Japanese L-Square and Calipers
date: label: date made
content: before 1876
notes: label: Description
content: This 6-1/2" brass T-square is composed of two L-shaped brass pieces. The bottom piece slides along a groove in the long leg of the top piece. The outer edges on one side and the inner edges of the other side of all four legs are divided into units of 1-3/16" (3 cm). Each unit is thus roughly equivalent to the <i>sun</i>, a traditional Japanese unit of length that is 1/10 of a <i>shaku</i>, a "foot" measure. The units are subdivided into 50 parts. Whole and half-units are marked with zeroes.
label: Description
content: The instrument was designed for measuring lengths, drawing right angles, and determining whether two lines are perpendicular to one another. When the two pieces are pulled apart, the instrument also functions as a caliper, to measure the width of a small object or the dimensions of part of a finished drawing. The English workshop of George Adams Jr. made a similar instrument from wood and brass in the late 18th century. Compare also to MA.261304 and to caliper rules such as MA.261299 and 1990.0099.01.
label: Description
content: In 1876 the Japanese Empire Department of Education exhibited many instruments at the Centennial International Exhibition, a World’s Fair held in Philadelphia. After the exhibition, John Eaton, the U.S. Commissioner of Education, arranged for the transfer of Japan's entire exhibit to the Bureau of Education (then part of the Department of the Interior) for a planned museum. The museum closed in 1906, and much of the collection, including this object, was transferred to the Smithsonian in 1910.
label: Description
content: References: William Ford Stanley, <i>Mathematical Drawing and Measuring Instruments</i>, 6th ed. (London: E. & F. N. Spon, 1888), 32–33; Howard Dawes, <i>Instruments of the Imagination: A History of Drawing Instruments in Britain, 1600–1850</i> (The Dawes Trust Ltd., 2009), 80; "Caliper Rules," in <i>A Source Book for Rule Collectors</i>, ed. Philip E. Stanley (Mendham, N.J.: Astragal Press, 2003), 178–180; Japan. Department of Education, <i>An Outline History of Japanese Education: Prepared for the Philadelphia International Exhibition, 1876</i> (New York: D. Appleton, 1876), 121–122, 191–202; U.S. Centennial Commission, <i>International Exhibition, 1876. Reports and Awards</i>, ed. Francis A. Walker (Washington, D.C.: Government Printing Office, 1880), viii:143, 335; U.S. Bureau of Education, <i>Annual Report of the Commissioner</i> (1876), ccxi–ccxii.
label: Location
content: Currently not on view
place: label: place made
content: Japan
topic: label: Subject
content: Mathematics
label: Subject
content: Education
label: Subject
content: Drafting, Engineering
setName: label: See more items in
content: Medicine and Science: Mathematics
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content: Squares and Triangles
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content: Science & Mathematics
creditLine: label: Credit Line
content: Transfer from Bureau of Education, Department of the Interior
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: MA.261296
label: accession number
content: 51116
label: catalog number
content: 261296
objectType: label: Object Name
content: set square
label: Object Name
content: L-square
physicalDescription: label: Physical Description
content: brass (overall material)
label: Measurements
content: overall: 16.8 cm x 8.8 cm x .4 cm; 6 5/8 in x 3 15/32 in x 5/32 in