26 1 



P V H 1 N 



to let it *ettli- ; after which it is fit t'.,r dyeing afiedi. 

 By observing these precaution-., M. I l.iusstiian preser- 

 ved tlie win. v.it in a statt- lit I'm 1 dyeing iliirin^ tno 

 yearn; and lir might ha\e kept it still longer, had it not 

 been for the accnniul.it ion of sediment, which at last 

 rendered it impracticable to dip the stuffs sufficiently 

 deep in the bath. 



'. Bergman mention* another vat, which answers 

 very well for dyeing thrc, d or cotton. 'J'lie following 

 is the process, as described l>y Scheffcr: To very strong 

 soap-boiler's ley, indigo well jiowdered is added, in the 

 proportion of three drachms to a quart ; and alter a few 

 minute*, when the colouring matter is well penetrated 

 by ttie ley, six drams of powdered orpinient arc added. 

 The bath is then well raked. In a few minutes it be- 

 ^reen, and exhibits the blue flower at the top, 

 when the lire is extinguished, and the dyeing pi 

 begun. 



371. Cotton and linen take very pale shades from 

 Saxon blue ; but Prussian blue may be applied more 

 successfully to the^e stall's, by the processes already de- 

 scribed, titan to wool or silk. 



CHAP. V. 



Processes for Dyeing Compound Colours. 



General 372. Compound colours, in dyeing, are such as are 



view of formed from various modifications of the simple coloui--, 

 compound whether by admixture or superinduction. If the proces- 

 eolour*. gpg {,y which these modifications are effected were of a 

 mechanical nature, the resulting colour arising from the 

 combination of particular colours might be prettv accu- 

 rately determined ; but the chemical action of the mor- 

 dant, employed in dyeing one colour, exerting its influ- 

 ence upon the mixed or superinduced colouring matter 

 employed in dyeing another, produces effects, which, in 

 most cases, can only be ascertained by observation and 

 experiment Trusting, therefore, but little to the de- 

 ductions of theory, our attention must be principally 

 directed to the effects of the chemical agents we em- 

 ploy. 

 P,,_. 373. Pure or unmixed colours are rarely found in na- 



i urc or un- , , . i />,. , 



mixed rare- ture ; and, indeed, in the preceding part of this article, 



ly exiM. we have described processes for dyeing colours, many 

 of which were, strictly speaking, of a compound nature. 

 Thus, red is almost uniformly found intermingled with 

 yellow, scarlet, and madder colours, being composed of 

 these principles; and indigo, which appears to furnish 

 tile most perfect blue, is always debased by a certain 

 admixture of yellow. We did not consider these devi- 

 ations, however, from the simple colours which we hare 

 already discussed, as a sufficient reason for separating 

 processes nearly connected with each other, and which 

 scarcely admit of any systematic arrangement that is 

 altogether free from objection. The compound colours 

 are as unlimited as the combinations of simple colours, 

 by means of which they are formed. We can only con- 

 sider, however, the principal mixtures ; and these may 

 be comprehended under the following classes. 

 Division of jgt, A mixture of blue and yellow, which produces 

 " mlul all the intermediate shades between the yellowish green, 

 and the dark green verging to black. 



2d, A mixture of red and blue, which comprehends 

 all the shades from a deep violet colour to a lilac. 



3d, A mixture of red and yellow, which embraces all 

 the shades from a scarlet colour to that of musk and 

 tobacco. 



-I. 



Pnccsiafor 'nilurct of Klue and 



Ytllmr, or (.';, 



374- Several plants .ire capable of affording green Methods 

 colours, but the dyes which they communicate are all pr. 

 of a fading nature. I)', \nibourney , indeed, asserts, th;.t ~ r " 

 he obtained a permanent green from the fermented lour ' 

 juice of the berries of tile < ling alder, by pre- 



paring the cloth with tartar, nitrous solution <i; 

 math, and common salt, and adding to the fermented 

 juice of the berries, when warmed, a little acetite of 

 lead. The cloth acquired in this bath a middle shade, 

 between parrot and grass green. < n-en is obtained by 

 the dyers from an admixture of blue anil yellow, either 

 of these colours In-ing first applied, and then the other. 

 It is usual, however, to apply the blue dye first, ai:< 

 terwards the yellow. The pastel vat is commonly em- 

 ployed ; but for some kinds of green, the solution of 

 indigo in the sulphuric acid is used. In the latter case, 

 the blue snd yellow are either dyed separatelv, i>r all 

 the ingredients are mixed together to dye by a single 

 operation. Sometimes greens are produced by enij 

 ing solutions of copper with yellow substances. 



I. Processes for Dyeing Wool Green. 



.">?.). The blue ground, which is usually applied first, Ground tin 

 ought to be proportioned in intensity to the deepness P vcn *' tl1 

 of the green we wish to obtain : Thus for the green 

 like that of a drake's neck, a ground of deep royal blue 

 is given ; for parrot green, a ground of sky blue, \c. 

 The cloth-; having received the proper ground, they are 

 washed in the fulling-mill, and then boiled as for com- 

 mon welding; but for the lighter shades, a Miiallcr 

 quantity of salts is used. In general, the cloths which 

 are to have the lighter shades are boiled first; and when 

 these are taken out, tartar and alum arc added; and this 

 practice is pursued until we come to the cloths intend- 

 ed for the darker shades, more and more tartar and 

 alum being successively added. 



376'. The process of welding is conducted in the same Welding.- 

 manner as formerly described for dyeing yellow, with 

 this difference, that a larger quantity of weld is employ- 

 ed, unless for the light shades, when the proportion is 

 rather diminished. Frequently, a succession of shades, 

 from the deepest to the lightest, is dyed at the same 

 time, lieginning with the deepest, and proceeding to 

 the lightest. Between each dip, which lasts from half 

 an hour to three quarters, water is added to the bath. 

 Some dyers give each parcel two dips, beginning the 

 first time with the deep -.hades, and the second with the 

 light ones. In that case, each parcel should remain a 

 shorter time in the bath, which should never be allow- 

 ed to reach the boiling point for the lighter shades, 

 1 )eep greens are browned with logwood, and a little sul- 

 phate of iron. 



377. The green obtained by means of solutions of in- 

 digo in sulphuric acid, known by the name of Saxon gi*- 

 green, is more beautiful than the green procured by the 

 preceding process, but it has less durability. According 

 to a description of the process published iu 17>~0, by the 

 French government, the cloth for this dye is lioiled for 

 half an hour with alum and tartar.and then taken out .ind 

 aired, without being washed. The bath is next to be 

 cooled, and the solution of indigo well mixed with it, 

 adding at first only one-half; the cloth is then put in 

 and turned rapidly, without boiling, for five or six mi- 

 nutes ; it is then taken out, that the remainder of the 



