Here, again, the southern house is exceptionally spacious, with its two courts (21 and 22) and a large hall opening on the central court. It must certainly have belonged to the highest state officials. Behind the great hall there are three chambers, much like courts, which with their respective side-chambers may have served for the administration of public business. From here, as well as from the adjoining house, which also comprised a number of rooms round 23, there was direct communication, only interrupted by many doors, with the royal private offices on the western side. On the north was a house with two courts (13 and 14) and two business offices opening on to the central court, and six one-court houses (15, 16, 17, 18, 19, 20). Unfortunately we do not know the purpose of the long large chamber near court 13. In the adjoining office there is a walled well, an unusual feature in a house. The paving of the court is similar to that already described, even to the repaving by Nabonidus, who covered the older flooring with his stamped paving blocks 50 centimetres broad. XIV THE VAULTED BUILDING From the north-east corner of the central court a wide passage leads to a building in the north-east corner of the Southern Citadel, which from every point of view occupies an exceptional place among the buildings of the Citadel and even of the whole city—one might almost say of the entire country. Fourteen cells, similar in size and shape, balance each other on the two sides of a central passage, and are surrounded by a strong wall. Round this slightly irregular quadrangle runs a narrow corridor, of which the far side to the north and east is in large measure formed of the outer wall of the Citadel, while other ranges of similar cells abut on it to the west and south. In one of these western cells there is a well which differs from all other wells known either in Babylon or elsewhere in the ancient world. It has three shafts placed close to each other, a square one in the centre and oblong ones on each side, an arrangement for which I can see no other explanation than that a mechanical hydraulic machine stood here, which worked on the same principle as our chain pump, where buckets attached to a chain work on a wheel placed over the well. A whim works the wheel in endless rotation. This contrivance, which is used to-day in this neighbourhood, and is called a _dolab_ (water bucket), would provide a continuous flow of water. We will speak later of the use to which we presume it to have been put. The ruin (Fig. 59) lies completely below the level of the palace floor, and is the only crypt found in Babylon. It was approached from the upper passage by steps of crude brick faced with burnt brick that led into one of the southern chambers. [Illustration: FIG. 59.—The Vaulted Building, from the south-west. ]