DYEING. 



267 



Processes the acetite of alumine ; dried again, rinsed, and final- 

 "' : "S- ly dyed with quercitron bark, employing twelve pounds 

 '""V"" of the latter to fifty pounds of cotton. 

 Olivegreen, 388. The various shades of olive green, and drake's 

 ' Vc - neck green, are given to thread after it has received a 



blue ground, by g;Jling it, and dipping it in a weaker 

 or stronger bath of the acetate of iron, then in the weld 

 bath with verdigrise ; and lastly, in the bath with sul- 

 pliate of copper. After the dyeing process is finished, 

 the colour is brightened with soap. 



Green from 389. In describing the processes of dyeing by means 

 2"" of Prussian blue, we described a method of applying 

 that colouring matter to cloth, which had been sug- 

 gested by Dr Bancroft: he also ascertained that if, 

 instead of dyeing the cloth with weld or quercitron 

 bark, and sulpliate of iron only, he used alum along 

 with the latter, an olive was produced ; and this being 

 soaked, as before mentioned, in warm diluted prussiatc 

 of potash (neutralized with sulphuric acid), it produced 

 a beautiful green ; the alum and quercitron bark or weld, 

 furnishing a sufficient quantity of yellow for that pur- 

 pose, and the Prussian blue, by its superior brightness, 

 giving the green an increased lustre. It is unnecessary 

 to mention, that this green would be instantly tarnished, 

 and at last decomposed entirely by soap. 



CLASS II. Processes for Dyeing Mixtures of Red and 

 Blue. 





bluc. 



Shades ob- 390. By various mixtures of red and blue, we obtain 

 ) violet, purple, dove-colour, pansey, amaranth, lilac, and 

 a SP 68 * numDe r f other shades, determined by the na- 

 turt ' an( ' proportion of the colouring matters used in 

 the production of the simple colours, and the mordants 

 employed to give them fixity, or heighten their lustre. 



I. Procettetfor Dyeing Wool, Violet, Purple, Sfc. 



TO.-V -i, 391. According to the observations of Hellot, stuffs 

 ' which have previously received the scarlet dye, take 

 purp e. an ,, ne qi,.,i colour when blue is superadded. The blue 

 is, therefore, given first, which even for violet and 

 purple ought not to be deeper than the shade distin- 

 gui-hl by the name of sky-blue. After a boiling has 

 been given with alum, mixed with two-fifths nf tartar, 

 the stuff is dipjH'd in a bath, composed of nearly two- 

 thirds as much cochineal as for scarlet, to which" tartar 

 is always mlded. The only circumstance in which the 

 process for dyeing purple differs from t!iat for dyeing 

 violet, i, that for the formi-r a lighter bhic ground i" 

 given, and a larger proportion of cochineal. Lilacs, 

 and other light shades of the same kind, may be pro- 

 duced, by employing these means more ipmringh , ,,r 

 by using the baths which have already l>een employed 

 for dyeing full violets and purple. A little solution of 

 tin is added, for some reddish shades, such as peach- 

 blossom. 



ij the ul- 392. Pcerncr has recommended the sulphate of incli- 

 <* go, instead of the indigo vat, as producing a brighter 

 blue, for the bahis of purple and violet, and that too by 

 a shorter and less expensive process The colours ob- 

 tained in this way, are, indeed, not so durable as when 

 the blue V is employed; but PUTIHT asserts that 

 their durability may be increased by the addition of al- 

 kali to the solution of indigo. I fe accordingly pre- 

 a pound of cloth, with three ounces of alum, by 

 boiling it for an hour and a half, and leaving it for n 

 night in the liquor after it is cold. He makes the bath 



with an ounce and a half of cochineal, and two ounces 

 of tartar, boiling it for three quarters of an hour, and 

 then adding two ounces of solution of indigo, he stirs, 

 and makes it boil gently for a quarter of an hour. He 

 thus obtains a very beautiful violet. Other shades, re- 

 sulting from the mixture of red and blue, are obtained, 

 by increasing or diminishing the proportion of solution 

 of indigo. He increases it as far as five ounces, and di- 

 minishes it to five drachms for each pound of cloth ; he 

 also reduces the quantity of cochineal, but never below 

 an ounce, as the colour would then become too dull ; 

 he changes the proportion of tartar ; and, lastly, he va- 

 ries the preparation given to the cloth, by the addition 

 of tartar, or solution of tin in different proportions. 



393. With respect to these processes, it is justly re- 

 marked by Dr Bancroft, that the cochineal colour will 

 only be united to the aluminous, and not to the tin basis ; 

 and, consequently, that they can only produce a crim- 

 son, of much less vivacity than the rose colour, which it 

 would afford with a nitro-muriate of tin. But this lat- 

 ter mordant has always been avoided in dyeing purple 

 and violet with indigo, on account, of the injurious ef- 

 fects which it produces on the colouring matter of that 

 substance. The same objection does not apply to the 

 murio-sulphate of tin, as the muriatic acid has no ef- 

 fect upon indigo, nor even the sulphuric in the very di- 

 luted state in which it is used in that mordant. Dr 

 Bancroft has, therefore, very happily introduced the 

 use of the murio-sulphate of tin with cochineal and 

 the sulphate of indigo, for dyeing the colours in ques- 

 tion, and produced violets and purples of greater beau- 

 ty and vivacity, than can be obtained by the preceding 

 processes. See Phil, of Perm. Col. vol. ii. p. 383. 



394. Logwood is sometimes employed to communi- 

 cate to wool, sloe, damascene, purple, and other shades, 

 which may be considered as modifications of red and 

 blue. This wood, with the addition of gulls, readily 

 affords all these colours to wool ; but they possess lit- 

 tle stability. Dccroi/.ille, a well-informed dyer in 

 France, has, however, disclosed a process to Berthol- 

 let, by which lie succeeded in obtaining, from logwood, 

 a very good and durable dye. The mordant Tie first 

 employed was composed of solution of tin, muriate of 

 soda, (common salt,) acidulous tartrite of potash, (cream 

 of tartar,) and sulpliate of copper. He afterwards 

 learned a better way of preparing it from M. Giros, 

 who formed it by dissolving the tin in a mixture of sul- 

 phuric acid and sea salt, with a suitable portion of water, 

 to which the tartrite of potash and sulphate of copper 

 were added afterward*. Wool, in the neeco, was dyed 

 with this mordant, by employing the latter in the pro- 

 portion of one-third of the weight of the stuff; but, 

 for cloth, one fifth was deemed sufficient. A bath was 

 prepared of a temperature which the hand could bear, 

 with which the mordant was well mixed. The wool 

 was then dipped in it and duly stirred, the same de- 

 gree of heat being kept up for two hours, and even 

 increased a little. The cloth was then taken out, aired, 

 and well washed. A fresh bath of pure water was then 

 prepared, to which a sufficient quantity of the decoc- 

 tion of logwood was added. The stuff was again iiu- 



I, stirred, and the bath raised to a boiling heat, 

 which was continued for a quarter of an hour. The 

 stuff was then taken out, carefully rinsed, and dried, 

 which finished the process. When a portion of Brazil 

 wood was added, the shade partook more of the red. 

 and afforded the colour known in France by the 

 of prune de Aforlsicnr. 



Processes 

 of Dyeing. 



Dr Ban- 

 croft's pro- 

 cess. 



Sloe, dama- 

 scene, pur- 

 ple, &c. 

 from log- 

 wood. 



Prune de 



Monsieur. 



