374 The Art of Dyeing. 



COLOURS WITH LOGWOOD AND COPPER MORDANT, NO. I. 



With 10 lbs. cloth, lib. logwood, and 3 lbs. bran, the 

 resulting colour is clear light-blue ; without the bran, it is 

 a dirty grayish-blue. The process is the same as with the 

 alum mordant. 



With madder-red and alum mordant, the action of the 

 bran is still more striking. It gives not only the red a 

 clearer colour, but it also increases the dyeing powers of 

 the madder ; since, with the same quantity of madder, by 

 the addition of bran, more cloth can be dyed than without 

 the bran. 



With 12 lbs. Avignon madder, 36 lbs. bran, and 9 lbs. 

 cloth, the colours in each of three successive emersions in 

 the vat become clearer and lighter red ; while without the 

 bran, the first emersion gives a very dark red, and the third 

 a light reddish yellow colour. The result shews that the 

 action of the bran consists in producing an uniform distri- 

 bution of the colouring matter of the madder over the cotton . 



The proportion of the bran to the madder as here given 

 (36 to 12) is the best. If less is taken, the madder colour 

 is not so dark; if more is employed, the same result fol- 

 lows — a pale-red only is obtained. 



The dyeing should be completed at the boiling tempera- 

 ture. The addition of bran to madder on a white ground 

 is very useful. If wheat-bran cannot be had, rye-bran may 

 be employed. 



The action of bran when added to solution of Fernambuc 

 is not less remarkable. The colour obtained is a clearer 

 red, than when it is dyed without bran. 



Bran thickens the solution much. This is an obstacle to 

 the dyer, as it compels him to employ more water than 

 usual, and only allows half as much cloth to be placed in 

 the vessel for dyeing at once, as formerly. This difficulty 

 may be removed by employing a decoction of the bran, in- 

 stead of the bran in substance ; the former possesses the 

 same action as the latter. 



The decoction is formed by boiling the bran with a suffi- 

 cient quantity of water, to form a thin paste. From this 

 the watery portion is strained ; the residue is boiled, and 

 again strained. The residual bran may be used for fodder. 



