PAIN 
was evidently a fpecies of indigo; the blues in the Nozze 
Aldobrandine, from their refilling the aftion of acids, 
and from the effefts of fire, are fuppofed to be compound¬ 
ed of the Alexandrian or Puzzuoli blue. Some blue co¬ 
lour was found in a pot taken from an excavation at Pom¬ 
peii, which proved to be a mixture of carbonate of lime 
■with Alexandrian frit. 
Sir H. Davy fuppofes, that the ftained glafs of the an¬ 
cients was tinged with oxyd of cobalt, and that the co¬ 
lours were fimilar to the modern fmalt. “ I have not,” 
fays he, “ found any powdered colour of this kind in the 
baths of Titus, or in any other Roman ruins; but the 
blue glafs, tinged with cobalt, is very common in thofe 
ruins, which, when powdered, forms a pale-coloured 
fmalt. I have examined many paftes and glaffes that con¬ 
tain oxyd of copper; they are all bluilli-green, or of an 
opaque watery blue. The tranfparent blue glafs veffels 
which are found with the vafes in the tombs in Magna 
Grascia, are tinged with cobalt, and are found to contain 
this mineral.” Sir H. examined l'ome Egyptian paftes, 
which are all tinged blue and green with copper; and, 
though he made experiments on nine different fpecimens 
of ancient Greek and Roman tranfparent blue glafs, he 
found copper in none, but cobalt in them. all. A gentle¬ 
man at Milan found fome time ago oxyd of cobalt in the 
blue glafs collefted from the ruins of Hadrian’s Villa ; 
and “ at this time,” fays our author, “ I had no idea 
that cobalt was known to the ancients.” 
Of tlw ancient Greens .—The deep fea-green colouring 
matter, taken from the ceiling of the chambers called the 
baths of Livia, proved to be foluble in acids, with effer- 
vefcence ; and, when precipitated from acids, it was re- 
difTolved in folution of ammonia, giving it a bright blue, 
produced by copper. There are feveral different (hades 
of green employed in the baths of Titus, and on the frag¬ 
ments found near the monuments of Caius Ceftius. Of 
the three different varieties, one, which approached to 
olive, was the common green earth of Verona; another, 
which was a pale grafs-green, had the character of carbo¬ 
nate of copper mixed with chalk; and a third, which was 
a fea-green, was a combination of copper mixed with the 
blue copper frit. 
Vitruvius mentions chryfocolla as a native fubftance 
found in the copper-mines ; and Pliny fpeaks of an arti¬ 
ficial chryfocolla made from the clay found in the neigh¬ 
bourhood of metallic veins, which clay was moll proba¬ 
bly impregnated with copper. The native chryfocolla 
was probably a carbonate of copper ; and the artificial was 
clay impregnated with l'ulphateof copper, rendered green 
by a yellow die. 
Among the fubftances found in the baths of Titus, 
were fome parts of a grafs-green colour, which proved to 
be carbonate of copper; but it had formed round longi¬ 
tudinal nuclei of red oxyd of copper, fo that probably 
thefe fubftances had been copper nails ufed in building, 
converted, by the adlion of the air during fo many cen¬ 
turies, into oxyd and carbonate. 
The ancients, according to Theophraffus, were well 
acquainted with verdegris, and Vitruvius mentions it 
among the pigments; and perhaps many of the ancient 
greens which are now carbonates of copper were origi¬ 
nally laid on in the State of acetite. The ancients had 
beautiful deep-green glaffes, whichyvere tinged with oxyd 
of copper; but it does not appear that they ufed thefe 
glaffes in a ftate of powder as pigments. 
Of the Purple of the Ancients .—The iro^tpv^a. of the 
Greeks, and the ojlrnm of the Romans, was regarded as 
their melt beautiful colour, and was prepared from Ihell- 
fifh. According to Vitruvius, the colour differed ac¬ 
cording to the country' from which the (hell-fifh was 
brought; it afforded a colour deeper and more approach¬ 
ing to violet from the northern countries, and a redder 
colour from the fouthern coafts. The fineft purple had a 
tint like that of a deep-coloured rofe ; and in painting, 
it was laid on to give the laft lullre to the J'andijx, a com- 
4 
TING. 219 
pofition made by calcining together red ochre and fanda- 
rach, and which, it is inferred, muft have been nearly the 
fame as our crimfom 
In the baths of Titus, there is a broken vafe of earthen¬ 
ware which contains a pale role-colour; which, from a 
number of curious and interefting experiments, appeared 
to be a compound of either vegetable or animal origin. It 
agreed with both the vegetable and animal lakes, in being 
immediately deftroyed by a folution of chlorine. The 
durability of this lake, whether vegetable or animal, is a 
very curious circumftance, and probably depends, in a 
great meafure, upon the attractive powers of fo large a 
mafs of alumina; for, whenever one portion of a fub¬ 
ftance is combined with many proportions of another 
fubftance, it is very' difficult to decompofe, or detach, the 
one proportion. After all his experiments, fir H. D. fays, 
it is impoflible to form an opinion whether it is of vege¬ 
table or animal origin. If of animal origin, it is proba¬ 
bly the Tyrian or marine purple. Mr. Chaptal confiders 
the lake which he found among the colours from Pompeii, 
as of vegetable origin; and he founds his opinion on the 
circumftance of its not giving-out by decompolition the 
fmell peculiar to animal fubftances; but, probably, (fays 
fir H.) this fmell, even if produced by recent purple co¬ 
louring-matter of animal origin, would not belong to co¬ 
louring-matter of 1700 years old; for the fmell is moft 
probably owingto albumen, or gelatine, not effential to 
the colouring particles, and much more rapidly decom- 
pofted. “ I have feen no colour of the fame tint as this 
ancient lake, in any of the ancient paintings in frefcoi■- 
The purplilh reds in the baths of Titus are mixtures of 
red ochres, and the blues of copper. In the Aldobran¬ 
dine picture, there is a purple garment of the Pronuba, 
but of an inferior hue; and this purple appears to be a 
compound mineral colour of the nature of thefe. It was 
not deftroyed by the folution of chlorine; and, udien a 
little of it was expoled to muriatic acid, it rendered the 
acid yellow, and the remainder yielded a refidual blue 
powder.” 
Of the Blacks and Browns .—There is one chamber in 
the baths of Titus of which the ground-work is black j 
and there are feveral fragments of ltucco painted black in 
the baths of Titus, and alio in fome ruins near the Porta 
del Popolo. Thefe colours were not sited on by acids or 
alkalies; they deflagrated with nitre, and had all the pro¬ 
perties of pure carbonaceous matter. 
Sir H. Davy found no blacks, but three different (hades 
of brown, in the vafe of mixed colours; one was fnuff- 
colour, one deep red-brown, and the third, a dark olive- 
brown. The two firlt proved to be ochres which had been 
probably partially calcined; the third contained oxyd of 
manganefe, as well as oxyd of iron, and afforded chlorine 
when adted on by muriatic acid. 
All the ancient authors defcribe the artificial Greek and 
Roman blacks as carbonaceous, and made either from the 
powder of charcoal, or the decompofition of refin, (a fpe¬ 
cies of lamp-black,) or from the lees of wine, or from the 
common foot of wood fires. Pliny mentions the inks of 
the cuttle-filh, but fays, ex his von ft. Pliny fpeaks of■ 
ivory-black as invented by Apelles: he fays likewife, that 
there is a natural foflil black, and another black prepared 
from an earth of the colour of fulphur. Probably both 
thefe fubftances are ores of iron and manganefe. 
That the ancients were acquainted with the ores of 
manganefe, is evident from the ule made of it in colouring 
glafs. “ I have examined two fpecimens of ancient Roman 
purple glafs, both of which were tinged with oxyd of 
manganefe.” Pliny (peaks of different browm ochres, and 
particularly of one from Africa, which he names cicercu- 
lum, which probably contained manganefe; and Theo- 
phraltus mentions a folfd which inflamed when oil was 
poured upon it, a property, belonging to.no other fiolfil 
fubftance now known, but the black wad, an ore of man¬ 
ganefe, and which is now found in Derbylhire. 
The browns in the paintings of the baths of Livia, and 
itt 
