He could then repeat the process with the next square, and so on, afterwards returning to the main channel and stopping the flow of water by blocking up the hole he had made in the bank. Such is the present process of irrigation in Mesopotamia, and there is no doubt that it was adopted by the early Babylonians. It was extremely simple, but needed care and vigilance, especially when water was being carried into several parts of an estate at once. Moreover, one main channel often supplied the fields of several farmers, and, in return for his share of the water, it was the duty of each man to keep its banks, where it crossed his land, in repair. If he failed to do so and the water forced a breach and flooded his neighbour's field, he had to pay compensation in kind for any crop that was ruined, and, if he could not pay, his goods were sold, and his neighbours, whose fields had been damaged, shared the proceeds of the sale. Similarly, if a farmer left his water running and forgot to shut it off, he had to pay compensation for any damage it might do to a neighbouring crop. The date-palm formed the chief secondary source of the country's wealth, for it grew luxuriantly in the alluvium and supplied the Babylonians with one of their principal articles of diet.[22] From it, too, they made a fermented wine, and a species of flour for baking; its sap yielded palm-sugar, and its fibrous bark was suitable for weaving ropes, while its trunk furnished a light but tough building-material. The early Babylonian kings encouraged the laying out of date-plantations and the planting of gardens and orchards; and special regulations were made with that object in view. For a man could obtain a field for the purpose without paying a yearly rent. He could plant and tend it for four years, and in the fifth year of his tenancy the original owner of the land took half the garden in payment, while the planter kept the other half for himself. Care was taken to see that the bargain was properly carried out, for, if a bare patch had been left in the plantation, it was reckoned in the planter's half; and should the tenant neglect the trees during his first four years of occupation, he was still liable to plant the whole plot without receiving his half of it, and he had to pay compensation in addition, which varied in amount according to the original condition of the land. In this way the authorities ensured that land should not be taken over and allowed to deteriorate. For the hire of a plantation the rent was fixed at two-thirds of its produce, the tenant providing all labour and supplying the necessary irrigation-water. [Illustration: FIG. 41. ASSYRIAN KELEK ON THE TIGRIS. (After Layard.)]