432 PROCEEDINGS OF THE AMERICAN ACADEMY. 



vacuum, but this iodine had to be exposed to the air while being intro- 

 duced into the cell. It gave a conductivity which was of the same order 

 of magnitude as previously observed. 



These experiments unfortunately were interrupted before completion. 

 We will therefore postpone a discussion of them until they can be 

 repeated with more care. 



It is our intention to return to this subject as soon as circumstances 

 permit, and also to study the solubility and conductivity of other salts in 

 iodine, to determine the molecular weight in these solutions, and finally, if 

 any suitable method can be found for attacking so difficult a problem, to 

 determine from the changes at the electrodes during the flow of the cur- 

 rent whether or not the conductivity is altogether electrolytic in character. 



Summary. 



Potassium iodide is readily soluble in liquid iodine, forming solutions 

 which when concentrated conduct the electric current as well as the best 

 aqueous solutions. 



The dependence of the conductivity upon the concentration is deter- 

 mined over a wide range. 



In dilute solutions the molecular conductivity increases linearly with 

 the concentration, rising to a maximum and then falling again. 



The probable connection is shown between this anomalous behavior 

 and the deviations from Ostwald's dilution law in water solutions. A 

 hypothetical explanation of both these phenomena is offered. 



The temperature coefficient of conductivity is negative for dilute solu- 

 tions, but with increasing concentration passes through zero and becomes 

 positive. 



Pure iodine in all probability possesses a conductivity of its own, but 

 this can be definitely determined only by further experiments. 



