DYEING. 



weld. An orange red is given by mad- 

 der with it, but not so deep as with a si- 

 milar quantity of alum. When sulphate 

 of copper is omitted, the wool is said to 

 be much harsher, and the mordant pre- 

 pared without it yields but indifferent 

 colours with logwood, and in particular 

 with Brazil wood. 



Of dyeing Silk violet or purple. 



Silk iuay be dyed violet in two differ- 

 ent modes ; the colour produced by the 

 one is called the fine colour, and that by 

 the other the false, the latter of which is 

 dyed by means of archil or Brazil wood. 

 "When the fine colour is required, the 

 silk must first be passed through a cochi- 

 neal bath, and afterwards be dipped in 

 the blue vat. The preparation and dye- 

 ing of silk with the cochineal are the 

 same as for crimson, with the omission of 

 tartar and solution of tin, by which the 

 colour is heightened. The quantity of 

 cochineal made use of, is always propor- 

 tioned to the required shade, whether it 

 be more or less intense ; but the usual 

 proportion for a fine violet colour, is two 

 ounces of cochineal for each pound of 

 silk. When the silk is dyed, it is wash- 

 ed at the river, twice beetled, dipped in 

 a blue vat, more or less strong in propor- 

 tion to the depth of the shade of violet 

 wanted, and then washed and dried, with 

 the precautions which all colours require 

 that are dyed in this vat. If the violet is 

 to have greater strength and beauty, it is 

 usual to pass it through the archil bath ; 

 without this, light shades would be too 

 dull. 



When silk has been dyed with cochi- 

 neal as above directed, only a very light 

 shade is requisite for purple ; the shades 

 which are deepest are dipped in a weak 

 blue vat, but those which are to be 

 lighter, it is sufficient to dip in water in- 

 corporated with a small quantity of the 

 liquor of the vat, because in the vat it- 

 self they would acquire too deep a tinge 

 of blue, however weak it might be. The 

 light shades of this colour, as gilly flower, 

 peach-blossom, Stc. are produced in this 

 manner, by diminishing the quantity of 

 cochineal. 



The false violet colour of the greatest 

 beauty is given to silk by archil, in the 

 various ways used for producing it; the 

 bath of which is to have its strength pro- 

 portioned to the colour required. The 

 silk having been beetled at the river, 

 after scouring, is turned in the archil bath 

 011 the skein sticks ; and when the colour 



is deemed sufficiently deep, a pattern is 

 tried in the blue vat, to ascertain whether 

 it takes the violet colour intended to b& 

 produced. If the shade is of the propel? 

 depth, the silk is beetled at the river, and 

 dipped in the vat in the same way as 

 for the fine violet colours ; and less either 

 of the blue or of the archil colour is 

 given, according as the .violet is intend- 

 ed to have the blue or red shade predo- 

 minant. 



A violet colour may be imparted to 

 silks by immersing them in water im- 

 pregnated with verdigris as a substitute 

 for uluming, and next giving them a bath 

 of logwood, in which they assume a blue 

 colour ; which is converted into a violet, 

 either by dipping them in a weaker or 

 stronger solution of alum, or by adding it 

 to the bath ; the alum imparts a red shade 

 to the colouring matter of the logwood. 

 This violet possesses but little beauty or 

 durability ; but if the alumed silk be im- 

 mersed in a bath of Brazil wood, and 

 next in a bath of archil, after washing it 

 at the river, a colour is obtained, possess- 

 ing a much higher degree of beauty 

 and intensity. M. Decroizilles' process, 

 above related, for dyeing wool, suc- 

 ceeds equally well, according to his ac- 

 count, in communicating a violet colour 

 to silk. 



Of dyeing Cotton and Linen violet. 



To communicate a violet colour to cot- 

 ton and linen, they commonly receive first 

 a blue ground in the vat, proportioned to 

 the shade required, and are then dried. 

 They are afterwards galled with the pro- 

 portion of three ounces of galls to every 

 pound of stuff', and being left in this bath 

 for 12 or 13 hours, are wrung out and 

 dried again. They are next passed 

 through a decoction of logwood, and 

 when thoroughly soaked and taken out, 

 the bath receives an addition of two 

 drams of alum, and one of dissolved ver- 

 digrise, for every pound of the yarn. Tt 

 skeins are then dipped again on the ske 

 sticks, and turned for about 15 minut 

 when they are taken out and aired ; tl 

 are next immersed in the bath for 15 

 nutes, taken out and wrung. To 

 plete the process, the vat employed 

 emptied ; half of the decoction of lo 

 wood not before used is now poured ii 

 with the addition of two drams of aV 

 and the yarn is again dipped in it ti 

 has acquired the shade proposed, whi< 

 must always regulate the strength 



