In the sayings of the philosopher Tso, the following remarks may be found: "Virtue existed during the times of the Hsia dynasty; drawings of all animals far and wide were made, and the metal from which the urn was made, for the purpose of engraving thereon the images of these animals, was presented as tribute by the feudal lords of the Nine Kingdoms. This urn contained the images of all manner and kinds of animals. This was for the purpose of letting the people know about their existence, so that they might avoid them in entering the mountains and forests, and the genii of the mountains and rivers. Hence the object of the classic treating on the 'Wonders by Land and Sea.'" When Yü assuaged the floods, the Emperor presented him with a red-coloured wand made of jadestones, and then abdicated his throne in his favour; on this account he ordered a tribute of metals from the feudal lords of the Nine Kingdoms, wherewith to cast the urn, on which were engraved all kinds of animals from far and wide, such as the wonderful animals and beings of mountains, rivers, grass, and wood, as well as the wonders to be found among walking animals and inhabitants of the air. Yü, when Emperor, caused the forms of these wonders to be described, how produced, and their natures; he also had them classified. When he had described those wonders, whether seen or heard of, or common or uncommon, or rarely heard of, all these he had described minutely, whereby, when the people heard of them, an exceeding fear fell on them. All animals and beings that were common in those days were described in the Annals of Yü, but such as were wonderful and rare were engraved on the nine urns. These urns when completed were placed in those parts of the empire where these wonders originally came from, in order that the people of that age might learn and see daily the things that were either heard of or seen by others.