compreliends both the tone and harmony of the Greeks. Our 
author then continues,—‘‘ There are three kinds of Sinopis, the 
pale, the red, and the intermediate. It is used both with the 
brush and for colouring wood. That which is of the deepest 
red is used for colouring partitions. The Sinopis known as the 
dull (jjressior) is tawny, and is used principally for the lowest 
partitions.” 
Then he speaks of Rubrica, which is either red ochre or oxide 
of iron, as a better kind of Sinopis, highly esteemed, and only 
sold in sealed vessels, hence called Sphragis, and as being used 
to adulterate or give an under coating to minium, which is 
probably a vermillion, and that it is found in Eg}"pt and 
Arabia in iron mines. Another variety he describes thus—“ It 
is from Rubrica that ochrea is prepared. The Rubrica being 
% 
buimt in new earthern pots, well luted with clay, and is very 
useful for plasters by reason of its desiccative properties.” 
Other varieties he describes under the term sil, which w'ere 
in all probability ochres. 
Thus then there can be no doubt that these various forms 
of ochre were used by the Romans as yellow, brown, or red 
pigments variously modified in their tints or shades by admix¬ 
ture with neutral substances, as we employ those minerals in 
the present day. 
The green colours which I examined were two in number. 
No. 1 was composed of the protoxide and a little peroxide of 
iron, silica, lime, alumina, and carbonic acid. 
This appears to be an exception to the usual ancient green 
pigments, which generally contain copper, whilst in this 
substance none is present. It is a carbonate of protoxide of 
iron or ferrous carbonate, with chalk, alumina, silica and a 
little ferric oxide. The only substance that I can find given by 
Pliny, agreeing with it occurs in this passage. “ There are 
also two colours of very inferior quality wRich have been 
recently discovered. One of these is knowm as Appianum, a 
fair imitation of Chrysocolla. This colour is prepared from a 
green chalk.” This passage is readily understood as we are 
acquainted with several minerals of a green colour wliich ow^e 
that colour to ferrous compounds. 
