Secrets in Ancient Books 1 When did China people know that the earth was round?

China people first proved that the earth is round by practice, which is recorded in the story of the idiom "Do the opposite".

From Wei Ce's "Warring States Policy": "Today, I came to see people in the big line. I drove in the north and told my ministers,' I want Chu. I said,' Will the monarch of Chu regard Xi as the north? Said, "My Ma Liang. The minister said:' Although the horse is good, this is not the way of Chu. Say,' I use it a lot. The minister said,' Although there are many uses, this is not the way of Chu. Say,' I'm good at guarding others. The better the number, the farther away from Chu. "

It shows that during the Warring States period, some ancient sages who had mastered the secrets of the earth realized that the earth was round and needed to prepare "the best means of transportation", "a lot of money and materials" and "the best guide" to travel around the world.