POTASSIUM IODIDE. 



27 



TABLE 7. Molecular conductivity of potassium iodide. Continued. 



The conductivity of solutions of potassium iodide in methyl alcohol had 

 already been determined by both Zelinsky and Krapiwin, 1 and Carrara, 2 

 but with such different results that the above measurements seemed neces- 

 sary. Our measurements agree very well with those of Zelinsky and Krapiwin, 

 as is seen from table 7. 



TABLE 8. Temperature coefficients o/ conductivity of potassium iodide. 



Some of the results given in table 7 are plotted in fig. 3. The curves are of 

 the same general form as the preceding. The chief points of difference are : 

 The minimum point has shifted to the right, corresponding now to an alcohol- 

 water mixture of about 65 per cent. The increase to the right of the mini- 

 mum is much less rapid than that to the left, the difference being due to the 

 fact that the temperature coefficient of conductivity is much greater in water 

 than in methyl alcohol. The alcohol-water mixture, having the same con- 

 ducting power as the solution in pure methyl alcohol, has also changed. In 

 this case it changes from an alcohol of about 19 per cent to an alcohol of about 

 30 per cent, depending upon the concentration of the solution. 



1 Ztschr. phys. Chem., 21, 35 (1896). 



2 Gazz. Chim. Ital., 26, (1) 119 (1896). 



