The Typical Cellulose and the Cellulose Group 3 



material is treated exhaustively with alcohol and with ether to 

 remove fatty or resinous by-products of the oxidation. 



Cellulose obtained in this way from raw fibrous materials, 

 e.g. cotton, flax, hemp, ramie, is a white substance distinguished 

 by more or less lustre and translucency, retaining the structural 

 characteristics of the raw material, of 1*5 sp.gr., and as a 

 chemical individual distinguished amongst C.H.O compounds 

 by its negative or non-reactive characteristics. 



In the brief account which ensues, of the general chemistry 

 of cellulose, cotton-cellulose is taken as the type. The points 

 of differentiation of other members of the group from the type 

 will be noted subsequently. 



The empirical composition of the pure cellulose is repre- 

 sented by the percentage numbers 



C 44'2 



H ,..., 6-3 



O .,..., 49'5 



corresponding with the statistical formula C 6 H 10 O 5 . These 

 numbers represent the composition of the ' ash-free ' cellulose. 

 All vegetable tissues contain a greater or less proportion of 

 inorganic constituents of which a certain proportion are 

 retained by the cellulose isolated, as described, or by any of 

 the processes practised on the large scale in the arts (infra}. 

 The celluloses burn with a quiet luminous flame, leaving these 

 inorganic constituents as an ash, retaining more or less the 

 form of the original. In cotton the average proportion of 

 ash is o*i-o'4 p.ct. The composition of the ash has, no 

 doubt, certain specific relationships to the several celluloses, 

 their constitution and origin ; but such correlations are at 

 present too obscure for useful discussion. 



In the preparation of filter paper for quantitative work it is 

 important to eliminate the ash constituents as far as possible, 

 and this is effected by treatment with hydrofluoric and other 



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