8o 



Conductivity of Aqueous Solutions. Part IV. 



ductance of a 0.01 normal sodium chloride solution between this electrode 

 and the sides of the bomb was determined. Brass electrodes of three dif- 

 ferent diameters (0.475, 0.72, and 0.95 cm.) were used. 



The lengths of the electrode were plotted against the conductances for 

 the three diameters and the diameters of the electrode against the conduct- 

 ances for the different lengths. From these plots, the ratio of the frac- 

 tional change in conductance to that in length for a given diameter or to 

 that in diameter for a given length can be computed. The values of the 

 ratios so derived for a series of lengths and diameters are given in table 



16, those of -zttt in the columns headed I and those of -~t, in the columns 



headed n. 



81/1 



hd/d 



Table 16. Change in conductance-capacity with the dimensions of the electrode. 



The variation in the conductance due to a change in diameter of the 

 large cylindrical vessel was determined in the presence and absence of a 

 cup by measuring the conductance of a 0.01 normal sodium chloride solu- 

 tion between the small electrode and brass cylinders (diameters of 3.66, 

 3.35, 2.39, and 1.75 cm.) placed successively inside of the outer cylinder. 

 The effect of the increase of diameter of the bomb which would occur even 

 up to 400 on the conductance-capacity was less than 0.1 per cent. 



The linear expansion coefficients (dl/l dt) used in computing the 

 change in conductance-capacity of the bombs were as follows : 



