=The Big Dipper.=—This group of seven stars is called the Big Dipper because if a broken line joined all the stars together a very good figure of a big dipper would be formed. A group of stars is called a _constellation_, and this constellation is shown as we see it in Fig. 6, and as the ancient shepherds and sailors pictured it in Fig. 7. [Illustration: FIG. 5.—LINE FOR SIGHTING THE NORTH STAR.] In England this group of stars, or constellation, is sometimes called the _Plough_, for our friends across the pond see in it the likeness of a plough as well as of a dipper. It is also called the _Great Bear_ the world over after the ancient name given it, but it requires some stretch of the imagination to liken it to that nubbly short-tailed animal. All these fancy names were given this great group of stars long before the birth of Christ and by these names the constellation is still familiarly called. Astronomers of the present time also call this constellation the Great Bear, but they say it in Latin and so it becomes _Ursa Major_, which is a very high toned and scholastic sounding word. But the Big Dipper is a name that is good enough for all ordinary purposes and so we’ll use it. [Illustration: FIG. 6.—THE BIG DIPPER AS WE SEE IT.] The stars forming the Big Dipper stand out so bright and clear in the northern sky that you won’t have the slightest trouble in finding it, especially if you have the star finder at hand to help you. In using the star finder there is one thing you should keep well in mind and that is that the Big Dipper as we see it turns round the North Star, like the hands of a clock, but in the opposite direction. That is, the Big Dipper, when below the North Star, _seems_ to turn round the North Star from left to right. [Illustration: FIG. 7.—THE GREAT BEAR AS THE ANCIENTS SAW IT.] In a word the North Star forms one end of the axis round which not only the Big Dipper but the whole starry heavens seem to revolve as though they were fastened to the spokes of a great wheel. This is the way it seems to us. As a matter of fact, though, all the stars are _fixed_ in their positions in the sky, and the reason they seem to revolve round the North Star is because the Earth from which we see the stars turns round instead. [Illustration: FIG. 8.—THE EARTH, POLE STAR AND DOG STAR.] By looking at the drawing shown in Fig. 8, it will be seen that the _north pole_ of our Earth is directly under the North Star,—hence the name Pole Star—and that if we could draw a line through the center of the Earth from the _south pole_ to the _north pole_ and extend the line far enough, or _produce_ it as it is called, it would finally meet the North Star.