J30 DYEING OF COTTONS. 



Red dye for taken out, rung, and dried by fufpending it in the open air, 

 or in a heated chamber. It is needful only to take care that 

 no water fliall drop upon the cotton, as that would produce 

 fpots in the dye. In this operation the thread muft be clofety 

 packed together, in order that the nut-gall may uniformly pe- 

 netrate its mafs. It is then conveyed into a folution of tin, 

 made as hereafter defcribed, and the deco&ion of nut-gall 

 muft be kept to be ufed in the aluming. The folution of tin 

 is prepared in the following manner: Sal ammoniac or fea fait 

 in fine powder is to be difiblved to faturation in lib. of aqua- 

 fortis; 2oz. of fine Englifti tin rafped, are added to this, or 

 as much of the metal as the acid can diffolve to faturation. In 

 another veffel, 2 oz. of fea-falt are to be difiblved in one pint 

 of rain water, and the folution of tin is to be poured drop by 

 drop with continual agitation into this fait water. The galled 

 thread is afterwards put into a done ware VetTel, clofely prefied 

 together, and the laft mentioned mixture poured thereon. 

 The thread muft be occafionally comprefled with the hand, in 

 order to aftift the penetration, and it muft then be covered from 

 the air and left to fieep for twenty-four hours, at the end of 

 which time it is taken out, rung and dried in the air or in a 

 fceated room, where it may remain for 48 hours. After this 

 it is warned in pure water again, dried, and emerfed in tl*e 

 alum-water, of which we fhall proceed to defcribe the com- 

 pofition. 



The remaining folution of tin is referved for a fubfequent 

 operation, for which, in that cafe, no more than three quarters 

 of a pound of aqua-forlis and the other ingredients in propor- 

 tion, need be taken for lib. of thread. 



The alum water is made as follows: Whatever may be the 

 kind of alum, it muft be previoufly calcined. One pound of 

 the crude alum is required for Jib. of thread. When it is cal- 

 cined it is pulverized and difiblved in one pint or Englifh quart 

 of water, and rather more than an equal meafure of the re- 

 maining deco6tion of nut-gall is added. Thefe being well 

 mixed and heated, are to be poured on the thread, which has 

 been treated as before with the folution of tin. It is left for 

 fourteen hours in this bath and afterwards prefied and dyed. 



The dying lib. of good bruifed or ground madder previ- 

 oufly foaked for fome hours in water, is put into a boiler of 

 fufficient fize,, which is to be filled with water and placed on 

 2 a moderate 



