The Robert Pearson Collection:
Patents
The Robert Pearson Collection:
Patents
| Porter 1907 | 868560 |
| Porter 1908 | 901617 |
| Porter 1910 | 953334 |
| Porter 1910 | 953335 |
| Porter 1910 | 953336 |
| Porter 1910 | 979165 |
| Porter 1912 | 1024778 |
| Baldwin 1910 | 959219 |
| Beumont 1880 | 232438 |
| Richards 1891 | 445601 |
| Richards 1891 | 445602 |
| Vauclain 1898 | 614041 |
| Pratt 1904 | 774778 |
| Korsmeyer 1905 | 794867 |
| Baum 1927 | 1628217 |