Still, there can be no doubt that the manufacture was one on which the Phoenicians eagerly seized, and which they carried out on a large scale and very successfully. Sidon, according to the ancients,[832] was the chief seat of the industry; but the best sand is found near Tyre, and both Tyre and Sarepta also seem to have been among the places where glassworks were early established. At Sarepta extensive banks of _débris_ have been found, consisting of broken glass of many colours, the waste beyond all doubt of a great glass manufactory;[833] at Tyre, the traces of the industry are less extensive,[834] but on the other hand we have historical evidence that it continued to be practised there into the middle ages.[835] The glass produced by the Phoenicians was of three kinds: first, transparent colourless glass, which the eye could see through; secondly, translucent coloured glass, through which light could pass, though the eye could not penetrate it so as to distinguish objects; and, thirdly, opaque glass, scarcely distinguishable from porcelain. Transparent glass was employed for mirrors, round plates being cast, which made very tolerable looking-glasses,[836] when covered at the back by thin sheets of metal, and also for common objects, such as vases, urns, bottles, and jugs, which have been yielded in abundance by tombs of a somewhat late date in Cyprus.[837] No great store, however, seems to have been set upon transparency, in which the Oriental eye saw no beauty; and the objects which modern research has recovered under this head at Tyre, in Cyprus, and elsewhere, seem the work of comparatively rude artists, and have little æsthetic merit. The shapes, however, are not inelegant.