116 CONDUCTIVITY AND VISCOSITY OF SOLUTIONS. 



SUMMARY. 



The viscosities and conductivities of a number of rubidium salts have 

 been measured in various mixtures of acetone and water. 



Rubidium salts increase the viscosity of all mixtures containing a 

 larger percentage of acetone. 



The curve representing the fluidities of a solution of any of these 

 salts in the various solvents crosses the curve for the solvents in the 

 neighborhood of the 50 per cent acetone-water mixture. 



Negative viscosity coefficients, wherever found, were much smaller 

 than corresponding values in water or glycerol. 



The temperature coefficients of fluidity of acetone-water mixtures 

 are very small and decrease with rise in temperature. 



The largest temperature coefficients occur in the mixture containing 

 50 per cent acetone, i. e., the curve representing temperature coeffi- 

 cients passes through a maximum at that point. 



\ Minima in the conductivity curves for rubidium salts correspond to 

 a higher percentage of acetone in the solvent mixtures than do those 

 in the fluidity curves, whereas the two curves are parallel for certain 

 other salts. A possible explanation based on the difference in solu- 

 bility is offered. 



A comparison of the temperature coefficients of conductivity and 

 fluidity shows that these are what is to be expected in the case of a 

 non-solvated salt in a mixture of associated solvents. 



A possible indication of solvation of rubidium salts in dilute solutions 

 is pointed out. 



