《宋史·志·卷一》
二叫纬，纬的规是一个，和经的规在南北两极中交会，像车轮斜靠着，南北距离极的度都是九十一度强。
二曰纬，纬之规一，与经交于二极之中，若车轮之倚，南北距极皆九十一度强。
The second is "latitude"; the "latitude" compass is one, and it intersects the "longitude" compass at the north and south poles, resembling a wheel tilting to one side; the northern and southern distances from the poles are both greater than 90 degrees.