Processes for preparing Lake from Madder. 1 1 g 



root, after it had been treated in Margraf's method, it 

 appeared tinned with so rich a red, that it was obvious that 

 by far the greater part of the colour still remained in it, 

 and that the most powerful and beautiful part. To extract 

 this, several ineffectual trials were made, which it wovdd 

 be useless to enter into ; but, on attentively examining the 

 appearances which took place on infusing the madder in 

 water, I began to suspect that the red colouring matter was 

 very little, if at all, soluble in water, and that it was only 

 mechanicallv mixed with the water when poured on the 

 root, and suspended in it by the mucilage, with which the 

 root abounds. 



A very small quantity, therefore, can be obtained by any 

 infusion or decoction, as the greater part smks down on 

 the root, or remains with it on the sieve, or in the bag, 

 through which the infusion or decoction is passed to render 

 it clear. I therefore was induced to try whether, by some 

 merely mechanical means, I could not separate the colour- 

 ing matter from the fibrous part of the root. In this at- 

 tempt mv success was fully equal to my hopes; and, after 

 several trials, I consider the process I am now about to 

 describe, as the most peifect I have been able to discover. 



Process 1. 



Enclose two ounces, troy \\eight, of the finest Dutch 

 madder, known in connnerce by the name of crop madder, 

 in a baor capable of containing three or four times that 

 quantity, and made of strong and fine calico. Put it into 

 a large marble or porcelain mortar, and pour on it about 

 a pint of cold soft water. The Than)es water, when filtered, 

 is as good as can be used; it being very nearly as pure as 

 distilfed water, at least when taken up a very little way 

 above London. With a marble or porcelain pestle, press 

 the bag stronalv in every directiou, and, as it were, rub and 

 ound it as much as can be done without endangering the 

 ag. The water will very soon be loaded with the colour^ 

 ing matter, so as to be quite opake and nuiddy. Pour off 

 the water, and add another pint of fresh water to the root, 

 agitating and triturating it in the manner before described; 

 and repeat the operation till the water comes off the root 

 very slightly tinged. About five pints of water, if well agi- 

 tated and rubbed, will extract from the root nearly the 

 whole of its colour; and if the residual root be taken out 

 of the ba'j; and diied, it will be found to weigh not more 

 than five drachms apothecaries weight; its colour will be a 

 kind of light nankeen, or cinnamon, and it w.'l! have en- 

 }i 4 tirely 



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