Hinged Parallel Rule

Hinged Parallel Rule

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Usage conditions apply
This 6" ebony instrument has three blades, apparently cut from a single rectangle of wood, and is held together by intricate brass hinges. Surveyors, cartographers, navigators, and draftsmen began using parallel rules in the 18th century to easily draw parallel lines separated by various widths. These instruments were also used for reducing or enlarging scaled drawings.
According to the donor, the rule was brought to this continent by Alexander Matheson (1788–1866), an English officer who brought troops from the West Indies to fight against the Americans in the War of 1812. After the war, he helped build the Rideau Canal and settled near Perth, Ontario. His grandson, Alexander Matheson Richey (1826–1913), a lumberman who moved to Chicago, also used the instrument.
References: Maya Hambly, Drawing Instruments: 1580–1980 (London: Sotheby's Publications, 1988), 111; Ken W. Watson, "Smiths Falls Locks 28–31," Rideau Canal World Heritage Site, http://www.rideau-info.com/canal/history/locks/h28-31-smithsfalls.html; "The Town of Perth: The Settlement of Retired Military Heroes on 'the Scotch Line,'" Toronto Daily Mail (May 14, 1887), 6–7, 10; accession file.
Currently not on view
Object Name
parallel rule
date made
early 19th century
place made
United Kingdom: England
Physical Description
brass (overall material)
ebony (overall material)
overall:.2 cm x 15.2 cm x 3.6 cm; 3/32 in x 5 31/32 in x 1 13/32 in
ID Number
catalog number
accession number
Credit Line
Gift of Ada B. Richey
Drafting, Engineering
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Measuring & Mapping
Parallel Rules
Data Source
National Museum of American History
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