Folding Rule

Artist/Maker: Unknown

Created: late 18th to early 19th century

Origin/Purchase: Unknown

Materials: boxwood, with brass fittings

Dimensions: L full: 61 (24 in.); 4 sections, L each: 15.2 (6 in.); W: 1.9 (3/4 in.)

Location: Monticello Visitor Center

Owner: Thomas Jefferson Foundation

Accession Number: 1984-44-5

Historical Notes: Over the course of his life, Jefferson made hundreds of drawings, ranging from rather wobbly freehand sketches to measured drawings on coordinate paper. He drew plats, maps, city plans, garden designs, and furniture, as well as sections, elevations, and floor plans for numerous buildings.^[1] He may have learned the rudiments of drafting from his father, the surveyor and mapmaker Peter Jefferson. Upon his father's death, Jefferson inherited his mathematical instruments, which certainly included the tools for drawing maps and plats.^[2]

As with scientific instruments, Jefferson preferred English-made drawing instruments. His first recorded purchases are from London firms in 1786.^[3] As late as 1806, Jefferson purchased drawing instruments from the same merchants with whom he first became acquainted in 1786, William & Samuel Jones.^[4]

Jefferson likely used the folding ruler and other instruments to make measured drawings, which were usually architectural. Recent studies of Jefferson's drawings reveal two techniques that he employed: pricking and scoring. Using a "pricker," a sharp pinlike object, Jefferson punctured sets of points in his drawings. These may have been used to lay out a new drawing or copy an existing one. Scoring employed a small, blunt tool called a scorer or tracer, to make indentations in paper that later could be filled in with ink or graphite.^[5]  

Prior to 1784, when Jefferson arrived in France, most if not all of his drawings were made in ink. In Paris, Jefferson began to use pencil for drawing, and adopted the use of coordinate, or graph, paper. He treasured the coordinate paper that he brought back to the United States with him and used it sparingly over the course of many years. He gave a few sheets to his good friend David Rittenhouse, the astronomer and inventor:

I send for your acceptance some sheets of drawing-paper, which being laid off in squares representing feet, or what you please, saves the necessity of using the rule and dividers in all rectangular draughts and those whose angles have their sines and co-sines in the proportion of any integral numbers. Using a black lead pencil the lines are very visible, and easily effaced with Indian rubber to be used for any other draught.^[6]

A few precious sheets of the paper survive today.

In addition to designing and improving his own houses, Jefferson was a willing contributor to public buildings, such as the Virginia State Capitol. He was involved in the planning of the city of Washington, D.C. and contributed an anonymous design in the competition for the President's House. His architectural knowledge was well known, and friends such as James Monroe solicited his help in designing their houses.^[7]

- Text from Stein, Worlds, 372-73

Further Sources

• Piedmont-Palladino, Susan A., ed. Tools of the Imagination: Drawing Tools and Technologies from the Eighteenth Century to the Present. New York: Princeton Architectural Press, 2007.