Tutor. That such a motion would be perceptible is evident, if the fixed stars were near the earth; but, compared with their distance, 190 millions of miles is but a mere point: therefore, the axis always inclines to the same points of the heavens.
Pupil. This is a greater proof of the inconceivable distance of the stars than what you mentioned before, and I thought that very astonishing:
Wonders on wonders constantly arise,
Whene’er we view the earth, or sea, or skies.
Tutor. It is very true. And the more we search, the more we have cause to admire the works of the Almighty.
Pupil. Pray, Sir, what is the next thing you propose?
Tutor. To make you acquainted with the other circles you see in the figure (Plate III. fig. 1.) as it is very necessary you should know them.
Pupil. Will you be kind enough to tell me their names, Sir, and I will endeavour to remember them?
Tutor. That line which divides the globe into two equal parts, called the northern and southern hemispheres, which answers to the equinoctial in the heavens, and is equally distant from the two poles, is called the equator; the other which crosses it, as I before told you, is the ecliptic; the smaller circle, north of the equator, is the tropic of Cancer; that south of it, the tropic of Capricorn; the circles next the poles are called the polar circles; or that next the north pole, the arctic circle, and that next the south pole, the antarctic circle; each of which is 23-1/2 degrees distant from its respective pole, as are the tropics from the equator.
Pupil. You have not mentioned the lines which cross the other circles, and terminate in the poles; what are they called?