In very magnificent buildings metal thresholds sometimes replaced those of stone or brick. In the British Museum there is a huge bronze sill that was found in a ruined temple at Borsippa, by Mr. Rassam. Its extreme length is sixty inches, its width twenty, and its thickness about three and a half inches. It bears an inscription of Nebuchadnezzar the arrangement of which proves that the sill when complete had double its present length, or about ten feet. Its upper surface is decorated with large rosettes within square borders. We need hardly say that it is a solid casting, and that its weight is, therefore, by no means trifling. The workmen who put in place and those who cast it must both have thoroughly understood what they were about. Even now, we are told, the latter operation would be attended by some difficulty.[301] The founders who produced this casting could have no difficulty over the other parts of the door-case, and we have no reason to doubt the statement of Herodotus, who thus ends his account of how the walls of Babylon were built: "The walls had a hundred gates, all of bronze; their jambs and lintels were of the same material."[302] These lintels and jambs must have been, like the Borsippa threshold, of massive bronze, or they would soon have been crushed by the weight they had to support. On the other hand, had doors themselves been entirely of that metal it would have been very difficult if not impossible to swing them upon their hinges, especially in the case of city gates like those just referred to. It is probable, then, that they were of timber, covered and concealed by plates of bronze. Herodotus indeed narrates what he saw, like a truthful and intelligent witness, but he was not an archaeologist, and it did not occur to him when he entered the famous city which formed the goal of his travels, to feel the shining metal and find out how much of it was solid and how much a mere armour for a softer substance behind.