Yellow brown from yellow wood and Iron Mordant. 61 



dant. The mordanted cloth is purified by passing it through 

 a cow-dung bath. To form a dark brown from oak bark 

 6 lbs of mordanted cloth are to be employed for 12 lbs of 

 oak bark. 



Dyeing. — When the oak bark is very finely pulverized a 

 number of small chips (as in the quercitron bark) stick to 

 the cloth. We should, therefore, employ a cool decoction 

 for dyeing, and heat the solution gradually to the boiling 

 point. Hot soap-suds effect no improvement of the colour. 



Properties of oak hark brown. — This colour is very perma- 

 nent in the air, light and soap-suds. When boiled with 

 soap-suds the colour becomes first darker, then brighter. 



Solution of potash makes reddish brown spots which 

 vinegar does not completely remove. 



Ammonia and vinegar produce no alteration. 



Lime water forms a scarcely perceptible brown spot, 

 which vinegar removes. 



Lime juice forms a grayish white spots, which ammonia 

 converts into dark brown. 



Tin mordants. No. 1 and 2, printed in a strong solution, 

 take the colour completely away and form a bright nut 

 brown. 



Solution of chloride of lime printed upon it acts in a similar 

 manner to the lime water, not destroying the colour, but 

 rendering it strongly brown. 



Remark. — Willow bark (especially the basket willow) 

 gives similar colours with the same properties. 



YELLOW BROWN FROM YELLOW WOOD AND IRON MORDANT. 



Light yellow brown from yellow wood is formed with 

 the solution of iron alum. No. 1. Dark yellow brown from 

 acetate of iron mordant. No. 2. 



When the cloth is passed through a hot cow-dung bath, 

 the dark colour becomes blacker. The cloth is purified by 

 rinsing it in running water. 



To produce a dark shade 8 lbs of mordanted cloth are 

 employed w^ith 3 to 5 lbs of yellow wood.* 



Properties of brown from yellow wood. — In light and air 

 this colour fades somewhat, while it acquires a bright but 

 not disagreeable colour. 



♦ With this dyestufF dark colours can only be obtained by adding a great excess. 



