When the pyramid was built, the star in the tip of the little bear's tail was not the pole star, as it is now. At that time the star that was nearest the pole was one of those in the dragon. Since the pole of the earth goes round in a complete circle among the stars every 25,000 years, the star in _Draco_ will some time be the pole-star again--in, say 20,000 more years! Peter had picked up the Almanac that Uncle Henry had borrowed from Katy and suddenly cried, "Oh, Uncle Henry, the Almanac has a lot of the Star People in it. It calls them 'The Signs of the Zodiac.' What's the Zodiac, Uncle Hen?" "We are going to find out right away, Pete," said Uncle Henry, "but first we must draw pictures of the twelve star folks that are the Zodiac signs. That means three drawings apiece. Pull up your chairs to the table and we'll draw on the sheets of scratch paper with Betty's colored pencils. Paul, you do the _Virgo_, _Leo_, and _Cancer_ the Crab; Peter will draw _Gemini_ the Twins, _Taurus_ the Bull, and _Aries_ the Ram; Betty will do the Fishes, called _Pisces_ in Latin, _Aquarius_ the Water Carrier, and _Capricornus_ the Goat; while I will draw _Sagittarius_ the Archer, _Scorpio_, and _Libra_ the Balance. All old friends of ours." "We'll put the Almanac here in the middle of the table where we can all see it while we copy the 'signs,' one on each sheet of paper." Everybody was very busy indeed for about half an hour. At the end of that time the twelve rough drawings were done and pinned up at equal distances apart around the walls of the playroom, three on each of the four walls. They were arranged around the room in the same order in which Uncle Henry had assigned them. The room then looked like this, though of course you see only three walls in a picture. You must imagine how the fourth wall looked. [Illustration] "Now Paul, suppose you walk around the table again, spinning on your own axis as you go, and we'll try to find out what the Zodiac is. You notice that the pictures are all pinned on the walls at the same height from the floor, which is just the height of the electric lamp bulb, and just the height of Paul's head too, no matter where he is in his walk around the lamp. The twelve constellations, or signs of the Zodiac are in the real sky also on the same level with the earth and the sun, no matter where the earth is in its journey round the sun. Astronomers say it this way: they say that the earth revolves around the sun 'in the plane of the ecliptic.' That simply means that if the sun was in the centre of an enormous horizontal pane of glass, the earth and all the signs of the Zodiac would also always be touching the pane of glass, which would then represent the 'plane of the ecliptic.' Put an l in 'pane' and you have 'plane.'" "Is each sign for a month?" asked Peter. "I see there are twelve of them."