138 



CONDUCTIVITY AND VISCOSITY 



ductivity curves are not as full as could be desired. For acetone the 

 value is taken from the data of Jones and Bingham 1 on potassium 

 iodide for a N/200 solution at 25. The data for rubidium bromide 

 in glycerol and in water are taken from the work of Jones and Davis. 2 

 The action of potassium and rubidium salts in relation to conductivity 

 are similar enough for the purpose of this comparison. The 2-1-1 

 ordinate shows that the measured conductivity is 19.2 per cent of the 

 calculated. That the curves have the same character is another evi- 

 dence for the close relation existing between conductivity and fluidity. 

 In figure 58 the solvents are arranged from left to right in the order 

 of the percentage of glycerol which they contain; hence the curves 

 show that the more glycerol the solvents contain, the more the con- 



FIG. 57. Conductivity and fluidity temperature coefficients 

 for N/10 solution of ammonium iodide in glycerol, 

 acetone, and water. 



ductivity and fluidity values depart from the calculated averages. 

 The theory of Jones and Veazey states that viscosity is due to the 

 friction between the particles of the liquid. It is clear that the smaller 

 the particles the greater will be the amount of frictional surface 

 between them; hence, the greater the viscosity of any homogeneous 

 liquid, the smaller must be the particles composing it. The density 

 of the liquid should also affect the viscosity. The densities of glycerol, 

 water, and acetone are 1.26, 1.00 and 0.79, respectively, while the 

 fluidities are in the ratio 1 : 702 : 1741 ; hence the variation in density 

 is so small in comparison with the variation in fluidity that the former 

 can be neglected. It seems probable that there is one other important 

 factor that affects fluidity, which must be considered in addition to 

 the size of the particle. The particle in a pure homogeneous liquid 

 would be either one molecule or an association of molecules. 



Carnegie Inst. Wash. Pub. No. 80. 



2 Ibid., No. 180. 



