DYEING. 



there is a considerable saving of time and 

 fuel. 



To give scarlet the bright lively red, 

 called fire colour, a yellow tinge is com- 

 municated to the cloth by boiling fustic 

 in the first bath, or by adding a little tur- 

 meric to the cochineal. A larger pro- 

 portion of the solution of tin also pro- 

 duces this yellow shade, but it renders 

 the cloth harsh, and limits the action of 

 the colouring matter. 



Dr. Bancroft recommends a method of 

 dyeing scarlet, in which a much smaller 

 portion of cochineal produces an equal 

 effect. He conceived scarlet, from his 

 experiments, to be a compound colour, 

 caused by about three-fourths of crimson 

 or rose colour, and one-fourth of pure 

 bright yellow. He therefore supposed, 

 that, when the natural crimson of the co- 

 chineal is made scarlet, by the usual pro- 

 cess, a fourth of the colouring matter of 

 the cochineal must be changed from its 

 natural crimson to a yellow colour by the 

 action of the solution of tin. For this 

 reason he introduced a bright yellow dye 

 into the bath with the cochineal, and re- 

 duced the quantity of this more expen- 

 sive ingredient. He also found that a 

 mixture of two pounds of sulphuric acid 

 with about three pounds of muriatic acid, 

 poured on fourteen ounces of granulated 

 tin, with exposure to heat, produced a so- 

 lution of tin, that had twice the effect of 

 the common nitro-muriatic solution, at 

 less than a third of the expense, and 

 which raised the colours more, without 

 producing a yellow shade, for the yel- 

 low dye, Dr. Bancroft used quercitron 

 bark. His process for dyeing scarlet, by 

 the use of this substance, and the above 

 preparation of tin, is as follows : 



An hundred pounds of cloth are to be 

 put into a tin vessel, nearly filled with 

 water, in which about eight pounds of 

 the murio-sulphuric solution of tin have 

 been previously mixed. The liquor is 

 made to boil, and the cloth is turned 

 through it by the winch for a quarter of 

 an hour in the usual manner. The cloth 

 is then taken out, and four pounds of co- 

 chineal, with two pounds and a half of 

 quercitron bark in powder, put into the 

 bath and well mixed. The cloth is then 

 returned into the liquor, which is then 

 made to boil, and the operation is conti- 

 nued, as usual, till the colour be duly 

 raised, and the dyeing liquor exhausted, 

 which will usually happen in about fif- 

 teen or twenty minutes ; after which the 

 cloth may be taken out, and rinsed as 



usual. In this method, the labour and fuel 

 necessary for the second bath are saved ; 

 the operation is finished in much less 

 time ; all the tartar will be saved, as well 

 as two-thirds of the expense of the solvent 

 for the tin, and at least oHe-fourth of the 

 cochineal usually employed ; and the co- 

 lour produced will not be inferior, in any 

 respect, to that dyed with so much more 

 expense and trouble in the ordinary way; 

 and, moreover, looks much better than 

 it by candle light. 



A rose colour may be readily and 

 cheaply dyed by the above process, by 

 only omitting the quercitron bark. 



Crimson is produced either by dyeing 

 the wool this colour at once, or by first 

 dyeing it scarlet, and then changing the 

 shade to that required. To dye crimson 

 by a single process, a solution of two 

 ounces and a half of alum, and an ounce 

 and a half of tartar, are employed in the 

 boiling for every pound of the stuff, for 

 each of which also an ounce of cochineal 

 is to be afterwards used in dyeing it. 

 It is customary to employ solution of tin, 

 but in smaller proportion than for dyeing 

 scarlet. To render the crimson deeper, 

 and give it more bloom, archil and pot- 

 ash are frequently used, but this bloom 

 is extremely fugacious. 



To produce a.crimson from a scarlet, 

 the alkalies, alum, and earthy salts are 

 used, all of which have this effect. Crim- 

 son is the natural colour of the cochineal, 

 and to produce it from a stuff' dyed 

 scarlet, the stuff is boiled for an hour 

 in a solution of alum, the strength of 

 which is to be regulated by the depth of 

 shade required. 



Of dyeing Silk red. 



The red colour obtained from madder 

 does not possess sufficient brightness for 

 silk; one of the best processes for its 

 use is the following of M. Guhliche : for 

 every pound of silk, four ounces of alum 

 and one of solution of tin are to be mix- 

 ed with water ; when the liquor has be- 

 come clear it is decanted, and the silk is 

 soaked in it for twelve hours, after which 

 it is immersed in a bath of half a pound 

 of madder to each pound of silk, soften- 

 ed by boiling with an infusion of galls in 

 white wine. The bath is to be kept mo- 

 derately hot for an hour, and then made 

 to boil for two minutes. The silk is then 

 to be taken out, washed in a stream of 

 water, and dried in the sun. The colour 

 thus obtained is very permanent. By 

 leaving out the galls it is clearer. 



