Though it is a long time ago, I can remember how surprised I was when I first understood that the sun was a star, and that there are other stars very much like him, but most of them so very far from us that it is not possible to measure their distance. We do know how far our sun--the Star of Day, as he is sometimes called--is from us. Perhaps it may help you a little if I tell you that the astronomers say that if the sun was as far away from us as the nearest of these stars, he would appear but a point of light; but I think you will best understand how great the distance is if I tell you that a train, rushing along at full speed, as you see the express go by, and never resting, day or night, would take two hundred and ten years to reach him. We cannot be surprised that very little is known certainly about a star so very far off, and yet nearer to us than any of the little points of light which you see so thickly sown over the sky; but we know that he is a great globe, like our earth, only twelve hundred thousand times as large--as much larger, I told the children when we were having our lesson in astronomy, as May's curly head was larger than the little blue bead which I put upon it. But this great globe is unlike the earth in one respect; for while _it_ is in itself quite dark, the sun which is used in the Bible as an emblem of God Himself shines by his own glorious light, and though he is believed to be made of the same materials as our earth, it is likely that they are in a state of very great heat. Astronomers, who look at the sun through their wonderful telescopes, and so get much nearer to him than we can, tell us that we never see the sun himself; but that what we look at is the bright garment of light which is wrapped around him. They tell us also about great holes which sometimes appear in this bright covering; and they believe that they have actually seen, through these holes, the dark globe which is the real sun. These holes are called spots upon the sun, and very dark they look upon his bright face. The astronomers have long tried to find out what makes the sun-spots, and some of them now think that they are caused by furious winds which make great rents in this bright garment; for they tell us that there are sun-storms far more terrible than any storm that ever raged on sea or land. It was while patiently watching the movement of these dark spots, through the little telescope which he had made and set up in Rome, that Galileo, nearly three hundred years ago, discovered that the sun moves round upon itself once during twenty-eight days, just as the earth turns round on herself once in twenty-four hours. But he lived in a time when it was believed that our earth was the centre of the universe, and that to say that it was only one of many planets moving round the sun was to deny the word of God; so to save his life, he pretended to give up what he knew to be true, and promised that he would never teach it again.