Parallel Rules

Parallel rules help draftsmen, surveyors, cartographers, architects, and navigators draw accurate parallel lines. The instrument comes in two main forms: two rectangular straight edges connected by brass or silver hinges, or a single frame surrounding a roller. The first type was known in Europe by 1600, while Englishman A. George Eckhardt is credited with inventing the second in 1771. The parallel rule was superseded for most uses by the T-square in the 19th century, but navigators continue to use parallel rules in conjunction with gridded charts.

The mathematics collections contain about twenty parallel rules and combination instruments, dating from the late 18th century to the late 20th century and ranging in length from 6 to 24 inches. The objects are made from ebony and other woods, brass, German silver, and plastic. They were manufactured in the United States, England, Italy, and Taiwan. They were used for military surveying, in navigation, in business, in art and technical drawing, and for placing handles on caskets. Several of the objects in this group illustrate innovations added to the basic instrument.

Acknowledgement

The digitization of this group of artifacts was made possible through the generous support of Edward and Diane Straker.

This instrument has a wooden handle attached by a large brass thumbscrew to a brass protractor that is divided to single degrees and numbered by tens in both directions from 10 to 170.
Description
This instrument has a wooden handle attached by a large brass thumbscrew to a brass protractor that is divided to single degrees and numbered by tens in both directions from 10 to 170. The protractor is screwed to a rectangular brass piece that slides in a groove in a rectangular wooden guide-piece. The guide-piece has brass clamps and thumbscrews for affixing the instrument on a table. The protractor is also attached by a split nut to a metal screw shaft that runs the width of the instrument. A thumb rest and gear on the left clamp rotates the screw shaft.
A T-square is a technical drawing instrument used by draftsmen primarily as a guide for drawing horizontal lines on a drafting table. In this instrument, the two blades of the T-square are not fixed in a perpendicular position but rather can be rotated to any angle on the protractor. The large thumbscrew can then be used as a handle to move the blades along the screw shaft, allowing the user to draw parallel lines.
Eugene James Towne (1847–after 1900) of North Dana, Mass., received a patent for this device in 1877. He submitted this example with his application as a prototype for the instrument, and the U.S. Patent Office marked it on the bottom: 187330 (/) L.1201.1228. Towne, a cabinetmaker, and J. W. Goodman, who made pianos, billiard table legs, and other wooden items in North Dana, apparently intended to manufacture the device together. However, the instrument likely was not widely adopted.
References: Eugene J. Towne, "Improvement in Parallel Rulers" (U.S. Patent 187,330 issued February 13, 1877); Edwin Eugene Towne, ed., The Descendants of William Towne (Newtonville, Mass., 1901), 284; The Worcester County Directory for 1878–79 (Boston: Briggs & Co., 1878), 41; 1870 and 1900 U.S. Census records.
Location
Currently not on view
date made
1877
maker
Towne, Eugene J.
ID Number
MA.308953
catalog number
308953
accession number
89797
The lower blade of this 24" brass hinged parallel rule is marked: KELVIN – WHITE CO. BOSTON – NEW YORK. The instrument has one rectangular wooden handle and one rectangular black plastic handle. Both handles are attached by crude welding.
Description
The lower blade of this 24" brass hinged parallel rule is marked: KELVIN – WHITE CO. BOSTON – NEW YORK. The instrument has one rectangular wooden handle and one rectangular black plastic handle. Both handles are attached by crude welding. They may have been added by the previous owner, since Kelvin & White catalog advertisements show round knobs in 1931 and no handles in 1940. The side and top edges of the rule are divided as a rectangular protractor, numbered by tens from 180 to 10 and from 360 to 180. Unlike MA.309661, MA.309662, and MA.309663, the bottom edge is not divided for a protractor or nautical compass points.
Australian shipbuilder Wilfrid O. White (1878–1955) studied in Glasgow, Scotland, with William Thomson, Lord Kelvin (1824–1907), before settling in Boston in 1902. White served as an agent for the Glasgow instrument workshop in which Kelvin Australian shipbuilder Wilfrid O. White (1878–1955) studied in Glasgow, Scotland, with William Thomson, Lord Kelvin (1824–1907), before settling in Boston in 1902. White started as an agent for a Glasgow instrument workshop which Kelvin had helped establish, sstaying there until about 1918 (after Kelvin's death). He then established the American firm of Kelvin & Wilfrid O. White.The company was renamed Wilfrid O. White & Sons, Inc., in 1950. Throughout its existence the firm charged $28.00 for the 24" brass version of "Captain Field's improved parallel rule," model number 554. The markings in this example are like those shown in the 1940 catalog.
References: Kelvin & Wilfrid O. White Company, 1931 Catalogue of . . . Navigational Instruments and Equipment (Boston, 1931), 37; Kelvin & Wilfrid O. White Company, Catalog No. 40–Y (Boston, 1940), 35; Peggy A. Kidwell, "American Parallel Rules: Invention on the Fringes of Industry," Rittenhouse 10, no. 39 (1996): 90–96; Deborah J. Warner, "Browse by Maker: Kelvin & Wilfrid O. White," National Museum of American History Physical Sciences Collection: Navigation , http://amhistory.si.edu/navigation/maker.cfm?makerid=43; T. N. Clarke, A. D. Morrison-Low, and A. D. Simpson, Brass & Glass: Scientific Instrument Making Workshops in Scotland (Edinburgh: National Museums of Scotland, 1989), 252–275.
White is listed as running his own business on his World War I draft card, dated september 12, 1918. This is available on ancestry.com.
Location
Currently not on view
date made
1932-1950
maker
Kelvin & Wilfrid O. White
ID Number
1984.1002.01
catalog number
1984.1002.01
accession number
1984.1002

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