The particular prominence of cyanus, besides, in the Cyprian armour of Agamemnon falls in admirably with what is known of the history of imitation lapis lazuli; Cyprus, owing to the abundant presence of the needful ores of copper, having become early celebrated for its production. In addition to some tubes of cobalt-glass, blue smalt trinkets in large quantities have been brought to light at Mycenæ. But if Homer took no notice of such small objects, it was probably because he deemed them too common for association with the noble or divine heroines of his song. Footnote 434: Lepsius, _Les Métaux_, &c. p. 61. Footnote 435: Helbig, _Das Homerische Epos_, p. 81. Footnote 436: Schuchhardt, _op. cit._ p. 117. Footnote 437: _De Lapidibus_, lv. The Scythian kind of cyanus was genuine lapis lazuli. That the Homeric cyanus was really a kind of ultramarine enamel, seems, then, thoroughly established. And it is the only form of glass recognised in the poems. Yet the colour-difficulty survives. Our poet remains under the imputation of inability to distinguish black from blue—unless, indeed, we admit with Helbig that the word ‘cyanus’ comprised a jetty as well as an azure smalt. There is a good deal to be said for the opinion. Theophrastus plainly distinguishes a dark and a light variety, and even speaks of one of the derived pigments as being _black_; and a black enamel formed part of the materials for the Mycenæan inlaid-work. The stripes of Agamemnon’s cuirass were, according to this hypothesis, of black, the curling snakes on either side of blue cyanus. And this might help to explain the comparison of the latter to rainbows. Not, to be sure, altogether satisfactorily, since the likening to a simply blue object of the brilliant arch Mille trahens varios adverso sole colores, strikes the modern sense as absolutely inappropriate. Nevertheless, we have to make allowance in Homer, above all as regards chromatic estimates, for an _aliter visum_. And it happens that the sole colour-epithet bestowed by him on the rainbow is _porphureos_, signifying purple of a peculiarly sombre shade. The ‘crocus wings’ of Iris were, then, less conspicuous to him than her violet sandals.