424 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



We note at once the marked decrease of conductivity with increase of 

 temperature. This negative temperature coefficient, although it suggests 

 the behavior of metals, in no way proves that we are dealing here with a 

 case of metallic conductivity. Many electrolytic conductors are known 

 which show the same behavior ; usually, it is true, in the case of solvents 

 not far removed from their critical temperatures, but even in water a 

 few substances, such as phosphoric acid, have negative coefficients. We 

 shall see presently how the temperature coefficient of the iodine solutions 

 changes with the concentration. 



It is also evident from the table that the conductivity increases rapidly 

 with the concentration and in fact more rapidly than the concentration 

 itself. This fact can be better shown if we pass at once to the considera- 

 tion of the following tables, containing Series 1 and 2. In these tables 



M represents the quotient ^, and is therefore for these dilute solutions 



proportional to the molecular conductivity. Before taking this quotient 

 we have subtracted from the observed values of L the specific conduc- 

 tivity of the iodine, thus correcting for the original conductivity of the 

 solvent, as is customary in aqueous solutions. 



TABLE II. 

 Series 1. 140° 



