“I didn’t understand it fully, but it seemed to work. They said the theory was proved because the surveyed distances on maps agreed with what they ought to be according to the theory. That I can understand, and it seems a good point. If the shape weren’t what they thought it was, the distances would certainly go haywire before you got very far from your standard point.”

“Quite right. I see your philosophers are quite well into geometry. What I don’t see is why they haven’t realized that there are two shapes that would make the distances come out right. After all, can’t you see that the surface of Mesklin curves downward? If your theory were true, the horizon would seem to be above you. How about that?”

“Oh, it is. That’s why even the most primitive tribes know the world is bowl-shaped. It’s just out here near the Rim that it looks different. I expect it’s something to do with the light. After all, the sun rises and sets here even in summer, and it wouldn’t be surprising if things looked a little queer. Why, it even looks as though the — horizon, you called it? — was closer to north and south than it is east and west. You can see a ship much farther away to the east or west. It’s the light.”

“Hmm. I find your point a little difficult to answer at the moment.” Barlennan was not sufficiently familiar with the Flyer’s speech to detect such a thing as a note of amusement in his voice. “I have never been on the surface far from the — er — Rim — and never can be, personally. I didn’t realize that things looked as you describe, and I can’t see why they should, at the moment. I hope to see it when you take that radio-vision set on our little errand.”

“I shall be delighted to hear your explanation of why our philosophers are wrong,” Barlennan answered politely. “When you are prepared to give it, of course. In the meantime, I am still somewhat curious as to whether you might be able to tell me when there will be a break in this storm.”