16 CONDUCTIVITY AND VISCOSITY IN MIXED SOLVENTS. 



holds, being independent of both temperature and concentration; that is, 

 the conductivities compared are approaching a limiting value at the same 

 rate, and either the dissociation is the same in the cases compared, or for 

 mixtures of alcohol and water conductivity is not a direct measure of disso- 

 ciation. Cohen is inclined to the latter view. 



Walker and Hambly 1 studied the conductivity of diethylammonium 

 hydrochloride in mixtures of water and ethyl alcohol. 



Hantzsch 2 made some interesting applications of results obtained by 

 studying conductivities in various mixtures. 



Tijmstra 3 investigated the conductivities of solutions obtained by the 

 action of mixtures of methyl or ethyl alcohol and water on sodium. In the 

 case of the mixtures of methyl alcohol and water the minimum was observed. 



Roth 4 made a careful study of the conductivity of potassium chloride in 

 mixtures of ethyl alcohol and water containing 8 and 20 per cent alcohol by 

 weight. He found that the relation given by Wakeman (loc. cit.) holds, 

 while that given by Cohen (loc. cit.) does not. The quotient 



/vH 2 O.Alc. 



was found to decrease with increasing dilution, and with increase in the amount 

 of alcohol in the mixture. This, Roth thinks, may indicate a decrease in 

 dissociation. The relation given by Arrhenius (loc. cit.) was also found to 

 be valid. 



The work of Wolf 5 and of Rudorf 6 needs no special consideration. 



CONDUCTIVITY AND VISCOSITY. 



That viscosity and conductivity are related is by no means a new idea. As 

 early as 1856, G. Wiedemann 7 studied aqueous solutions of copper sulphate, 

 and concluded that the conductivity of a solution is directly proportional 

 to the concentration, and inversely proportional to the viscosity. When for- 

 mulated this would be 



Kr] 



= constant 

 P 



where K is the conductivity of the solution of concentration p, and t] the 

 viscosity. 



Grotrian, 8 in 1876, measured the conductivity and viscosity of solutions at 

 different temperatures, but obtained indecisive results. 



1 Journ. Chem. Soc., 71, 61 (1899). 4 Ztschr. phys. Chem., 42, 209 (1903). 



2 Ztschr. anorg. Chem., 25, 332 (1900). B Ibid., 40, 222 (1902). 



Ber. d. chem. Gesell., 35, 1001 (1902). Ibid., 43, 257 (1903). 



'Proc. Kon. Akad. te Amsterdam, 7 Pogg. Ann., 99, 229 (1856). 



1903, p. 104. 8 Ibid., 157, 130 (1876). 



