164 DISCUSSION OF EVIDENCE. 



At the end of the work done by Carroll, we seemed justified in 

 concluding that the conductivities of binary electrolytes in such sol- 

 vents as those already considered, are inversely proportional to the 

 coefficients of viscosity of the solvent and are directly proportional to 

 the association of the solvent. Bassett 1 showed that silver nitrate in 

 mixtures of methyl alcohol and water gave a conductivity minimum 

 at both and 25 ; also that the effect of one solvent on the other was 

 greater at than at 25. This would be expected, since the dissocia- 

 tion diminishes with rise in temperature, and each solvent would 

 probably diminish the association of the other less, the smaller its own 

 association or the higher its temperature. 



Bingham 2 not only measured the conductivities, but also the viscos- 

 ities of a number of solvents and solutions in these solvents. He found 

 minima in the conductivity curves in mixtures of acetone and water. 

 The distinctly new feature brought out by the work of Bingham was 

 that lithium and calcium nitrates in mixtures of acetone with methyl 

 and ethyl alcohols showed a pronounced maximum in the conduc- 

 tivity curves. This must be due either to an increase in dissociation 

 in such mixtures, increasing the number of ions present, and conse- 

 quently increasing the conductivity, or it must be due to a diminution 

 in the complexity of the solvates around the ions, increasing their 

 velocities. The dissociation was measured in the mixtures in question 

 and found not to account for the phenomenon. This eliminates 

 increase in dissociation and leaves the other alternative, diminution 

 in the complexity of the solvate, to account for the phenomenon. 



The ion must drag with it through the solvent any molecules of the 

 liquid with which it had combined. This would increase the effective 

 mass and diminish its velocity. Anything which would diminish the 

 complexity of the solvate about the ion would increase its velocity, 

 and consequently the conductivity. We must therefore conclude that 

 the solvates in those mixtures of acetone with the alcohols are simplest 

 where the conductivity is the greatest. 



Rouiller 3 studied both the velocities of the ions and the conductivities 

 of electrolytes in mixtures of acetone with the alcohols. Silver nitrate 

 in methyl alcohol and acetone gave a decided maximum of conduc- 

 tivity. His work on the velocities of the ions in these mixtures indi- 

 cated that the above explanation of the maxima offered by Jones 

 and Bingham was correct; there is a change in the complexity of the 

 solvate about the ion. 



McMaster 4 extended the work in the same solvents used byBingham- 

 water, methyl alcohol, ethyl alcohol, and acetone and in mixtures 

 of these with one another. He found conductivity results of the same 

 general character as those obtained by the earlier workers. Conduc- 



r. Chem. Journ., 32, 409 (1904). 3 Ibid., 36, 443 (1906). 



*Ibid., 34, 481 (1905). *Ibid., 326 (1906). 



