Williams and Joslin Ellipsograph Patent Model
date: label: date made
content: 1859
name: label: maker
content: Williams, Thomas
label: maker
content: Joslin, William C.
notes: label: Description
content: This brass device is a patent model for a “new and improved instrument for drawing curves and figures approximating in form ovals” (U.S. Patent 22910, February 8, 1859). An oval shape, the ellipse is one of the four conic sections, the others being the circle, the parabola, and the hyperbola. Ellipses are important curves used in the mathematical sciences. For example, the planets follow elliptical orbits around the sun. Ellipses are required in surveying, engineering, architectural, and machine drawings for two main reasons. First, any circle viewed at an angle will appear to be an ellipse. Second, ellipses were common architectural elements, often used in ceilings, staircases, and windows, and needed to be rendered accurately in drawings. For this reason, several drawing devices that produce ellipses, called ellipsographs or elliptographs, were developed and patented in the late 19th and early 20th centuries.
label: Description
content: Developed by Thomas William and William Joslin of Fishersville, Connecticut, in the 1850s, this invention consists of a circular disc that freely moves along the slot in the base of the model as it rotates. The base of the steel arm is fixed while the point fits by means of a pin into one of several holes in the disc which are at various distances from the center. The shape and movement of the arm is reminiscent of an hour hand on a clock. Attached to the bottom of the disc is an armature that can be set in various positions and has an attachment for a pencil. As the disc is rotated by hand, the arm is constrained to move side to side. This in turn forces the disc to move in a perpendicular direction along the slot. Finally, the pencil arm below the disc will move in an elliptical path. By changing the connection point of the arm on the disc as well as the distance of pencil is from the center of the disc, ellipses of different sizes and eccentricities can be produced.
label: Description
content: The Smithsonian also owns the 1852 patent model of a machine for making cordage designed by William Joslin (U.S. Patent 8825).
label: Description
content: This model was transferred to the Smithsonian from the U.S. Patent Office in the early 20th century along with several other patent models.
label: Description
content: References:
label: Description
content: U.S. Patents, Google Patents.
label: Location
content: Currently not on view
place: label: place made
content: United States: Connecticut, North Grosvenor Dale
topic: label: Subject
content: Mathematics
setName: label: See more items in
content: Medicine and Science: Mathematics
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content: Science & Mathematics
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content: Ellipsographs
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: MA.315255
label: accession number
content: 219305
label: catalog number
content: 315255
objectType: label: Object Name
content: ellipsograph
physicalDescription: label: Physical Description
content: steel (overall material)
label: Physical Description
content: cork (overall material)
label: Physical Description
content: brass (overall material)
label: Measurements
content: overall: 4.5 cm x 25.5 cm x 7.7 cm; 1 25/32 in x 10 1/32 in x 3 1/32 in