No; it is a question of brightness, and not of size. 14. What do we really mean by Stars of the First Magnitude? We mean those stars in our sky which shine more brightly, as seen from the Earth, than any other stars. 15. Does not brighter shining show greater size? It may sometimes show greater size, or it may only show greater nearness to the Earth. 16. How many Stars of the First Magnitude are there? About twenty altogether, round the whole sky. CHAPTER XXI. STAR-GROUPS. The names of different Star-Groups are very old indeed. On a map or globe of the heavens you may see them pictured, with the figure of an animal or a man from which the name of the Constellation is taken. These figures were no doubt a help, in very early times, when people wished to learn the different stars; though the star-groups can hardly be said to bear any real likeness to the figures. As we journey round the Sun, month by month, we see him against different Star-groups in the heavens--against one constellation after another. Actually, of course, we do _not_ see the Sun against the stars, since all stars beyond the Sun are hidden by his brightness. But we see at night those stars which lie in the _opposite_ direction, and we know each month, without seeing, which group lies exactly _behind the Sun_. Suppose you are in a room with a lighted lamp on a table in the middle. And suppose you walk slowly round the table. As you go you will see the lamp against different parts of the room in turn. First, perhaps, against a window, then against a wall, then against a fireplace, then against a door, then against another wall, then against a sideboard or chiffonier, and so on. The lamp itself does not stir; but you, by moving onward, change its background and give it a sort of “seeming pathway” round the room. If it were very far away, instead of very close, it might really appear to you to be moving. This is how we see the Sun seem to travel among the different star-groups. He does not go any nearer to the stars than usual; he only comes _between_ them and us. In fact he does not really go or come; but as we move on we make him lie between us and one star-group after another. Twelve constellations are behind this seeming pathway of the Sun, and they are called “The Signs of the Zodiac.” It would be a good plan to learn them by heart some day. Here are the names of the twelve star-groups in English and in Latin: The Ram Aries. The Bull Taurus. The Twins Gemini. The Crab Cancer. The Lion Leo. The Virgin Virgo. The Scales Libra. The Scorpion Scorpio. The Archer Sagittarius. The Goat Capricornus. The Water-carrier Aquarius. The Fishes Pisces. In all these twelve groups we find only five stars of the first magnitude.