Since the Great Kaan occupied the city he has ordained that each of the 12,000 bridges should be provided with a guard of ten men, in case of any disturbance, or of any being so rash as to plot treason or insurrection against him. [Each guard is provided with a hollow instrument of wood and with a metal basin, and with a time-keeper to enable them to know the hour of the day or night. And so when one hour of the night is past the sentry strikes one on the wooden instrument and on the basin, so that the whole quarter of the city is made aware that one hour of the night is gone. At the second hour he gives two strokes, and so on, keeping always wide awake and on the look out. In the morning again, from the sunrise, they begin to count anew, and strike one hour as they did in the night, and so on hour after hour. Part of the watch patrols the quarter, to see if any light or fire is burning after the lawful hours; if they find any they mark the door, and in the morning the owner is summoned before the magistrates, and unless he can plead a good excuse he is punished. Also if they find any one going about the streets at unlawful hours they arrest him, and in the morning they bring him before the magistrates. Likewise if in the daytime they find any poor cripple unable to work for his livelihood, they take him to one of the hospitals, of which there are many, founded by the ancient kings, and endowed with great revenues.{6} Or if he be capable of work they oblige him to take up some trade. If they see that any house has caught fire they immediately beat upon that wooden instrument to give the alarm, and this brings together the watchmen from the other bridges to help to extinguish it, and to save the goods of the merchants or others, either by removing them to the towers above mentioned, or by putting them in boats and transporting them to the islands in the lake. For no citizen dares leave his house at night, or to come near the fire; only those who own the property, and those watchmen who flock to help, of whom there shall come one or two thousand at the least.] Moreover, within the city there is an eminence on which stands a Tower, and at the top of the tower is hung a slab of wood. Whenever fire or any other alarm breaks out in the city a man who stands there with a mallet in his hand beats upon the slab, making a noise that is heard to a great distance. So when the blows upon this slab are heard, everybody is aware that fire has broken out, or that there is some other cause of alarm. The Kaan watches this city with especial diligence because it forms the head of all Manzi; and because he has an immense revenue from the duties levied on the transactions of trade therein, the amount of which is such that no one would credit it on mere hearsay.