《论衡·卷十一·谈天篇》
相离万里，所看见的太阳大小不变，可见如今中国占有的土地面积，是很小的。
相去万里，小大不变，方今天下，得地之广，少矣。
Although separated by thousands of miles, the sun looks the same size. This shows that the land area currently occupied by China is very small.