are again fused to obtain pure glass and cakes of white glass.’ Pliny, in this confused account, where we have apparently materials from different sources imperfectly welded together, appears to contrast an older method of manufacture, practised formerly at Sidon, whose glass-works he seems to refer to as things of the past, with the newer processes now in use in Italy. It will be noted that in both cases a preliminary frit was prepared, although the term _ammonitrum_, a word of Greek origin, is applied to this frit in the latter case only. ‘Already,’ says Pliny, ‘the new art of melting sand with soda (literally “of tempering sand”) has spread through Gaul and Spain.’ He then goes on to tell, but with an expression of incredulity quite unusual with him, the story of the discovery of a malleable glass. According to this tale (in its earliest form), Tiberius ordered the workshop of the man who so tempered glass that it became flexible, to be pulled down, lest the value of bronze, silver, and gold should be depreciated. This story was the delight of the renaissance writers on glass. With regard to the more amplified and tragic version usually quoted from Petronius, we must remember that the remarks put by that writer into the mouth of Trimalchio are not always to be taken seriously. In later days a similar tale was told of a French inventor—in this Richelieu takes the place of Tiberius. After mentioning the _calices pteroti_, the costly ‘winged cups’ of Nero, Pliny gives some account (quite out of its proper place, by the way) of obsidian, a black stone much resembling glass, which was shaped not only into various dishes for use at the table, but also into figures of some size—statues of the divine Augustus, for instance, for that monarch much prized the material. _Vitrum hæmatinum_, ‘a red opaque glass,’ is passed over rapidly. ‘White glass is made also, and murrhine and glass resembling the hyacinth and the sapphire and glass of all other colours.[50] There is no substance easier to work or to which brighter colours can be given. The highest place must, however, be accorded to the white transparent glass which much resembles crystal; for drinking, it has driven out vessels of gold and silver.’ This passage is of the greatest importance. We see that a pure white glass was still, even in Pliny’s time, something noticeable. This was, as we shall see, again the case at the time of the Renaissance, when it was the aim of the glass-makers, all over Western Europe, to imitate the _Vetro di cristallo_ of the Venetians.