238 THE CARBOHYDRATES 



employed for rendering canvas waterproof and for making 

 cinematograph films, etc. 



Viscoid, which is congealed viscose, is a hard mass obtained 

 by mixing viscose with various substances and allowing the 

 mixture to decompose spontaneously and harden ; it is used 

 for mouldings, cornices, statuettes, etc. 



Solid Spirit. — The substance sold under this name is ob- 

 tained by pouring a solution of cellulose acetate in glacial 

 acetic acid into alcohol ; a white solid is produced which does 

 not melt, and burns when ignited without leaving any ash. 



Cellulose acetate, in which there are approximately five 

 acetyl groups to the Cjg cellulose unit, is soluble in acetone, and 

 is used largely as a dressing for the fabric of aeroplane wings. 



Cellite is acetyl cellulose which is soluble in a mixture 

 of ethyl acetate and ethyl alcohol. Mixed with camphor it 

 is used in the manufacture of non-flammable cinematograph 

 films. 



Willesden Paper is paper waterproofed by treatment with 

 cuprammonia, whereby the fibres are gelatinized, and, when 

 dry, are impervious to water. 



Finally, mention may be made of a few substances, which 

 are made from cellulose as a starting-point, but which are 

 produced only by the profound decomposition of the molecule. 

 Thus by heating cellulose with a strong solution of caustic 

 potash and soda, oxaHc acid is produced, and by the de- 

 structive distillation of wood, acetic acid, acetone and methyl 

 alcohol are obtained. 



FURTHER REFERENCES. 



Cross and Bevan : " Researches on Cellulose," London, 1895, 1901, 

 1906, 1912, 1922. 



Cross and Bevan : " A Text-Book of Paper Making," London, 1916. 



Cross and Bevan : " Cellulose," London, 191 8. 



Cross, Bevan, and Sindall : " Woodpulp and its Uses," London, 191 1. 



Fuchs : " Die Chemie des Lignins," Berlin, 1926. 



Hawley and Wise : " The Chemistry of Wood," New York, 1926. 



Heuser : " Lehrbuch der Cellulosechemie," Berlin, 1927. 



Schorger : " Chemistry of Cellulose and Wood," London, 1926. 



Schwalbe : " Die Chemie der Cellulose," Berlin, 1912. 



Worden : " Nitrocellulose Industry," London, 191 1. 



