[archibald-fulton] 



ESTIMATION OF IRON 



247 



mother liquor as well as that dissolved by the wash Water should be 

 determined. The iron solution used in this series contained, as estim- 

 ated through the hydroxide and oxide, 11-402 grams of Fe CI3 per 

 litre, yielding 0-1403 gram of Fe2 O3 for every 25 cc. taken. The iron 

 in the wash water was determined by evaporating, adding a little 

 nitric acid, precipitating the iron with ammonium hydroxide, filter- 

 ing, igniting and weighing the oxide. In the case of the mother liquor 

 this was evaporated almost to dryness, treated with nitric acid to 

 destroy the excess of cupferron, finally diluted, and the iron pre- 

 cipitated with ammonium hydroxide and determined as before. 



The acid concentration of the washing solution was varied as 

 set forth in the table. The volume of this solution was 75 cc. for each 

 estimation. Each result tahrulated is the mean of two closely agreeing 

 values. 



Table III 



