218 



REV. S. M. JOHNSTON 



These results are interesting from the standpoint of reading values from curves.* 



1 have also plotted equivalent conductivity against the number of litres to the 

 gramme equivalent (fig. 11). 



This was done that the curves obtained in this way might be compared with the 

 corresponding curves obtained from Krannhals' conductivity values. The curves 

 obtained in this manner from his data and mine were quite similar in form. 



Jones and West t have pointed ' out that the dissociation of a salt in a solution of 

 known concentration decreases as the temperature of the solution is raised from 0° 

 Centigrade to 35° Centigrade. As they have determined the ionization of some salts 

 at temperatures varying from 0° Centigrade to 35° Centigrade, for which I have 

 determined it at 99 '4° Centigrade, I have been able to make a comparison between 

 the ionizations at the lower temperatures at which they worked and those at 99'4° 

 Centigrade. In every instance the ionization at the higher temperature was found 

 to be smaller than that at the lower temperature. 



The following is an illustration taken from the ionizations of ammonium chloride 

 from Jones and West's data and mine. 



Litres per 

 Gramme eq. 



Ionization 



Ionization 



Ionization 



at 0° C. 



at 35° C. 



at 99-4° C. 



Jones and West. 



Jones and West. 



M ine. 



1 







•629 



2 



•840 



■777 



•681 



4 







•751 



8 



•884 



•854 





10 







•808 



16 



•908 



•886 





20 







•857 



32 



•938 



•919 





40 







•895 



80 







•913 



128 



•976 



•965 





200 







•960 



512 



•994 



■989 





1000 







1-000 



1024 



1-000 



1000 





The figures given above show that the effect of increase of temperature on ionization 

 is to diminish ionization for a solution of given concentration, and that the diminution 

 of ionization increases with the concentration of the solution, and becomes zero at 

 zero concentration, as one would expect, the ionization coefficient at any temperature 

 having become unity. Consequently, were the above results represented graphically 

 by curves obtained by plotting litres per gramme equivalent against the ionization 

 coefficients for several temperatures, the temperature being constant for the same curve, 



* In a paper read recently at the Royal Society, Edinburgh, Dr Gibson has pointed out a somewhat similar result, 

 t Am. Ghent. Journ., vol. xxxiv.. No. 4, 373 (1905). 



