Dividers

A collection of dividers and compasses in the Division of Medicine and Science's Mathematics collection.

These objects include "plain" dividers, which consist of just the legs, and "wing" or "bow" dividers, which have a crosspiece that may be used to adjust the precision of the instrument and fix its width in place. Most of the oldest instruments in the overall group are dividers.

Search term: *:* Topic: Drawing Instruments Clear All

Dod Protractor and Parallel Rule

This brass semicircular protractor is divided by single degrees and marked by tens from 10° to 90° to 10°. It is attached with metal screws to a set of brass parallel rules. Brass S-shaped hinges connect the rules to each other.
Description
This brass semicircular protractor is divided by single degrees and marked by tens from 10° to 90° to 10°. It is attached with metal screws to a set of brass parallel rules. Brass S-shaped hinges connect the rules to each other. The bottom left screw on the parallel rules does not attach to the bottom piece. A rectangular brass arm is screwed to the center of the protractor. A thin brass piece screwed to the arm is marked with a small arrow for pointing to the angle markings. The protractor is stored in a wooden case, which also contains a pair of metal dividers (5-1/4" long).
The base of the protractor is signed: L. Dod, Newark. Lebbeus Dod (1739–1816) manufactured mathematical instruments in New Jersey and is credited with inventing the parallel rule protractor. He served as a captain of artillery during the Revolutionary War and made muskets. His three sons, Stephen (1770–1855), Abner (1772–1847), and Daniel (1778–1823), were also noted instrument and clock makers. The family was most associated with Mendham, N.J. (where a historic marker on N.J. Route 24 indicates Dod's house), but Dod is known to have also lived at various times in Newark.
ID number MA.310890 is a similar protractor and parallel rule. Compare also to a Dod instrument owned by the Metropolitan Museum of Art in New York, http://www.metmuseum.org/Collections/search-the-collections/5535.
References: Bethuel Lewis Dodd and John Robertson Burnet, "Biographical Sketch of Lebbeus Dod," in Genealogies of the Male Descendants of Daniel Dod . . . 1646–1863 (Newark, N.J., 1864), 144–147; Alexander Farnham, "More Information About New Jersey Toolmakers," The Tool Shed, no. 120 (February 2002), http://www.craftsofnj.org/Newjerseytools/Alex%20Farnham%20more%20Jeraey%20Tools/Alex%20Farnham.htm; Deborah J. Warner, “Surveyor's Compass,” National Museum of American History Physical Sciences Collection: Surveying and Geodesy, http://americanhistory.si.edu/collections/surveying/object.cfm?recordnumber=747113; Peggy A. Kidwell, "American Parallel Rules: Invention on the Fringes of Industry," Rittenhouse 10, no. 39 (1996): 90–96.
Location
Currently not on view
date made
late 1700s
maker
Dod, Lebbeus
ID Number
1978.2110.06
accession number
1978.2110
catalog number
336732

Plain Dividers Retailed by Keuffel & Esser

These plain dividers have grooved brass legs with steel points and are held together with a screw. Two small holes are in the joint on either side of the bottom end of the screw.
Description
These plain dividers have grooved brass legs with steel points and are held together with a screw. Two small holes are in the joint on either side of the bottom end of the screw. The instrument arrived at the Smithsonian in a case (now lost) marked: Keuffel & Esser Co., New York. The dividers are similar to the 4-1/2" plain dividers from Switzerland advertised (without a case) in James Queen's 1883 catalog for $1.50. The instrument slightly resembles 4-1/4" plain dividers from France sold by K&E in the 1880s and 1890s for between 24 and 85 cents. It is not depicted in K&E's 1909 and 1936 catalogs.
References: James W. Queen & Co., Priced and Illustrated Catalogue of Mathematical Instruments (Philadelphia, 1883), 22; Catalogue and Price-List of Keuffel & Esser Co., 23rd ed. (New York, 1892), 62, 102; Trade Price List. An Annex to the General Catalogue (Twenty-Eighth Edition) of Keuffel & Esser Co. (New York, n.d.), 30.
Location
Currently not on view
date made
late 19th century
ID Number
MA.335341
accession number
305958
catalog number
335341

Bow Dividers

This steel and brass instrument is called a bow divider because the nut on the side may be tightened or loosened to hold the instrument at a desired width. This example is similar to one sold by Keuffel & Esser, although the top of the handle is different.
Description
This steel and brass instrument is called a bow divider because the nut on the side may be tightened or loosened to hold the instrument at a desired width. This example is similar to one sold by Keuffel & Esser, although the top of the handle is different. There is no maker's mark.
Reference: Catalogue of Keuffel & Esser Co. , 33rd ed. (New York, 1909), 62.
Location
Currently not on view
date made
ca 1900
ID Number
1978.2110.12
accession number
1978.2110
catalog number
336738

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.