This kind of tabernacle is bounded, above and at the back of the god, by a wall of which there is nothing to show the exact nature. Its graceful, sinuous line, however, seems to exclude the idea, sufficiently improbable in itself, of a brick vault. It may possibly have been of wood, though it would not be easy to obtain this elegant curve even in that material. But such forms as this are given with the greatest ease in metal, and we are ready to believe that what the artist here meant to represent was a metal frame, which could at need be hidden under a canopy of leather or wool, like those we have already encountered in the Assyrian bas-reliefs (Figs. 67 and 68). The artist has in fact made use of a graphic process common enough with the Egyptians.[256] He has given us a lateral elevation of the tabernacle with the god in profile within it, because his skill was unequal to the task of showing him full front and seated between the two columns of the facade. The single column thus left visible has been represented with great skill and care; the sculptor seems to have taken pleasure in dwelling upon its smallest details. Slender as it is, it must have been of wood. The markings upon it suggest the trunk of a palm, but we may be permitted to doubt whether it was allowed to remain in its natural uncovered state. Even in the climate of Chaldaea a dead tree trunk exposed to the air would have no great durability. Sooner or later the sun, the rain, the changes of temperature, would give a good account of it, and besides, a piece of rough wood could hardly be made to harmonize with the luxury that must assuredly have been lavished by the people of Sippara upon the sanctuary of their greatest divinity. It is probable, therefore, that the wood was overlaid with plates of gilded bronze, fastened on with nails.