The Typical Cellulose and the Cellulose Group 13 



with lead oxide, but of variable composition ; the compound 

 (C G N 10 O 5 .PbO) appears to result from the treatment of the 

 ammoniocupric solution with finely divided lead oxide. 



This property of gelatinising and dissolving cellulose has 

 been taken advantage of in important industrial applications 

 of the cuprammonium compounds. Vegetable textile fabrics 

 passed through a bath of the cuprammonium hydroxide are 

 ' surfaced * by the film of gelatinised cellulose, which retains 

 the copper oxide (hydrate) in such a way that it dries of a bright 

 'malachite' green colour. By this treatment the fibres are 

 further compacted together, and the fabric acquires a water- 

 resistant character. The presence of the copper oxide is also 

 preservative against the attacks of mildew, insects, &c. If the 

 fabrics are rolled or pressed together when in the gelatinised 

 condition they become firmly welded together on drying, and 

 a variety of compound textures are produced in this way. 



These fabrics are sold under the style or description of 

 1 Willesden ' goods ; the manufacture being in the hands of a 

 company whose works are situated at Willesden. The 

 company's processes are based on the patents of Drs. J. 

 Scoffern and C. R. A. Wright (q.v.\ 



AMMONIACAL CUPROUS OXIDE. According to M. Rosen- 

 feld (Berl. Ber. 12, 954) a concentrated solution of cuprous 

 chloride in ammonia dissolves cellulose rapidly. 



The reaction of cuprammonium with cellulose, although iden- 

 tified with the name of Schweitzer, appears to have been first 

 noticed by Mercer. He employed a solution of ammonia of 0-920 

 sp.gr. saturated at the ordinary temperature with the cupric oxide 

 (hydrate) and diluted with three volumes of water. Mercer investi- 

 gated the reaction in regard to the influence of the conditions of 

 treatment, showing that it was retarded by the presence of salts, 

 and hence that the solutions obtained by decomposing the copper 

 salts with excess of ammonia were much less active than equivalent 

 solutions of the pure hydrate. He also showed that the activity of 



