104 ON THE CALCULATION OF THE CONDUCTIVITY OF 
in each row applying to solutions found as above to be isohydrie 
with one another : 
HCl (COOH), | C,H, 0, | HCOOH |CH, COOH 
151.5 WEG eal p beast: by scene 
42.3 5c Ms vce UL oD oacoee  e 
22.08 21.37 1007. | - 52.01 oy ere 
4.48 4,09 4.17 4.42 3.96 
1.38 1.24 1.25 1.44 1.38 
0.379 0.397 Get saves 0.402 
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,; C O O which were im 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 (8) the difference 
between the values of uw» 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 caleulated* the econductivi- 
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). 
