| US Patent: 50,980 
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| Improvement in Parallel Rulers Rolling Rule
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| Patentee: |  |
 | W. L. Woods (exact or similar names) - Washington, DC |  
 
 
 
 
| Manufacturer: |  | Not known to have been produced |  
 
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| Patent Dates: |  
| Granted: | Nov. 14, 1865 |  USPTO (New site tip)
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                        Ralph Brendler
 
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| Description: |  | This is a simple parallel rule for navigation, which uses one or more rolling
    bars instead of the traditional twin ruler setup.  In addition, these bars
    are graduated with one or more scales to allow them to not only mark parallel
    lines, but to measure the distance between them as well. |  |