It will be noticed that Pliny makes no mention of the method of preparation of the alkali used in making glass (in ‘tempering the sand,’ as he puts it). From the context it would seem that the _nitrum_ was always of the same nature as that brought by the mariners to the Phœnician coast—this is, however, very unlikely. Nor have we any information about the arrangement of the furnaces. These glass houses were, however, well known to the beggars and loungers of the time—we hear of them as places of resort in cold weather for those who had no other way of warming themselves. In the Greek Anthology (No. 323), of all places in the world, there is a fragment by one Mesomedes, a contemporary and favourite of Hadrian, giving an account of a visit to a glass-house. Just at the point where the little poem breaks off, the workman is described as placing the molten mass between the blades of the pincers or shears. Strabo tells us that when he was at Alexandria—he was there, we know, in the early part of the reign of Augustus (_circa_ 24 B.C.)—he was assured by the glass-workers (ὑαλουργοί) that their ‘many-coloured and sumptuous glass’ could not be made without the addition of a certain glassy earth which was only found in Egypt, a story which points to the jealousy of foreign competition on the part of these craftsmen. So on the Phœnician coast he hears from some of the wonderful qualities of the Sidonian sand, while others tell him that one sand is as good as another. Strabo goes on to speak of the improvements made ‘quite lately’ in the clear crystal glass of which the manufacture had not long since been established at Rome. Compare with this the account of Pliny; in view of his certainly rather vague statements, we should hardly have looked for this _cristallo_ in Italy at so early a date.