[ 175 ] 184 



silk to lose a portion of its substance, and, in doing so, it also loses 

 its brilliancy and solidity. 



Dr. Bancroft says, that " silk ought never to be subjected to a boil- 

 ''ing heat, either when the mordant is applied, or afterwards, in the 

 "dying operation; where a high temperature, besides injuring the 

 "texture and lustre of the silk, would detach and separate the mor- 

 "dant before the coloring matter could have combined, and produced 

 "an insoluble union with both."* 



The injury of subjecting silk to a boiling heat, is further proved by 

 the experiments of those eminent French chemists, Thenard and Ho- 

 ard, which show that " alumed silks take color more intensely when 

 "they are died at a low temperature, than when they are plunged at 

 "once into boiling water. The reason is, that, in the first case, the 

 " action of the boiling water on the mordants is so quick, that the co- 

 **loring matter has not time to be fixed on it, in order to give insolu- 

 '*bility to the combination; but, in the second case, this cannot take 

 "place."! 



Of ungumming and boiling Silk for white. % 



Make up the silk into hanks, that is to say, run a thread around 

 each hank, which consists of a certain quantity of skeins tied together. 

 After that, the hanks are to be untied, and several of them to be bound 

 together to make up a bundle, the size and names whereof vary ac- 

 cording to the nature of the article to be manufactured. 



This precaution of making up into hanks is necessary, that the silk 

 may be more easily managed, more conveniently handled, and to pre- 

 vent them from being entangled. 



After this operation, soap is to be dissolved in water, heated in a 

 kettle, in the proportion of thirty pounds to every hundred weight of 

 silk. (A dier of silk, to whom these directions were submitted, says, 

 "that 15 lbs. of soap are enough for 100 lbs. of silk; more would 

 "destroy its lustre." The Idnd of soap will cause difference in re- 

 sults.) Cut the soap into small slices, to promote its solution; after 

 the soap has been dissolved, tiie kettle is to be filled up with fresh wa- 

 ter, and the doors of the furnace closed, leaving only a few live coals 

 in it, in order that the bath may be kept quite hot, but without boil- 

 ing; for, should the bath boil, it would cause the silk to open, and to 

 become flossy, more particularly the fine silk. 



Whilst this bath is preparing, the hanks are to be put upon the pegs, 

 or pins, and when the bath is ready, the silk is to be put into it, and 

 left therein, until all the part dipped is wholly freed from its gum; 

 which will be easily seen, by the whiteness and flexibility which the 

 silk acquires when deprived of it. The hanks are then placed again 

 on the rods, to undergo the same operation in the parts not yet steeped; 

 they are then to be taken out of the bath, in proportion as they arr 



• Philosophy of Permanent Colors, vol. 1. p. 289. 



f Annales de Chimie, June, 1810. 



\ Nouveau Manuel du Ttftiturier par Baillot, Maitre Teinturier.~Paris, 1810 



