As the Earth travels, her north pole always points exactly in one direction--always _towards the Pole-star_. If a man were standing at the north pole and looking upwards, he would see the Pole-star always, at any hour of the night, in just the very same spot. When we think of our Earth as a globe floating in the sky, we must try to remember that in the Sky there is no real “up” or “down.” This you have heard before. Our “up” is always towards the sky, and away from the ground. But as the Earth turns round and round our “up” is every hour in a fresh direction. For the blue heaven is all around us, and from every part of the Earth we look up into the depths of the sky. We speak of some stars being in the “northern sky,” and of other stars being in the “southern sky.” For our own use we have given the name “northern sky” to one part of the heavens, and the name “southern sky” to another part. Only “north” does not mean up, and south does not mean “down.” The only true “up” for us is from any part of the Earth where we may be towards the sky over our heads, and the only true “down” is towards the middle of our Earth, under our feet. QUESTIONS. 1. What is a Year? The time that our Earth takes to journey round the Sun. 2. How long is the Earth’s Year? Twelve months, or about 365 days. 3. How many times does the Earth turn round on her axis in one Year? Three hundred and sixty-five times. 4. What is meant by the Seasons? Spring, Summer, Autumn and Winter. 5. How are the Seasons caused? The Earth travels round the Sun with her axis slanting. 6. How does it slant? Always in one direction, with her north pole pointing to the Pole-star. 7. What brings summer to us in the north? When the Earth is on one side of the Sun her north pole is towards the Sun, and the northern half of the Earth gets most of his heat and light. 8. What brings winter to us? When the Earth gets round to the other side of the Sun her north pole is turned away from him, and so we in the north have less heat and light. 9. Do they have summer and winter in the south of the world? The southern half of the world has summer when we have winter in the north, and winter when we have summer in the north. 10. How is this? When the north pole is towards the Sun the south pole is turned away, and when the north pole is away from the Sun the south pole is towards him. 11. When are the Equinoxes? In Spring and Autumn, half-way between Summer and Winter. 12. In which part of the world is the Equinox? All over the world at once. 13. Which pole is then turned towards the Sun? Neither pole. The Earth’s axis is then sideways to the Sun, and his light falls on north and south pole alike. 14. What is the Ecliptic? The path which the Sun seems to take in the sky through one year. 15. Where would a man at the north pole see the Pole-star? Always exactly overhead. CHAPTER XI. OTHER WORLDS.