Sundials - World's Oldest Clocks

North American Sundial Society

Kennett Square  

Sundial 328
State/Province:  Pennsylvania Country:  USA
Dial Type:  Analemmatic Condition:  Excellent
Latitude:   39° 52' 22" N Longitude:   75° 40' 29" W
Location:
  • Longwood Gardens on US 1
    South east of the conservatory, in the topiary garden at ground level,
    West Tour.
 
Description:
  • 37.2 ft x 23.8 ft. This is probably the world's largest analemmatic, unusually designed to show standard time directly. It took 8 years of daily readings to perfect the sundial, which is accurate to within 2 minutes. Hour markers are bronze Roman numerals. Minute lines inscribed in limestone curbing. The gnomon itself is a moveable pole that is set on an AM or PM daily curve. NASS member P. Kenneth Seidelman was instrumental in correcting this design in 1978.
 
General Information:
  • Owner: Longwood Gardens, Inc.
  • Designer: Knowles R. Bowen
  • Builder: Pierre S. du Pont
  • Construction Date: 1939
 
References:
  • Sawyer, Fred. 'Of Analemmas, Mean Time and The Analemmatic Sundial - Part 1', BSS Bulletin, 94.2 (June 1994), pp. 2-6, and 'Part 2', in 95.1, (February 1995, pp. 39-44.

Last Revised: 6/27/2012 15:25