Cone mosaics and the insertion of vases among the bricks afforded after all but a poor opportunity to the decorative architect. Had the builders of Chaldaea possessed no more efficient means than these of obtaining beauty, their structures would hardly have imposed themselves as models upon their rich and powerful neighbours of Assyria so completely as they did. Some process was required which should not restrict the decorator to the curves and straight lines of the simpler geometrical figures, which should allow him to make use of motives furnished by the animal and vegetable kingdom, by man and those fanciful creations of man's intellect that resulted from his attempts to figure the gods. We can hardly doubt that the Chaldaeans, like their northern neighbours, made frequent use of paint in the decoration of the wide plaster walls that offered such a tempting surface to the brush. No fragment of such work has come down to us, but we have every reason to believe that the arrangement of motives and the choice of lines were the same as in Assyria. We may look upon the mural paintings in the Ninevite palaces as copies preserving for us the leading characteristics of their Chaldaean originals. Even in Chaldaea, which had a drier climate than Assyria, paintings in distemper could not have had any very long life on external walls. They had not to do with the sky of Upper Egypt where years pass away without the fall of a single shower. Some means of fixing colour so that it should not be washed away by the first rain was sought, and it was found in the invention of enamel, in the coating of the bricks with a coloured material that when passed with them through the fire would be vitrified and would sink to some extent into their substance. A brick thus coated could never lose its colour; the latter became insoluble, and so intimately combined with the block to which it was attached that one could hardly be destroyed without the other. Sir H. Layard tells us that many fragments of brick found in the Kasr were covered with a thick glaze, the colours of which had in no way suffered with time. Fragments of ornaments and figures could be distinguished on some of them. The colours most often found were a very brilliant blue, red, dark yellow, white, and black.[352] We have again to look to the Assyrian ruins for information as to the way in which these enamelled bricks were composed into pictures. No explorer has found anything in the remains of a Chaldaean city that can be compared to the archivolt of enamelled bricks discovered by M. Place over one of the gateways of the city founded by Sargon.[353] We can hardly doubt however that the art of the enameller was discovered in Chaldaea and thence transported into Assyria. Everything combines to give us that assurance, an examination of the ruins in Mesopotamia and of the objects brought from them as well as the explicit statements of the ancients.