DYEING. 



251 



Procese of water. The silk is allowed to remain twenty- four 



cf Dyeing. nourg j n this solution ; it is then taken out. and washed 



S """" Y "" 1 ^ in clean water till it ceases to render it turbid. The 



silk is dyed by boiling it a quarter of an hour with five- 



sixtlis of its weight of cochineal, in a small quantity of 



water. 



286. Scheffer describes some variations in his pro- 

 cess, by which different shades are obtained. If the 

 silk be wrung out of the solution of tin, left all night in 

 a cold solution of alum, (composed of an ounce to a 

 quart of water,) wrung and dried, then washed, and 

 afterwards boiled with cochineal, it will take only a 

 pile poppy colour. If the silk be steeped twelve hours 

 in the solution of tin diluted with eight parts of water, 

 then left all night in the solution of alum, washed, dried, 

 and passed through two baths of cochineal as before, 

 adding to the second bath a little sulphuric acid, it will 

 assume a fine poppy red. 



287- Berthollet remarks, with respect to these pro- 

 cesses, tliat though he varied his experiments in several 

 ways, he was never able to obtain a shade comparable 

 to scarlet ; and he adds, that by the information he 

 obtained from persons who assisted at Macquer's trials 

 at the Gobelins, the silk dyed by his process never 

 reached tliut colour. Scarlet, however, is so much in 

 request, that the attention of several individuals has 

 been excited to discover means of giving it to silk. 

 Those who have been most successful in France, begin 

 with dyeing the silk crimson ; this dye is covered over 

 with one of carthamus, by a process which we 

 afterwards describe ; and, lastly, they give it a yellow- 

 dye without heat. By these means, a fine colour is 

 produced, but the action of the air soon destroys the 

 dye of the carthamus, and darkens the shade. 



288. Dr Bancroft recommends the following process : 

 Soak the silk for the space of two hours, in a solution 

 of the murio-sulphate of tin, diluted witli about five 

 times its weight of water ; take it out of the solution, 

 and let it be moderately squeezed or pressed, and ;:fur- 

 wards partially dried ; and, lastly, dye it as usual, in a 

 bath prepared with cochineal and quercitron bark, in 

 the proportion of four parts of the former to three of 

 the latter. The colour thus imparted to the silk will 

 approach very nearly to a scarlet. A better body may 

 be communicated to it by a farther slight immVrsion 

 into the diluted murio-sulphate of tin, and a M 

 dyeing in the bath with cochineal and quercitron bark. 

 If afterwards a little of the red colouring matter at 

 flower be superadded, by the usual method of applying 

 it, a good scarlet may be produced. 



289. A colour denominated false crimson, to distin- 

 guish it from the cochineal crimson, is imparted to silk, 

 by means of Brazil wood. To apply this dye, the silk 

 should be tailed with soap, in the proportion of twenty 

 pounds, of the latter to a hundred of the former, anil 

 afterwards alumed. Less aluming is required for this 

 than for g>aiu or cochineal crimson. Having refreshed 

 it at the river, it is dipped in a bath more or less charged 

 with the colour of the Brazil wood, according to the 

 shade to be given. If water containing no earthy salt 



ployed, the colour will be too red for crimson ; 

 but this may be remedied by passing the stuff through 

 a slight alkaline solution, or by the addition of a little 

 alkali to the bath. False crimsons may be rendered 

 deeper, by adding juice of logwood to the Brazil bath, 

 alter the >ilk has been impregnated with the latter. To 

 imitate poppy or fire colour, the silk sliui.ld receive an 

 annotta ground ; after which it is washed, alumed, and 



dyed with the Brazil juice, to which a little soap-suds Processes 

 is usually added. 



290. Madder is seldom used for dyeing silk, as its 

 colour is not sufficiently delicate and bright for the pur- re( j. 

 pose. The following processes, however, have been 

 recommended. According to the process of De la Fo- De la Fo- 

 lie, half a pound of alum is to be dissolved in each lie's pro- 

 quart of hot water, to which two ounces of potash are cess- 



to be added ; after the effervescence has ceased, and 

 the liquor has begun to grow clear, the silk must be 

 soaked in it for two hours, and then washed and put 

 into a madder bath. The process of Scheffer is some- Scheffer's 

 what different : the silk is to be alumed in a solution of process. 

 four ounces of alum, with six drachms of chalk, for 

 each pound of scoured silk ; when a sediment is form- 

 ed, the solution is to be decanted; and after having 

 become quite cold, the silk is to be put into it, and to 

 be left eighteen hours. It is then taken out and dried, 

 aftet which it is dyed with an equal weight of madder, 

 when it takes a pretty good, but rather dark colour. 

 Chihliche also describes a process for dyeing silk with Guhliche's 

 madder; for one pound of silk, he orders a bath of four P roccss - 

 ounces of alum, and one ounce of a solution of tin. 

 The liquor is to be left to settle, when it is decanted, 

 and the silk carefully soaked in it, and left for twelve 

 hours. It is then immersed in a bath, containing half 

 a pound of madder, softened by tailing, with an infu- 

 sion of galls in white wine : this bath is kept moderate- 

 ly hot for i\ii hour, after which it is to be made to boil 

 for two minutes. After being taken out of the bath, 

 the silk is to be washed in a stream of water, and dried 

 in the sun. The brightness of the colour may be rais- 

 ed, by afterwards passing it through a bath of Brazil- 

 wood, towluch an ounce of solution of tin has been added. 



291. Carthamus is employed for dyeing silk poppy- Various 

 colour, a bright orange red, cherry, rose, and flesh- sl >ailes of 

 colour. The processes differ according to the in- ^rthamus. 

 tensity of the colour to be given, and the degree in 



which it is to approach that of fire : but the carthamus 

 bath, which varies in the mode of using it, is prepared 

 in the following manner: After having extracted the 

 yellow matter of the carthamus, and opened the cakes, 

 it is put into a deal trough, where it is sprinkled at 

 different times with soda, well powdered and sifted, in 

 the proportion of six pounds to a hundred. The car- 

 thamus being well mixed with the alkali, is put into n 

 email trough, with a grated liottom, lined with a close- 

 ly woven cloth. \Vhcn this cloth is nearly half filled, 

 it is placed upon the large one, and cold water is pour- 

 ed on it till the lower trough is full. The carthamus 

 is then set over another trough till the water comes 

 from it almost colourless ; a little more alkali is then 

 added, and fresh water poured on. These operations 

 are repeated till the carthamus is exhausted and becomes 

 yellow. The silk being distributed on the rods in hank*, 

 lemon juice, or one of the acids formerly recommend- 

 ed, (82.), is poured into the bath, till it assumes a 

 fine cherry colour. Having stirred the bath well, the 

 silk is dipped in, and turned on the skain sticks, as long 

 as it appears to gain colour. For poppy colour, it is p opp y co . 

 taken out, wrung, drained, and passed through a new i OU r. 

 bath, where it is treated as in the former. It is then 

 dried, and passed through fresh baths, washing and 

 drying it after every operation, till it acquires the de- 

 sired shade. When it has taken the proper colour, it 

 is brightened, by turning it seven or eight times in a 

 bath of' hot water, to every bucket of which, about a 

 gallon of lemon juice is to he added. 



