300 Cellulose 



ever, much more diversified ; and their scientific basis, so far as 

 regards the chemical function of the fibre-substance as an active 

 cause, is even less elucidated than in the more simple operations 

 of dyeing. In the absence of any specific contributions of 

 investigators, no attempt can be made to deal with so wide a 

 range of effects. With a wider knowledge of the chemical 

 functions of the constituent groups of the fibre-substances, it 

 will be easy to devise critical experiments in solution of the 

 very various problems presented. 



The industrial uses of the celluloses and compound cellu- 

 loses are of wide and varied range. They depend, of course, 

 largely upon the external and physical properties of the natural 

 products : but if less obviously, certainly in a not less important 

 degree upon the special chemistry of these substances. Their 

 industrial value again depends upon the conditions of supply, 

 the agricultural questions of yield, and the economic questions 

 of production and preparation in a fit state for the further manu- 

 facturing operations by which they are finally shaped for use. 



In the province of textile fibres this threefold qualification 

 constitutes an effectual limitation of the number available, and 

 the numerous abortive attempts to exploit others of the end- 

 less variety of vegetable fibres have invariably followed from 

 neglect of one or other of the essential conditions of qualifica- 

 tion. These qualifications are in effect the constants of the 

 fibres, all expressible in numbers, the results of measurements 

 or observations of quantitative relationships. Thus, to select 

 in illustration the flax fibre, the following are the * constants * 

 which mainly determine its value : 



Agricultural (constants of 1 Yield of * straw ' per acre, 

 raw material) . . . / Yield of fibre on 'straw.' 

 Morphological or structural 1 L of uhimate fibre . 



(physical constants of fibres) J 



r Proportion of cellulose and resist- 



Chemical . . . .4 ance of cellulose to hydrolysis 

 I and oxidation. 



