Experimental and Applied 307 



It is high time, as we have said before, that a public opinion 

 should be formed upon this subject, and it can only be formed 

 upon a recognised classification of papers, based upon their 

 chemical and mechanical ' constants,' which are determinable 

 by laboratory investigation. In Germany considerable pro- 

 gress has been made in the fixing of standards of quality and 

 securing their adoption by the trade. This classification by 

 fixed standards has been systematically worked out in the 

 Government Testing Station at Charlottenburg, and the records 

 of the institution contain a number of important monographs 

 upon the various factors of quality of papers. As these, how- 

 ever, contain no very direct contributions to the chemistry of 

 cellulose, we have only to call attention to the general result of 

 the investigations. In our own country the character of the 

 paper trade differs in many respects from that of the Continent ; 

 and this would necessitate a special classification and series of 

 standards. So far, however, as this classification is based upon 

 differences of chemical composition the lines of demarcation 

 are simple and sharp, and the general recognition of these will 

 initiate a movement in the direction of specific uses of papers 

 according to their qualities and properties. 



Outside the province of textiles and papers there are many 

 other uses of cellulose of great industrial importance, many 

 of which have been dealt with incidentally in the foregoing 

 pages. The nitrates of cellulose are the basis of manufactures 

 which have been developed within our own period of history. 

 They are used on the one hand as a plastic and constructive 

 material, on the other as an explosive and destructive agent ; 

 these uses affording remarkable illustrations of the chemical 

 and physical properties of cellulose. In regard to the former, 

 the use of the nitrated compounds of cellulose is open to the 

 very obvious objection of high inflammability. The combined 

 nitric acid is in fact a necessary evil ; and from what we now 



