Red from Madder and Alum Mordant. 453 



The mordanted calico is cleansed by rinsing it in running- 

 water. 



As in no department of dyeing is there more detriment 

 experienced than in madder-dyeing, by allowing any mor- 

 dant to remain uucombined with the cloth, and to dissolve 

 in the solution ; it is proper to pass the cloth after rinsing 

 through warm water. 



Common madder-red, when it comes out of the boiler, 

 has either a brown or a dirty brick-red colour, and it ac- 

 quires, with great difficulty, the proper red shade. The 

 latter it acquires, however, in a high degree by the addition 

 of bran in dyeing. If we employ a greater quantity of 

 bran than 3 lbs. bran to 1 lb. madder, we obtain brighter 

 colours. The result is equally good whether we employ 

 9 lbs. mordanted calico, 12 lbs. madder, 36 lbs. bran, or 

 24 lbs. madder and 72 lbs. bran. 



If the proportion of the bran to the madder is diminished, 

 colours are produced which approach a brown shade. 



The quantity of madder required to dye colourless 

 grounds depends on the kind employed. Avignon and 

 Dutch madder are almost equal in their powers of dyeing, 

 while the red kinds are less so. By different trials, I have 

 ascertained that 5 lbs. of Silesian summer-red madder 

 does not produce darker colours than '2\ lbs. of Avignon 

 madder. 



The varieties of madder raised by Herr Charles Milde, at 

 Breslaw, with great care, are equal to the superior madders. 



In general, it may be said, that equal weights of mor- 

 danted cloth and madder afford a sufficiently saturated red, 

 although in many kinds a fourth more is required. 



The dyeing of madder-colours, in order to be equable, 

 requires a considerable time. When there is so much 

 cloth as to require 2 or 3 hours, the temperature of the so- 

 lution, during the first hour, should not exceed 99"£ or 

 J.10°-f; from the first to the second hour, from 155 '-'-* 1o 

 167°; from the second to the third hour, the solution may 

 be brought to the boiling-point, and kept there for half an 

 hour. 



Clearing. — Madder-red dyed with the addition of bran, 

 requires to be cleared by passing it through soap-suds con- 



