120 THE CONSTELLATIONS. \ 



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and Babylon. Endowed with a lively fancy, they divided i 

 the stars into different companies or constellations, each of ^ 

 which they supposed to represent the -image of some animal, | 

 or other terrestrial object. Of these ancient constellations 

 there were fifty, to which the moderns have added about ^ 

 thirty others. Twelve of these constellations are in the zo- ; 

 diac, bearing the same names with the signs of the zodiac j 

 or ecliptic. But these constellations and signs do not coin- ; 

 cide, for the equinoctial points are not stationary, but move i 

 backward, and the sign Aries always begins at one of them, 

 and all the other signs each succeed Aries in order ; it fol- , 

 lows therefore that all the signs of the ecliptic or zodiac J 

 move backward with the equinoxes. The distance which ; 

 they move annually is about fifty seconds of a degree ; so i 

 that with respect to the fixed stars the equinoctial points fall | 

 backwards thirty degrees, in about two thousand two hun- ; 

 dred years, whence the stars will appear to have gone for- '■■ 

 ward thirty degrees, with respect to the signs of the ecliptic, ^ 

 which are always reckoned from the equinoctial points, j 

 This shows the importance of distinguishing between the 

 signs of the zodiac and the constellations of the zodiac ; for ^ 

 stars, which are in one sign at one time, will be in the sue- i 

 ceeding one at another. Thus, the stars which were for- i 

 merly in Aries, are now in Taurus, and so on. When these j 

 names were given to the signs and constellations, it is sup- i 

 posed that each sign coincided with the constellation of the I 

 same name ; but on account of this moving of the equinoc- \ 

 tial points, or, as it is termed, the precession of the equinoxes, - 

 there is now about one sign or thirty degrees difference. 

 The period will be completed in about twenty-six thousand 

 years. 



Among the northern constellations, none are more re- 

 markable than that which is nearest to the north pole, and 

 termed the little bear. The last star of its tail is but two de- 

 grees from the pole ; hence it is called the polar star. It is | 

 easily distinguished from the neighbouring stars, because it 

 scarcely appears to change its position, and is ahvays in the 

 same part of the heavens. By its fixed situation it becomes 

 a guide to travellers, and particularly to mariners who are 

 sailing on the open seas. Before the discovery of the com- 

 pass sailors had no surer guide than the polar star ; and 

 even now, when the sky is serene, they repose in many cases 



