[Footnote A:  The penta-nitrate C_{12}H_{15}O_{5}(NO_{3})_{5} = 12.75 per cent. nitrogen.]

[Footnote B:  In the Cordite Trial (1894) Sir F.A.  Abel said, “Before 1888 there was a broad distinction between soluble and insoluble nitro-cellulose, collodion-cotton being soluble (in ether-alcohol) and gun-cotton insoluble.”  Sir H.E.  Roscoe, “That he had been unable to make a nitro-cotton with a higher nitrogen content than 13.7.”  And Professor G. Lunge said, “Gun-cotton always contained soluble cotton, and vice versa.”  These opinions were also generally confirmed by Sir E. Frankland, Sir W. Crookes, Dr Armstrong, and others.]

Dodeca-nitro-cellulose C_{24}H_{28}O_{20}(NO_{2})_{12} = 14.16 per cent.
  nitrogen. (= old tri-nitro-cellulose)
Endeca-nitro-cellulose C_{24}H_{29}O_{20}(NO_{2})_{11} = 13.50 per cent.
  nitrogen. 
Deca-nitro-cellulose C_{24}H_{30}O_{20}(NO_{2})_{10} = 12.78 per cent.
  nitrogen. 
Ennea-nitro-cellulose C_{24}H_{31}O_{20}(NO_{2})_{9} = 11.98 per cent.
  nitrogen. 
Octo-nitro-cellulose C_{24}H_{32}O_{20}(NO_{2})_{8} = 11.13 per cent.
  nitrogen. (= old di-nitro-cellulose)
Hepta-nitro-cellulose C_{24}H_{33}O_{20}(NO_{2})_{7} = 10.19 per cent.
  nitrogen. 
Hexa-nitro-cellulose C_{24}H_{34}O_{20}(NO_{2})_{6} = 9.17 per cent.
  nitrogen. 
Penta-nitro-cellulose C_{24}H_{35}O_{20}(NO_{2})_{5} = 8.04 per cent.
  nitrogen. 
Tetra-nitro-cellulose C_{24}H_{36}O_{20}(NO_{2})_{4} = 6.77 per cent.
  nitrogen. (= old mono-nitro-cellulose)

It is not unlikely that a long series of nitrates exists.  It is at any rate certain that whatever strength of acids may be used, and whatever temperature or other conditions may be present during the nitration, that the product formed always consists of a mixture of the soluble and insoluble nitro-cellulose.

Theoretically 100 parts of cotton by weight should produce 218.4 parts of gun-cotton, but in practice the yield is a good deal less, both in the case of gun-cotton or collodion-cotton.  In speaking of soluble and insoluble nitro-cellulose, it is their behaviour, when treated with a solution consisting of 2 parts ether and 1 of alcohol, that is referred to.  There is, however, another very important difference, and that is their different solubility in nitro-glycerine.  The lower nitrates or soluble form is soluble in nitro-glycerine under the influence of heat, a temperature of about 50 deg.  C. being required.  At lower temperatures the dissolution is very imperfect indeed; and after the materials have been left in contact for days, the threads of the cotton can still be distinguished.  The insoluble form or gun-cotton is entirely insoluble in nitro-glycerine.  It can, however, be made to dissolve[A] by the aid of acetone or acetic ether.  Both or rather all the forms of nitro-cellulose can be dissolved in acetone or acetic ether.  They also dissolve in concentrated sulphuric acid, and the penta-nitrate in nitric acid at about 80 deg. or 90 deg.  C.