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Ivory Parallel Rules, 19th-20th Centuries

Ivory Parallel Rules, 19th-20th Centuries

Usage conditions apply
Parallel rules were part of a mariner’s basic navigational tool kit, along with dividers and a compass. This device was used for finding a ship’s bearing (compass direction), plotting a course and then transferring it to different sections of a ship’s navigational chart for wayfinding purposes. This pair is made of thin slices of ivory resembling piano keys in size and thickness. The metal hinge pieces are machined and turned.
Currently not on view
Object Name
scrimshaw parallel ruler
Object Type
date made
19th-20th century
Physical Description
ivory (overall material)
overall: 4 1/2 in x 1 1/4 in x 1/8 in; 11.43 cm x 3.175 cm x.3175 cm
ID Number
accession number
catalog number
Credit Line
Gift of Dr. and Mrs. Wilbur J. Gould
See more items in
Work and Industry: Maritime
Cultures & Communities
Data Source
National Museum of American History
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