Dr. T. Ewaii. On the 



/ 0-1042 gram FeoO 3 . 

 250 c.c. of a solution of the salt gave < O .e 6 qq Ao-H 



I U t>^>Oi7 ,, AgX/1. 



142 



Pi 



From which ratio = 1'913. 

 Fe 



Ratio calculated for Fe 2 Cl 6 = 1-903. 



Two other solutions which were subsequently analysed, con- 

 tained 



and 



1*882 grams eqs. Fe per litre to 1*864 grams eqs. Cl. 

 0-0303 0-0296 



The dilute solutions made by diluting a concentrated solution of 

 known concentration, were allowed to stand for some weeks at the 

 ordinary temperature (15 16), so that a condition of equilibrium 

 was almost certainly reached. 



The following table contains the results of the filtration experi- 

 ments. The concentrations are here (as elsewhere in the paper) 

 given in gram molecules per litre, the molecule of the ferric salts 

 being always taken, for convenience, as the quantity containing one 

 atom of iron. 



Table XL 



The decrease in the concentration of chlorine in the solutions, 

 caused by filtration, is so small (in one case there was even an in- 

 crease), that it appears probable that the substance separated from 

 the solutions is really a hydroxide of iron, and contains no chlorine. 

 The changes of concentration of the chlorine are probably sufficiently 

 explained by the errors inherent in the method used, which have 

 been already mentioned. On the other hand the loss of iron in- 

 creases as the solutions become more dilute. 



Walker* found, in an investigation on the hydrolysis of the salts 

 of some weak bases, that the decomposition took place in agreement 



* ' Zeitschrift f. Phys. Chem.,' vol. 4, p. 319, 1889. 



