EFFECT OF GROUND PERMEABILITY 473 



of them are tabulated for values of (x from 1 to 1.7 to provide for the 

 computation of P and Q for values of ry up to 2. 



Equation (1)^ is unchanged but there is a new definition for a 



a = 47rX/xco. 



Since curl E = — {dldt)yLH equations (2) and (3) have the factor ^ 

 added to their left hand sides. 



The next change is in the application of the boundary conditions. 

 At the surface of the ground H,- and filLj must be continuous. The 

 equations to be solved for F{t) and 0(r) now become 



1 



whence 



-^ Vr'' + la F{t) = 2/e-''- + 0(r), 

 ^tF{t) = lie-''-' - cP(t), 



^w-,/;-^': 47, (11) 



'Vr'' -\- la -\- IJ.T 



4>{r)= '^;]^'^- ^e~"r2L (12) 



Vr- + la + jXT 



The new equations (13), (14), (18), (19), (20), (23) and (24) are 



£, = - 7'4co/m r ^"^.•^ " - f-r''+W^^+^^^^ (13) 



Jq vt' + ia + /UT" 





(14) 



• 00 ,,-(ft'+2/')r 



Ez — — lAo^Ifx I , cos .v'rJr 



f2c./log^-^F, (18) 



p OS 



'00 p-{h'+p')T 



^•00 ^-(ft'+2^')T " 



'/4w/m . ^r - i2a;/log— + TV, (19) 



Jo Vr" + i + ;ur ^ 



n = (G + tcoC) r z + /2co log^' 



-]- 7'4a;/i 



-\- I + tXT 



, (20) 



