Beam Compass

This German silver instrument has steel points. The two trammels, or frames for the pencil and needle points, have thumbscrews on their fronts. These thumbscrews are ridged around the edge and have a circular pattern on their tops. The number 19 is engraved inside each trammel. Smaller thumbscrews attach holders for needle and pencil points. These holders have horizontal scrolling but are not identical to each other. Another thumbscrew allows the needle point to be reversed. A micrometer adjustment is below one of the trammels.
A separate adjustable pen point appears to belong to a regular drawing compass, rather than to this beam compass, because it is longer than the other holders and shaped differently. Compare this piece to MA*335338 and MA*335340. No bar for connecting the trammels was received with the instrument.
This beam compass is similar but not identical to Dietzgen model number 1033, which sold for $6.90, and to Keuffel & Esser model 770, which sold for $7.00. These beam compasses are also similar but not identical to each other. Although this beam compass could not be identified, it probably was made in Germany and dates to the first decade of the 20th century, like the advertised instruments.
Leslie Leland Locke (1875–1943) earned bachelor's (1896) and master's (1900) degrees from Grove City College. He taught mathematics at Michigan State College, Adelphi College, and Brooklyn College and its Technical High School. He was interested in the Peruvian quipu. He donated his collection of early calculating machines to the Smithsonian and his early American textbooks to the University of Michigan.
References: Catalogue of Keuffel & Esser Co. , 33rd ed. (New York, 1909), 116; Catalogue & Price List of Eugene Dietzgen Co., 7th ed. (Chicago, 1904), 136; Louis C. Karpinski, "Leslie Leland Locke," Science n.s., 98, no. 2543 (24 September 1943): 274–275.
Currently not on view
Object Name
beam compass
date made
early 20th century
Physical Description
german silver (overall material)
steel (overall material)
overall: 2 cm x 8 cm x 9.5 cm; 25/32 in x 3 5/32 in x 3 3/4 in
ID Number
accession number
catalog number
Drawing Instruments
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Dividers and Compasses
Data Source
National Museum of American History, Kenneth E. Behring Center


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