| All Patents in class 33/348 |
Patents 1 -
10
of 10
      |
| Picture | Number | Date | Patentee | Title |
 | 30,914 | Dec. 18, 1860 | T. Joyce, G.N. Fairchild | Collimator |
 | 159,882 | Feb. 16, 1875 | E.L. Barnes | Improvement in spirit levels |
 | 217,015 | Jul. 01, 1879 | S. Longfellow | Add-on corrective magnets |
 | 397,043 | Jan. 29, 1889 | R.D. Werden | Spirit Level |
 | 692,097 | Jan. 28, 1902 | J.R. Wood | Cat's Eye Level |
 | 756,628 | Apr. 05, 1904 | J. Happle | Level, Plumb, and Inclinometer |
| | 786,269 | Apr. 04, 1905 | L.M. Curry | Spirit Level |
 | 1,036,601 | Aug. 27, 1912 | D.W. Frank, Sr. | Conbined Level, Plumb and Grade Finder |
 | 1,318,162 | Oct. 07, 1919 | E.J. Loring | Luminous Level |
 | 1,409,537 | Mar. 14, 1922 | H.M. Franzen | Universal Level |
