GENERAL SUMMARY AND CONCLUSIONS. 223 



It was also shown in this investigation that the hyperbola, and not the 

 straight line, is the normal curve of viscosity. 



While the work of Rouiller had to do more especially with the velocities of 

 ions in mixed solvents, yet he studied the conductivities of silver nitrate in 

 acetone, in mixtures of acetone with water, in mixtures of methyl alcohol with 

 ethyl alcohol, in methyl alcohol and acetone, and in ethyl alcohol and ace- 

 tone. 



Silver nitrate, in mixtures of methyl alcohol and acetone, and ethyl alcohol 

 and acetone, shows a pronounced maximum in conductivity strictly analogous 

 to calcium nitrate, which had been studied in these solvents by Bingham. 

 This maximum is pronounced at both and 25, appearing in the 25 per cent 

 acetone mixture in the more concentrated solutions, and shifting with increase 

 in dilution through the 50 per cent to the 75 per cent mixture. 



The work of Rouiller on the migration velocity of ions in mixtures of these 

 solvents would indicate that the explanation of the conductivity maximum 

 offered by Jones and Bingham is correct there is a change in the atmos- 

 phere of the solvent about the ions. 



The investigation of McMaster included the same solvents that had been 

 used by Bingham water, methyl alcohol, ethyl alcohol, and acetone, and 

 binary mixtures of these solvents. 



The electrolytes used were lithium bromide and cobalt chloride. The con- 

 ductivities of a large number of solutions of these substances in the above 

 solvents and in binary mixtures of these solvents were measured. 



The fluidities of water, methyl alcohol, ethyl alcohol, and acetone, and 

 binary mixtures of these solvents, were also measured. The conductivities in 

 mixtures of the alcohols with water, and in the mixtures of acetone with water, 

 show a well-marked minimum. This minimum in conductivity was more 

 pronounced at the lower temperature, and was intimately connected with the 

 minimum in fluidity observed in the above mixtures. 



The conductivity curves in mixtures of methyl and ethyl alcohols are nearly 

 straight lines, obeying the law of averages, as we should expect. Lithium 

 bromide dissolved in mixtures of methyl or ethyl alcohol with acetone, shows 

 a pronounced maximum in conductivity. The conductivity maximum was 

 also given by cobalt chloride in mixtures of acetone with ethyl alcohol. 



The fluidities of lithium bromide in mixtures of acetone with the alcohols were 

 found to be what would be expected from the rule of averages the fluidity 

 curves being nearly straight lines. The same was found for the pure solvents. 

 This would indicate that the alcohols and acetone do not form more complex 

 aggregates when mixed than when alone. 



We are therefore forced to the same conclusion as that reached by Jones and 

 Bingham, i. e., that the size of the ionic spheres is an important factor in 

 determining conductivity, and that changes in the sizes of these spheres in 



