Lenoir Reflecting Circle

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The Chevalier de Borda developed this type of reflecting circle, and published a description of it in Paris in 1787. This example has a silvered scale that is graduated every 20 minutes and read by two verniers with tangent screws and magnifiers to single minutes. The circle bears the inscription "Lenoir A Paris no 10." It was made by Étienne Lenoir (1744-1832), the French craftsman who is credited with having made Borda’s first instrument of this sort. It belonged to Columbia College (now University) in New York, and probably dates from the 1790s.
Ref: A. J. Turner, From Pleasure and Profit to Science and Security. Étienne Lenoir and the transformation of precision instrument-making in France, 1760-1830 (Cambridge: Whipple Museum of the History of Science, 1989).
Currently not on view
date made
Lenoir, Etienne
place made
France: Île-de-France, Paris
overall: 10 1/2 in; 26.67 cm
overall in case: 3 in x 12 3/4 in x 12 1/2 in; 7.62 cm x 32.385 cm x 31.75 cm
ID Number
catalog number
accession number
Credit Line
Columbia University
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Medicine and Science: Physical Sciences
Measuring & Mapping
Data Source
National Museum of American History


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