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US Patent: 100,072
Improvement in Instruments for Drawing Geometrical Lines
Patentee:
William Ritchie - Wilmington, IL

USPTO Classifications:
33/26

Tool Categories:
layout tools : compasses

Assignees:
None

Manufacturer:
Not known to have been produced

Witnesses:
John Campbell
John C. Thompson
Gustave Dietrich
Jno. E. Snooks

Patent Dates:
Granted: Feb. 22, 1870

Patent Pictures:
USPTO pdf tiff
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Description:
This clever but complicated compass features a pair of sliding arms that fit into a rotating center block. By adjusting the travel of the arms, one can easily draw circles, ellipses, involutes, and epicycloids.

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