If the centre of the world changes, the column changes its position accordingly.

This column has moved three different times of its own accord.

This is because, in great convulsions of nature, at three different times, masses of the earth -- whole ranges of mountains, probably--have flown off into space, thus lessening the diameter of the earth, and changing the exact locality of its centre by a point or two.

This is a very curious and interesting circumstance, and is a withering rebuke to those philosophers who would make us believe that it is not possible for any portion of the earth to fly off into space.
To satisfy himself that this spot was really the centre of the earth, a sceptic once paid well for the privilege of ascending to the dome of the church to see if the sun gave him a shadow at noon.

He came down perfectly convinced.