228 .-- Parti-coloured glass goblets of Nesikhonsu.] Glass was known to the Egyptians from the remotest period, and glass- blowing is represented in tombs which date from some thousands of years before our era (fig.

224).

The craftsman, seated before the furnace, takes up a small quantity of the fused substance upon the end of his cane and blows it circumspectly, taking care to keep it in contact with the flame, so that it may not harden during the operation.

Chemical analysis shows the constituent parts of Egyptian glass to have been nearly identical with our own; but it contains, besides silex, lime, alumina, and soda, a relatively large proportion of extraneous substances, as copper, oxide of iron, and oxide of manganese, which they apparently knew not how to eliminate.

Hence Egyptian glass is scarcely ever colourless, but inclines to an uncertain shade of yellow or green.