SAPPHIRUS.                                 277
	coarse thick blue enamel, intended to give them the appear­ance of being carved out of this valuable mineral (Cyanus, p. 125). But the Romans, who carried the manufacture of pastes to such perfection as regards colour and hardness, were eminently successful in their production of an artificial Lapis-lazuli, hardly to be distinguished when polished from the genuine stone. The most wonderful example of the art ever produced is the Townley Bonus Eventus (British Museum), where the youthful deity is represented at three-quarter length and in half relief, in the most finished style of Roman art, upon a slab of this composition about eight inches square. The relief has been carefully worked over after leaving the matrix in the same manner as a cameo in hard stone ; and nothing can be more perfect than the imi­tation of the azure and texture of the actual Lapis-lazuli. The figure is evidently the portrait of some youthful Cœsar, represented according to custom under the character of this deity of promise : the features, harsh and surly in their expression, though somewhat softened down by the artist, are indubitably those of the young Caracalla, thus inap­propriately personified.