[Illustration:  293.jpg A MODERN MACHINE FOR IRRIGATION ON THE EUPHRATES.]

As the current turns the wheel, the bottles on the rim dip below the surface and are raised up full.  At the top of the wheel is fixed a trough made by hollowing half the trunk of a date-palm, and into this the bottles pour their water, which is conducted from the trough by means of a small aqueduct into the irrigation-channel on the bank.

The convenience of the water-wheel will be obvious, for the water is raised without the labour of man or beast, and a constant supply is secured day and night so long as the current is strong enough to turn the wheel.  The water can be cut off by blocking the wheel or tying it up.  These wheels are most common on the Euphrates, and are usually set up where there is a slight drop in the river bed and the water runs swiftly over shallows.  As the banks are very high, the wheels are necessarily huge contrivances in order to reach the level of the fields, and their very rough construction causes them to creak and groan as they turn with the current.  In a convenient place in the river several of these are sometimes set up side by side, and the noise of their combined creakings can be heard from a great distance.  Some idea of what one of these machines looks like can be obtained from the illustration.  At Hit on the Euphrates a line of gigantic water-wheels is built across the river, and the noise they make is extraordinary.

Where there is no current to turn one of these wheels, or where the bank is too high, the water must be raised by the labour of man or beast.  The commonest method, which is the one employed generally on the Tigris, is to raise it in skins, which are drawn up by horses, donkeys, or cattle.  A recess with perpendicular sides is cut into the bank, and a wooden spindle on wooden struts is supported horizontally over the recess.  A rope running over the spindle is fastened to the skin, while the funnel end of the skin is held up by a second rope, running over a lower spindle, until its mouth is opposite the trough into which the water is to be poured.  The beasts which are employed for raising the skin are fastened to the ends of the ropes, and they get a good purchase for their pull by being driven down a short cutting or inclined plane in the bank.  To get a constant flow of water, two skins are usually employed, and as one is drawn up full the other is let down empty.

The third primitive method of raising water, which is commoner in Egypt than in Mesopotamia at the present day, is the shadduf, and is worked by hand.  It consists of a beam supported in the centre, at one end of which is tied a rope with a bucket or vessel for raising the water, and at the other end is fixed a counterweight.* On an Assyrian bas-relief found at Kuyunjik are representations of the shadduf in operation, two of them being used, the one above the other, to raise the water to successive levels.  These were