London Bridge

Tbe Britoiis theruselves were quite unablt! to construct a bridge of any kind unless in tbe primitiva methods observed at Post bridge and ïwo bridges, on Dartmoor, by a slab of stone laid across two bowlders. Thework, tberefore, was eertainly undertaken by Roman eugineers. We bave, in tbe next place, toinquire wbat kind of bridge was built at tbat time by the Romans. They built bridges of wood and of stone. Many of these stone bridges still remain; iu other oases the pieoes of bewn stone still remain. Tbe bridge over tbe Thaines, bowever, was of wood. Tbis is proved by the fact that bad it been of the solid Roman construction in stoue the piers wonld be still remaining; also by the fact tbat London bad to be oonteuted with a wooden bridge till tbe year 1176, wben tbe first bridge of stone was commenoed. Considerations as to the comparativa insignifioanceof London in tbe first century, as to tbe absence of stoue in tbe iieighborhood and as to tbe plentiful Bupply of tbe best wood in the world froru the forests nortb of the city confirm tbe tbeory that the bridge was built of wood. We bave only, tberefore, to learn bow Roman engineers built bridges of wood elsewbere in order to know bow tbey built a bridge of wood over tne