram. 



(2) For very small cables of a, the current penetrating to the 

 core of the wire. J (*>s/i) 2 



JiU' \/T) = m si* 



\ 17 / 2 1 ' y 



ar loo; — 

 °a 



We may neglect unity in comparison with the large term 

 which follows, and so obtain 



, + ^ = 77rr (5) 



'V lo s, 



, = . % /l ,- ( 

 fr=l • («) 



