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LXIII. Water- Analysis, Determination of Cellulose and mo- 

 dified Cellulose in Drinking- Water. By J. A. WANKLYN 

 and W. J. Cooper*. 



THE ammonia process of water-analysis provides an index 

 to the nitrogenous organic matter in drinking-water ; but 

 it does not deal with the non-nitrogenous organic matter, and 

 some method whereby the non-nitrogenous organic matter 

 might be reached is still a desideratum. This desideratum the 

 Frankland-and-Armstrong combustion process aims at sup- 

 plying, but (as is now pretty well understood among chemists) 

 fails to supply. The old permanganate process, which we owe 

 to Forchhammer, which notoriously failed in practice, would 

 accomplish the object in view if the practical difficulties which 

 Beset it could be overcome. 



If the quantity of oxygen required to oxidize cellulose or 

 sugar be calculated, it will be seen that rather more than its 

 own weight of oxygen is consumed by a given weight of cellu- 

 lose or sugar. The estimation, therefore, of cellulose or sugar 

 by means of the oxygen consumed in burning down to car- 

 bonic acid and water would rank along with the more advan- 

 tageous operations of analytical chemistry. 



Forchhammer's process, as hitherto practised, does not effect 

 any thing approximating to complete oxidation down to car- 

 bonic acid and water, as was illustrated by some experiments 

 published by Frankland and Armstrong in 1868 (vide Chem. 

 Soc. Journ. vol. vi. p. 82), which I quote : — 



Name of substance Oxygen Oxygen 



(30 parts dissolved absorbed required 



in 1 ? 0G0 ; 000 parts during for complete 



of water). six hours. oxidation. 



Gum arabic . . . 035 35 '5 



Cane-sugar .... 0'15 33*7 



Starch 0'30 33-5 



showing that, as usually carried out, the oxidizing process 

 does not avail to accomplish more than about one hundredth 

 part of the task set before it. The manner in which the per- 

 manganate of potash is applied to drinking-water in Forchham- 

 mer's process is by simply mixing measured volumes of the 

 permanganate-solution with a known volume of the water to 

 be operated upon, and observing how many volumes are de- 

 colorized by the action of the organic matter. A quantity of 



* Communicated by the Authors. 



