Metal can hardly be said to have been used for purely architectural purposes at all, and when employed seems rather to have been added for the adornment of the more conspicuous parts of the building, than used as an integral part of the structure. There are, however, one or two exceptions to this generalization. The sills were sometimes made of metal in the more luxurious buildings, and a bronze sill measuring 60 × 20 × 3-1/2 inches, with an inscription of Nebuchadnezzar has actually come to light, and is now in the British Museum, while another object of a singularly unique character, consisting of a bronze gate-socket set in lead, has similarly found its way to that famous institution. Herodotus furthermore tells us in his account of Babylon that the walls had a hundred gates “all of bronze; their jambs and lintels were of the same material.” Some of the bas-reliefs also exhibit structures, parts of which must seemingly have been made of metal: the royal pavilion carved on the tablet from Abû Habba (Sippar) for example (cf. Pl. XIV) is provided with a curved back wall which at the same time is bent right over so as to form a roof; this wall and roof may indeed have been constructed of wood, but metal would clearly have adapted itself the more easily to such a form. Of other minor building materials, such as tools, and nails which played a subsidiary part in Mesopotamian architecture, we know comparatively little, though a number of nails have been recovered from different sites. TEMPLES It would be quite impossible to give an account of all the temples and palaces in Mesopotamia, excavated during the last sixty years, we must therefore confine ourselves to a brief description of a few of the better explored buildings, which may with reserve be regarded as typical. The temples have not weathered the deteriorating effects of time and climate so well as the palaces, the reason for which is to be found in the fact that, generally speaking, the object of the temple-builder was so far as possible to erect a structure whose top should metaphorically “reach unto heaven,” whereas the culminating glory of palaces lay not in the height to which they were reared but in the extent of ground which they covered.