Mathematical Bridge

The Mathematical Bridge is a wooden footbridge in central Cambridge that spans the River Cam between two parts of Queens’ College. It stands about thirty metres northwest of Silver Street Bridge and is officially called the Wooden Bridge or Queens’ Bridge. The bridge is a Grade II listed building and has been rebuilt twice, in 1866 and 1905, while keeping its original design. It looks like an arch but is made entirely of straight timbers arranged in a sophisticated engineering pattern. The unusual structure earned it the name ‘Mathematical Bridge’. The bridge was designed by William Etheridge and built by James Essex in 1749. A smaller replica was added near Iffley Lock in Oxford in 1923. The original design used iron spikes hidden in the joints, which later gave rise to the myth that the bridge was held together without bolts. Sir Isaac Newton could not have built it, since he died twenty-two years before construction began. The timbers form a tangent and radial truss, making the bridge rigid and self-supporting. Visitors find a neat wooden bridge with straight beams arranged in elegant curves over the river. The structure shows how forces are carried through the timbers without visible bolts. The bridge sits in a quiet part of Cambridge, close to college buildings and the flowing Cam. It offers a clear view of the river and the surrounding colleges. The design remains a fine example of 18th-century engineering.