Sundials - World's Oldest Clocks

North American Sundial Society

Pittsburgh  

Sundial 641
State/Province:  Pennsylvania Country:  USA
Dial Type:  Horizontal Condition:  Poor
Latitude:   40° 26.473' N Longitude:   80° 00.583' W
Location:
  • Fort Pitt Block House
    101 Commonwealth Place
    Point State Park
    Pittsburgh, Pennsylvania 15222
 
Description:
  • A 12 inch octagonal carved sandstone horizontal dial with Roman hour numerals from 4 AM to 8 PM. The gnomon is missing. Dial face includes carved figures of a snake and a thistle and is marked latitude 40 35.

    The 1763 date ascribed to the dial's origin is coincident with the relief of the siege of Fort Pitt during Pontiac's Rebellion in that year. The 42nd and 77th Regiments of the Highland Guard and the 60th Regiment of the Royal Americans defeated the Native forces (Delaware, Shawnee, Mingo and Huron Tribes) at the Battle of Bushy Run in August, 1763, successfully quelling the Indian uprising in Southwestern Pennsylvania. The Highland Guard is artistically represented on the sundial by the thistle and the Royal Americans by the snake. Although the assignment of the 1763 date to the dial is not conclusive, the history of Fort Pitt, together with the design elements seen on the sundial and the location of its discovery, provides a plausible conclusion.

    This dial is reported to have been found at the site of the Fort Pitt Block House during its 1894 restoration by the Pittsburgh Chapter of the Daughters of the American Revolution who still own and preserve the structure and the sundial as a private museum. The Block House is the only surviving structure of Fort Pitt. Following the sundial's discovery in 1894, the dial was housed in the archives of the Carnegie Museum in Pittsburgh until 1916 when it was placed on a pedestal on the grounds of the Fort Pitt Block House for display. The dial was unfortunately exposed to acid rain then later covered with protective glass (later Plexiglas) that inadvertently accelerated its deterioration. Fortunately, an excellent picture taken between 1894 and 1900 shows the dial was in good condition when originally recovered. The dial was moved to a display case inside the Fort Pitt Block House in 2006.

    Today, the dial face is grainy and light gray. The reverse side is an irregular brownish gray that features an arrangement of holes that formerly served to mount the dial; four smaller holes marked by rust stains likely date to the 1980s when the dial was placed on a new, square granite pedestal. The dial face may be covered with a slip coating that was carved to produce the dial features.

    Measurement and analysis of the sundial hour line angles by Roger Bailey of NASS shows the dial was correctly designed for the latitude of Fort Pitt and even included a noon gap to correct for the thickness of the (now missing) gnomon.
 
General Information:Inscription:
  • Owner: Fort Pitt Society, Pittsburgh Chapter NSDAR
  • A coiled snake representing the Royal American Regiment (60th) and a carved thistle representing the Scottish Highland Regiments (42nd and 77th) who served at Fort Pitt during the French and Indian War. Center of dial shows "Lat 40 35" in script.
  • Designer:
  • Builder:
  • Construction Date: 1763 approximately
 
 
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