FAWN COLOURS. 405 



reduced to powder by means of a mill. An infusion 

 of this yields a fawn colour bordering on green. It 

 is a substantive colour, but may be altered and im- 

 proved by the judicious application of mordants. 

 The principal use, however, of sumach in dyeing is 

 the production of black, by means of the large 

 quantity of gallic acid which it affords. 



The different kinds of sumach known in com- 

 merce are the Sicily, Malaga, Trieste, and Verona; 

 the first of these being of the best quality. Its im- 

 port duty is Is. per cwt. ; and its price averages 

 from 12s. to 15s. per cwt. The average annual im- 

 portation for the five preceding years is 100,101 cwts. 



The colouring matter of the husks of walnuts 

 forms an excellent dye for wool, both by itself and as 

 a basis for other colours. This dye is much used 

 and esteemed among the French dyers, because it 

 gives agreeable and very durable shades without the 

 assistance of mordants. In consequence only one 

 simple and not expensive operation is required, while 

 the softness of the wool is preserved. But though a 

 substantive colour, an alum mordant may be used 

 with advantage, as it increases the density of the dye 

 and makes it somewhat lighter in colour. 



When the walnuts have attained to maturity they 

 are gathered, and the outer peels are preserved for 

 dyeing. For this purpose they are put into large 

 casks or tubs, and water is poured over them. In 

 this state they may be kept with advantage for one 

 or two years. They then furnish much more co- 

 louring matter than when fresh, but it emits a very 

 unpleasant putrid odour. The root of the walnut-tree 

 gives the same shades, but to produce an equal effect 

 a greater proportionate quantity must be employed. 



The decoction of this substance consists almost 

 entirely of pure tannin and gallic acid. All barks of 



