| [37] | The contents have been described by the late Canonico Passini, in a magnificent work published by Ongania of Venice, in which nearly every piece of importance is reproduced in colour or by photography. |
| [38] | There is among the Roman glass in the museum at Cologne a shallow bowl about a foot in diameter, painted on the back, as in the later verre églomisé, with a female head. The colours—black, red, and white—are but slightly burnt in, and therefore much decomposed. |
| [39] | This part is stated to be a distinct piece cemented on to the bottom of the vessel. So at least says Mr. Apsley Pellatt in his Curiosities of Glass-making, writing, I think, before the vase was broken. In the same book will be found a careful account of the process of ‘casing’ as now practised. It was probably by some such plan, in the case of the Portland vase, that the paraison of blue glass was blown into the previously prepared vessel of opaque white. |
| [40] | I shall return to this sculptured work when treating of Byzantine glass in the next chapter. |
| [41] | By the courtesy of Lord Rothschild I have had an opportunity of examining this wonderful cup. It is undoubtedly carved from one piece of glass. The spirited execution would seem to point to a date hardly much later than the beginning of the third century. The internal depressions were made perhaps with the object of lighting up the external figures. The glass by transmitted light is of a fiery red, tending to purple, but the figure of Lycurgus is exceptionally of a fine amethystine tint. I think that in both cases the colour is probably due to a skilful use of manganese. |
| [42] | The abrading material employed along with the wheel was probably in most cases corundum or emery (the adamas of the ancients) in a powdered form; not the diamond, which was excessively rare, nor the emerald, as is sometimes stated. This last stone is not only much rarer than corundum, but it is also not so hard. |
| [43] | Compare what is said below on p. [82] of Greek-speaking Syrian artisans. |
| [44] | For some account of what these writers tell us about glass, see below, [Chap. VII.] |
| [45] | Theophilus, however, writing a century earlier than the pseudo-Heraclius, appears to speak of the marver as a slab of stone (see below, [Chap. VII.]). |
| [46] | The sand of this river as a material for the manufacture of glass is already mentioned by Theophrastus, a pupil of Aristotle. |