The regulation of transportation on the canals was also under the royal jurisdiction. The method of reckoning the size of ships has already been described, and there is evidence that the king possessed numerous vessels of all sizes for the carrying of grain, wool, and dates, as well as for the wood and stone employed in his building operations. Each ship seems to have had its own crew, under the command of a captain, and it is probable that officials who regulated the transportation from the centres where they were stationed were placed in charge of separate sections of the rivers and of the canals. It is obvious, from the account that has been given of the numerous operations directly controlled and superintended by the king, that he had need of a very large body of officials, by whose means he was enabled to carry out successfully the administration of the country. In the course of the account we have made mention of the judges and judicial officers, the assessors and collectors of revenue, and the officials of the palace who were under the king’s direct orders. It is also obvious that different classes of officers were in charge of all the departments of the administration. Two classes of officials, who were placed in charge of the public works and looked after and controlled the public slaves, and probably also had a good deal to do with the collection of the revenue, had special privileges assigned to them, and special legislation was drawn up to protect them in the enjoyment of the same. As payment for their duties they were each granted land with a house and garden, they were assigned the use of certain sheep and cattle with which to stock their land, and in addition they received a regular salary. They were in a sense personal retainers of the king and were liable to be sent at any moment on a special mission to carry out the king’s commands. Disobedience was severely punished; for, if such an officer, when detailed for a special mission, did not go but hired a substitute, he was liable to be put to death and the substitute he had hired could take his office. Sometimes an officer was sent for long periods some distance from his home to take charge of a garrison, and when this was done his home duties were performed by another man, who temporarily occupied his house and land, but gave it back to the officer on his return. If such an officer had a son old enough to perform his duty in his father’s absence, he was allowed to do so and to till his father’s lands; but if the son was too young, the substitute who took the officer’s place had to pay one-third of the produce of the land to the child’s mother for his education. Before departing on his journey to the garrison it was the officer’s duty to arrange for the proper cultivation of his land and the discharge of his local duties during his absence. If he omitted to do so and left his land and duties neglected for more than a year, and another had