132 



we may assume 



which give 



? 1 =i 



and we find from the equations of conduction, 



CASE IV. Cable of six wires symmetrically arranged. 

 Equations of mutual influence, 



&c. &c. &c. 



Equations of conduction, 



- 

 dt dtf \fa? dy?r\da? d^J da*' 



Then assuming 



which require that 



W i+w 2 + ft> 3 =0, and 

 we have 



These equations, integrated hy v the usual process to fulfil the pre- 

 scribed conditions, determine <r, S, w lt w. 2 , u) 3 , p l} p 2 , p 3 ; and we then 

 have, for the solution of the problem, 



