CONSTRUCTION. 163 the office of a roller. When some heavy fall of rain by wetting and softening the upper surface of the terrace, gives an oppor- tunity for repairing the ravages of a long drought, the stone is taken backwards and forwards over the yielding pise. It closes the cracks, kills the weeds that if left to themselves would soon transform the roof into a field, and makes the surface as firm as a threshing-floor. The roofs of Assyrian buildings must have required the same kind of treatment, and we know that in the present day it is actually practised. M. Place mentions rollers of lime-stone, weighing from two to three hundredweight, pierced at each end with a square hole into which wooden spindles were inserted to faciliate their management. 1 A certain number of these rollers were found within the chambers, into which they must have fallen With the roofs. As soon as the terraces ceased to receive the care necessary for keeping down the weeds and shrubs and keeping out the water, the process of disintegration must have been rapid. The rains would soon convert cracks into gaping breaches, and at the end of a few years, every storm would bring clown a part of the roof. A century would be enough to destroy the vaults, and with them the upper parts of the walls to which they were closely allied by the skill of the constructor. The disappearance of the archivolts and the great heaps of ddbris are thus accounted for. The roof materials were too soft, however, to damage in their fall the figures in hi^h relief or in the round o o o that decorated the chambers beneath, or the carved slabs with which their walls were lined. In spreading itself about these sculptures and burying them out of sight and memory, the soft clay served posterity more efficiently than the most careful of packers. Among the first observers to suspect the truth as to the use of the vault in Mesopotamia, were Eugene Flanclin, who helped Botta to excavate the palace of Sargon, 2 and Felix Thomas, 3 the colleague of M. Place. The reasons by which M. Thomas was led to the conclusion that the rooms in the Ninevite palaces 1 PLACE, Ninive, vol. i. pp. 293-294. - E. FLANDIN, Voyage archcologiqw a Ninive. i. 1} Architecture assyrienne. 2. La Sculpture assyricnnc (Revue des Dcux-Mondes, June 15 and July i, 1845). 3 For all that concerns this artist, one of the most skilful draughtsmen of our time, see the biographical notice of M. de Girardot : Felix Thomas, grand Prix de Rome Archi/ecte, Peintre, Gravcur, Sculpteiir (Nantes, 1875, 8vo.).
