VISCOSITY 



267 



TABLE X 



Concentration of KOH neutralized to phenolphthalein by 

 Casein =0.0250 N 



Walden (loc. cit.) found that for solutions of tetraethylammo- 

 nium iodide in thirty organic solvents the product of the molec- 

 ular conductivity of the salt at infinite dilution ( = u + v or, 

 the sum of the migration-velocities of its ions) and the viscosity 

 of its infinitely dilute solution is nearly constant, indicating an 

 inverse proportionality between the viscosity of the solution 

 (or what comes to the same thing at infinite dilution, the solvent) 

 and the migration-velocities of the ions which it contains. In 

 the accompanying table are given the values of p (u + v) X f? sol- 

 vent, for the various solutions investigated. 



TABLE XI 



It is evident that the product of the ionic mobility of potas- 

 sium caseinate ions at infinite dilution and the viscosity of the 

 solvent varies very much less than either of these quantities 

 taken alone, indicating in a qualitative sense at all events, that 

 the ionic mobilities of the caseinate ions are in the main determined 

 by the viscosity of the solvent. The observed increase in the ionic 

 mobility of the caseinate ions on increasing the alcohol content 

 of the solvent from 60 to 75 per cent, in view of the fact that the 

 viscosity of the solvents passes through a maximum at from 50 



