NA VI G A TION. 



called Polaris, or the pole star, and it will probably, 

 if there is continuity of men and books upon the 

 earth, still have the same name twelve thousand 

 years hence, when it will be 47-| from the north 

 celestial pole. 



SCYGNI 



FIG. 2. Illustrating Precession. 



In the dawn of human history the earth's axis 

 pointed to a star not enduringly named till nearly 

 2000 years later, when the pole had moved about 

 10 or 1 1 from it, and it was called by the Greeks 

 a Draconis. 



14. The diagram before you, Fig. 2, shows how 



