Set of Copenhagen Ship Curves by Eugene Dietzgen Company of Chicago, Model 2219

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By 1902, dealers like Eugene Dietzgen of Chicago offered sets of several dozen “Copenhagen ship curves” in wood and hard rubber. In their 1904-1905 catalog, Dietzgen added curves of transparent amber. By 1926, transparent celluloid had replaced these materials. The number of curves rose from 45 in 1902 to 121 in 1926 and 1931. This selection of curves in this set matches the description of the 1938 Dietzgen catalog, which lists a set of fifty-six celluloid (not acrylic) curves. Dietzgen offered them through at least 1949. Dietzgen first used the term Clearcite in commerce in 1946, filed for a trademark February 29, 1952, and received the trademark June 23, 1953. Hence the curves are from after that date.
The curves are stored in a wooden case with metal hooks. A mark on a tag on the front of the case reads: DIETZGEN (/) MADE IN U.S.A.
By the 1970s, flexible drawing curves were replacing fixed ones like these.
The objects were given to the Smithsonian in 1986.
The donor, Philip Krupen (1915–2001), was a physicist who graduated B.S. from Brooklyn College in 1935, worked on the development of the proximity fuse during and after World War II, earned a master's degree in physics from George Washington University, and spent a total of thirty-eight years working for the U.S. government before he retired in 1973.
Benjamin Pike, Jr., Pike’s Illustrated Descriptive Catalog, vol. 1, New York, 1856, pp. 40-43. This catalog includes ship curves, but not with the standard numbers used by Keuffel & Esser from at least 1890.
Keuffel & Esser Company, Catalog, New York, 1890, pp. 138-139.
Eugene Dietzgen Company, Catalog, Chicago, 1902.
Eugene Dietzgen Company, Catalog, Chicago, 1905, p. 218.
Eugene Dietzgen Company, Catalog, Chicago, 1910, p. 274. The numbering of ship curves in the 1890, 1902, 1905, and 1910 Dietzgen catalogs is not the same as that adopted by 1926.
Eugene Dietzgen Company, Catalog, Chicago, 1926, pp. 226-227. The numbering of ship curves in this and later Dietzgen catalogs follow a scheme used by Keuffel & Esser at least as early as 1890. This is the same numbering system used on these curves.
Eugene Dietzgen Company, Catalog, Chicago, 1931, pp. 245-246.
Eugene Dietzgen Company, Catalog, Chicago, 1938, pp. 310-311.
Eugene Dietzgen Company, Catalog, Chicago, 1949, pp. 310-311.
TESS, U.S. Patent and Trademark Office, Trademark Registration 0576302.
Currently not on view
date made
ca 1955
place made
United States: Illinois, Chicago
Physical Description
plastic (curves material)
wood (case material)
brass (fastening material)
paper (label material)
overall: 5.9 cm x 65.8 cm x 19 cm; 2 5/16 in x 25 29/32 in x 7 15/32 in
ID Number
accession number
catalog number
Credit Line
Gift of Philip Krupen
Drawing Instruments
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Data Source
National Museum of American History


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