114 CONDUCTIVITY AND VISCOSITY IN MIXED SOLVENTS. 



(2) Jones and Carroll have proved that, even in the case of alcohol and 

 water, there is practically no increase in dissociation in the mixtures. 



(3) Furthermore, the maximum migrates from the 25 per cent mixture, 

 at high concentration, to the 75 per cent mixture in the more dilute solutions. 

 This would hardly be expected if the dissociating power is greatest in a certain 

 mixture. 



(4) Potassium iodide shows no tendency towards a maximum of conduc- 

 tivity in the most concentrated solution with which we worked. 



(5) Very recent measurements, at extreme dilution, have failed to show 

 any great difference in the dissociating power of the mixtures from that of the 

 pure solvents. 



We, therefore, seemed justified in the conclusion that the maximum in 

 conductivity is due to a change in the dimensions of the atmospheres about 

 the ions. 



The conclusion of Dutoit and Friderich and of Jones and Carroll, that con- 

 ductivity is proportional to the dissociation, and inversely proportional to 

 the viscosity, has been shown to be incomplete in not taking into consideration 

 possible changes in the size of the ionic spheres. 



The conductivities of lithium nitrate and calcium nitrate, in mixtures of 

 acetone and water, again show a tendency towards a maximum, in spite of 

 the great diminution in fluidity. 



Finally, it has been pointed out that the tendency to form a maximum in 

 conductivity increases from potassium iodide, through calcium nitrate, to 

 lithium nitrate, which seems to show these effects most strongly. This may 

 be connected with the migration velocities of these ions. 



