Madder Dyeing 51 



long boiling, loses scarcely any thing, although the soapy 

 water is tinged reddish. Carbonate of soda, in the propor- 

 tion of 1 to 8 cloth, acts upon both kinds of red advantage- 

 ously. The red without chalk it makes slightly redder ; but 

 it withdraws much colour, as the tinging of the liquid shews. 

 The red with chalk becomes more vivid, the alkali scarcely 

 extracting any colour. When 3 parts clay are boiled for a 

 quarter of an hour with 1 part of cloth in 240 water, no 

 action takes place on either of the reds. 



The action of the sun in July, during an exposure of 60 

 hours, produces even less effect upon madder-red dyed with 

 chalk than upon madder-purple red. Madder-red, when 

 used as a dye, is characterized by its combination with 

 alumina, in the absence of any additional substance, being 

 a dull, useless colour; but when, on the other hand, clay 

 or chalk is added, a fine saturated red is produced. 



Madder-orange. — The distinction of madder-orange, and 

 its separation from madder-purple and madder-red, depend 

 upon its little solubility in spirits. To separate the madder- 

 orange in a state of purity, a cold infusion (aufguss) of 

 Alizari, at 59° F. should be prepared. The latter should 

 be carefully edulcorated, washed well with pure water, then 

 digested with eight times as much water, and macerated 

 for 16 hours. The brown-coloured infusion should now be 

 strained through muslin, and its place supplied by fresh 

 water. This should remain for 16 hours in contact with 

 the alizari ; it should then be strained and mixed with the 

 first infusion. After four or six hours repose the liquid 

 should be poured off from the sediment, and the madder- 

 orange separated by filtering through fine paper. The 

 liquid exhibits, on being stirred, a quantity of small crystals 

 of madder-orange, which remain on the filter. These should 

 be well washed with cold water, afterwards boiled with 

 spirit, and the solution filtered while hot. From this solu- 

 tion madder-orange precipitates on cooling, which is to be 

 washed with spirit until it dissolves in sulphuric acid with 

 a fine yellow colour (without mixture of red). When this 

 dye possesses still a reddish-colour, it, is a proof that the 

 orange is mixed with madder-purple, or madder- red. A 

 still surer proof of the purity of the madder-orange is derived 

 from the circumstance of its imparting a nankin colour, 



B 2 



