Discoveries- Water way

Xiake explored the waterway sources of many rivers, such as the left and right rivers in Guangxi, the Xiao and Binershui tributaries of the Xiangjiang River, the Erpan River in the north and south of Yunnan, and the Yangtze River, among which the Yangtze River was the most deep. Where the Yangtze River originated has been a mystery for a long time. A geography book of the Warring States period, "Yu Gong", has the saying "Minjiang Daojiang", and later books have used this saying. Xu Xiake was suspicious of this. With this question, "The Northern Calendar of the Three Qins, the Five Ridges of the South Pole, and the West Out of the Shimen Jinsha", he found that the Jinsha River originated in the southern foothills of the Kunlun Mountains, more than a thousand miles longer than the Min River, so he concluded that the Jinsha River was the source of the Yangtze River. No one found him for a long time after that, and it was not until 1978 that the state sent an expedition to confirm that the source of the Yangtze River was the Tuotuo River in Gradamdong, the main peak of Tanggula Mountain.