The Typical Cellulose and the Cellulose Group 39 



cellulose with it, and on the state of the physical division of 

 the cellulose itself. 



Knop, and also Kamarsch and Heeren, found that a mixture 

 of sulphuric acid and nitric acid also formed nitrates of cellu- 

 lose ; and still later (1847), Millon and Gaudin employed a 

 mixture of sulphuric acid and nitrates of soda or potash, 

 which they found to have the same effect. 



Although gun cottons, or pyroxylines, are generally spoken of 

 as nitro-celluloses, they are perhaps more correctly described 

 as cellulose nitrates, for unlike nitro-bodies of other series, 

 they do not yield, or have not as yet done so, amido-bodies on 

 reduction with nascent hydrogen. Eder gives the following as 

 general properties of the cellulose nitrates : (i) when warmed 

 with alkaline solutions, nitric acid is removed in varying quan- 

 tities dependent on the strength of the alkaline solutions 

 employed ; (2) treatment with cold concentrated sulphuric 

 acid expels almost the whole of the nitric acid ; (3) on boiling 

 with ferrous sulphate and hydrochloric acid, the nitrogen is 

 expelled as nitric oxide ; the reaction is used as a method of 

 nitrogen estimation in the cellulose nitrates ; (4) the alkaline 

 sulphydrates, ferrous acetate, and many other substances 

 convert the nitrates into ordinary cellulose. 



Several well-characterised nitrates have been formed, but it 

 is a very difficult matter to prepare any one in a state of purity, 

 and without admixture of a higher or lower nitrated body. 



The following are known : 



Hexa-nitrate, Ci 2 H 14 O 4 (NO 3 ) 6 , 1 gun cotton. In the 

 formation of this body, nitric acid of 1-5 sp.gr. and sulphuric 

 acid of 1-84 sp.gr. are mixed, in varying proportions, about 3 

 of nitric to i of sulphuric; sometimes this proportion is reversed, 



1 To represent the series of cellulose nitrates so as to avoid fractional 

 proportions the ordinary empirical formula is doubled and the nomen- 

 clature has reference to this double molecule. 



