344 H. D. Newton — Iron hy Potassium Permanganate, 



cooled, diluted a little, and filtered. To these concentrated 

 solutions of titanium sulphate, zinc was added until reduction 

 was complete, and while there was some zinc left in the flask 

 the solution was quickly filtered through a platinum cone into 

 about two liters of freshly distilled water contained in a small 

 reservoir, the latter being set up and connected with burette 

 and hydrogen generator as described by Knecht and Hibbert.* 



A test solution of ferric sulphate was prepared by treating 

 ferrous ammonium sulphate with oxalic acid, drying and 

 igniting the resulting ferrous oxalate, dissolving the ferric oxide 

 thus formed with concentrated hydrochloric acid, and convert- 

 ing the ferric chloride to sulphate by digesting with concen- 

 trated sulphuric acid. After diluting and filtering, the solution 

 was made up to known volume and standardized by drawing 

 from a burette into 50 cm3 flasks several portions, reducing each 

 b}^ a definite amount of zinc of known iron content, cooling, 

 pouring into a liter of cold distilled water and immediately 

 titrating with tenth normal potassium permanganate. 



In the following table are recorded results obtained by 

 effecting the reduction of carefully measured amounts of the 

 ferric sulphate solution by addition of an excess of titanous 

 sulphate in the cold, destroying this excess by treating with a 

 little bismuth oxide, filtering from the excess of bismuth oxide 

 and reduced bismuth into about a liter of cool distilled water 

 and titrating with permanganate. 







Taken 



Found 





2 (S0 4 ) 3 



KMu0 4 



Fe 2 3 



Fe 2 3 



Error 



cm 3 



cm 8 



grm. 



grm. 



grm. 



20 



13-46 







1063 



0-1064 



+ 0-0001 



20 



13-42 







1063 



0-1060 



— ; 0003 



20 



13-44 







1063 



0-1062 



— o-oooi 



20 



13-44 







1063 



0-1062 



— o-oooi 



20 



13-41 







1063 



0-1060 



— 0-0003 



30 



20-18 







1594 



0-1594 



o-oooo 



30 



20-20 







1594 



0-1596 



+ 0-0002 



30 



20-20 







1594 



0-1596 



+ 0-0002 



30 



20-22 







1594 



0-1598 



+ 0-0004 



30 



20-19 



9 



1594 



0-1595 



+ 0-0001 



40 



26-92 







212V 



0-2127 



o-oooo 



40 



26-90 







2127 



9-2125 



— 0-0002 



40 



26-90 







2127 



0-2125 



— 0-0002 



40 



26-93 







2127 



0-2128 



+ 0-0001 



40 



26-90 







2127 



0-2125 



— 0-0002 



In later experiments it was found that the bismuth oxide 

 failed to oxidize the sesquioxide of titanium when there was 



*Loc. cit. 



