242 PLIKY*S NATURAL HISTOUT. [Book XXXV. 



the black, for writing, having an admixture of gum, and that 

 for coating walls, an admixture of glue. Ulack pigment that 

 has been dissolved in vinegar is not easily effaced by washing. 



CHAP. 2G. ruurcKissuii. 



Among the remaining colours which, as already stated, 54 

 o\viiig to their dearness are furnished by the employer, pur- 

 purissuin holds the highest rank. For the purpose of prepar- 

 ing it, argentaria or silver chalk 57 is dyed along with purple 58 

 cloth, it imbibing the colour more speedily than the wool. The 

 best of all is that which, being thrown the very first into the 

 boiling cauldron, becomes saturated with the dye in its primi- 

 tive state. The next best in quality is that which has been 

 put into the same liquor, after the first has been removed. 

 Each time that this is done, the quality becomes proportionally 

 deteriorated, owing, of course, to the comparative thinness 

 of the liquid. The reason that the purpurissum of Puteoli 

 is more highly esteemed than that of Tyiv, Gxtulia, or Laconia, 

 places which produce the most precious kinds of purple, is the 

 fact that it combines more readily with hysginura, 6 * and that 

 it is made to absorb the colouring liquid of madder. The 

 worst purpurissuni is that of Lanuvium/ 



The price of purpurissum is from one to thirty denarii per 

 pound. Persons who use it in painting, place a coat of sandyx 

 beneath; a layer on which of purpuriasum with glair -of egg, 

 produces all the brilliant tints of minium. If, on the other 

 hand, it is their object to make a purple, they lay u coat of 

 cxruleuin 61 beneath, and purpurissum, with egg, 62 upon it. 



CHAP. 27. IXDICUM. 



Xext in esteem to this is indicum, 63 a production of India, 

 being a slime 64 which adheres to the scum upon the reeds there. 



* In Chapter 12 of this Book. 



5r Plate powder. See B. xvii. c. 4, and Chapter 58 of this Book. 



M See B. ix. c. 60. 



41 See B. ix. c. Co, and B. xxi. cc. 33, 97. According to Vitruvius,it is 

 a colour between scarlet and purple. It may possibly have been made 

 from \vo:l. M See B. iii. c. 1C. 6> Sec B. xxxiii. c. 67. 



c - White of egg 1 , probably. 



63 Indigo, no doubt, is the colourmeant. See B. xxxiii. c. 57. 



t It is the produce of the liidi^ofera tiuctoria, and comes from Bengal 

 more particularly. Beckmaim and Dr. Bancroft have each investigated this 

 subject at great length, and though Pliny is greatly mistaken 08 to the 



