St. John's College in Annapolis in Anne Arundel County, Maryland — The American Northeast (Mid-Atlantic)

Ptolemy Stone

Photographed by Devry Becker Jones (CC0), September 9, 2023

1. Ptolemy Stone Marker

Inscription.

"Mathematics, by contemplating the uniformity, order, symmetry and calm of divine things, makes its followers lovers of this divine beauty." Ptolemy (c. 100 CE - c. 170 CE)

One of the earliest astronomical devices, the Ptolemy Stone measures elevation of the sun at noon.

By this means, the latitude of the device and the irregularity of the sun's motion may be calculated.

Erected by St. John's Colege.

Topics. This historical marker is listed in these topic lists: Air & Space • Science & Medicine. A significant historical year for this entry is 100 CE.

Location. 38° 58.928′ N, 76° 29.549′ W. Marker is in Annapolis, Maryland, in Anne Arundel County. It is in St. John's College. It is on College Avenue (Maryland Route 450) south of King George Street ( Route 450), on the right when traveling south. Touch for map. Marker is at or near this postal address: 60 College Ave, Annapolis MD 21401, United States of America. Touch for directions.

Regionally, this marker is in Central Maryland.

It is also in the American Mid-Atlantic

and in the Chesapeake Bay Region.

Globally, it is in the North Atlantic Region,

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North America,

the Western Hemisphere,

the Western World,

and the Anglosphere.

Historically, it finds itself in what was once one of the original Thirteen Colonies

and also the Antebellum South.

Other nearby markers. At least 8 other markers are within walking distance of this marker: Max and Elke Schiff (a few steps from this marker); Take a Tour of St. John's College–Steeped in United States and Maryland History (within shouting distance of this marker); Edmund Berkeley Iglehart (about 300 feet away, measured in a direct line); Alexander Magruder (about 300 feet away); This Cannon (about 400 feet away); Francis Scott Key (about 400 feet away); a different marker also named Take a Tour of St. John's College–Steeped in United States and Maryland History (about 400 feet away); King William's School (about 400 feet away). Touch for a list and map of all markers in Annapolis.

Ptolemy Stone Display image. Click for full size.

Photographed by Devry Becker Jones (CC0), September 9, 2023

2. Ptolemy Stone Display

Credits. This page was last revised on December 14, 2023. It was originally submitted on September 9, 2023, by Devry Becker Jones of Washington, District of Columbia. This page has been viewed 1,038 times since then and 80 times this year. Photos: 1, 2. submitted on September 9, 2023, by Devry Becker Jones of Washington, District of Columbia.