| US Patent: 186,638 
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| Improvement in Mariner's Compass Compass needle combines ultra-low friction with high polar moment of inertia.
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| Patentee: |  |
 | William Thomson (exact or similar names) - Glasgow,  Scotland |  
 
 
 
 
| Manufacturer: |  | Not known to have been produced |  
 
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| Patent Dates: |  
| Applied: | Dec. 08, 1876 |  
| Granted: | Jan. 23, 1877 |  
 
USPTO (New site tip)| Patent Pictures: |  |  |  | Condensed view of all the patent's images |  Google Patents
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                        Steve Gosselin (GL)
 
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| Description: |  | Sir William Thomson's invention maximizes the period of oscillation of the compass needle and minimizes friction in order to stabilize the position of the needle and thereby minimize errors in guiding the course of the vessel. |  |