2h? 



again the independence of such influences — and as moreover it 

 was evident from these experiments that solutions, thus prepared, 

 were more constant and therefore more fit for experiment, we finally 

 carried out OHr measurements of the lower concentrations on acid 

 solutions only. 



So here too the constancy of n showed itself. 



To be able to calculate the results, special measurements were 

 required on sulphuric acid and out of the following dates the 

 average value for lower concentrations 'i AO^ =z — 0.358 is used. 



The dates, marked * are taken from Cabrkra '). 



TABLE III. Sulphuric acid. 



Notwithstanding tliis, there still I'emained the first deviations in 

 the strongly diluted solutions and the question was to which cause 

 they ought to be attributed. 



It was natural to consider the increased magnetisation as the effect 

 of oxydation, the more so since Cabrkra and we found higher 

 values for the ferric sulfate. 



However, a solution of 0.25% with an excess of acid of J.047o) 

 gave, after having been heated in boiling water and cooled again, 

 exactly the same value. 



This experiment might be considered as a disproof. At the same 

 time it shows how (he addition of an acid is an essential condition 

 to the constancy of the solution, so tiiat finally the chief cause seems 

 to be the hydrolysis, which is checked by the acid. 



1) Cabrera, Arch, des Sc. Ph. et Nat. Dec. 1913 Geneve. 



