Edwin Thacher's Calculating Instrument
| Edwin Thacher's 1881 U.S. patent |
| The description from Thacher's manual |
| Photos and description of a Thacher calculating instrument |
| American Artifacts Table of contents |
| Edwin Thacher's 1881 U.S. patent |
| The description from Thacher's manual |
| Photos and description of a Thacher calculating instrument |
| American Artifacts Table of contents |