the
proceedings of Nature in the creation of the Onyx : the body of the
vase was first moulded in the translucent dark-blue pot-metal, over
which was fused a layer of opaque white, which was cut away * with the
drill and the diamond-point to produce the cameo. Such a vase (êáíêßïí, caucus in later Latin) is the subject of the epigram (An-thol. ix. 749) :—
" Why Cupid on the cup ? Enough for wine To inflame the heart : why fire with fire combine ? "
Though
perfect vases in this style are the rarest of the rare, yet fragments
of such are not uncommon : all that have come under my observation
display the same marvellous taste in the design and equal delicacy of
finish.f
One
of the most remarkable specimens of this manufacture is the scyphus
four inches in diameter found at Colchester, and belonging to Mr.
Pollexfen. It is embossed with a chariot-race, exhibiting the Spina of
the Circus with its usual decorations ; the names of the respective
charioteers are affixed to their figures.
Glass
vessels thus embellished were the "toreumata vitri " of Martial (xii.
74, xiv. 94), in whose age the word had lost, with the loss of the art,
its proper meaning of a chasing in metal, and come to iniply a relievo on a gem or paste ; in short, our " cameo." Compared with the fashionable Murrhina, these
glasses, deriving their sole value from the engraver's hand, were of
but trifling cost and fell within the means of our necessitous poet :—
* A process to which refers Pliny's expression, " aliud argenti modo cœlatur."
t
This was the " vitrum fabro sigillatum," deemed not unworthy to figure
on the table of the wealthy Byrrhsena amongst " crystallum im-punctum
argentum alibi clarum et aurum fulgurans et succinum miro cavatum in
capidas ut bibas .... gemmas formatas in pocula vini vetusti " (Apul.
Met. II.).
