GUN-COTTON. 447 



yet still preserving the aspect of the cotton, but which becomes 

 gelatinous without actually dissolving in a mixture of alcohol 

 and ether and in acetic ether. 



If the acid is more diluted, such as 



(N0 3 H + -75H 2 0), 



the cotton becomes dissolved in such an acid, producing a viscous 

 liquor which can be precipitated by water. The product ob- 

 tained is similar in its characteristic features to hexanitric 

 cellulose 



C M H 28 (N0 3 H) 6 14 . 



It swells in acetic ether without dissolving. A mixture of 

 alcohol and ether does not act on the substance. 



With the acid N0 3 H mixed with + 1/375 to 1-5 H 2 0, we 

 obtain friable products, without any action on acetic ether or 

 on the mixture of alcohol and ether, and which vary between 

 the following formulae : 



C 34 H 32 (N0 3 H) 4 17 . 1 



With a more diluted acid, the nitrification is incomplete, the 

 products still being darkened by iodine ; that is to say, it is no 

 longer possible to distinguish the nitro compounds properly so 

 called from their mixture with the unaltered cellulose. 



3. GUN-COTTON PROPERLY so CALLED. 



1. Gun-cotton 2 preserves the appearance of cotton, although 

 it is slightly rougher to the touch. It is not hygroscopic, and 

 it also possesses the property of becoming electrified by friction. 

 Plates for electric machines have even been constructed with 

 nitrified paper. 



Gun-cotton is soluble in acetic ether, but insoluble in most 

 other solvents (water, alcohol, ether, acetic acid, and ammoniacal 

 copper oxide). 



It may be moistened, and when dried resumes its properties. 



When in lumps, its apparent density is only 01 ; if it be 



1 Table of the volumes of nitric oxide obtained by Schloassing's process from 

 various celluloses by Vieille. One grm. gives 



I Collodion cotton 1178 



Heptanitric 162 



Hexanitric ... 146 



Pentanitric 



Tetranitric 108 



2 For its preparation see " Traite" sur la poudre," par Upman et Meyer, 

 traduit et augmente" par Desortiaux, etc., p. 350. 



