《明史·志·卷七》
南北东西差都是依据黄道，那么时差又怎能不依据黄道来论定它的初段末段以推求中限呢？
盖南北东西差俱依黄道，则时差安得不从黄道道论其初末以求中限乎？
South, north, east and west differences are all based on the ecliptic, then how can the time difference not based on the ecliptic to establish its initial section and end section to infer the mid-limit?