74 CORDAGE FIBRES 



sulphite of soda and hydrochloric acid, the sixth hyposulphite 

 of soda and the seventh a solution of hydrochloric acid alone. 

 On leaving the latter bath the fibre is washed in pure water 

 and then steeped in a weak solution of soap and water, in 

 order to give it back a little of the oleaginous matter extracted 

 by the action of the soda. The material should be passed 

 through these successive baths between endless openwork 

 travelling aprons, in thin layers, in order that the fibre may 

 preserve its parallelism and not become too much matted. 

 Between each bath it passes between wringing rollers to 

 remove superfluous moisture. 



- True China grass, from which much of the gum has been 

 removed by hand scraping, -does not require such severe 

 chemical treatment as that just described; it is sufficient to 

 boil it in soda lye, to steep it in chloride of lime solution 

 and then in an acid bath, repeating these two latter processes, 

 with a washing in pure water between each, until the gum 

 has completely disappeared and a pure white filasse is pro- 

 duced. The fibre should be placed in a kier or boiling pot 

 between trays of wire network one above the other to prevent 

 the matting of the fibre. The trays of fibre are placed in 

 the pot with the lye at 3 Tw. and allowed to boil for about 

 seven hours. The fibre is then taken out, rinsed in pure 

 water to remove all traces of soda and then steeped for ten or 

 twelve hours in chloride of lime solution at J Tw., contained 

 in a stone trough. When taken out of this steep it is 

 again rinsed in pure water and placed in a solution of sulphuric 

 acid or vitriol at i Tw., where it is left for some hours and 

 then again thoroughly washed. If all traces of gum have not 

 completely disappeared, the two latter processes are repeated 

 as frequently as required. 



Chemical treatment has also been frequently tried in con- 

 nection with the separation of flax and hemp fibre from the 

 straw, but without any real success except as regards shortening 

 the time occupied in the process. An energetic chemical treat- 



