152 ON THE CHEMICAL PROPERTIES OF SILK. 



its chemical properties changed, that by the addi- 

 tion of half the original portion of muriatic acidj 

 the liquid might be employed for a first immersioi^ 

 of the raw silk. 



The bleaching operation was completed by pour- 

 ing upon the silk forty-eight pounds of pure spiril 

 of wine, which was allowed to remain from twenty- 

 four^ to thirty hours on the silk. There is great! 

 difficulty in freeing the muriatic acid from the silk, 

 which can only be effectually done by subjecting it 

 to a continued stream of running water for some 

 hours.* 



In England a different process is pursued, which 

 is by immersing the silk in a solution of soap in 

 river water, while it is kept at the boiling point for 

 two or three hours ; when it is taken out, well 

 beaten either with a machine constructed for the 

 purpose, or with a wooden mallet, and afterwards- 

 washed in river water. It is then wrung, and 

 again immersed in soap and water, in a cold state, 

 with the addition of a small portion of indigo, andi 

 brought to the boiling point ; at which it is allowed 

 to continue for a short time. It is then taken out,, 

 wrung, and shaken ; and dried in a stove construct- 

 ed for the purpose, over the fumes of burning, 

 sulphur, which render it of the most beautiful' 

 whiteness. 



* See URE'S Diet, of Chemistry, article Bleaching, for a 

 more full detail of this process. 



