Surveyor's Vernier Compass
name: label: user
content: Johnson, John
label: maker
content: Rittenhouse and Evans
notes: label: Description
content: The "RITTENHOUSE & EVANS" inscription on this compass refers to Benjamin Rittenhouse and his nephew, Benjamin Evans, who worked together in Worcester Township, Pennsylvania, around 1798-1801. A variation arc on the south arm extends 15 degrees either way; the "folded" vernier is moved by rack and pinion and reads to 5 minutes. John Johnson (1771-1841), the Surveyor-General of Vermont, used this compass in 1817-1820 while surveying the boundary between Maine and Canada. His notes refer to it as "a Circumferentor of 2.5 inches Radius made at Philadelphia by Rittenhouse and Evans and graduated to every 5 Minutes by the help of a nonius."
label: Description
content: Ref: "John Johnson" in Abby M. Hemenway, ed., <i>The Vermont Historical Gazeteer</i> (Burlington, Vt., 1868), vol. 1, pp. 596-599
label: Description
content: "John Johnson," in <i>National Cyclopaedia of American History</i>, vol. 17, pp. 290-291
label: Description
content: Johnson's report on the Maine-Canada boundary survey, in University of Vermont Library.
label: Location
content: Currently not on view
place: label: place made
content: United States: Pennsylvania
setName: label: See more items in
content: Medicine and Science: Physical Sciences
label: See more items in
content: Surveying and Geodesy
label: See more items in
content: Measuring & Mapping
publisher: label: Related Publication
content: Hemenway, Abbey Maria. Vermont Historical Gazetteer
label: Related Publication
content: National Cyclopedia of American History
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: PH.309543
label: accession number
content: 95588
label: catalog number
content: 309543
objectType: label: Object Name
content: Surveyor's Vernier Compass
physicalDescription: label: Measurements
content: overall length: 13 3/4 in; 34.925 cm
label: Measurements
content: needle: 5 in; 12.7 cm
label: Measurements
content: overall in case: 4 in x 14 1/4 in x 7 5/16 in; 10.16 cm x 36.195 cm x 18.57375 cm