456 On Madder, and [Dec 



in this way is a light crystalline powder, of a beautiful 

 orange yellow colour. 



The operation of washing ground madder is important, 

 and accompanied with loss. The Levant madder is easily 

 washed, and should, therefore, be employed for the separa- 

 tion of madder purple. It contains, however, of all the 

 varieties, the greatest quantity of colourless matter soluble 

 in w^ater, and must, therefore, be macerated and washed 

 with fresh w^ater six times for 12 hours, when cut up into 

 considerable pieces. In order to save time and water, six 

 vessels may be made use of, which communicate with each 

 other. Each of them is to be filled half full of Levant 

 madder (Alizari); the first vessel is to be filled up with water. 

 After 12 hours, the water should be drawn off" and digested 

 on the madder in vessel No. 2. Then the first vessel 

 should be again filled up with fresh water. After the lapse 

 of 12 hours, the water in No. 2 is to be transferred to the 

 vessel No. 3, while that in the first takes its place, and the 

 first is again filled up with fresh water. This operation is 

 repeated until fresh water has been introduced six times 

 into the first vessel. The madder of this vessel is now suffi- 

 ciently washed, and is fitted for the separation of the mad- 

 der purple. 4 lbs. of Alizari in large pieces, after being 

 w^ashed six times, weigh in the moist state 15J lbs. It is 

 then very soft and is readily reduced to pulp. To separate 

 the madder purple from the washed Alizari, take \6\ lbs. 

 of moist Alizari, 12 lbs. alum and 70 lbs. water, boil for an 

 hour, and filter the red solution, which is a combination of 

 madder purple with solution of alum. Then the residual 

 root is boiled with 6 lbs. alum and 70 lbs. water for half 

 an hour, the filtered solution mixed with the portion of 

 fluid formerly, withdrawn, and allowed to remain at rest for 

 four hours, in order to clarify. The boiled roots should 

 again be boiled with 70 lbs. of water, and the solution em- 

 ployed for digestion with fresh madder. When the alum 

 solution containing the madder-purple has become com- 

 pletely clear, and acquired a dark rose colour, it should be 

 drawn olF from the sediment, which is principally madder- 

 red, mixed, and well stirred, with a solution of 8 lbs. sul- 

 phuric acid and 9 lbs. water. In the course of a few days 

 the liquid becomes of a yellow colour, and reddish-yellow 

 flocks separate. These should be collected on a filter and 



