Overview: Like Egypt, Sumer, and Mesoamerica, ancient China represents a hydraulic civilization—one that maintained its population by diverting rivers to aid in irrigation—and one that developed writing thousands of years ago. Today, we’re going to focus on the time of the Northern and Southern Song Dynasties, a time of great technical innovation. But, before we get to the Song, let’s take a tour through the ages and explore key elements of Chinese scientific culture.