62 The Art of Dyeing. 



When boiled for \ of an hour in soap-suds consisting of 

 1 lb soap to 200 lbs water, it loses much of its colour and 

 acquires a light yellow brown shade. 



Solution of potash forms reddish brown spots, which are 

 completely removed by vinegar. 



Ammonia dissolves the dye and becomes yellowish. 



Lime water and vinegar have no injurious action. 



Lime juice forms light yellow spots, which after being 

 moistened with ammonia become greenish. 



Tin mordants. No. 1 and 2, printed upon it, form a pure 

 yellow. 



Solution of chloride of lime printed upon it, forms a dirty 

 brown. 



BROWN FROM TANNIN AND IRON MORDANT. 



Light tannin brown is formed with the solution of alum, 

 No. 1 ; dark tannin brown with the acetate of iron mor- 

 dant, No. 2. The colour is purified by passing it through 

 a cow-dung bath. 



To form dark tannin brown 13 lbs of mordanted cloth 

 are employed with 5 lbs of tannin. The dyeing is per- 

 formed by gradually raising the heat to boiling. Soap-suds 

 do not improve the colour. The bright tannin brown be- 

 comes darker by being passed through hot soap-suds. 



Properties of tannin brown, — Tannin colours which are 

 fixed by iron mordants are on the whole very permanent in 

 air and light, and stand washing very well. 



Lime water and ammonia do not alter the dark tannin 

 brown. 



Solution of potash produces a reddish brown colour, which 

 is completely removed by vinegar. 



Lime juice makes yellowish white spots which are re-dis- 

 solved by ammonia. 



Vinegar has no injurious action. 



Tin mordants, No. 1 and 2, when printed on it form a 

 sulphur yellow, and cannot, therefore, be employed to dis- 

 charge it. 



Solution of chloride of lime produces no change on the 

 dark tannin brown. 



BLACK FROM LOGWOOD AND IRON MORDANTS. 



Light logwood black, which is a peculiar gray, like all 

 black colours becomes gray by dilution. It is formed 



