In many old flat Earth books the fact that Polaris can be seen as far South as 23.5 degrees (Tropic of Capricorn) is spoken of as a generally-accepted fact:

“If the Earth is a sphere and the pole star hangs over the northern axis, it would be impossible to see it for a single degree beyond the equator, or 90 degrees from the pole. The line-of-sight would become a tangent to the sphere, and consequently several thousand miles out of and divergent from …