on the colours used in painting by the Ancients. 117 
oxide of iron, and afforded chlorine when acted on by muriatic 
acid. 
All the ancient authors describe the artificial Greek and 
Roman 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 
soot 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 sul- 
phur. 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 manganese. — Pliny 
speaks of different brown ochres, and particularly of one 
from Africa, which he names Cicerculum, which probably con- 
tained manganese: and Theophrastus mentions a fossiff 
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 manganese, and which is now found in 
Derbyshire. 
The browns in the paintings in the baths’of Livia, and in the 
Aldobrandini picture, are all produced by mixtures of ochres 
* i e. the atramentum. 
t Theophrastus says it is like decomposed wood nuponoios wv $jv\u> (runpa, 
12th pdge of John de Laet’s edition. 
