Potts Surveyor's Vernier Compass

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William Lukens Potts (1771-1854) worked with Benjamin Rittenhouse in the years 1796-1798, making plain and vernier compasses. In 1800, now in business on his own, he advertised "surveying instruments of all kinds, and Rittenhouse' Circumferentors, with each a nounes and spirit level compleat." "Nounes" here refers to a nonius, a term sometimes used in place of vernier.
This example is marked "W.L. POTTS Bucks Penna." It was made between 1807, when Potts bought land in Bucks County, Pa., and 1817, when he moved to Philadelphia. It has a variation arc on the south arm that extends 15 degrees either way; the "folded" vernier is moved by rack and pinion, and reads to 5 minutes. There is a spirit level on the north arm. A copy of Thomas Whitney's 1814 discussion of "The Variation of the Compass" is pasted into the inside cover of the wooden box.
Currently not on view
date made
Potts, William Lukens
place made
United States: Pennsylvania, Bucks county
overall length: 14 1/4 in; 36.195 cm
needle: 5 in; 12.7 cm
overall in case: 3 13/16 in x 14 1/2 in x 7 3/8 in; 9.68375 cm x 36.83 cm x 18.7325 cm
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accession number
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Medicine and Science: Physical Sciences
Measuring & Mapping
Surveying and Geodesy
Data Source
National Museum of American History