| Inventor | Duc, Henry A. jr. |
| Invention | Attrition Mill |
| Residence | Charleston |
| Dated | 12/27/1881 |
| Patent | 251,535 |
| Class | 241/57 |
| Assign | * |
| US Patent Office Record | http://patft1.uspto.gov/netacgi/nph-Parser?patentnumber=0251535 |
| Local Copy of Patent Docs | http://library.clemson.edu/scpatimages/index.php?pn=251535 |