“We shall briefly state therefore that, as has been made clear by what we said before, both poles are in the horizon for those who inhabit the parallel that is the equator. As one moves toward the north, however, the elevation of the pole increases the farther one moves away from the equator. The elevation of the pole indicates the distance of places from that parallel, for the distance of any place from the equator varies as the elevation of the pole from that place.” (Cosmographiae introductio, cap. IX)