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.[4] 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 probably the contrivances usually employed by the early Babylonians for raising the water to the level of their fields, and the fact that they were light and easily removed must have made them tempting objects to the dishonest farmer. Hammurabi therefore fixed a scale of compensation to be paid to the owner by a detected thief, which varied according to the class and value of the machine he stole. The rivers and larger canals of Babylonia were used by the ancient inhabitants not only for the irrigation of their fields, but also as waterways for the transport of heavy materials. The recently published letters of Hammurabi and Abêshu’ contain directions for the transportation of corn, dates, sesame seed, and wood, which were ordered to be brought in ships to Babylon, and the code of Hammurabi refers to the transportation by water of wool and oil. It is therefore clear that at this period considerable use was made of vessels of different size for conveying supplies in bulk by water. The method by which the size of such ships and barges was reckoned was based on the amount of grain they were capable of carrying, and this was measured by the _gur_, the largest measure of capacity. Thus mention is made in the inscriptions of vessels of five, ten, fifteen, twenty, thirty, forty, fifty, sixty, and seventy-five gur capacity. A boat-builder’s fee for building a vessel of sixty gur was fixed at two shekels of silver, and it was proportionately less for boats of smaller capacity.