538 



Mr. G. U. Yule on tlie Passage of 

 Fig. 4. 



Electric 





■■ 







1 SI 1 





















1 Si il 























Centimetres 



120 



Transmission-curve (1) for 95 per cent, alcohol. 



, 9 s n f 3 vols. 95 per cent, alcohol. 

 ^ I01 { 1 vol. water. 



Numerical Results. 



For the very low conductivities with which we are here 

 dealing, we may safely regard the values given by the maxima 

 of the curves as the true wave-lengths, a correction for con- 

 ductivity being quite negligible. As the wave-length in air 

 is known to us, we may determine the coefficients of refrac- 

 tion (n) and the dielectric constants (k) of the various liquids 

 used by the ordinary relation 



-"-©• 



where X a , \ are the wave-lengths in air and the liquid re- 

 spectively. These wave-lengths are given in the first column 

 of Table II., and the corresponding values of the two con- 

 stants in the second and third columns. 



The experiments with zinc-sulphate solution show that an 

 addition of salt which largely affects the conductivity of a 



