Application in Dyeing. 57 



tlie fustic examined. The solution from which the tannin 

 had been separated gave a dark olive precipitate with solutions 

 of the salts of iron, and a copious yellow one with the solutions 

 of tin ; — it consisted of colouring matter and'gallic acid. In a 

 former experiment the amount of aqueous extract was 15'05 

 per cent: after deducting 5'95 grains of tamiin and gum, there 

 remains 9"10 grains of gallic acid and colouring matter. 

 100 grains of fustic are composed of 



Woody fibre 74 



Resin 9 



Gum 2 



Tannin 3*95 



Colouring matter and gallic acid . . 9*10 

 Loss 1*95 



100-00 



The large amount of loss is probably occasioned by the great 

 difficulty in bringing substances, which attract moisture so 

 rapidly as woody fibre, to the same hygrometric state. 



On the applications of Fustic. 



The colouring matter of fustic is seldom employed in the 

 dyeing of yellow : the only case in which it is so applied is as 

 a cheap substitute for weld or quercitron ; but for woollen 

 goods intended to be dyed a true green in the indigo vat, the 

 required shade of yellow is first given by means of fustic. 



The dyeing vessel may be of iron; and for 120 yards of 

 woollen cloth, weighing lib. 4oz. to the yard, ^Slbs. of fustic 

 in chips with 6lbs. of alum will be found sufficient for ordinary 

 shades of green. If the shade required be bright, ^Ibs. of 

 solution of tin may be added with advantage, but for bottle- 

 green an additional proportion of fustic will be required : some 

 dyers use the fustic alone without any mordant, and the affinity 

 of woollen fibre for the colouring matter of fustic is sufficiently 

 powerful to fix the whole; the addition of a mordant, however, 

 gives much greater durability. After the fustic and alum have 

 been boiled a few minutes in a dyeing vessel containing from 

 300 to 400 gallons of water, 20 gallons of cold water are added 

 and the cloths entered, turning quickly a few minutes and 

 afterwards more slowly, and boiled from fifty minutes to an 

 hour. They are afterwards well washed, and the requisite 

 shade of blue given in the indigo vat. 



Fustic is employed in all the shades known as Saxon green. 

 In this class of colours the blue is obtained from indigo, but 

 by means of its solution in sulphuric acid known by dyers as 



New Series. Vol. 1. No. 1. Jan. 1827. I Chemic. 



