Beam Compass

This instrument consists of a wooden beam and a single German silver trammel with a micrometer and needle point. A large round hole in one end of the beam allows the instrument to be hung. The other end of the beam is marked in pencil at each of the first six inch points. The trammel is similar but not fully identical to Dietzgen's model number 646, which sold with a pair of trammels, two needle/pencil points, and a pen point for $9.20 in 1904–1905. This instrument was owned by the renowned American designer of steam engines, Erasmus Darwin Leavitt Jr. (1836–1916), and donated by his granddaughter, Margaret van D. Rice.
Reference: Catalogue & Price List of Eugene Dietzgen Co., 7th ed. (Chicago, 1904), 71.
Currently not on view
date made
ca 1900
Physical Description
metal (overall material)
wood (overall material)
overall: 34.5 cm x 6.4 cm x 1.4 cm; 13 19/32 in x 2 17/32 in x 9/16 in
ID Number
accession number
catalog number
Credit Line
Gift of Margaret van D. Rice
Drawing Instruments
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Dividers and Compasses
Data Source
National Museum of American History


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