Dod Protractor and Parallel Rule
date: label: date made
content: late 1700s
name: label: maker
content: Dod, Lebbeus
notes: label: Description
content: This brass semicircular protractor is divided by single degrees and marked by tens from 10° to 90° to 10°. It is attached with metal screws to a set of brass parallel rules. Brass S-shaped hinges connect the rules to each other. The bottom left screw on the parallel rules does not attach to the bottom piece. A rectangular brass arm is screwed to the center of the protractor. A thin brass piece screwed to the arm is marked with a small arrow for pointing to the angle markings. The protractor is stored in a wooden case, which also contains a pair of metal dividers (5-1/4" long).
label: Description
content: The base of the protractor is signed: L. Dod, Newark. Lebbeus Dod (1739–1816) manufactured mathematical instruments in New Jersey and is credited with inventing the parallel rule protractor. He served as a captain of artillery during the Revolutionary War and made muskets. His three sons, Stephen (1770–1855), Abner (1772–1847), and Daniel (1778–1823), were also noted instrument and clock makers. The family was most associated with Mendham, N.J. (where a historic marker on N.J. Route 24 indicates Dod's house), but Dod is known to have also lived at various times in Newark.
label: Description
content: ID number MA.310890 is a similar protractor and parallel rule. Compare also to a Dod instrument owned by the Metropolitan Museum of Art in New York, http://www.metmuseum.org/Collections/search-the-collections/5535.
label: Description
content: References: Bethuel Lewis Dodd and John Robertson Burnet, "Biographical Sketch of Lebbeus Dod," in <i>Genealogies of the Male Descendants of Daniel Dod . . . 1646–1863</i> (Newark, N.J., 1864), 144–147; Alexander Farnham, "More Information About New Jersey Toolmakers," <i>The Tool Shed</i>, no. 120 (February 2002), http://www.craftsofnj.org/Newjerseytools/Alex%20Farnham%20more%20Jeraey%20Tools/Alex%20Farnham.htm; Deborah J. Warner, “Surveyor's Compass,” <i>National Museum of American History Physical Sciences Collection: Surveying and Geodesy</i>, http://americanhistory.si.edu/collections/surveying/object.cfm?recordnumber=747113; Peggy A. Kidwell, "American Parallel Rules: Invention on the Fringes of Industry," <i>Rittenhouse</i> 10, no. 39 (1996): 90–96.
label: Location
content: Currently not on view
place: label: place made
content: United States: New Jersey, Newark
topic: label: Subject
content: Mathematics
label: Subject
content: Protractor
label: Subject
content: Parallel Rule
label: Subject
content: Dividers
label: Subject
content: Drawing Instruments
label: Subject
content: Revolutionary War
setName: label: See more items in
content: Medicine and Science: Mathematics
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content: Science & Mathematics
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content: Protractors
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content: Parallel Rules
creditLine: label: Credit Line
content: Gift of Ruth A. Ming
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1978.2110.06
label: accession number
content: 1978.2110
label: catalog number
content: 336732
objectType: label: Object Name
content: protractor
label: Object Name
content: protractor and parallel rule
label: Other Terms
content: protractor; Semi-Circular, with Parallel Rule
physicalDescription: label: Physical Description
content: leather (overall material)
label: Physical Description
content: wood (overall material)
label: Physical Description
content: brass (overall material)
label: Measurements
content: overall: 2.9 cm x 33.5 cm x 14 cm; 1 5/32 in x 13 3/16 in x 5 1/2 in