Messer Marco Polo (Paperback)

"But the scholars are a queer and blind people, Brian Oge. I've heard tell there's a doctor in Spain can weigh the earth. But he can't plow a furrow that is needful, for planting corn. The scholars can tell how many are the feathers in a bird's wing, but it takes me to inform the doctors why the call comes to them, and they fly over oceans without compass or sextant or sight of land.