306 Cellulose 



contrary, paper being very much cheapened by the use of these 

 celluloses, a great advantage is gained. It must be insisted 

 upon, however, that authors and publishers should have a defi- 

 nite judgment as to the papers to which they commit their 

 productions, and it would be of the greatest utility to exhaus- 

 tively investigate these particular celluloses from the point of 

 view of their resistance to the natural processes of decay. 



CLASS C. The presence of lignocellulose is a more extreme 

 departure from the sound basis of composition represented by 

 Class A. The lignocelluloses are not only more generally 

 reactive than the celluloses of Class B, but are easily attacked 

 by atmospheric oxygen (see p. 174). Added to these chemical 

 defects they are inferior in the mechanical properties which 

 contribute to the strength of the sheet of paper, and therefore 

 papers of this class are only permissible where lasting properties 

 are a question of no moment whatever. 



In addition to these questions of the composition of the 

 fibres or pulps, the practice of loading papers with china-clay, 

 sulphate of calcium, and so forth, is also another of the causes 

 which lead to disintegration of modern papers as compared 

 with those of former days. There is, of course, the other side 

 to this question, the addition of these mineral diluents having 

 certain positive advantages not to be overlooked. The danger 

 of any practices of this kind only enters when they are 

 not measured at their proper utility. Paper is largely ' taken 

 for granted' by consumers. In a great many, perhaps the 

 majority of cases this unenquiring consumption is not attended 

 with any serious consequences ; but, on the other hand, it is 

 quite obvious that it is attended with dangers of a very grave 

 character, when we are dealing with records of value for all 

 time. This, of course, is largely a question for posterity, to 

 whom we are handing down a literature produced upon 

 grounds for the most part of mere commercial expediency. 



