i6o 



Conductivity of Aqueous Solutions. Part VI. 



The following are the data of these determinations, all of which were 

 made at 17.93 : 



Table 47. Conductance-capacity of the bomb. 



* To 18 and for the conductance of the water. 



It is evident from these results that the change of the conductance- 

 capacity with the time and the difference in the values of it determined 

 with the two solutions is trivial. The mean value, 0.14800, is therefore 

 employed in all the calculations of this article. 



The change of the conductance-capacity with the temperature was cal- 

 culated by the method and with the help of the data described in section 

 36, Part IV. The only really significant factor in this case determining 

 the correction was the expansion of the platinum-iridium electrode, which 

 had a height of 9.81 mm. and a diameter of 7.19 mm. The computation 

 shows that the conductance-capacity at 18 should be decreased by the 

 following percentage amounts at the following temperatures : 50 by 

 0.05; 75 by 0.07; 100 by 0.10; 125 by 0.14; 156 by 0.18; and at 218 

 by 0.26. These corrections were always applied. 



Measurements of some of the sodium hydroxide solutions were also made 

 in a U-shaped vessel. The conductance-capacity of this was determined by 

 measuring in it a 0.1 normal solution of potassium chloride made by dis- 

 solving 7.455 grams of the salt (weighed in air) in one liter of water at 

 18. The equivalent conductance of this solution was taken to be 112.03 

 as given by Kohlrausch and Maltby. As an accident happened to one of 

 the electrodes in the course of the experiments, the capacity had to be 

 redetermined, so that there are two values designated "Cell i" and "Cell 

 ii." The data obtained at 17.93 are given in table 48. 



