Sometimes she is outside the Earth, away from the Sun; and then we see her as Full Moon. Sometimes she is between the Earth and the Sun--only a little higher or lower, and not exactly between:--and then she is New Moon, with her bright face turned from us, so that we cannot see her. Suppose the Moon, instead of being at “New Moon” a little higher or lower, were to pass just _exactly_ between the Sun and us; what would happen? We should see her as a dark round body, creeping over the face of the Sun, and hiding him from us. And this is precisely what we do see, from time to time. Once in a while the Moon does come into the line between; and then we have an Eclipse of the Sun: we see the moon’s dark body covering or partly covering his face. You must not think that the Moon is at such times any darker than usual. She always has a dark side and a bright side. At New Moon the dark side is towards us, and so we cannot see it at all--_unless_ she happens to be just between the Sun and us. But you must not suppose for a moment that she really touches the face of the Sun. The Moon is no nearer to the Sun than usual. She is only _between_ him and us. If you are in a room with a lamp on the table, and somebody holds a big ball just between your eyes and the lamp, what happens? The lamp is eclipsed. It does not leave off shining, but to you it is eclipsed, or hidden. You see the dark ball, not the bright globe of the lamp beyond it. That is how we have an eclipse of the Sun. Now and then, at New Moon, our Moon glides exactly between, just as the ball came between your eyes and the lamp. And then the light of the Sun is cut off from part of the Earth. An eclipse of the Sun is always known about beforehand. The Moon’s pathway and the Earth’s pathway are so well understood by astronomers that they can tell when she will pass a little higher, or a little lower, and when she will go just between, so as to eclipse the Sun. Then, when the moment comes, we look earnestly at the Sun, perhaps with telescopes, perhaps only with pieces of smoked glass to protect our eyes; and we see-- A dark round body touching the bright side of the Sun, then slowly crossing his face and blotting out his radiance. Not that the Sun is dimmed, or that for a moment he leaves off shining. Other worlds see him still, as brilliant as ever. But to us, for a short space, his light is hidden by the solid Moon floating between. For a few seconds, and no more, we have almost darkness. Then, on the side of the Sun where the moon seemed first to touch him, a line of light is seen. This widens fast, as the dark round moon draws away to the opposite edge and then vanishes, and the whole Sun shines out as usual. Even when an eclipse can be seen it is often only a _Partial_ eclipse, not _Total_. Only part of the Sun is hidden, not all of him. The Moon creeps over one edge, or perhaps over half of the Sun’s face, but she does not cover him quite.