| Patents Granted on 1820-03-?? |
Patents 1 -
12
of 12
      |
| Number | Date | Patentee | Title | Type |
| 3,177X | Mar. 03, 1820 | J.B. Smith, P. Marshall | Plough | plows |
| 3,178X | Mar. 06, 1820 | A. Brewster | Improvement in ship building | |
| 3,179X | Mar. 06, 1820 | E. Griffiths | Improvement in fire places | |
| 3,180X | Mar. 06, 1820 | T. Mussey | Hollow or Guttered Grid Irons | fireplace tools |
| 3,181X | Mar. 08, 1820 | H. Bronson | Wind power pump | pumps |
| 3,182X | Mar. 16, 1820 | M.M. Duplat | Construction of privies | |
| 3,183X | Mar. 16, 1820 | R. Eastman, J. Jaquith | Circular saw for making clap boards | clapboard machines |
| 3,184X | Mar. 18, 1820 | J. Lamb | Fire hearth for vessels | |
| 3,185X | Mar. 20, 1820 | P. Williamson | Coffee Roaster | coffee roasters |
| 3,186X | Mar. 23, 1820 | S. Fraser | Tobacco press | tobacco machinery |
| 3,187X | Mar. 23, 1820 | S.F. Hooker (Tooker), I.L. Skinner | Apparatus for removing earth in making roads, etc. | |
| 3,188X | Mar. 28, 1820 | E. Bryant | Fire engine | fire engines |
