DECORTICATION 73 



still in a green state, because when they become dry the 

 outside skin becomes hard and brown and most difficult to 

 remove. Up to the present time no machine has been found 

 to give such good results, as regards yield and clean fibre, 

 as the manual processes practised by the women and children 

 in China, who produce from the ramie or rhea plant the fibre 

 known as China grass. Hand decortication is a long and 

 costly process, because a woman can produce only a few 

 pounds of fibre per day. This she does by placing a few 

 green stems on a flat board and scraping them with a piece 

 of wood, in order to remove the woody matter with as much 

 of the gum as possible. The best cleaned fibre still contains 

 from 20 to 30 per cent, of gum, which must be removed 

 before it can be spun into fine yarns. 



Especially in the case of water-retted flax and hemp straw, 

 a good deal of gum still remains in the fibre, and must do so 

 until after the yarn is spun, for the ultimate fibres of the 

 flax and hemp plants are short as compared with those of 

 ramie and are held together by the pectic matter referred to. 

 In the wet spinning process this gum is softened by the action 

 of the hot water so that the fibres may be drawn out, but 

 hardens again when the thread has been twisted and dried, 

 binding the fibres together and giving the yarn strength and 

 a smooth hard surface. 



To make ramie or rhea, which has not been scraped, fit for 

 spinning at all, and to render China grass fit for spinning 

 into fine yarns, it must be subjected to chemical treatment 

 to dissolve out the gum. Perhaps the best process for the 

 purpose is that of Boyle, It consists in passing the material 

 through a trough containing weak soda lye and then through 

 a feeble solution of hydrochloric acid which acts upon the 

 soda remaining in the fibre and sets up fermentation. The 

 material is then passed on to a third tank similar to the first 

 and then to a fourth containing a solution of permanganate of 

 potash. The fifth tank contains a mixed solution of hypo- 



