Surveyor's Vernier Compass
name: label: maker
content: Helffricht, William
notes: label: Description
content: William Helffricht was born in Frankfurt in 1807, moved to Philadelphia in 1825, and became a citizen in 1830. By the early 1830s he was advertising as a "Mathematical, Optical, & Philosophical Instrument Maker At the old established stand of the late Wm. DAVENPORT, Sign of the Quadrant, No. 25, South Front Street." Helffricht remained at this address until 1848.
label: Description
content: This compass is inscribed "Wm Helffricht, Maker Philadelphia." It has a variation arc on the north arm that extends 25 degrees either way. The vernier reads to 5 minutes, and is moved by a rack and pinion under the south arm. There are two level vials on the south arm. A card in the wooden box reads "Wm. Helffricht No. 25 South Street, Philadelphia."
label: Description
content: The compass was owned by Daniel Dunklin (1790-1844), who was elected governor of Missouri in 1832. Dunklin resigned the governorship in 1836, when Andrew Jackson named him surveyor-general of Missouri, Illinois, and Arkansas. He probably bought the compass at this time, and used it to trace the boundary between Missouri and Arkansas, and to lay out numerous counties in these three states.
label: Description
content: Ref: "Daniel Dunklin" in <i>National Cyclopaedia of American Biography</i>, vol. 12, p. 303.
label: Location
content: Currently not on view
place: label: place made
content: United States: Pennsylvania, Philadelphia
setName: label: See more items in
content: Medicine and Science: Physical Sciences
label: See more items in
content: Surveying and Geodesy
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content: Measuring & Mapping
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 2001.0161.01
label: accession number
content: 2001.0161
label: catalog number
content: 2001.0161.01
objectType: label: Object Name
content: Surveyor's Compass
label: Object Name
content: surveyor's compass
physicalDescription: label: Measurements
content: overall length: 14 in; 35.56 cm
label: Measurements
content: needle: 5 in; 12.7 cm
label: Measurements
content: overall: 3 13/16 in x 14 1/2 in x 7 7/16 in; 9.68375 cm x 36.83 cm x 18.89125 cm