One of these must certainly have corresponded to a very primitive arrangement that is in general use at the present day in Mesopotamia, particularly along the Tigris, where the banks are high and steep. A recess or cutting with perpendicular sides is driven into the bank, and a wooden spindle is supported on struts in a horizontal position over the recess, which resembles a well with one side opening on to the river. A rope running over the spindle is fastened to a skin in which the water is raised from the river, being drawn up by horses, donkeys, or cattle harnessed to the other end of the rope. To empty the skin by hand into the irrigation channel would, of course, entail considerable time and labour, and, to avoid this necessity, an ingenious contrivance is employed. The skin is sewn up, not in the form of a closed bag, but of a bag ending in a long narrow funnel. While the skin is being filled and drawn to the top, the funnel is kept raised by a thin line running over a lower spindle and fastened off to the main rope, so that both are pulled up together by the beasts. The positions of the spindles and the length of the ropes are so adjusted, that the end of the funnel stops just above a wooden trough on the bank below the struts, while the rest of the skin is drawn up higher and shoots its water through the funnel into the trough. The trough is usually made from half the trunk of a date-palm, hollowed out, and one end leads to the irrigation-channel on the bank. To give the beasts a better purchase in pulling up the weight of water, an inclined plane is cut in the ground, sloping away from the machine, and up and down this the beasts are driven, the skin filling and emptying itself automatically. To increase the supply of water, two skins are often employed side by side, each with its own tackle and set of beasts, and, as one is drawn up full, the other is let down empty. Thus a continuous flow of water is secured, and not more than one man or boy is required to keep each set of beasts moving. No more effective or simpler method could be devised of raising water to a considerable height, and there can be no doubt that, at the period of the First Dynasty, cattle were employed not only for ploughing, but for working primitive irrigation-machines of this character.