The two questions of the roofing and lighting of the Assyrian palaces are so closely connected together that they will most conveniently be treated in combination. The first conjecture published on the subject of roofing was that of M. Flandin. who suggested that the chambers generally--the great halls at any rate--had been ceiled with a brick vault. He thought that the complete filling up of the apartments to the height of fifteen or twenty feet was thus best explained; and he believed that there were traces of the fallen vaulting in the _debris_ with which the apartments were filled. His conjecture was combated, soon after he put it forth, by M. Botta, who gave it as his opinion--first, that the walls of the chambers, notwithstanding their great thickness, would have been unable, considering their material, to sustain the weight, and (still more to bear) the lateral thrust, of a vaulted roof; and, secondly, that such a roof, if it had existed at all, must have been made of baked brick or stone-crude brick being too weak for the purpose--and when it fell must have left ample traces of itself within the apartments, whereas, in none of them, though he searched, could he find any such traces. On this latter point M. Botta and M. Flandin--both eye witnesses--were at variance. M. Flandin believed that he had seen such traces, not only in numerous broken fragments of burnt brick strewn through all the chambers, but in occasional masses of brick-work contained in some of them actual portions, as he thought, of the original vaulting. M. Botta, however, observed--first, that the quantity of baked brick within the chambers was quite insufficient for a vaulted roof; and, secondly, that the position of the masses of brickwork noticed by M. Flandin was always towards the sides, never towards the centres of the apartments; a clear proof that they had fallen from the upper part of the walls above the sculptures, and not from a ceiling covering the whole room. He further observed that the quantity of charred wood and charcoal within the chambers, and the calcined appearance of all the slabs, were phenomena incompatible with any other theory than that of the destruction of the palace by the conflagration of a roof mainly of wood.