270 



D V E I N 0. 



^ ri 

 - .1 --. 



( . .. i.,,.:i 



Dr Ban- 

 croft's ob- 

 jectiotu to 

 Ik 



Bergman's 



j ri 1 i-si. 



Black from 



muscus pul- 

 monarius. 



Common 

 process. 



half of yellow-waod (morns Uxctoria), five pounds of 

 logwood, and ten pounds of sumach. After Ixiilir 

 cloth in this bath for tlnee horns, it i- taken 

 ten pound* of snlph .n arc put into the copper, 



and the cloth is kept in it igcr: it is then 



aired, put into the hath a a 'Hiii I r another hour, and, 

 washed and fulled. 



413. Broad cloth may be made to acquire a black, in 

 every respect unexceptionable, by boiling it two hours in 

 a decoction previously prepared with about one-seventh 

 of its weight of galls, ond as much chipped logwood ; af- 

 terwards passing it for another two hours through a so- 

 lution of one-tenth of its weight of sulphate of iron, and 

 keeping the solution at a scalding heat only. Most dyers 

 arc satisfied with a smaller proportion of galls, and sup- 

 ply the deficiency by increasing the quantity of logwood, 

 and by adding al.so a portion of .sumach. 



111. For coarse stuffs, and cheap woollens, the blue 

 ground froin woad is omitted, its place being badly sup- 

 plied by logwood and .sulphate of copper or verdigrise; 

 or the latter is dissolved with the sulphate of iron to 

 convert a part of the colouring matter of the logwood in- 

 to a kind of blue. Dr Bancroft disapproves of this prac- 

 tice. He says, that the only use of the sulphate of cop- 

 per, or verdigrise, is, to produce a logwood blue, which 

 soon changes to a rusty brownish colour ; and that it 

 would be better to use the logwood with the sulphate of 

 iron alone : (Pliil. of Perm. Col. ii. 454.) He adds, that, 

 with sulphate of iron and logwood, it is not difficult to 

 produce a full and deep black, but that it is not so last- 

 ing as the black with sulphate of iron, and galls or su- 

 mach, cither alone, or with a moderate proportion of log- 

 wood ; which last certainly improves the appearance of 

 the black dyed from galls and iron, by rendering it more 

 intense, glossy, and soft. All black cloths, for the dye- 

 ing of which a large proportion of logwood has been 

 used, are reddened by the application of muriatic acid ; 

 a little liquid ammonia restores the colour. 



415. About the year 1753, Bergman strongly recom- 

 mended a method of dyeing cloth black, by dipping 

 woollens which had previously received a blue ground, 

 in a bath composed of eight pounds of cream of tartar, 

 sixteen jxHinds of sulphate of iron, two pounds of verdi- 

 grise, and ten pounds of woad, to a hundred pounds 

 weight of cloth, and afterwards boiling it for two hours 

 in a decoction of a hundred and fifty pounds of ura ursi, 

 or bear's foot. 



4 1 6. Dr Bancroft states, tliat a fine lasting black may 

 be dyed, without iron or any other basis, upon blue cloth, 

 from a species of lichen, muscus pulmonarius, (91.) ; 

 and that, if this substance could be readily and copious- 

 ]y obtained, it would, probably, deserve to be preferred 

 to madder and weld for rendering blue cloth black. 



417. The proportions of ingredients for dyeing black, 

 usually employed by the dyers of this country, are, for a 

 hundred pounds of woollen cloth, dyed first a deep blue, 

 about five pounds of sulphate of iron, the same quantity 

 of galls, and thirty pounds of logwood. The cloth is 

 first galled, and then passed through the decoction of 

 logwood, to which the sulphate of iron has been added. 

 \Vlien the cloth is completely dyed, it is washed in a 

 i iver, and fulled till the water comes off clear and co- 

 lourless. Some recommend fine cloths to be fulled with 

 soap-suds; hut this operation requires an experienced 

 workman to free the cloth perfectly from the soap. Many 

 advise to give the cloth a dip in a bath of weld when it 



Drabs. 



comes from the fulling-mill, which is said to soften, and 



Slack. 



1 1 S. To give a browning, the stuff which has been 

 just dyed, is dipped in a solution of sulphate of iron, to 

 which an astringent has lcen added. More frequently 

 a small portion of Mention of iron is mixed with a bath 

 of water ; and more is added, till the .stuff dipped in it 

 has atuuned the desired shade. Prerner frequently soaks 

 the stuff in a solution of sulphate of iron ; to which he 

 sometimes adds other ingiedirnts ; and, when taken out 

 of this moidant, he dips it in the dye bath. The first 

 method is employed for marrones, coffee, daniasceae 

 colours, and other shades of browns ; a more or less deep 

 colour being given them, according to the shade we wish 

 to obtain by browning : a bath is then prepared of galls, 

 sumach, and alder bark, with the addition of sulphate of 

 iron. The stuffs intended for the lighter shades are dip- 

 ped first ; and, when they are finished, the browner ones 

 are dipped ; a quantity of sulphate of iron, proportionate 

 to the end proposed, being added for each operation. 



41<l. Drab colours, of various shades, are very con- 

 venicntly and cheaply dvcd, by the quercitron-bark, and 

 an iron basis. For this purpose, Dr Bancroft recom- 

 mends the bark to l>e boiled for a few minutes in a cop- 

 per vessel, with one-third or one-fourth of its weight of 

 sulphate of iron ; and the liquor having been well mix- 

 ed, and a little cooled, the cloth may be dyed in it as 

 usual. To sadden and darken the colour still farther, a 

 little sumach may be employed with the bark. See Phil. 

 ti/'Perni. Col. ii.' M k 



II. Processes for Dyeing Silt, Black, $c. 



420. Silk which is intended to be dyed, is common- Galling. 

 ly boiled four or five hours with a fifth of its weight of 

 white soap, after which it is beetled and carefully washed. 



It is then galled, by leaving it from twelve to thirty-six 

 hours in a decoction prepared with about three-fourths 

 of its weight of galls, which have been boiled three or 

 four hours ; after which it is taken out, and washed in the 

 river. 



421. As silks are capable of combining with a greater Light and 

 or less quantity of the astringent principle, they receive, 



when dyed black, a greater or a less augmentation to 

 their weight, not only from the astringent principle, but 

 also from the oxide of iron which combines with it in 

 like proportion. The dyeing process is, therefore, vari- 

 ed, according as the operator is desirous of rendering 

 the silk more or less heavy. Hence the distinction of 

 light and heavy black. 



422. The difference in the process for obtaining heavy 

 black, consists in leaving the silk a longer time in the 

 decoction of galls, in repeating the galling, in dipping 

 ilie silk in the dye a greater number of times, and leav- 

 ing it longer in the bath each time. 



423. Silk dyers usually preserve a vat for the black, Vat for 

 and its composition, which generally consists of many su- W> 

 perfluous ingredients, and varies greatly in different dye 

 houses. The vat is frequently continued for many \ 



tJie black dye being always renewed when it is nearly ex- 

 hausted. Macquer has given a description of one of 

 these vats ; it contained seeds of fenugreek, flea-wort, 

 cummin, colocynth, buckthorn berncs, agaric, nitre, am- 

 moniac, sal gem, litharge, antimony, lend ore, orpiment, 

 corrosive muriate of mercury, together with a vaiiet\ of 

 other ingredients apparently added at random. M IX 



