on the Colours used in Painting ly the Ancients. 417 



garment of the Prcnuba, but of an inferior hue ; and this pur- 

 ple appears to be a compound mineral colour of the nature of 

 these. — It was not destroyed by solution of chlorine ; and when 

 a little of it was exposed to muriatic acid, it rendered the acid 

 yellow, and the remainder yielded a residual blue powder. 



VII.- Of the Blacks and Brotvns of the Ancients. 



There is one chamber in the baths of Titus of which the ground- 

 work is black. I have found several fragments of stucco painted 

 black both in tlie baths of Titus and in the vineyard above men- 

 tioned, and also in some ruins near the Porta del Popolo. — I 

 scraped off some of theje colours and submitted them to experi- 

 ments: they were not acted on by acids or alkalies, they defla- 

 grated with nitre, and had all the properties of pure carbonaceous 

 matter. 



I found no blacks, but three different shades of brown in the 

 vase of mixed colours ; one was snuff-colour, one deep red brown, 

 and the third a dark olive brown. The two first proved to be 

 ochres which had been probably partially calcined ; the third 

 contained oxide of manganese, as well as oxide of iron, and af- 

 forded chlorine when acted on by muriatic acid. 



All the ancient authors describe the artificial Greek and Ro- 

 man blacks as carbonaceous, and made either from the powder 

 of charcoal or the decomposition of resin, (a species of lamp- 

 black,) or from the lees of wine, or from the common scot of 

 wood fires. Pliny mentions the inks of the cuttle-fish, but says, 

 *^ex his non fit*." Some years ago I examined this substance, 

 and found it a carbonaceous body mixed with gelatine. Pliny 

 speaks of ivory-black as invented by Apelles ; he says likewise 

 that there is a natural fossil black, and another black prepared 

 from an earth of the colour of sulphur. Probably both these 

 substances are ores of iron and manganese. 



That the ancients were acquainted with the ores of manga- 

 nese is evident from the use made of it in colouring glass. I 

 have examined two specimens of ancient Roman purple glass, 

 both of which were tinged with oxide of nianganese. — Pliny 

 speaks of different brown ochres, and particularly of one from 

 Africa, M'hich he names Cicerculiim, which probably contained 

 manganese : and Theophrastus mentions a fossil f which inflamed 

 when oil was poured upon it, a property belonging to no other 

 fossil substance now known but the black wad, an ore of man- 

 ganese, and which is now found hi Derbyshire. 



The browns in the paintings in the baths of Livia, and in the 



* i. e. the atramentum. 



t Theophrastus says it is like decomposed wood, Ta^i/ioitis uv liy-f an^^ti, 

 12th pMgc of .Tolin de Laet's edition. 



Vol. 45. No. 206. June 181. '5. D d Aldobran- 



