Page:In the high heavens.djvu/66

Fig. 9.—The Movement of the Celestial Pole.

At first one might hastily say that there must be such a difference, for it will be remembered that I have defined the North Pole in the earth as that point through which the tube passes which would permit an eye placed at the centre of the earth to view the North Pole in the sky. If, therefore, the North Pole in the sky had undergone a great change in its position, it might seem obvious that the tube from the earth's centre to its surface which would now conduct the vision from that centre to the north celestial Pole would emerge at a different point of the earth's crust from that which it