84 REELING SILK. 



CLEANSING SILK. 



Though cleansing silk, comes more appropriately 

 within the province of the manufacturer, than the cul- 

 turist, yet as the manufacture of sewing silk and twist 

 may be profitably connected with the growing, we 

 subjoin the method by which it is cleansed and pre- 

 pared for dyeing. 



Silk, as left by the worm, contains certain impuri- 

 ties which must be separated from it. especially, when 

 it is intended for particular kinds of fabrics. Yellow 

 silk contains gum, coloring matter, wax and an oil 

 similar to the essential oils of many vegetables. 

 White silk also contains gum, wax and an oil slightly 

 tinged with coloring matter, resembling the liquid in 

 the chrysalis of the worm. By chemical experiments 

 it has been ascertained that the amount of gum is 

 from 23 to 24 per cent. It is dry, friable, and when 

 pulverized, of a yellowish red color soluble in water. 

 The coloring matter is resinous; but exists in a very 

 small proportion supposed to be from 3^ to e\> per 

 cent. The wax is hard, but brittle and slightly col- 

 ored. Its proportion is about one half per cent. 

 These substances affect the whiteness and flexibility 

 of silk, and the process by which they are extracted 

 is called " cleansing silk." It is also varied according 

 to the nature and kind of the article for which it is 

 designed. 



These processes are called " ungumming," " sul- 

 phuring" and " aluming." Silk also intended to re- 

 main white, is boiled and gummed, while that intend- 

 ed for dyeing is boiled, but left ungummed, on the 

 supposition that the gum has some affinity for the 

 coloring matter with which it is to be incorporated. 



