DYEING. 



scouring. This substance acts probably 

 the part of a mordant, and having a 

 stronger affinity for the stuff' and the co- 

 louring matter, than the stuff has for the 

 latter, the colour communicated is more 

 durable, when the silk or cotton is 

 dyed in the unbleached or unsecured 

 state. 



Of the Procettfsfor dyeing blade. 



According to the method described by 

 Hellot, woollen cloth to be dyed black 

 ought to have received the deepest blue 

 tint, to have been washed in the river as 

 soon as taken out of the vat, and to have 

 afterwards been cleaned at the fulling- 

 mill. 



For an hundred pounds of the stuff, 

 ten pounds of logwood, and ten pounds 

 of Aleppo galls powdered, are put into a 

 bag, and boiled for twelve hours in a mid- 

 dle sized copper, with a sufficient quan- 

 tity of water. One-third of this bath is 

 put into another copper, with two pounds 

 of verdegris, and into this the stun is im- 

 mersed, stirring it continually for two 

 hours, and observing to keep the bath 

 very hot, without letting it boil. The 

 stuff is then taken out, and a portion of 

 the bath equal to the former is put into 

 the copper, with eight pounds of vitriol, 

 or sulphate of iron. The fire is now to be 

 diminished, and the bath suffered to cool 

 for half an hour, whilst the vitriol dis- 

 solves ; the stuff is then put in again, 

 moved about well for an hour, and after- 

 wards taken out to air. Lastly, the re- 

 mainder of the bath is added, taking care 

 that the bag be well pressed out. Fif- 

 teen or twenty pounds of sumach are now 

 put in, and the bath is made to boil once, 

 and then immediately stopped with a 

 little cold water ; two pounds more of 

 the sulphate of iron are added, and the 

 stuff' is kept another hour. The stuff is 

 now washed, aired, and again put into 

 the copper, constantly stirring it for an 

 hour : it is then carried to the river, well 

 washed, and then fulled. When the wa- 

 ter comes off clear, another bath is pre- 

 pared with weld, which is made to ooil 

 for a moment, and after being cooled, 

 the stuff' is passed through it, to soften 

 it, and render the black more firm. In 

 thib manner a very beautiful black is 

 obtained, without makir.g the stuff too 

 harsh. 



In general, more simple processes are 

 employed. Cloth previously dyed blue 

 is merely boiled in a bath of gulls for two 

 hours; it is then kept two hours in the 



bath of logwood and sulphate of iron, 

 without boiling, and afterwards washed 

 and fulled. M. Hellot has also found the 

 following method to succeed. For fif- 

 teen ells of deep blue cloth, a bath is to 

 be made with a pound and a half of yel- 

 low wood, five pounds of logwood, and 

 ten pounds of sumach. After having 

 boiled the cloth in this bath for three 

 hours, it is taken out, ten pounds of sul- 

 phate of iron are put into the copper, 

 and the cloth is then put into it for two 

 hours more. It is then aired, put into the 

 bath again for another hour, and after- 

 wards washed and fulled. This black is 

 less velvety than that of the process first 

 described. 



Black may be dyed without a blue 

 ground, and this is usually done for stuffs 

 of low price. In this method the stuff' is 

 djed of a brown, or root colour, with 

 green walnut, peels, or the root of the 

 walnut tree : they are then blackened as 

 above directed. 



The proportions used by the English 

 dyers are, for every hundred pounds of 

 woollen cloth, dyed first of a deep blue, 

 about five pounds of sulphate of iron, five 

 pounds of galls, and thirty of logwood. 

 They begin with galling the cloth, and 

 then pass it through the decoction of log- 

 wood, to which the sulphate of iron has 

 been added. 



Some recommend fine cloths to be full- 

 ed with soap suds; but this operation re- 

 quires an experienced workman, to 

 cleanse the cloth perfectly of the soap. 

 Many advise to give the cloth a dip in a 

 bath of weld when it comes from the full- 

 ing mill, which they say softens it, and 

 fixes the black. Lewis says, the weld 

 bath is totally useless when the cloth lias 

 been treated with soap-suds, though in 

 other cases it may be of advantage. He 

 ascribes its effects entirely to the alkali 

 with which the dyers commonly prepare 

 its decoction. 



The leaves of the uva ursi may be em- 

 ployed instead of galls. They must be 

 carefully dried in autumn, so that they 

 may remain green. M hen they are to 

 be used, 100 pounds of wool are boiled 

 for two hours with sixteen pounds of sul- 

 phate of iron and eight of tartar : the day 

 following the cloth is to be rinsed as af- 

 ter aluming: 150 pounds of uva ursi are 

 then to be boiled in water for two hours, 

 and after their being taken out, a little 

 madder is to be added to the liquor, at 

 the same time putting in the cloth, 

 which is to remain there an hour and ft 

 half, or an Lour aud three quarters, after 



