To ensure that the boat-builder should not scamp his work, regulations were drawn up to fix on him the responsibility for unsound work. Thus if a boat-builder were employed to build a vessel, and he put faulty work into its construction so that it developed defects within a year of its being launched, he was obliged to strengthen and rebuild it at his own expense. [4] The fourth class of machine for raising water employed in Mesopotamia at the present day consists of an endless chain of iron buckets running over a wheel. This is geared by means of rough wooden cogs to a horizontal wheel, the spindle of which has long poles fixed to it, to which horses or cattle are harnessed. The beasts go round in a circle and so turn the machine. The contrivance is not so primitive as the three described above, and the iron buckets are of European importation. The hire of a boatman was fixed at six gur of corn to be paid him yearly, but it is clear that some of the larger vessels carried crews commanded by a chief boatman, or captain, whose pay was probably on a larger scale. If a man let his boat to a boatman, the latter was responsible for losing or sinking it, and he had to replace it. A boatman was also responsible for the safety of his vessel and of any goods, such as corn, wool, oil, or dates, which he had been hired to transport, and if they were sunk through his carelessness he had to make good the loss. If he succeeded in refloating the boat after it had been sunk, he was only under obligation to pay the owner half its value in compensation for the damage it had sustained. In the case of a collision between two vessels, if one was at anchor at the time, the owner of the other vessel had to pay compensation for the boat that was sunk and its cargo, the owner of the latter estimating on oath the value of what had been sunk. Boats were also employed as ferries, and they must have resembled the primitive form of ferry-boat in use at the present day, which is heavily built of huge timbers, and employed for transporting beasts as well as men across a river. [Illustration: 297.jpg KAIKS, OR NATIVE BOATS ON THE EUPHRATES AT BIREJIK.] Employed for ferrying caravans across the river. There is evidence that under the Assyrians rafts floated on inflated skins were employed for the transport of heavy goods, and these have survived in the keleks of the present day. They are specially adapted for the transportation of heavy materials, for they are carried down by the current, and are kept in the course by means of huge sweeps or oars. Being formed only of logs of wood and skins, they are not costly, for wood is plentiful in the upper reaches of the rivers. At the end of their journey, after the goods are landed, they are broken up. The wood is sold at a profit, and the skins, after being deflated, are packed on to donkeys to return by caravan.