About nine such ropes joined together. 12. If we should let one inch stand for 2,000 miles, how large would the Moon be? A ball one inch through. 13. How large would the Earth be? A ball four inches through. 14. In that case, how far would the Moon be from the Earth? About ten feet off. 15. How do the Earth and the Moon shine? By giving out again, or throwing back, the sunlight which falls upon them. CHAPTER VI. THE MOON’S CHANGES. The Moon in our sky does not always seem to be of the same shape. Sometimes she is quite round, like a plump laughing child-face, with eyes and nose and mouth marked in grey shadows. Sometimes a part of the round face seems to be shaven off on one side. Sometimes she is a half-round. Sometimes she is a bright crescent, wider or narrower. Sometimes she is only a slender sickle of light. Now, how is this? What causes so many changes in the Moon? You know in what way our Earth shines--as shine she does, if only we were far enough off to see it. You know that she is bright on that side alone which faces the Sun. And you know too that, as she spins daily on her axis, each country in turn comes into the Sun’s rays, is lighted up for awhile, then passes away into the night-time of darkness which is on the side of the Earth turned away from the Sun. And you also know that as the Earth shines so the Moon shines. The Moon has no radiance of her own. She can only, like a looking-glass, reflect the Sun’s radiance. In other words, she receives his light and throws it off again. As the Earth spins, so the Moon spins, but very much more slowly. It takes our big Earth only twenty-four hours to whirl once round upon her axis. It takes the Moon about twenty-eight days to spin once round upon her axis. Only that half of the Moon upon which the Sun shines is bright. Half of her is turned towards the Sun, and this half is bright. Half of her is turned away from the Sun, and this half is dark. And we from Earth can see, usually, only the _bright_ side of the Moon, or just so much of the bright side as happens to be towards us. Sometimes the whole of the bright side is turned towards us. Sometimes only a part of it, and sometimes none of it is turned towards us. Now and then we catch a little glimpse of the dark body of the Moon when it is not shining in the sunlight. We see a round dark ball held in the arms of the silver crescent. That is because our own Earth shines so brightly upon the _dark_ side of the Moon as to light it up and show it to us. But more often we only perceive the sunlighted side, and the darker part is quite hidden. [Illustration: _The New Moon._] You have noticed the Full Moon, of course, because the Moon then is at her best and brightest. Once a month we always have a Full Moon. It is only on one night that the Moon is really quite full; but for two or three days before and after she is very nearly so.