- 8 A History of Art in Chald^a and Assyria.
was doubtless thought too common a material for such uses, and as for glass, they had not yet learnt how to make it a worthy substitute for pietra dura, as the Greeks and Romans did in later years. Before we quit the subject of glass we must not forget to mention a very curious object found by Layard at Nimroud, in the palace of Assurnazirpal, and in the neighbourhood of the glass bottle and the two alabaster vases on which the name of Sargon appears. It is a lens of rock-crystal ; its convex face seems to have been set up, with some clumsiness, opposite to the lapidary on his wheel. In spite of the imperfect cutting, it may have been used either as a magnifying, or, with a very strong sun, as a burning, glass. 1 The fineness of the work on some of the cylinders, and the minuteness of the wedges on some of the terracotta tubs, had already excited attention, and it was asked whether the Assyrians might not have been acquainted with some aid to eyesight like our magnifying glass. It is difficult, however, to come to any certain conclusion from a single find like this ; but if any more lenses come to light we may fairly suppose that the scribes and lapidaries of Mesopotamia understood how thus to reinforce their eyesight. In any case it is pretty certain that this is the oldest object of the kind transmitted to us by antiquity. § . 2 . — Metal lu rgy. Even at the time to which we are carried back by the oldest of the graves at Warka and Mugheir, metallurgy was already far advanced in Chaldaea. Tools and weapons of stone are still found in those tombs in great numbers ; 2 but side by side with them we find copper, bronze, lead, iron, and gold. Silver alone is absent. Copper seems to have been the first of all the metals to attract the notice of man, and to be manufactured by him. This is to be accounted for partly by the frequency of its occurrence in its 1 A detailed description of this curious object will be found in a note supplied to Layard by Sir David Brewster, who made a careful examination of the lens {Discoveries, p. 197). 2 See RaWLINSON, The Five Great Monarchies, &c, vol. i. pp. 95-97.
