100 



WORK OF H. R. KREIDER. 



Fig. 43 for dissociation corresponds to fig. 39 for molecular conductivity. The 

 relation between these two figures is similar to the relation between figs. 43 and 40. 

 In both cases the mixed solvents are ethyl alcohol and water. In this case we have 

 a binary salt, and the curves for figs. 41 and 43 are strikingly similar. 

 90- 



70- 



3 

 T3 

 C 



o 



05 



3 



50 



30 



Fig. 39. 



Conductivity of cobalt chloride in mixtures 

 of ethyl alcohol and water at 0. 



10 



25 50 75 



Per cent, of ethyl alcohol 



100 



The curves representing dissociation in ethyl alcohol-water mixtures are sometimes 

 upward curves, taking a direction opposite to that of the curves representing conduc- 

 tivity, which are downward curves. This fact is especially apparent when fig. 35, 

 giving the curves for the conductivity of potassium iodide in mixtures of ethyl alcohol 

 and water at 0, is compared with fig. 41, which gives the curves for the dissociation 

 of these same solutions. This plainly indicates that the greatly diminished conduc- 

 tivity in mixed solvents is due not to diminished dissociation, but to the other factor 

 conditioning conductivity, viz, diminished velocity of the ions through the solution. 

 Though it had been previously pointed out that this diminished conductivity is due 

 almost entirely to increased viscosity of the mixed solvent, it was not definitely 

 known what the magnitude of the dissociation in these mixed solvents is, nor was it 

 suspected that this dissociation might be greater in the mixed than in the pure sol- 

 vents, as is shown to be the case by the curves for dissociation, some of these curves 

 having maxima, while those of conductivity have decided minima. These facts are 

 quite marked where ethyl alcohol- water mixtures are used as solvent. In such cases 



