Proportional Dividers by Kern

Engineers and surveyors have long used proportional dividers to mark off equal segments on a line or the circumference of a circle. This instrument also permits a draftsman to proportionally enlarge or reduce a portion of a drawing while reproducing the drawing. Although drawing instruments such as dividers were the first objects produced when Jakob Kern established his workshop in Switzerland in 1819, this example dates from the early 20th century, by which time Kern & Co. of Aarau was internationally prominent.
The two main slides are nickel silver, and the points are steel. On one end, the points are 1/2" long; on the other, they are 3" in length. The longer points are quite rusted. The slides are connected with a screw. A smaller steel slide is attached by two screws to the slide for planes and solids. There are two scales, each divided proportionally, on each slide. On one slide, the first scale is marked by ones from 2 to 10 and engraved SOLIDS. The second scale is marked by ones from 2 to 10 and engraved PLANES. On the second slide, one scale is marked by ones from 6 to 20, with a division marked GS at the lower end of the scale and CIRCLES engraved at the upper end of the scale. The second scale is marked irregularly (11/12; 9/10; 7/8; 5/6; 4/5; 3/4; 2/3; 3/5; 2; 2/5; 3; 4; 5; 6; 7; 8; 9; 10) and engraved LINES.
The maker’s mark—KERN & CO. [/] AARAU SWISS—is obscured by a museum mark. The number 640 is engraved near the maker’s mark and above the company logo, a K within a pair of dividers. The dividers are housed in a case of morocco leather over wood, lined with green velvet and locked by a button on the side. The top of the case is imprinted with a rectangle that has a fleur-de-lis at each corner. Inside the case, the Museum number (321-781) is written on a ribbon pasted over the maker’s mark, which reads: SWISS; KERN & CO. A word precedes “Swiss,” but it is illegible. The Interstate Commerce Commission transferred these dividers to the Smithsonian in 1963.
Currently not on view
Object Name
proportional dividers
date made
early 20th century
Kern & Co.
Physical Description
german silver (overall material)
leather (overall material)
wood (overall material)
velvet (overall material)
overall: 1.9 cm x 22.3 cm x 2.8 cm; 3/4 in x 8 25/32 in x 1 3/32 in
place made
Schweiz: Aargau, Aarau
ID Number
accession number
catalog number
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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