60 The Art of Dyeing, 



s2LTy when it is required to give a number of pieces of calico 

 an equal mordanting, to add after each impregnation with 

 the mordant a definite quantity of fresh mordant, or for 

 the sake of great accuracy, to divide the mordant into as 

 many portions as there are pieces of calico to be mordanted 

 and impregnate each by itself therein. The remainder 

 should be again collected and rinsed together. 



BROWN FROM QUERCITRON AND IRON MORDANT. 



Light quercitron brown is formed with the solution of 

 iron alum. No. 1. Dark quercitron is produced with the 

 acetate of iron mordant. No. 2. The mordanted cloth is 

 purified by passing it through a cow-dung bath. To pro- 

 duce the dark quercitron brown, 3 lbs. of quercitron powder 

 are employed for 12 lbs of mordanted cloth. 



For the purpose of dyeing it, the decoction of quercitron 

 bark is employed, being made lukewarm by the addition 

 of cold water. The dyeing is prolonged by gradually raising 

 the temperature to boiling. The addition of lime is unne- 

 cessary. Hot soap-suds do not improve the colour. 



Properties of quercitron brown. — This colour is very per- 

 manent ; light and air alter it very little, and soap-suds by 

 continued action only make it a little paler, while the solu- 

 tion itself becomes yellow. 



Solution of potash forms reddish brown spots which are 

 removed by vinegar. 



Ammonia and vinegar produce no alteration. 



Lime water forms a scarcely perceptible brown spot which 

 vinegar removes. 



Tinmordants, No. 1 and 2 printed in strong^solution, pro- 

 duce (especially No. 1) a pure yellow, and may be used as 

 dischargers. 



Solution of chloride of lime acts similar to lime-water, 

 rendering the colour brown, but not destroying it. 



Remark. — Persian berries give a similar colour with si- 

 milar properties, only that the yellow which the zinc mor- 

 dants produce is more lively and saturated. 



BROWN FROM OAK BARK AND IRON MORDANT. 



Light brown from oak bark is produced with the solu- 

 tion of iron alum ; dark brown with the acetate of iron mor- 



