INTRODUCTION. 3 



Potassium iodide, strontium iodide, and lithium nitrate give minima in the 50 per 

 cent mixture at 0, which move to the 75 per cent mixture at 25. 



A method was then devised for comparing the variations in fluidity and conduc- 

 tivity, and for studying the effect on conductivity of changes in fluidity. The dif- 

 ferences between the (calculated) average values and the observed conductivities 

 and fluidities in the various mixtures were expressed in percentages, and in all cases 

 the variation in fluidity was found to be greater than the variation in conductivity. 



Letting A< and A^ represent the two variations, then -'represents the rela- 



A<p 



tive effect of variation in fluidity on conductivity. If the two effects are equal, the 

 expression becomes equal to zero. It was found that in the 40 per cent mixtures 

 the effect of change in fluidity on conductivity is greatest. Finally, the tempera- 

 ture coefficients of conductivity and of fluidity were not found to differ markedly; 



in other words, is nearly a constant. 



Jones and Carroll therefore conclude that the decrease in conductivity in binary 

 mixtures is due primarily to a decrease in the fluidity of the solvent, and, conse- 

 quently, a decrease in the ionic mobility, and secondarily to the effect of one asso- 

 ciated solvent on the association of another. 



A quantitative study of the relation between the conductivity and viscosity of 

 different solutions was then made. In order that data for different solvents might 

 be comparable, measurements were made with "comparable equivalent solutions," 

 that is, solutions containing the same number of gram-molecules of electrolyte in 

 the same number of gram-molecules of solvents. The result was that the conduc- 

 tivities of such solutions were found to be inversely proportional to the viscosity 

 of the solvent, and directly proportional to the association factor of the solvent, or 

 to the amount of dissociation of the electrolyte in that solvent. Otherwise expressed, 



= constant, or- 5 - = constant. 

 x a 



The work of Bassett 1 showed that silver nitrate, in mixtures of methyl alcohol 

 and ethyl alcohol with water, presented phenomena entirely in accord with the obser- 

 vations of Jones and Lindsay and of Jones and Carroll. The conductivity curves 

 for ethyl alcohol-water solutions fall far below the straight line of averages, but give 

 no minima; the methyl alcohol-water curves, on the other hand, give well-marked 

 minima at both and 25, the variation from the average being more pronounced at 

 the lower temperature. 



Jones and Bingham 2 introduced another solvent into the investigation, namely, 

 acetone. The electrolytes studied were lithium nitrate, potassium iodide, and 

 calcium nitrate, and quite unexpected results were obtained. Lithium nitrate, in 

 mixtures of acetone and water, gave curves with an inflection-point at low dilutions' 

 and at 0, which developed minima in the higher dilutions at 0. The conductivity 

 curves for solutions in mixtures of methyl and ethyl alcohols with acetone gave 

 maxima which, in the higher dilutions, occurred always in the mixtures containing 

 75 per cent acetone. The curves are very nearly straight lines below this point, but 



lAmer. Chem. Jour., 32, 409 (1904). Vbid., 34, 481 (1905). 



