51 
Earthen Vases known hy the Name of Etruscan. 
pellucid, varnish-like coating of clay, by which the colour of 
the clay is heightened a little, so as to have a dusky or dark red 
appearance. 
A black colour, corresponding with the black coating of some 
kinds, is very common in the paintings of vases. Other colours 
appear much more rarely and less extensively applied. 
This black colour, therefore, we shall examine first, as being, 
of all things connected with vases, in so far as regards art, the 
most worthy of accurate investigation. It is usually of a pitchy 
tint, sometimes passing into brown, or, when thinly applied, ap- 
pearing even of a coffee colour. It seldom passes into livid or 
green, which I have observed, however, in some vases of the 
Florentine and Roman Collections. The lustre of the colour is 
of various degrees of brightness, sometimes it is scarcely appa- 
rent, and is always more like that of varnish than of glass. In 
other respects, also, the black coating is always dissimilar to glass : 
when minutely examined, however, with the microscope, it has 
the appearance of being fused *. It is of different degrees of 
thickness, seldom so great as to be sensible to the touch. The 
black coating is firmly adherent to the surface, although it does 
not penetrate into the clay, nor is conjoined with its particles by 
fusion. Its adhesion is firmer in the finer vases than in those of 
coarser quality. None of those cracks or fissures are seen in 
it, which frequently occur in the glaze of earthen-ware *J\ It is 
not dissolved by acids or any other fluid. I have exposed frag- 
ments of painted vases for a long time to the action of nitric and 
muriatic acids, but never observed any effect produced upon 
them. It even sustains a considerable heat without injury J, 
and it may be exposed for a long time to the blowpipe without 
undergoing any distinct change. When the condensed flame 
was directed toward part of the paintings for some time, I have 
observed that the nearest parts of the clay were covered over with 
a black exhalation ; but I cannot say whether this exhalation be 
* That the black coating has the appearance of fusion, has been justly observ- 
ed by Chaptal.—Mem. de l' Inst . 1808, p. 234. 
t Boettiger's Grieck. Vasengemalde , Bo. i. Heft. 3. p. 27. — Millingen, Peint. des 
Vases Ant. ; Joe. cit. 
£ Milling en, Peint. des Vases Ant., p. 7. No, 27. 
D 2 
