Chap. 22.] SATTDARACH. 239 



lands of Theodotus at SmjTna, which the ancients made use of 

 for painting ships. At the present day, all ceruse is prepared 

 artificially, from lead and vinegar, ^^ as already stated. 



CHAP. 20. — USTA. 



Usta^^ was accidentally discovered at a fire in the Piragus, 

 some ceruse having been burnt in the jars there. Mcias, the 

 artist above-mentioned,^^ was the first to use it. At the 

 present day, that of Asia, known also as " purpurea," is con- 

 sidered the best. The price of it is six denarii per pound. It 

 is prepared also at Rome by calcining marbled sil,^^ and 

 quenching it with vinegar. Without the use of usta shadows 

 cannot be made.^" 



CHAP. 21. EEETRIA. 



Eretria takes its name from the territory^" which produces 

 it. Nicomachus*^ and Parrhasius made use of it. In a medi- 

 cinal point of view, it is cooling and emollient. In a calcined 

 state, it promotes the cicatrization of wounds, is very useful 

 as a desiccative, and is particularly good for pains in the head, 

 and for the detection of internal suppurations. If the earth, 

 when applied^^ with water, does not dry with rapidity, the 

 presence of purulent matter is apprehended. 



CHAP. 22. SANDARACH. 



According to Juba, sandarach and ochra are both of them 

 productions of the island of Topazus,*^ in the Red Sea ; but 

 neither of them are imported to us from that place. The 



's Cenise, white lead, or carbonate of lead, is prepared in much the same 

 manner at the present day. Ajasson is of opinion that the native pigment 

 discovered on the lands of Theodotus, was native carbonate of lead, the 

 crystals of which are found accompanied by quartz. 



36 " Burnt" ceruse. This was, in fact, one of the varieties of " minium," 

 red oxide of lead, our red lead. Yitruvius and Dioscorides call it "san- 

 daraca," differing somewiiat from that of Pliny. 37 In Chapter 10. 



38 See B. xxxiii. cc. 56, 57. 



^3 It was possibly owing to this that the colour known as " umber" re- 

 ceived its name, and not from Ombria, in Italy. Ajasson says that sha- 

 dows cannot be successfully made without the use of transparent colours, 

 and that red and the several browns are remarkably transparent. 



^^ See B. iv. c. 21. *^ As to both of these artists, see Chapter 36. 



« To the chest. « See B. vi. c. 34, and B. xxxvil. c. 32. 



