WHY THE EARTH MOVES ROUND THE SUN.
Papa—Lucy.
Papa. You remember, Lucy, that I explained to you some time ago what was the cause that things fell to the ground.
Lucy. O yes; it was because the ground drew them to it.
Pa. True. That is a consequence of the universal law in nature, that bodies attract each other in proportion to their bulk. So a very small thing in the neighbourhood of a very large one, always tends to go to it, if not prevented by some or other power. Well—you know I told you that the sun was a ball a vast many times bigger than the ball we inhabit, called the earth; upon which you properly asked, how then it happened that the earth did not fall into the sun.
Lu. And why does it not?
Pa. That I am going to explain to you. You have seen your brother whirl round an ivory ball tied to the end of a string, which he held in his hand.
Lu. Yes; and I have done it myself, too.
Pa. Well, then—you felt that the ball was continually pulling, as if it tried to make its escape?
Lu. Yes; and one my brother was swinging did make its escape, and flew through the sash.