Let us go back to Fig. 2. If we draw a straight line through the two stars marked α and β which form the right side of the square, and produce it beyond α to a distance equal to five times that from β to α, or to a distance equaling that from α to the end of the tail, η, we find a star a little less brilliant than at the extremity of a figure similar to the Great Bear, but smaller and pointing in the opposite direction. This is the _Little Bear_, or the _Little Chariot_, also formed of seven stars. The star to which our line leads us—that which is at the tip of the tail of the Little Bear, or at the end of the pole of the Little Chariot—is the _polar star_. [Illustration: Fig. 3] The polar star enjoys a certain fame, like all persons who are distinguished from the common, because, among all the bodies which scintillate in the starry night, it alone remains motionless in the heavens. At any moment of the year, by day or by night, when you observe the sky, you will always find it. All the other stars, on the contrary, turn in twenty-four hours round it, taken as the centre of this immense vortex. The pole star remains motionless at the pole of the world, from whence it serves as a fixed point to navigators on the trackless ocean, as well as to travelers in the unexplored desert. [Illustration: Fig. 4] In looking at the pole star, motionless in the midst of the northern region of the sky, we have the south behind us, the east to the right, the west to the left. All the stars turn round the pole star in a direction contrary to that of the hands of a watch; they should, then, be recognized according to their mutual relations rather than by reference to the cardinal points. On the other side of the pole star, with reference to the Great Bear, is found another constellation which we can also recognize at once. If from the middle star, δ, we draw a line to the pole, and produce this line by the same distance (see Fig. 3), we arrive at _Cassiopeia_, formed of five principal stars arranged somewhat like the strokes of the letter M. The little star χ, which completes the square, gives the constellation the form of a _chair_. This group assumes all possible positions in turning round the pole; it is found sometimes above, sometimes below, sometimes to the right, and sometimes to the left; but it is always easily recognized, for, like the preceding group, it never sets, and is always opposite to the Great Bear. The pole star is the axle round which both these constellations turn. [Illustration: Fig. 5 Fig. 6]