The necessity for the presence of a thick roof between the sun and the inside of the rooms is here very clearly affirmed. It will also be noticed that the general form of apartments in Susiana and Assyria did not escape the observer in question. As he saw very clearly, the great disproportion between their length and their width was to be explained as easily by the requirements of a wooden roof as by those of a clay vault.
In his attempt to describe Babylon, Strabo says[215]: "In the absence of timber, properly speaking, beams and columns of palm-wood were used in the buildings of Babylonia. These pillars were covered with twisted ropes of rushes, over which several coats of paint were laid. The doors were coated with asphalte. Both doors and houses were very high. We may add that the houses were vaulted, in consequence of the absence of wood.... There were, of course, no tile roofs in countries where it never rains,[216] such as Babylonia, Susiana and Sittacenia."
Strabo himself never visited Mesopotamia. This we know from the passage in his introduction, in which he tells us exactly how far his voyages extended, from north to south, and from east to west.[217] When he had to describe Asia from the Taurus to India, he could only do so with the help of passages borrowed from various authors, and in the course of his work it has sometimes happened that he has brought into juxtaposition pieces of information that contradict each other.[218] Something of the kind has happened in the lines we have quoted, in which he first speaks of pillars and timber roofs, and ends by declaring that all the Chaldæan houses were vaulted, although vaults and timber could not exist together. The truth is, in all probability, that one system of covering prevailed here and another there, and that the seeming contradiction in the text is due to hasty editing. We may conclude from it that travellers had reported the existence of both systems, and that each was to be explained by local conditions and the varying supply of materials.
The two systems still exist side by side over all Western Asia. From Syria to Kurdistan and the Persian Gulf the hemispherical cupola upon a square substructure continually occurs. The timber roof is hardly less frequent; when the apartment in which it is used is of any considerable size it is carried upon two or three rows of wooden columns. These columns rest upon cubes of stone, and a tablet of the same material is often interposed between them and the beams they support. A sort of rustic order is thus constituted of which the shaft alone is of wood. We reproduce a sketch by Sir H. Layard in which this arrangement is shown. It is taken from a house inhabited by Yezidis,[219] in the district of Upper Mesopotamia called Sinjar ([Fig. 58]).
Fig. 58.—Interior of a Yezidi house; from Layard.
We are inclined to think that both systems were occasionally found in a single building. The tunnel vault and the joisted ceiling were equally well suited to the long galleries of Assyrian palaces. In one room, or suite of rooms, nothing but brick may have been used, while in others wood may have had the preference. Still more probably, one architect may have had a predilection for timber, while another may have preferred clay vaults. In either case the general arrangement, what we may call the spirit of the plan, would remain the same.
When wooden roofs were used were they upheld by wooden uprights or by columns of any other material? Botta was at first inclined to say yes to this question, but he did not attempt to conceal that excavation had discovered little to support such an hypothesis.[220] Such pillars, were they of stone, would leave traces among the ruins in the shape of broken columns; were they of burnt bricks (and there could be no question of the crude material), those bricks would be found on the spot they occupied and would easily be recognized by their shape, which, as we have already shown, would have been specially adapted to the work they had to do.[221] The points of junction with the pavement would also be visible. If we contend that they were of wood, like those of the house figured above, we must admit that, at least in the more carefully built houses, such precautions as even the peasants of the Yezidis do not neglect must have been taken, and the timber columns raised upon stone bases which would protect them from the sometimes damp floors. Neither these bases nor any marks of their existence have been found in any of the ruins; and we are therefore led to the conclusion that to search for hypostyle halls in the Assyrian palaces, would be to follow the imagination rather than the reason.
If we admit that architects made no use of columns to afford intermediate support to the heavy roofs, we may at first be inclined to believe that wooden ceilings were only used in very narrow apartments, for we can hardly give a length of more than from twenty-four to twenty-seven feet to beams that were called upon to support a thick covering of beaten earth as well as their own weight.[222] Perhaps, however, the skill of their carpenters was equal to increasing the span and rigidity of the beams used by a few simple contrivances. One of these is shown in our [Fig. 60], a diagram composed by M. Chipiez to give an idea of the different methods of construction used by, or, at least, at the command of, the Assyrian builder.