SUMMARY. 113 



case of mixtures which tend to reduce the large atmospheres of the dilute 

 solutions, the mass action of the solvent is much diminished. 



Calcium nitrate is intermediate in its behavior between potassium iodide 

 and lithium nitrate. It seems reasonable to connect this with the migration 

 velocity. It would be interesting to experiment with sodium, the ion of 

 which has a slow migration velocity; but, as we have shown, sodium iodide, 

 although soluble, is unsuited for this purpose. 



SUMMARY. 



We have measured the fluidities of mixtures of acetone with methyl alcohol, 

 ethyl alcohol, and water, and of a few solutions of calcium nitrate in these 

 mixtures. 



We have measured the conductivity of various concentrations of lithium 

 nitrate, potassium iodide, and calcium nitrate, dissolved in the above 

 mixtures. 



These conductivities, in the case of mixtures of acetone and water, exhibit 

 the minimum in conductivity previously observed by several other workers. 

 Moreover, this minimum in conductivity has been shown to be intimately 

 connected with the minimum in fluidity observed in these mixtures, but the 

 conductivity curves of different salts show marked differences. 



In the mixtures of acetone and the alcohols, the fluidities are what we 

 should expect from the law of averages, i. e., the fluidity curve is nearly a 

 straight line. From this fact we have concluded that acetone and the alco- 

 hols thus far studied do not form more complex molecular aggregations when 

 mixed than were originally present before mixing. 



The conductivities of potassium iodide, in mixtures of acetone with methyl 

 alcohol or ethyl alcohol, are also what we should expect from the law of 

 averages the conductivity curves are nearly straight lines at all dilutions. 

 Again, the conductivity has been shown to be intimately connected with 

 fluidity. 



Lithium nitrate and calcium nitrate, however, give a very pronounced 

 maximum in conductivity, in mixtures of acetone with methyl alcohol or ethyl 

 alcohol. Evidently this was an unexpected phenomenon; to explain it, all 

 of the factors that could reasonably influence conductivity were collected. 

 After the elimination of several of them, the possible explanations were 

 shown to be, either an increase in dissociation giving rise to more ions, or 

 a diminution in the size of the ionic spheres already in the solution. 



It was then shown to be possible to eliminate one of these factors by the 

 following considerations : 



(1) The fluidity of the mixtures of acetone and alcohol shows that there is 

 no increase in molecular aggregation, hence we should not expect increased 

 dissociation, if we accept the hypothesis of Dutoit and Aston. 



