French Equinoctial Sundial

French Equinoctial Sundial

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Usage conditions apply
This French universal equinoctial dial dates from c. 1870. It consists of a hinged silver hour ring, a folding silver latitude arc, a metal rod gnomon on a folding metal piece transversing the hour ring, and an inset compass. The dial is housed in a square wooden case with a hinged lid and 2 brass hooks for securing the lid. The hour ring is calibrated from IV to XII to VIII by I with lines for each 15 minutes. The latitude arc is calibrated from 0 to 70 by 10 with lines for each degree. The compass is lettered with 8 cardinal points and is marked for variation at 20 degrees west of North. There is a ring around the compass which is calibrated from 0 to 360 by 20 degrees with lines marking each 2 degrees. A ring securing the inset compass with 3 screws is engraved with the latitudes for London, Paris, and Vienna. The dial opens to a maximum height of 10.8 cm.
Currently not on view
Object Name
sundial, equinoctial
date made
ca 1870
place made
overall: 2.8 cm x 9.3 cm x 9.3 cm; 1 3/32 in x 3 21/32 in x 3 21/32 in
ID Number
catalog number
accession number
Credit Line
Gift of Leo T. Thibodeau
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Medicine and Science: Mathematics
Science & Mathematics
Data Source
National Museum of American History
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