LEWIS AND WHEELER. — CONDUCTIVITY OF SOLUTIONS. 



423 



by Kahlbaum, the other was made according to the method of Andrews, * 

 by heating together potassium bichromate and potassium iodide. Both 

 varieties were further purified by resublimation and gave identical 

 results. For determining the conductivity of pure iodine a still purer 

 variety was desired. Its preparation will be described later. 



Experimental Results. 



In the first experiments measurements were made at the three tem- 

 peratures, 120°, 140°, and 160°. Later, on account of certain irregu- 

 larities at the lowest temperature, measurements were confined to the two 

 higher at which uniformity in the composition of the solution could be 

 established with less difficulty. 



A large number of experiments made before the technical difficulties 

 were entirely overcome need not be considered in detail, as they were 

 followed by more accurate experiments covering the whole field. The 

 example given in Table I (Preliminary Series) will suffice to show the 

 general character of the results. L represents the specific conductivity. 

 C expresses the strength of the solution in grams of potassium iodide to 

 100 grams of iodine. For the sake of convenience we will refer to this 

 as the concentration. We have not yet made exact enough determina- 

 tions of the specific gravities of the different solutions to enable us to give 

 the true concentrations in gram-molecules per liter, but for dilute solu- 

 tions this molecular concentration may be considered as proportional to C. 



TABLE I. 

 Preliminary Series. 



* Amer. Cliem. Jour. 30, 428 (1903). 



