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.

Astronomy for Young Australians · 第 20 / 50 题