On three sides, as already observed, the hall had (so far as appears) no windows--the places where windows might have been expected to occur being occupied by niches.

The apparent openings are consequently reduced to some fifteen, viz., the eight doorways, and seven windows, which looked out upon the portico, and were therefore overhung and had a north aspect.

It is clear that sufficient light could not have entered the apartment from these--the only visible--apertures.
We must therefore suppose either that the walls above the niches were pierced with windows, which is quite possible, or else that light was in some way or other admitted from the roof.

The latter is the supposition of those most competent to decide.

M.Flandin conjectures that the roof had four apertures, placed at the points where the lines drawn from the northern to the southern, and those drawn from the eastern to the western, doors would intersect one another.