Surveyor's Compass

Surveyor's Compass

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Some American surveyors and instrument makers working in the second half of the 18th century may have been familiar with Irish compasses like this one, which was probably made by the eldest of three men named James Lynch who worked in Dublin during the period 1767–1846.
This compass is made of brass, and the face is silvered. The rose reads counterclockwise, a feature that David Rittenhouse introduced to American practice in the 1760s. The vertical sights are held with a narrow and relatively flimsy bar. The graduated needle rim reads clockwise to 360 degrees, rather than in quadrants from north and south as was usually the case. Another graduation is at the outer edge of the face, numbered in quadrants from north and south. The compass box can be detached from the bar. The inscription on the face reads "Lynch * Dublin *."
Ref: J. E. Burnett and A. D. Morrison–Low, "Vulgar and Mechanick" The Scientific Instrument Trade in Ireland 1650–1921 (Dublin, 1989), pp. 29–35.
Gloria Clifton, Directory of British Scientific Instrument Makers 1550–1851 (London, 1995).
Currently not on view
Object Name
Surveyor's Compass
Lynch, James
place made
Ireland: Dublin, Dublin
overall length: 18 1/4 in; 46.355 cm
needle: 5 1/2 in; 13.97 cm
overall in case: 5 in x 19 3/8 in x 8 5/16 in; 12.7 cm x 49.2125 cm x 21.11375 cm
ID Number
accession number
catalog number
Credit Line
John J. Boyd
See more items in
Medicine and Science: Physical Sciences
Measuring & Mapping
Surveying and Geodesy
Data Source
National Museum of American History
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