According to Sir H. Layard, the blue which was spread in such great quantities on the enamelled bricks was given by an oxide of copper mixed with a little lead, the latter metal being introduced in order to render the mixture more fusible.[352] This analysis applies only to the bricks of Nimroud. In the Sargonid period another process, borrowed, perhaps, from Egypt, seems to have been employed. Place tells us that in the course of his excavations he found two blocks of colour in one of the offices at Khorsabad. One of these blocks, weighing some two pounds and a little over, was blue. An artist was at the time engaged in copying in water-colours the decoration of one of the walls covered with enamelled bricks. In order to get as near as possible to the tint of the original the notion occurred to him to make use of the Assyrian blue. But the latter was stubborn and would not mix; it left a vitreous deposit at the bottom of the cup. At first it was supposed that its long sojourn in the earth had deprived it of some of its qualities, but later analysis explained the difficulty in a more satisfactory manner. Its unfitness for use as water-colour was not the result of any alteration. Being intended for use as a glaze or enamel upon pottery, it was composed of lapis-lazuli reduced to powder.[353] [Illustration: PLATE XIII From Layard Sulpis sc. ENAMELLED BRICK FROM NIMROUD British Museum] [Illustration: PLATE XIV. From Layard Sulpis sc. 1. ENAMELLED BRICK 2. FRAGMENT OF PAINTING ON STUCCO From Nimroud] [Illustration: PLATE XV After F. Thomas Sulpis sc. ENAMELLED BRICKS IN THE HAREM Khorsabad Imp. Ch. Chardon] The Chaldæans made a wide use of lapis, which they imported from central Asia. The fatherland of that mineral is the region now called Badakshan, in Bactriana, whence, in ancient times, came what Theophrastus calls the Scythian stone. The caravans brought it into the upper valley of the Tigris, whence it made its way to Babylon and even as far as Egypt. The inscriptions of Thothmes III. mention the good _khesbet_ of Babylon among the objects offered to Pharaoh by the Rotennou, or people of Syria.[354] This fine lapis-powder, intimately united with the clay by firing, gave a solid enamel of a very pure colour. If mixed with a body of some consistence it might be used upon the sculptures; perhaps the blue with which certain accessories were tinted was thus obtained.