You remember that our earth has an atmosphere, a globe of air which wraps it round. We are told that the sun, too, has an atmosphere--a colour-globe, as it is called, because it is believed to be not air, but fiery gas. Then, outside this colour-globe, is something very lovely; that corona, or crown, of silvery light, which can be seen only during an eclipse of the sun. But what is an eclipse? When the moon, which has no light of her own, passes directly between the earth and the sun, so as to hide his face from us, we say there is a solar eclipse, or obscuring of the sun's light. When the earth comes directly between the moon and the sun, instead of the sun's light falling upon the moon, _she_ is eclipsed by the dark shadow of the earth passing over her face. I think you may have watched an eclipse of the moon: a solar eclipse is a much rarer sight, and there is something awful about it: as the darkness deepens, the stars begin to shine out, and it seems so much like night that the cocks and hens have been known to go to roost at midday. It is then, when the bright, dazzling face of the sun is hidden, that his lovely crown is seen, as a ring of soft light appearing all round the dark face of the moon. Now let us think of some of the things that this wonderful Star of Day does for us. In the first place, he is the great source of light and heat, as he shines, not for us alone, but upon all the other planets--those which are so near to him as to get more heat than we could bear, and those which are so far away that it seems to us as if they must be very cold indeed. But, if we leave these distant worlds and think of our own, how wonderful it is to know that, as we learnt when speaking of Light itself, not from the sun alone, but from every star, waves of light and heat, like tiny messengers from them to us, are always speeding on their noiseless way. They travel to us through space, or rather through something finer than air or water, which fills all the room between us and them--for no place in the universe is really empty. You may be surprised to hear that these messengers come from the stars by day as well as by night; but remember that they are _always_ shining in their places in the sky. We cannot see the starlight waves while the sun's great light is shining upon us; but you know how beautifully they shine on clear nights, when there is neither sunlight nor moonlight to quench their soft beams. But after all, the stars are so far away that we must think specially of our own star, the sun, as the source of light and heat; he also makes for us all form and colour, and gives us the pictures drawn by his light which we call photographs, and which make us know something of people we have never seen, and places which we may never visit.