Wave-trains through a Conducting Dielectric. 333 



I Ir I'" 



As y asymptotes to zero, and j- asymptotes to _I (70), 



-L lo I 



j 1 ^f — - > asymptotes towards the value 1— I!"/I : that is 



to say, when the layer of electrolyte gets very thick all is 

 absorbed but the ray reflected from the first surface. 



The expression for ~ given in (71) may be checked bv 



putting a 2 zero. Taking the three parts (65) (69) (70) sepa- 

 rately, the first becomes at once 



v 



where j- is the expression given in (51) or the following 

 equation. The second part reduces to 



S 1 °) l-2£ 2 cos2S + ? 4 -1-^ -(l + 5 2 )^ 



The third part gives simply b c \ Adding up we get 



The expression for ^ also becomes greatly simplified if we 

 take the incident ray to be non-damped. In this case 



secx=x>, (o = ^=zhe kd 

 as before, and 



Ir_C 2 / 2 f 4 



t 



1 6 2 l-2f cos2S + f 4 



-2cf P- cos (^ + a -- 2S )-P co s(^ + «) 

 * m * " l-2g 2 cos2S + £ 4 



+*■ • • • . (71a) 



If wenow put a 2 =0, we have &> = f = b, and S=^ and so 

 on, as given on p. 325, and the expression becomes 



