| The rotating globe | Site
map
Timeline Reconstruction Acknowledgements |
 |
Kircher's magnetic clock contained a
rotating hollow copper globe. The globe contained a hidden bar magnet,
oriented with its North-South axis in a horizontal plane, parallel to the
North-South axis of the magnet hidden in the base of the clock. The rotating
copper globe was marked with 12 (or 24, in another version) meridian lines,
corresponding to lines of longitude on the Earth. Kircher suggested painting
the copper sphere in oils to represent the Earth's surface "by the Geographic
Art". The numbers on the outside of the sphere represent 2 hour intervals,
assuming that the sphere rotates once every twenty-four hours.
We have based the worldmap used in the reconstruction on Joan Blaeu's 1662 Atlas Maior. Following Blaeu, and a tradition that goes back to Ptolemy, we have also placed the prime meridian just to the West of Ireland, at the limits of the ancient world. As a 24-hourly movement of the sphere, although important for the cosmological implications of the machine, would be imperceptible to the eye, we have given the globe a rotation of 1 rpm for the installation. |
Website created by Michael
John Gorman, April 2001. Comments, questions or suggestions to mgorman@stanford.edu