PKOGKESS IN EXPLOSIVES GUTTMAISTN. 277 



impurities. As a matter of fact, imcarded cotton waste as used for 

 gun cotton generally contains a quantity of strings, wicks, colored 

 threads, india rubber, or elastic cords, and similar leavings, showing 

 the origin of the waste, and no amount of hand picking can free the 

 cotton absolutely from such impurities. I have further found in 

 cotton supplied by manufacturers of the best repute a large amount 

 of chlorine, sulphate of lime, and sulphides, besides organic and 

 mineral dust, which gives the cotton quite a gray appearance. 



Is it not also strange that it never occurred to anybody — at least as 

 far as I know — to ascertain whether the impurities in the cotton, 

 brought about by forcible treatment with bleaching agents and acids, 

 are responsible for a great deal of the instability of certain finished 

 gun cotton and smokeless powders? I am convinced that this is the 

 case. 



Nobody seems to have given it a thought that such a complex com- 

 pound as cellulose in the shape of cotton must vary to an enormous 

 extent, both in its phj-sical and its chemical structure, and thereby 

 also the nitrocellulose made from it. 



Let us examine the possible changes. In the first instance we have 

 the cotton itself, which may be in any stage of ripeness. 



The investigations of Leo Vignon " on the formation of oxycellu- 

 loses and hj^lrocelluloses, and the behavior of their nitro compounds, 

 show plainly how cotton and cotton waste may, by the nature of the 

 treatment they undergo, be partly transformed into oxycellulose, 

 which gives an unstable nitro compound, and into hydrocellulose, 

 which has a different rate of nitration than ordinary cellulose. 



I have repeatedly stated on previous occasions that in my opinion 

 the process of nitration with a mixture of sulphuric and nitric acids 

 results, in the first instance, in an attack on the cotton by the sul- 

 phuric acid similar to that in the manufacture of vegetable jDarch- 

 ment, and that the sulphuric acid is gradually displaced by the nitric 

 acid penetrating the fiber. 



It seems a fact that the more oxycellulose is formed in the cotton 

 before nitration, the more unstable are the compounds formed in the 

 nitrocellulose. Other impurities in the cotton are all the more likely 

 to endanger the stabilitj^ of nitrocellulose, as their nature is always 

 unknown, and varies from sweepings to india-rubber elastics, while 

 almost all are sure to produce unstable compounds. 



How far the nature and origin of the acids may have an influence 

 upon the ultimate product has still to be investigated. 



I do not think that difi'erences in apparatus used for the manufac- 

 ture of nitro-cellulose have much to do with its stability. I have 

 strong reasons for not recommending iron vessels for stabilization in 



= Comptes rendus, June 6, 1898, September 10 and 17, 1900. 



