About one hundred yards from the sun travels a tiny ball, not half an inch in diameter, passing slowly round the sun--slowly, because as sizes and distances are lessened, speed must in due proportion be lessened also. This is Mercury. About two hundred yards from the sun travels another tiny ball, one inch in diameter. This is Venus. Nearly a quarter of a mile from the sun travels a third tiny ball, one inch again in diameter; and at a distance of two feet and a half from it a still smaller ball, one quarter of an inch in diameter, journeys round it and with it. These are the earth and the moon. About half as far again as the last-named ball, travels another, over half an inch in diameter. This is Mars. Then comes a wide blank space, followed by a large number of minute objects, no bigger than grains of powder, floating round the sun in company. These are the Asteroids. Another wide blank space succeeds the outermost of them. About one mile distant from the sun journeys a globe, ten inches in diameter. Round him, as he journeys, there travel five smaller balls, the largest of which is about the third of an inch in diameter. Their distances from the bigger globe vary from one and a third to twelve and a half feet. These are Jupiter and his moons. Nearly two miles distant from the sun journeys another globe, about eight and a half inches in diameter. Eight tiny balls and three delicate rings circle round him as he moves. These are Saturn and his belongings. About four miles distant from the sun journeys another globe, four inches in diameter, with four tiny balls accompanying him--Uranus and his moons. Lastly, at a distance of six miles from the sun, one more globe, not much larger than the last, with one tiny companion, pursues his far-off pathway. These proportions as to size and distance will serve to give a clear idea of the Solar System. CHAPTER VI. THE MOON. Come, and let us pay a visit to the moon. We seem to feel a personal interest in her, just because she is, in so peculiar a sense, our own friend and close attendant. The sun shines for us; but, then, he shines for all the members of the Solar System. And the stars--so many as we can see of them--shine for us too; but no doubt they shine far more brilliantly for other and nearer worlds. The moon alone seems to belong especially to ourselves. Indeed, we are quite in the habit of speaking about her as “our moon.” Rather a cold and calm friend, some may think her, sailing always serenely past, whatever may be going on beneath her beams; yet she has certainly proved herself constant and faithful in her attachment.