104 ON THE CALCULATION OF THE CONDUCTIVITY OF 



in each row applying to solutions found as above to be isohydrio 

 with one another : 



It will be observed that while the numbers in the various 

 horizontal rows shew a general agreement, they differ very 

 considerably from one another, the extreme differences ranging 

 from 0.7 to 20.5 per cent. 



He found also that two solutions of ammonium acetate and 

 acetic acid respectively, which were determined in the above 

 way to be isohydric with one another, contained, according to 

 Kohlrausch, amounts of the ion C H 3 COO which were in the 

 ratio 1 : 0.79, a ratio which is only very roughly equal to unity. 



So far as result is concerned, these tests are not satisfactory; 

 but the lack of agreement may have been due to various causes : 

 (1.) the data for calculation may have been defective, (2) the 

 change of volume which would doubtless occur on mixing, even 

 with very dilute solutions, may have been too great for the : 

 application of Arrhenius's deduction, and (3) the difference 

 between the values of fi x in simple solution and in a mixture, may 

 be too great to admit of the identification of isohydric solutions 

 by the method employed. 



On the other hand, Arrhenius has calculated* the conductivi- 

 ties of two dilute solutions containing in each case given 

 quantities of two acids, employing for this purpose a series of 

 approximations based on his own observations of isohydric 



*Wiedemann's Annalen, xxx, p. 73 (1887). 



