DYEING. 



Crimson produced on silk by cochineal 

 is called grain crimson, to distinguish it 

 from a colour called false crimson, dyed 

 with Brazil wood. For the grain crimson, 

 the silk, being well cleansed from soap 

 at the river, is to be immersed for a night 

 in alum liquor of the full strength ; it is 

 then to be washed, and twice beetled at 

 the river. The bath is prepared by fill- 

 ,ing a long boiler two-thirds with water, to 

 .which are added, when it boils, from 

 half an ounce to two ounces of powdered 

 white galls for every pound of silk. 

 When it has boiled for a few moments, 

 from two to three ounces of cochineal, 

 powdered and sifted, are put in for every 

 pound of silk, and afterwards one ounce 

 of tartar for every pound of cochineal. 

 When the tartar is dissolved, one ounce 

 of solution of tin is added for every ounce 

 of tartar. Macquer recommends this 

 solution of tin to be made by dissolving 

 .six ounces of fine grain tin, with two 

 ounces of sal ammoniac, in a pound of ni- 

 .tric acid, diluted with twelve ounces of 

 water. When these ingredients are mix- 

 ed together, the boiler is to be filled with 

 .cold water, the proportion of which, for 

 ^every pound of silk, is about eight or ten 

 quarts. In this bath the silk is to be 

 immediately immersed, and turned on 

 the winch till it appears of an uniform 

 colour ; the fire is then increased, and 

 the bath is kept boiling for two hours, 

 taking care to turn the silk occasionally ; 

 the fire is afterwards put out, and the 

 silk immersed in the bath, where it is 

 suffered to remain a few hours longer ; it 

 is then taken out, washed at the river, 

 twice beetled, and dried. 



To obtain other shades of red, the 

 above processes must be varied. If, af- 

 .ter the silk has been wrung out of the 

 solution of tin, it is steeped for a night 

 in a cold solution of alum, in the propor- 

 tion of one ounce to a quart of water, 

 wrung, dried, then washed, and boiled 

 with cochineal, it will appear of a pale 

 poppy colour. But a fine poppy -red 

 may be procured by steeping it twelve 

 hours in the solution of tin, diluted with 

 eight parts of water, then leaving it all 

 night in the solution of alum, after which 

 ( il is to be washed, dried, and passed 

 through two baths of cochineal, taking 

 care to add to the second bath a small 

 quantity of sulphuric acid. 



The colour that comes nearest to scar- 

 let has been produced, on silk, by first 

 dyeing it crimson and then dyeing it 

 v -vith carthamus, and afterwards submit- 



VOL. IV. 



ting it to a yellow bath without heat. The 

 colour thus given is very fine, but the dye 

 of carthamus is not permanent. In Dr. 

 Bancroft's process, the silk is soaked for 

 two hours in a solution of tin, in the 

 murio-sulphuric acid, after which it is 

 wrung out and dried partially. It is then 

 to be dyed in a bath, prepared with four 

 parts of cochineal and three of quercitron, 

 bark. In this way a colour approaching to 

 scarlet is obtained. To give the colour 

 more body, the immersion may be repeat- 

 ed in the solution of tin, and in the dye- 

 ing bath ; the brightness of the scarlet 

 is increased by the addition of carthamus. 

 A lively rose colour is produced by omit- 

 ting the quercitron bark, and dyeing with 

 the cochineal alone. 



Of dyeing Cotton and Linen red. 



To dye cotton and linen red, madder 

 is used; which cotton attracts more 

 strongly than linen. The madder-red of 

 cotton is distinguished into two kinds, 

 the one is called simple madder-red ; the 

 other, which is much brighter, is called 

 Turkey, or Adrianople red. 



The process used at Rouen for the 

 simple madder-red is as follows. The 

 cotton must be scoured, galled with one 

 part of galls to four of cotton, and then 

 alumed with four ounces of Roman alum 

 to one pound of cotton, and an equal 

 weight of water : to the solution of alum 

 one twentieth part of a solution of soda, 

 consisting of half a pound of soda to a 

 quart of water, must be added. When 

 the cotton is taken out of this mordant, it 

 is slightly wrung with the pin and dried ; 

 the colour is more beautiful as the dry- 

 ing is slow ; twenty pounds of cotton are 

 usually dyed at once, but ten would be 

 better, because when many hanks are 

 dyed at a time it is difficult to make the 

 colour equal. To prepare the bath for 

 ten pounds of cotton, about two hun- 

 dred and twenty quarts of water should 

 be heated in a copper, and when almost 

 too hot for the hand, six pounds of good 

 Dutch grape madder are to be carefully 

 dispersed through it. When it is well 

 mixed, the cotton is to be immersed, 

 hank by hank, on sticks. When all the 

 cotton is in, it is to be well worked, and 

 the hanks turned on the sticks for three 

 quarters of an hour, the bath being kept 

 constantly at the same degree of heat, 

 without boiling ; at the end of this time 

 the cotton is to be taken out and left on 

 the edges of the copper, a pint of the 



It 1 



