WOOL. 185 



dissected. The vertical warp threads, some of which are partly detached, 

 represent the cotton warp, and the transversely interlaced threads are 

 the wood pulp weft. So long as the wood pulp weft is kept intact in 

 the fabric and not submitted to much strain, it seems to behave very 

 well. The weft has a glossiness almost equal to some lustres of silk,- 

 but its want of strength requires to be overcome before it can be made 

 a success. Its inflammability might also be considerably reduced. 



This Wood Pulp Silk, or " Artificial Silk," to be more correct, is made 

 by treating cotton or wood pulp with a mixture of nitric and sulphuric 

 acid, which converts it into uitro-cellulose. This is then dissolved in a 

 mixture of ether and alcohol. This solution is then driven through fine 

 apertures to form a thread. The solvents evaporate away, leaving the 

 nitro- cellulose as a silky, lustrous fibre. 



The various patents of Chardonnet and Lebner are for various 

 methods of dealing with the solution of the nitro-cellulose to obtain the 

 fibre from it. By treatment with sulphide of ammonia the fibre can be 

 denitrated, and so rendered much less inflammable. 



WOOL. 



THIS term is used to define the hairs and wool fibres of the wild 

 arid domestic sheep. These fibres serve as the protective covering to 

 the hide of the sheep, and when made into a woollen fabric they are 

 serviceable to be worn next to the skin. 



Vegetable fibres differ in that a cotton or linen fabric worn next to 

 the skin conducts heat, becomes moist, and keeps the skin damp and 

 cool. 



The " Jaeger " fabrics of pure wool become saturated with perspiration 

 when worn next the skin, and this applies to all real pure wool fabrics. 



The fibres of wool on the sheep's back would felt one into the other, 

 and spoil their manufacturing properties, if it were not for their natural 

 yolk. This yolk gives a greasy feel to the fibres. It is a natural secretion 

 from the skin and protects the fibres from wear and injury. The yolk 

 is most prevalent on the back and shoulders, from which the best wool 

 fibres are generally obtained. It is essential that the yolk should be 

 plentiful amongst the fibresA They then assume a softer_appearance, the 

 elasticity of the staple is much increased, and the fibres are better 

 adapted, ultimately, for spinning and manufacturing purposes. 



The wool fibre does not contain any cellulose substance. In this 

 respect it differs from the cell of the cotton fibre, which is rich in 

 cellulose and highly inflammable ; wool, on the other hand, does not 



