 He began by classifying China’s notable mountains, great rivers and connecting valleys; its birds and beasts; the fruitfulness of its water and soils, and its rare products; and from this extended his survey to what is beyond the seas, and men are unable to observe. Then starting from the time of the separation of the Heavens and the Earth, and coming down, he made citations of the revolutions and transmutations of the Five Powers (Virtues), arranging them until each found its proper place and was confirmed (by history). (Shi ji ch 76, slightly modified from Needham 1956b, 232–33).