Houghton Common Theodolite

This is an example of the "new theodolate" for which Rowland Houghton (about 1678-1744), a Boston mechanic, received a patent from the General Court of the Colony of Massachusetts in 1735. This was the second patent for a mechanical invention issued in the British colonies of North America. The patent did not describe Houghton's instrument, but stated simply that it was designed "for surveying of lands, with suitable instruments, with greater ease and dispatch than any surveying instrument heretofore projected or made within this province." The only other contemporary reference to this instrument appears in Houghton's 1737 advertisement for aqueducts, which states that "Said Houghton has lately improv'd on his new Theodolate (sic), by which the art of Surveying is rendered more plain & easy than heretofore."
The horizontal circle is graduated to degrees and numbered in quadrants. One side is also numbered from VI to XII to VI, as for a sundial. The sight vanes for the alidade are missing. The compass card—marked "J. R. LINCOLN, BOSTON”—is a 19th-century replacement.
When the Smithsonian acquired this instrument, it was the only known surviving example. Another example, however, has recently come to light.
Ref: Silvio Bedini, "Rowland Houghton's 'New Theodolate,'" Rittenhouse 1 (1987): 30-39.
Raymond V. Giordano, "Some Notes on the Two Extant Rowland Houghton New Theodolates," Rittenhouse 15 (2001): 93-97.
Currently not on view
Houghton, Rowland
place made
United States: Massachusetts, Boston
alidade: 11 1/2 in; 29.21 cm
needle: 5 1/8 in; 13.0175 cm
overall: 2 5/8 in x 11 1/2 in x 6 5/8 in; 6.6675 cm x 29.21 cm x 16.8275 cm
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accession number
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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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