176 SILK. 



PREPARING SILK. 



Preparatory to being dyed, silk should be cleans- 

 ed. As spun by the worm, silk contains several 

 substances. First, colouring matter; second, gum; 

 third, wax; and fourth, an oil resembling in its nature 

 the essential oils of vegetables. The gum is of a 

 iriable texture, and appears of a reddish yellow co- 

 lor. Silk, when analyzed, is found to contain 23 to 

 25 per cent, of gum it is soluble in water. The 

 wax is of a harder texture and very brittle, but is 

 never found in a proportion of more than one per 

 cent ; oftentimes less. The proportion of coloring 

 matter is very small. 



While these substances are in the silk, it is stiff and 

 unpliable, and the process of extracting them is call- 

 ed preparing or cleansing silk. Whenever it is in- 

 tended to be dyed, the silk is boiled and afterward 

 gummed, the gum having an affinity for the dye. But 

 when the silk is to remain white, it is simply boiled 

 and the gumming omitted. 



To ungum silk, many skeins should be united to- 

 gether, so that they may not tangle in the process. 

 These are put into strong suds. From fifteen to 

 twenty pounds of soap (some use thirty) are required 

 for every hundred pounds of silk. The soap should 

 be thoroughly dissolved in water, over a gentle fire, 

 and the temperature raised nearly to boiling heat, 

 but should never boil, as it would injure, if not ruin, 



