330 Cellulose 



acetate, used more particularly as a dressing for the fabrics 

 which constitute the covering of the wing planes of aircraft. 

 The acetate generally adopted is the acetone-soluble product 

 of which the analysis generally shows an acetylation ratio of 

 5 acetyls per Ci 2 cellulose unit. 



The industry in viscose products shows considerable ex- 

 pansion. The manufacture of artificial silk and threads takes 

 a leading position. In this the special advantage of the viscose 

 product as against the alternative forms of cellulose is well set 

 forth in a paper by L. P. Wilson (J. Soc. Chem. Ind. vol. 

 36, 817, 1917). The author gives the main points of economic 

 and technical advantage of the viscose methods and products. 

 It appears that considerable control is now exercised over the 

 form of the thread as demonstrated by cross-sectional outlines ; 

 and an advance has also been made in control of the physical 

 properties of the regenerated cellulose, specially in regard to 

 resistance to water. A comparison of the strength of the thread 

 when wetted with that of the original shows that the proportion 

 50 to 60 p.ct. is generally obtained. 



There are now some thirty factories producing the viscose 

 textile thread in the leading industrial centres of the world. 



In regard to the history of this matter, the following are the 

 well-marked stages : 



The process was originally brought to practical demonstra- 

 tion at the experimental works of the Viscose Spinning 

 Syndicate, Kew, Surrey. In this pioneer work the inventors 

 collaborated with Messrs. Stearn & Topham, who made very 

 notable advances in the mechanical and other methods con* 

 cerned in the production and finishing of the thread. The pro- 

 cess was first launched as an industry in Germany (Sydowsaue), 

 under the auspices of the Continental Viscose Company with 

 Fuerst Haenckel von Donnersmarck ; but the first successful 

 results were obtained by the Societe Frangaise de la Viscose 



