US Patent: 65,744
|
Improvement in Scale-Rules
|
Patentee:
|
|
William Hay (exact or similar names) - Dumbarton, Scotland |
Manufacturer: |
Not known to have been produced |
|
Patent Dates:
|
Granted: |
Jun. 11, 1867 |
USPTO (New site tip) Google Patents
Report data errors or omissions to steward
Ralph Brendler
|
Description: |
This rule features special scales to allow direct reading of the radius, circumference, and area of a circle. |
|