The father of Yü, by name K'un, being ordered by the Emperor to assuage the floods, was unable to do so; the Emperor Yao therefore ordered Yü, the son, to do so. Yü used four things in his journey around to make the floods flow away. He first cut away the trees on high mountains to obtain a view of the surrounding country; and having settled as to which was the highest mountain, and which the largest river, Yih and Peh Ye undertook to drive away the wild beasts and birds abounding in the country, and named the mountains and rivers, and classified the fauna of the country, and pointed out which was water and which was land. The feudal lords assisted Yü in his work, and thus he traversed the four quarters of the Empire, where footprint of man seldom could be found, and where boats and carts scarcely reached. He named the five mountain divisions of the Empire and eight seas that bound it. He noted where each kind of precious stone could be found, and the wonderful things he had seen. The abode of animals of land and sea, flora of the country, birds of the air, and beasts of the field, worms, the unicorn, and the phœnix, all these he fixed, and also made known their hiding-places; also the furthest removed kingdom of the earth, and men who were different from human beings. Yü divided the Empire into nine divisions, and determined upon the tribute to be given by each division, and Yih and his comrade noted which was hurtful and which was harmless for the "Book of Wonders by Land and Sea."