106 Cellulose 



acid (in separate vessels), the specimens were exposed for a short 

 time to a temperature of 100 in a water-oven and weighed. The 

 combined chlorine was then estimated. The following are the 

 results : 



J (a) (*) 



Weight of fibre-substance chlorinated , * 1-912 I '6 12 



Combined chlorine determined * 0*142 O^SS 



2-054 1765- 



Chlorinated fibre obtained . 2*038 1763 



Loss due to oxidation .... 0-016 0-002 



These results, in conjunction with independent observations of 

 the hydrochloric acid formed, further confirm the conclusion as to 

 the simplicity of the reaction. 



The percentages of chlorine combining viz. (a} 7*4, (&} 9-4 

 vary on either side of what may be taken as the mean number, viz. 

 8-0 p.ct. In both cases it was no doubt impossible, under the con- 

 ditions of the after treatment, to entirely remove the HC1. The 

 difference in favour of (a) shows the importance of the preliminary 

 treatment with the alkali ; without this the chlorination is incomplete. 



Estimations of Secondary Constituents. (a) 

 Methoxyl (O.CH 3 ) is estimated by the now well-known and, in 

 fact, standard method of Zeisel. The fibre-substance is boiled 

 with hydriodic acid ; the resulting methyl iodide is washed in an 

 apparatus of special construction, to remove traces of hydriodic 

 acid, and passed into an alcoholic solution of silver nitrate, 

 with which it reacts to form silver iodide. A constant current 

 of carbonic anhydride is passed into the reaction flask and 

 through the entire apparatus, so that the methyl iodide may be 

 continuously carried forward and quantitatively decomposed. 



The calculation from silver iodide to methoxyl is, of course, 

 simple (AgI=O.CH 3 ). 



This constituent of the lignocellulose molecule we have 

 every reason to regard as a characteristic constant, and its 

 determination is therefore of importance. Its constitutional 

 relationship will be discussed subsequently. 



(b) The CO.CH^ residue. In a number of decompositions 



