US Patent: 100,072
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| Improvement in Instruments for Drawing Geometrical Lines
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Patentee:
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| William Ritchie (exact or similar names) - Wilmington, IL |
| USPTO Classifications: |
| 33/26 |
| Manufacturer: |
| Not known to have been produced |
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Patent Dates:
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| Granted: |
Feb. 22, 1870 |
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Ralph Brendler
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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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