21(5 DURABLE AND SUPERIOR LAKE. 



lour produced by this mode was of a pale red, and very opake, 

 although the eminent author of the procefs ftales the colour he 

 produced to be that of " le fang enflamme," which probably 

 means a deep blood colour. It may, however, be obferved, 

 that colours prepared with a bads of alumine will appear much 

 deeper when ground in oil than they do in the lump, the oil 

 rendering the alumine nearly tranfparent. This advantage is 

 however, loft in water-colours. On examining the refiduum 

 of the madder root, after it had been treated in MargraPs me- 

 thod, it appeared tinged with fo rich a red, that it was obvious, 

 iecaufc moft that by far the greater part of the colour ftill remained in it, 



rtmamed^the and that the moft P owerfuI and beautiful part. To extradt 

 root, this, feveral ineffectual trials were made, which it would be 



ufelefs to enter into; but, on attentively examining the ap- 

 pearances which took place on infufing the madder in water, I 

 began to fufpect that the red colouring matter was very little, 

 Water takes up if a t all, foluble in water, and that it was only mechanically 

 colour. C mixed with the water when poured on the root, and fufpended 

 in it by the mucilage, with which the root abounds. 



A very fmall quantity, therefore, can be obtained by any in- 

 fufion or decoction, as the greater part (inks down on the root, 

 or remains with it on the fieve, or in the bag, through which 

 Whence mecha- the infufion or decoction is pafled to render it clear. I there- 

 advifahle. Ur S ^ ore was i n ^ uce d to try whether, by fome merely mechanical 

 means, I could not feparate the colouring matter from the fi- 

 brous part of the root. In this attempt my fuccefs was fully 

 equal to my hopes ; and, after feveral trials, I confider the 

 procefs I am now about to defcribe, as the moft perfect I have 

 been able to difcover. 

 Procefs i. Procefs 1 . Enclofe two ounces, troy weight, of the fineft 



Two ounces of j) utcn ma dder, known in commerce by the name of crop 



madder were ... _ . 



pounded in a madder, in a bag, capable of containing three or four times 



bag with a pint that quantity, and made of ftrong and fine calico. Put it into 

 of water " . 



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



pint of cold foft water. The Thames water, when filtered, 



is as good as can be ufed ; it being very nearly as pure as dif- 



tilled water, at leaft when taken up a very little way above 



London. With a marble or porcelain peftle, prefs the bag 



fhongly in every direction, and, as it were, rub and pound it 



as much as can be done without endangering the bag. The 



water will very foon be loaded with the colouring matter, fo 



as 



