The relatively rare Howe truss, patented in 1840 by Massachusetts millwright William Howe, includes vertical members and diagonals that slope up towards the center, the opposite of the Pratt Truss. In contrast to the Pratt Truss, the diagonal web members are in compression and the vertical web members are in tension.
William Howe, from Spencer, Massachusetts, patented his new truss design in 1840, and extended the patent in 1850 with design improvements. The Howe Truss was originally designed to combine diagonal timber compression members and vertical iron rod tension members, as seen in the Comstock Bridge. However, the Howe Truss was later used in steel bridges. It's impressive strength over long spans contributed to its overwhelming popularity as a railroad bridge.
The only Howe Truss bridges on the Mendocino Coast of which we have photos were both part of the L.E.White operations at Elk. The engineering marvel shown right was built near Elk Creek. It was 95 feet long and had a curvature of 18 degrees.
The second Howe Truss bridge was adjacent to the L.E. White mill as shown in the photograph on left.