Well, I think the earth must be a good big ball to roll about among the stars.
You ought to know its size.
I have been told that it is 25,000 miles round; but who has measured it.
Why as to that, you and I might measure it some evening by the stars. You know that the great space between the Belt and Polar Star is one-quarter of the great circle of the heavens.
Of course.
Every circle is reckoned to be divided into spaces called degrees, of which 360 go to form the circumference; so that one-fourth will be ninety degrees. You can imagine that space divided into ninety of these portions, called degrees.
What rare compasses that would take!
Those two bright stars overhead, which are about twice the same distance apart as the apparent diameter of the Sun, would be nearly equal to one of these ninety portions. Now, you know that if you were at the pole, you would have the Polar Star above you; and, if at the equator, Orion’s Belt would be over your head.
I understand all that, father.
You know, then, that you might be in a place where one of those two bright stars would be overhead, and you might journey on to another place further south, where the other one would be at the zenith or overhead.