《晋书·志·第七章》
从前，圣人用璇玑模拟北极星的运行，观测天的运行以考察日影的长短、日月五星的运动状况，划分天在地上对应的区域，辨明历法，敬授农时，使万物兴盛，逭关系到调和阴阳，治理万物。
昔者圣人拟宸极以运璿玑，揆天行而序景曜，分辰野，辨躔历，敬农时，兴物利，皆以系顺两仪，纪纲万物者也。
In the past, the sages used the Xuanyi instrument to observe the circumpolar stars, observe the movement of the heavens to calculate the length of the day/night, the movement of the sun, the moon, and the five planets, delineate the corresponding areas between the heavens and the earth, clarify the calendar, teach the farmers when to plant, so that all things would flourish. It was not only about the harmony of yin and yang but also about the governing of all things.