150 



! 



ON THE CHEMICAL PROPERTIES OF 

 SILK. 



THE rich yellow colouring matter which tinges 

 all silk, more or less in its raw state, is in combi- 

 nation with -the gum. Immersing the cocoons in 

 hot water will dissolve, to a certain extent, this 

 gum, and leave a yellow tinge in the water. Bui 

 the use of alcohol instead of water, will dissolve 

 this matter in greater quantity. This tincture will 

 retain its colour with little loss of intensity, even 

 after being long exposed to the rays of the sun. 

 The fact of this affinity of the colouring matter of silk 

 for alcohol, suggested to Mons. Baume the idea oi 

 bleaching silk in the following manner. 



He constructed a twelve gallon stoneware vessel, 

 of a form nearly conical, with a wide opening at 

 the top, and a smaller one, of about an inch in 

 diameter, at the bottom, which was stopped by a 

 cork ; through the centre of which was passed 

 glass tube, of a quarter of an inch diameter. This 

 tube was always stopped by a cork, except at the 

 time wken the liquid required to be drawn off. 

 The inside of the vessel was polished very smooth 

 with pumice-stone, to prevent the roughness fr< 

 breaking the threads in their first state. 



