220 Proceedings of the Royal Society of Victoria. 



Possibly this may account for Maumen^, Feilitzen and Tollens 

 and others obtaining results indicating that MnjOg and not 

 MnOa is precipitated by sugar from solutions of KMnO^. 



Morse and Reese (Am. Chem. lourn.., 20, July) contend that 

 the evolution of oxygen observable in most cases where K]\[n04 

 is reduced to MnOa is due to this action of the precipitated 

 peroxide on the excess of KMnO^. 



Jones {Journ. Chem. Soc, 1878, p. 95), Tivoli (1890) and 

 Gorgen {Compt. Rend., 110, p. 958) have examined the action of 

 various reducing agents on KMnO^, and obtained results 

 confirming this opinion. 



Two German Chemists, Meyer and Recklinghausen (Berichte 

 d. Chem. Ges., 29, p. 2828), found that when Hydrogen or 

 Carbon monoxide was absorbed by strong solutions of KMn04 

 oxygen was evolved and MnO.^ precipitated ; but they argue that 

 this liberation of oxygen was not due to the action of MnO.^ on 

 KMnO^, as the evolution took place mainly, and in some 

 experiments entirely, whilst the Hydrogen on carbon monoxide 

 was being absorbed by the solution. 



Further evidence has been produced on both sides, but so far 

 the question can hardly be regarded as settled either one way or 

 the other. 



However, it will certainly be necessary to bear this secondary 

 action in mind whilst examining the oxidation of cane sugar. 



Experimental Part. 



(a) Objects aimed at. 



The preliminary experiments previously described having 

 approximately shewn that each molecule of sugar requires 16 

 molecules of KMn04, at least under certain circumstances, my 

 attention has been directed towards ascertaining under exactly 

 what conditions this complete oxidation of the sugar takes jilace, 

 and investigating the nature and extent of any secondary 

 reactions or other modifying influences. 



To do this it was necessary to determine by series of experi- 

 ments the effect of varying 



(i.) the ratio of the sugar, acid and permanganate to 

 one another. 



