CARBOUYDHATKS lit) 



If the above mentioned soda-cellulose is treated with 

 carbon disulphide a compound is formed called "viscose," 



O— CeH 9 04 



/ 

 s=c 



\ 



S— Na 



which is soluble in water to a viscous liquid. On spon- 

 taneous decomposition in the air, viscose loses carbon 

 disulphide and sodium hydroxide. The former disappears 

 by volatilization and the latter may be washed out. A 

 hard, transparent, vitreous mass of cellulose is left. This 

 is called "viscoid" or "cellophane" and finds a variety of 

 uses. On treating cotton with nitric and sulphuric acids 

 there are obtained, according to conditions, a hexanitrate 

 of cellulose, GoHi-A^XOsJe, or a tetranitrate of cellulose, 

 Ci2Hi60e(N03)4. The former, insoluble in alcohol and 

 ether, is known as guncotton, the explosive; the latter, 

 soluble in alcohol and ether, is called pyroxylin or soluble 

 cotton. The solution of pyroxylin in alcohol and ether is 

 known as collodion which finds a variety of uses in surgery 

 as a dressing for wounds, and in photography for making 

 films. If pyroxylin is intimately mixed with camphor, 

 celluloid results. 



The thick viscous solutions of cellulose in ammoniacal 

 cupric hydrate, of viscose, and of collodion, all serve as 

 materials for making artificial silk. By squeezing the thick 

 liquid through exceedingly fine holes, and winding the 

 resulting filaments into a thread, a lustrous imitation silk 

 is made after regenerating the cellulose. In the case of the 

 ammoniacal copper hydrate solution the cellulose is formed 

 by treating the threads with dilute sulphuric acid and 

 washing; in the case of viscose, by simple drying and wash- 

 ing; and in the case of collodion by denitrating with alkaline 

 sulphides. 



Under proper conditions cellulose will unite with acetic 

 acid to form a tetra-acetate C 6 H 6 0(C2H3CK)4, soluble in 

 nitrobenzol. On evaporation of the solvent there is formed 



