“The more I study the stars, father, the more their motions bother me.
How is that, my son?
When we first left England I saw the Polar star and Great Bear a good height up in the heavens, toward the north, and Sirius low down toward the south.
Have they been playing any tricks with you?
I do not know that. But as we have been sailing towards the equator, I have observed the Great Bear going gradually down, and Sirius as gradually coming up. I am afraid I shall lose the Polar star altogether soon. And now I have another trouble. I do not know what to make of a number of new stars coming up from the southward.
Would it be owing to the shape of the earth, think you?
Aye, I never thought of that.
If we were sailing on a flat surface all this long way, would you see these ups and downs of the stars?
No, I think not. The truth is, it seems to me that we have been going up a hill, if the stars do not move.
That will account for your Great Bear going down; but what should cause these new stars to appear in the south?