56 The Art of Dyeing. 



YELLOW FROM YELLOW WOOD AND ALUM MORDANT, 



This yellow colour is very fleeting. Its want of per- 

 manence can be well exhibited by dyeing a piece of calico 

 with Persian berries and another with yellow wood. The 

 former retains its deep colour, while the latter fades to a 

 straw tint. 



VIOLET FROM ALKANET AND ALUM MORDANT. 



Bright alkanet violet is produced with the alum mor- 

 dant, No. 3. Dark violet with No. 1. 



The mordanted cloth is cleared by immersing it in run- 

 ning water, and then in warm water. 



Dyeing. — Alkanet-root has its dye-stuff, only in the bark ; 

 therefore, much is required for a dark colour ; as 4 lbs. 

 mordanted cloth to 10 lbs. alkanet root. The colouring 

 matter dissolves in water only by means of spirit of wine. 

 But it is important to use as little spirit as possible. The 

 10 lbs. of alkanet are therefore placed in 5 different vessels 

 (1, 2, 3, 4, 5.) So much spirit (of 80°) is poured on the first 

 as covers it. After 12 hours the red solution which has 

 been formed should be poured off, and re-placed by fresh 

 spirit. The latter should be decanted after 12 hours, and 

 poured upon the roots in the vessel. No. 2. After 12 hours 

 it will also be saturated with colouring matter. It should 

 be decanted and mixed with the first red solution, and em- 

 ployed for dyeing. Fresh spirit should then be poured on 

 No. 2, and this is again poured on No. 3, and thus in suc- 

 cession until the roots are deprived of colouring matter. 



The solution of colouring matter in spirit described, 

 should then be diluted with water, well mixed, and the 

 mordanted cloth dyed in this. The water must be com- 

 pletely free from lime and gypsum, otherwise a great loss 

 of colouring matter will be sustained by precipitation. The 

 heat should be pushed very slowly to boiling, otherwise 

 the spirit, which contains the colouring matter in solution, 

 would be too rapidly volatilized. 



Boiling soap-suds give the colour a lilac shade. 



Properties of alkanet violet. — These are very remarkable. 

 It is not altered by lime water, ammonia, vinegar, lime juice, 

 tin mordants, nor by chloride of lime ; and the blue spot 

 produced by potash will even after 24 hours be removed 



