s of ancient Assyria were far thicker than the rubble
and plaster ones of modern Mossoul, so that more light could be admitted to
the rooms without compromising their freshness. It seems to be proved that
in at least the majority of rooms at Khorsabad the architect provided other
means of lighting and ventilation besides the doorways, wide and high
though the latter were. He pierced the roof with numerous oblique and
vertical openings, he left square wells in the timber ceilings, and
circular eyes in the domes and vaults. If these were to fulfil their
purpose of admitting light and air into the principal rooms, the latter
must have had no upper stories to carry. At Mossoul, walls are much thinner
than at Nineveh, and interiors are simpler in arrangement and decoration.
The twenty or five-and-twenty feet of clay of the Assyrian walls would make
it impossible to give sufficient light through the doors alone to the
sculptures and paintings with which the rooms were adorned. We cannot doubt
that a top light was also required. The rooms of the palaces must,
therefore, have succeeded one another in one horizontal plan. Slight
differences of level between them were connected by short flights, usually
of five carefully-adjusted steps.[232] In spite of all its magnificence the
royal dwelling was no more than a huge ground floor.

With such methods of construction as those we have described, it would have
been very difficult to multiply stories. Neither vaults nor timber ceilings
could have carried the enormous masses of earth of which even their
partition-walls for the most part consisted, so that the architect would
have had no choice but to make his upper chambers identical in size with
those of his ground floors. This difficulty he was not, however, called
upon to face, because the necessity for providing his halls and corridors
with a top light, put an upper floor out of the question. No trace of such
a staircase as would have been required to give access to an upper story
has been discovered in any of the Assyrian ruins,[233] and yet some means
of ascent to the terraced roofs must have been provided, if not for the
inhabitants of the chambers below--who are likely, however, to have passed
the nights upon them in the hot season--at least for the workmen whose duty
it was to keep them in repair.

Some parts of the palace, on the other hand, may have been raised much
above the level of the rest. Sir Henry Layard found the remai