Annapolis, Maryland -
Ptolemy Stone - The Last One

Claudius Ptolemy, whose geocentric universe model was the standard until Copernicus, Galileo and Newton blew it out of the water, used a specific tool of his own design to find the angle the sun made with his position on the earth. The device later became known as a "Ptolemy Stone", and was the basis for various navigational devices such as the sextant. The device became known as a "Ptolemy Stone", and now the only remaining one on the planet is at St. John's College in Annapolis. [Jack O'Brien, 06/15/2002]